Climate change mitigation (or decarbonisation) is action to limit the
greenhouse gases
Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. Unlike other gases, greenhouse gases absorb the radiations that a planet emits, resulting in the greenhouse effect. T ...
in the atmosphere that cause
climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
. Climate change mitigation actions include
conserving energy and
replacing fossil fuels with
clean energy sources. Secondary mitigation strategies include changes to land use and
removing carbon dioxide (CO2) from the atmosphere. Current climate change mitigation policies are insufficient as they would still result in global warming of about 2.7 °C by 2100, significantly above the 2015
Paris Agreement
The Paris Agreement (also called the Paris Accords or Paris Climate Accords) is an international treaty on climate change that was signed in 2016. The treaty covers climate change mitigation, adaptation, and finance. The Paris Agreement was ...
's goal of limiting global warming to below 2 °C.
Solar energy
Solar energy is the radiant energy from the Sun's sunlight, light and heat, which can be harnessed using a range of technologies such as solar electricity, solar thermal energy (including solar water heating) and solar architecture. It is a ...
and
wind power
Wind power is the use of wind energy to generate useful work. Historically, wind power was used by sails, windmills and windpumps, but today it is mostly used to generate electricity. This article deals only with wind power for electricity ge ...
can replace fossil fuels at the lowest cost compared to other
renewable energy
Renewable energy (also called green energy) is energy made from renewable resource, renewable natural resources that are replenished on a human lifetime, human timescale. The most widely used renewable energy types are solar energy, wind pow ...
options.
[IPCC (2022]
Summary for policy makers
i
Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change
Cambridge University Press, Cambridge, United Kingdom and New York, NY, United States The availability of sunshine and wind is variable and can require
electrical grid
An electrical grid (or electricity network) is an interconnected network for electricity delivery from producers to consumers. Electrical grids consist of power stations, electrical substations to step voltage up or down, electric power tran ...
upgrades, such as using
long-distance electricity transmission to group a range of power sources.
[Ram M., Bogdanov D., Aghahosseini A., Gulagi A., Oyewo A.S., Child M., Caldera U., Sadovskaia K., Farfan J., Barbosa LSNS., Fasihi M., Khalili S., Dalheimer B., Gruber G., Traber T., De Caluwe F., Fell H.-J., Breyer C]
Global Energy System based on 100% Renewable Energy – Power, Heat, Transport and Desalination Sectors
. Study by Lappeenranta University of Technology and Energy Watch Group, Lappeenranta, Berlin, March 2019. Energy storage
Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an Accumulator (energy), accumulator or Batte ...
can also be used to even out power output, and
demand management
Demand management is a planning methodology used to forecast, plan for and manage the demand for products and services. This can be at macro-levels as in economics and at micro-levels within individual organizations. For example, at macro-leve ...
can limit power use when power generation is low. Cleanly generated
electricity can usually replace fossil fuels for powering transportation, heating buildings, and running industrial processes. Certain processes are more difficult to decarbonise, such as
air travel
Air travel is a form of travel in vehicles such as airplanes, jet aircraft, helicopters, hot air balloons, blimps, Glider (aircraft), gliders, Hang gliding, hang gliders, parachuting, parachutes, or anything else that can sustain flight. and
cement production.
Carbon capture and storage
Carbon capture and storage (CCS) is a process by which carbon dioxide (CO2) from industrial installations is separated before it is released into the atmosphere, then transported to a long-term storage location.IPCC, 2021Annex VII: Glossary at ...
(CCS) can be an option to reduce net emissions in these circumstances, although fossil fuel power plants with CCS technology is currently a high-cost climate change mitigation strategy.
Human land use changes such as
agriculture
Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...
and deforestation cause about 1/4th of climate change. These changes impact how much is absorbed by plant matter and how much organic matter decays or burns to release . These changes are part of the fast
carbon cycle
The carbon cycle is a part of the biogeochemical cycle where carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycl ...
, whereas fossil fuels release that was buried underground as part of the slow carbon cycle.
Methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...
is a short-lived greenhouse gas that is produced by decaying organic matter and livestock, as well as fossil fuel extraction. Land use changes can also impact precipitation patterns and the
reflectivity of the surface of the Earth. It is possible to cut emissions from agriculture by reducing
food waste
The causes of food going uneaten are numerous and occur throughout the food system, during food production, production, food processing, processing, Food distribution, distribution, Grocery store, retail and food service sales, and Social clas ...
, switching to a more
plant-based diet
A plant-based diet is a diet consisting mostly or entirely of plant-based foods. It encompasses a wide range of dietary patterns that contain low amounts of animal products and high amounts of fiber-rich plant products such as vegetables ...
(also referred to as
low-carbon diet
A low-carbon diet is any diet that results in lower greenhouse gas emissions. Choosing a low carbon diet is one facet of developing sustainable diets which increase the long-term sustainability of humanity. Major tenets of a low-carbon diet in ...
), and by improving farming processes.
Various policies can encourage climate change mitigation.
Carbon pricing
Carbon pricing (or pricing) is a method for governments to Climate change mitigation, mitigate climate change, in which a monetary cost is applied to greenhouse gas emissions. This is done to encourage polluters to reduce fossil fuel combustion, ...
systems have been set up that either
tax emissions or
cap total emissions and trade emission credits.
Fossil fuel subsidies
Fossil fuel subsidies are energy subsidies on fossil fuels. Under a narrow definition, fossil fuel subsidies totalled around $1.5 trillion in 2022. Under more expansive definition, they totalled around $7 trillion. They may be tax breaks on c ...
can be eliminated in favour of clean
energy subsidies
Energy subsidies are measures that keep prices for customers below market levels, or for suppliers above market levels, or reduce costs for customers and suppliers. Energy subsidies may be direct cash transfers to suppliers, customers, or relat ...
, and incentives offered for installing energy efficiency measures or switching to electric power sources. Another issue is overcoming environmental objections when constructing new clean energy sources and making grid modifications. Limiting climate change by reducing greenhouse gas emissions or removing greenhouse gases from the atmosphere could be supplemented by climate technologies such as
solar radiation management
Solar radiation modification (SRM) (or solar geoengineering) is a group of large-scale approaches to reduce global warming by increasing the amount of sunlight that is reflected away from Earth and back to space. It is not intended to replace e ...
(or solar geoengineering). Complementary
climate change action
Climate action (or climate change action) refers to a range of activities, mechanisms, policy instruments, and so forth that aim at reducing the severity of human-induced climate change and its impacts. "More climate action" is a central demand o ...
s, including
climate activism
The climate movement is a global social movement focused on pressuring governments and industry to take action (also called ''climate action'') addressing the causes and Effects of climate change, impacts of climate change. Citizens and environme ...
, have a focus on political and cultural aspects.
Definitions and scope
Climate change mitigation aims to sustain
ecosystem
An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...
s to maintain
human civilisation. This requires drastic cuts in greenhouse gas emissions.
[IPCC (2022]
Chapter 1: Introduction and Framing
i
Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change
Cambridge University Press, Cambridge, United Kingdom and New York, NY, United States The
Intergovernmental Panel on Climate Change
The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations. Its job is to "provide governments at all levels with scientific information that they can use to develop climate policies". The World Met ...
(IPCC) defines ''mitigation'' (of climate change) as "a human intervention to reduce
emissions or enhance the
sinks
A sink (also known as ''basin'' in the UK) is a bowl-shaped plumbing fixture for washing hands, dishwashing, and other purposes. Sinks have a tap (faucet) that supplies hot and cold water and may include a spray feature to be used for faste ...
of
greenhouse gas
Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. Unlike other gases, greenhouse gases absorb the radiations that a planet emits, resulting in the greenhouse effect. T ...
es".
It is possible to approach various mitigation measures in parallel. This is because there is no single pathway to limit global warming to 1.5 or 2 °C.
There are four types of measures:
#
Sustainable energy
Energy system, Energy is sustainability, sustainable if it "meets the needs of the present without compromising the ability of future generations to meet their own needs." Definitions of sustainable energy usually look at its effects on the e ...
and
sustainable transport
Sustainable transport is transportation sustainability, sustainable in terms of their social and Environmental issue, environmental impacts. Components for evaluating sustainability include the particular vehicles used; the source of energy; and ...
#
Energy conservation
Energy conservation is the effort to reduce wasteful energy consumption by using fewer energy services. This can be done by using energy more effectively (using less and better sources of energy for continuous service) or changing one's behavi ...
, including
efficient energy use
Efficient energy use, or energy efficiency, is the process of reducing the amount of energy required to provide products and services. There are many technologies and methods available that are more energy efficient than conventional systems. For ...
#
Sustainable agriculture
Sustainable agriculture is agriculture, farming in sustainability, sustainable ways meeting society's present food and textile needs, without compromising the ability for current or future generations to meet their needs. It can be based on an ...
and
green industrial policy
Green industrial policy (GIP) is strategic government policy that attempts to accelerate the development and growth of green industries to transition towards a low-carbon economy. Green industrial policy is necessary because green industries such ...
# Enhancing
carbon sink
A carbon sink is a natural or artificial carbon sequestration process that "removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere". These sinks form an important part of the natural carbon cycle. An overar ...
s and
carbon dioxide removal
Carbon dioxide removal (CDR) is a process in which carbon dioxide () is removed from the atmosphere by deliberate human activities and durably stored in geological, terrestrial, or ocean reservoirs, or in products.IPCC, 2021:Annex VII: Glossar ...
(CDR), including
carbon sequestration
Carbon sequestration is the process of storing carbon in a carbon pool. It plays a crucial role in Climate change mitigation, limiting climate change by reducing the amount of Carbon dioxide in Earth's atmosphere, carbon dioxide in the atmosphe ...
The IPCC defined carbon dioxide removal as "Anthropogenic activities removing carbon dioxide () from the atmosphere and durably storing it in geological, terrestrial, or ocean reservoirs, or in products. It includes existing and potential anthropogenic enhancement of biological or geochemical sinks and
direct air carbon dioxide capture and storage (DACCS) but excludes natural uptake not directly caused by human activities."
Emission trends and pledges
Greenhouse gas emissions from human activities strengthen the
greenhouse effect
The greenhouse effect occurs when greenhouse gases in a planet's atmosphere insulate the planet from losing heat to space, raising its surface temperature. Surface heating can happen from an internal heat source (as in the case of Jupiter) or ...
. This contributes to
climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
. Most is
carbon dioxide
Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
from burning
fossil fuel
A fossil fuel is a flammable carbon compound- or hydrocarbon-containing material formed naturally in the Earth's crust from the buried remains of prehistoric organisms (animals, plants or microplanktons), a process that occurs within geolog ...
s: coal, oil, and natural gas. Human-caused emissions have increased atmospheric carbon dioxide by about 50% over pre-industrial levels. Emissions in the 2010s averaged a record 56 billion tons (Gt) a year.
In 2016, energy for electricity, heat and transport was responsible for 73.2% of GHG emissions. Direct industrial processes accounted for 5.2%, waste for 3.2% and agriculture, forestry and land use for 18.4%.
Electricity generation and transport are major emitters. The largest single source is
coal-fired power station
A coal-fired power station or coal power plant is a thermal power station which burns coal to generate electricity. Worldwide there are about 2,500 coal-fired power stations, on average capable of generating a gigawatt each. They generate ...
s with 20% of greenhouse gas emissions.
Deforestation
Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
and other changes in land use also emit carbon dioxide and methane. The largest sources of anthropogenic methane emissions are
agriculture
Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...
, and
gas venting
Gas venting, more specifically known as natural-gas venting or methane venting, is the intentional and controlled release of gases containing alkane hydrocarbons - predominately methane - into Earth's atmosphere.
It is a widely used method for ...
and
fugitive emissions
Fugitive emissions are leaks and other irregular releases of gases or vapors from a pressurized containment – such as appliances, storage tanks, pipelines, wells, or other pieces of equipment – mostly from industrial activities. In addition t ...
from the fossil-fuel industry. The largest agricultural methane source is livestock.
Agricultural soils emit
nitrous oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or factitious air, among others, is a chemical compound, an Nitrogen oxide, oxide of nitrogen with the Chemical formula, formula . At room te ...
, partly due to fertilizers. There is now a political solution to the problem of fluorinated gases from
refrigerant
A refrigerant is a working fluid used in the cooling, heating, or reverse cooling/heating cycles of air conditioning systems and heat pumps, where they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are ...
s. This is because many countries have ratified the
Kigali Amendment
The Kigali Amendment to the Montreal Protocol is an international agreement to gradually reduce the consumption and production of hydrofluorocarbons (HFCs). It is a legally binding agreement designed to create rights and obligations in internati ...
.
Carbon dioxide
Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
() is the dominant emitted greenhouse gas.
Methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...
() emissions almost have the same short-term impact.
Nitrous oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or factitious air, among others, is a chemical compound, an Nitrogen oxide, oxide of nitrogen with the Chemical formula, formula . At room te ...
(N
2O) and
fluorinated gases
Fluorinated gases (F-gases) are a group of gases containing fluorine. They are divided into several types, the main of those are hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6). They are used in refrigeration, air co ...
(F-Gases) play a minor role. Livestock and manure produce 5.8% of all greenhouse gas emissions.
But this depends on the time frame used to calculate the
global warming potential
Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific time period, relative to carbon dioxide (). It is expressed as a multiple of warming caused by the same mass of carbon dioxide ( ...
of the respective gas.
Greenhouse gas (GHG) emissions are measured in
equivalents. Scientists determine their equivalents from their
global warming potential
Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific time period, relative to carbon dioxide (). It is expressed as a multiple of warming caused by the same mass of carbon dioxide ( ...
(GWP). This depends on their lifetime in the atmosphere. There are widely used
greenhouse gas accounting methods that convert volumes of methane, nitrous oxide and other greenhouse gases to
carbon dioxide equivalents. Estimates largely depend on the ability of oceans and land sinks to absorb these gases.
Short-lived climate pollutants
The Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants (CCAC) was launched by the United Nations Environment Programme (UNEP) and six countries—Bangladesh, Canada, Ghana, Mexico, Sweden, and the United States—on 16Februar ...
(SLCPs) persist in the atmosphere for a period ranging from days to 15 years. Carbon dioxide can remain in the atmosphere for millennia.
Short-lived climate pollutants include
methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...
,
hydrofluorocarbons (HFCs),
tropospheric ozone
Ground-level ozone (), also known as surface-level ozone and tropospheric ozone, is a trace gas in the troposphere (the lowest level of the Earth's atmosphere), with an average concentration of 20–30 parts per billion by volume (ppbv), with clo ...
and
black carbon
Black carbon (BC) is the light-absorbing refractory form of Chemical_element, elemental carbon remaining after pyrolysis (e.g., charcoal) or produced by incomplete combustion (e.g., soot).
Tihomir Novakov originated the term black carbon in ...
.
Scientists increasingly use satellites to locate and measure greenhouse gas emissions and deforestation. Earlier, scientists largely relied on or calculated estimates of greenhouse gas emissions and governments' self-reported data.
Needed emissions cuts

The annual "Emissions Gap Report" by
UNEP
The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations system. It was established by Maurice Strong, its first director, after the Declaration of the United Nati ...
stated in 2022 that it was necessary to almost halve emissions. "To get on track for limiting global warming to 1.5°C, global annual GHG emissions must be reduced by 45 per cent compared with emissions projections under policies currently in place in just eight years, and they must continue to decline rapidly after 2030, to avoid exhausting the limited remaining atmospheric
carbon budget
A carbon budget is a concept used in politics of climate change to help set greenhouse gas emissions reduction targets in a fair and effective way. It examines the "maximum amount of cumulative net global anthropogenic carbon dioxide () emission ...
."
[United Nations Environment Programme (2022)]
Emissions Gap Report 2022: The Closing Window — Climate crisis calls for rapid transformation of societies
Nairobi. The report commented that the world should focus on broad-based economy-wide transformations and not incremental change.
In 2022, the Intergovernmental Panel on Climate Change (IPCC) released its
Sixth Assessment Report
The Sixth Assessment Report (AR6) of the United Nations (UN) Intergovernmental Panel on Climate Change (IPCC) is the sixth in a series of reports which assess the available scientific information on climate change. Three Working Groups (WGI, II, ...
on climate change. It warned that greenhouse gas emissions must peak before 2025 at the latest and decline 43% by 2030 to have a good chance of limiting global warming to 1.5 °C (2.7 °F). Or in the words of Secretary-General of the United Nations
António Guterres
António Manuel de Oliveira Guterres (born 30 April 1949) is a Portuguese politician and diplomat who is serving as the ninth and current secretary-general of the United Nations since 2017. A member of the Socialist Party (Portugal), ...
: "Main emitters must drastically cut emissions starting this year".
A 2023 synthesis by leading climate scientists highlighted ten critical areas in climate science with significant policy implications. These include the near inevitability of temporarily exceeding the 1.5 °C warming limit, the urgent need for a rapid and managed fossil fuel phase-out, challenges in scaling carbon dioxide removal technologies, uncertainties regarding the future contribution of natural carbon sinks, and the interconnected crises of biodiversity loss and climate change. These insights underscore the necessity for immediate and comprehensive mitigation strategies to address the multifaceted challenges of climate change.
Pledges
Climate Action Tracker
Climate Action Tracker (CAT) is an independent scientific project with the aim of monitoring government action to achieve their reduction of greenhouse gas emissions
Greenhouse gas (GHG) emissions from human activities intensify the greenhouse e ...
described the situation on 9 November 2021 as follows. The global temperature will rise by 2.7 °C by the end of the century with current policies and by 2.9 °C with nationally adopted policies. The temperature will rise by 2.4 °C if countries only implement the pledges for 2030. The rise would be 2.1 °C with the achievement of the long-term targets too. Full achievement of all announced targets would mean the rise in global temperature will peak at 1.9 °C and go down to 1.8 °C by the year 2100. Experts gather information about climate pledges in the
Global Climate Action Portal - Nazca
Global Climate Action, originally known as Non-state Actor Zone for Climate Action (NAZCA), is a web portal
A web portal is a specially designed website that brings information from diverse sources, like emails, online forums and search engines, ...
. The scientific community is checking their fulfilment.
There has not been a definitive or detailed evaluation of most goals set for 2020. But it appears the world failed to meet most or all international goals set for that year.
One update came during the
2021 United Nations Climate Change Conference
The 2021 United Nations Climate Change Conference, more commonly referred to as COP26, was the 26th United Nations Climate Change conference, held at the SEC Centre in Glasgow, Scotland
Scotland is a Countries of the United Kingdom, coun ...
in Glasgow. The group of researchers running the Climate Action Tracker looked at countries responsible for 85% of greenhouse gas emissions. It found that only four countries or political entities—the EU, UK, Chile and Costa Rica—have published a detailed official policyplan that describes the steps to realise 2030 mitigation targets. These four polities are responsible for 6% of global greenhouse gas emissions.
In 2021 the US and EU launched the Global Methane Pledge to cut methane emissions by 30% by 2030. The UK, Argentina, Indonesia, Italy and Mexico joined the initiative. Ghana and Iraq signalled interest in joining. A White House summary of the meeting noted those countries represent six of the top 15 methane emitters globally. Israel also joined the initiative.
Low-carbon energy

The
energy system
An energy system is a system primarily designed to supply #Energy-services, energy-services to end user, end-users. The intent behind energy systems is to minimise energy losses to a negligible level, as well as to ensure the efficient use of ...
includes the delivery and use of energy. It is the main emitter of carbon dioxide ().
Rapid and deep reductions in the carbon dioxide and other greenhouse gas emissions from the energy sector are necessary to limit global warming to well below 2 °C.
IPCC recommendations include reducing fossil fuel consumption, increasing production from low- and zero carbon energy sources, and increasing use of electricity and alternative energy carriers.
Nearly all scenarios and strategies involve a major increase in the use of renewable energy in combination with increased energy efficiency measures.
It will be necessary to accelerate the deployment of
renewable energy
Renewable energy (also called green energy) is energy made from renewable resource, renewable natural resources that are replenished on a human lifetime, human timescale. The most widely used renewable energy types are solar energy, wind pow ...
six-fold from 0.25% annual growth in 2015 to 1.5% to keep global warming under 2 °C.

The competitiveness of renewable energy is a key to a rapid deployment. In 2020, onshore wind and solar photovoltaics were the cheapest source for new bulk electricity generation in many regions.
Renewables may have higher storage costs but non-renewables may have higher clean-up costs. A
carbon price
Carbon pricing (or pricing) is a method for governments to mitigate climate change, in which a monetary cost is applied to greenhouse gas emissions. This is done to encourage polluters to reduce fossil fuel combustion, the main driver of climat ...
can increase the competitiveness of renewable energy.
Solar and wind energy

Wind and sun can provide large amounts of low-carbon energy at competitive production costs. The IPCC estimates that these two mitigation options have the largest potential to reduce emissions before 2030 at low cost.
Solar
photovoltaics
Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commerciall ...
(PV) has become the cheapest way to generate electricity in many regions of the world. The growth of photovoltaics has been close to exponential. It has about doubled every three years since the 1990s. A different technology is
concentrated solar power
Concentrated solar power (CSP, also known as concentrating solar power, concentrated solar thermal) systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight into a receiver. Electricity is generated whe ...
(CSP). This uses mirrors or lenses to concentrate a large area of sunlight on to a receiver. With CSP, the energy can be stored for a few hours. This provides supply in the evening.
Solar water heating
Solar water heating (SWH) is water heating, heating water by sunlight, using a solar thermal collector. A variety of configurations are available at varying cost to provide solutions in different climates and latitudes. SWHs are widely used for ...
doubled between 2010 and 2019.

Regions in the higher northern and southern latitudes have the greatest potential for wind power. Offshore
wind farms
A wind farm, also called a wind park or wind power plant, is a group of wind turbines in the same location used to produce electricity. Wind farms vary in size from a small number of turbines to several hundred wind turbines covering an exten ...
are more expensive. But offshore units deliver more energy per installed capacity with less fluctuations. In most regions, wind power generation is higher in the winter when PV output is low. For this reason, combinations of wind and solar power lead to better-balanced systems.
Other renewables

Other well-established renewable energy forms include hydropower, bioenergy and geothermal energy.
*
Hydroelectricity
Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...
is electricity generated by
hydropower
Hydropower (from Ancient Greek -, "water"), also known as water power or water energy, is the use of falling or fast-running water to Electricity generation, produce electricity or to power machines. This is achieved by energy transformation, ...
and plays a leading role in countries like Brazil, Norway and China.
but there are geographical limits and environmental issues.
Tidal power
Tidal power or tidal energy is harnessed by converting energy from tides into useful forms of power, mainly electricity using various methods.
Although not yet widely used, tidal energy has the potential for future electricity generation. T ...
can be used in coastal regions.
*
Bioenergy
Bioenergy is a type of renewable energy that is derived from plants and animal waste. The Biomass (energy), biomass that is used as input materials consists of recently living (but now dead) organisms, mainly plants. Thus, Fossil fuel, fossil fu ...
can provide energy for electricity, heat and transport. Bioenergy, in particular
biogas
Biogas is a gaseous renewable energy source produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste, Wastewater treatment, wastewater, and food waste. Biogas is produced by anaerobic ...
, can provide
dispatchable electricity generation. While burning plant-derived
biomass
Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...
releases , the plants withdraw from the atmosphere while they grow. The technologies for producing, transporting and processing a fuel have a significant impact on the lifecycle emissions of the fuel. For example, aviation is starting to use renewable
biofuel
Biofuel is a fuel that is produced over a short time span from Biomass (energy), biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricu ...
s.
*
Geothermal power
Geothermal power is electricity generation, electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation i ...
is electrical power generated from
geothermal energy
Geothermal energy is thermal energy extracted from the crust (geology), crust. It combines energy from the formation of the planet and from radioactive decay. Geothermal energy has been exploited as a source of heat and/or electric power for m ...
. Geothermal electricity generation is currently used in 26 countries.
[Geothermal Energy Association]
Geothermal Energy: International Market Update
May 2010, p. 4-6. Geothermal heating
Geothermal heating is the direct use of geothermal energy for some heating applications. Humans have taken advantage of geothermal heat this way since the Paleolithic era. Approximately seventy countries made direct use of a total of 270 PJ o ...
is in use in 70 countries.
[Moomaw, W., P. Burgherr, G. Heath, M. Lenzen, J. Nyboer, A. Verbruggen]
2011: Annex II: Methodology. In IPCC: Special Report on Renewable Energy Sources and Climate Change Mitigation (ref. page 10)
/ref>
Integrating variable renewable energy
Wind and solar power production does not consistently match demand. To deliver reliable electricity from variable renewable energy
Variable renewable energy (VRE) or intermittent renewable energy sources (IRES) are renewable energy sources that are not dispatchable due to their fluctuating nature, such as wind power and solar power, as opposed to controllable renewable ener ...
sources such as wind and solar, electrical power systems must be flexible. Most electrical grids were constructed for non-intermittent energy sources such as coal-fired power plants. The integration of larger amounts of solar and wind energy into the grid requires a change of the energy system; this is necessary to ensure that the supply of electricity matches demand.
There are various ways to make the electricity system more flexible. In many places, wind and solar generation are complementary on a daily and a seasonal scale. There is more wind during the night and in winter when solar energy production is low. Linking different geographical regions through long-distance transmission lines also makes it possible to reduce variability. It is possible to shift energy demand in time. Energy demand management
Energy demand management, also known as demand-side management (DSM) or demand-side response (DSR), is the modification of consumer energy demand, demand for energy through various methods such as financial incentives and behavioral change through ...
and the use of smart grids
The smart grid is an enhancement of the 20th century electrical grid, using two-way communications and distributed so-called intelligent devices. Two-way flows of electricity and information could improve the delivery network. Research is main ...
make it possible to match the times when variable energy production is highest. Sector coupling can provide further flexibility. This involves coupling the electricity sector to the heat and mobility sector via power-to-heat
Power-to-X (also P2X and P2Y) are electricity energy transformation, conversion, energy storage, and reconversion pathways from surplus renewable energy.
Power-to-X conversion technologies allow for the decoupling of power from the electricity s ...
-systems and electric vehicles.
Energy storage helps overcome barriers to intermittent renewable energy. The most commonly used and available storage method is pumped-storage hydroelectricity
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing (electrical power), load balancing.
A PSH system stores energy i ...
. This requires locations with large differences in height and access to water. Batteries are also in wide use. They typically store electricity for short periods. Batteries have low energy density
In physics, energy density is the quotient between the amount of energy stored in a given system or contained in a given region of space and the volume of the system or region considered. Often only the ''useful'' or extractable energy is measure ...
. This and their cost makes them impractical for the large energy storage necessary to balance inter-seasonal variations in energy production. Some locations have implemented pumped hydro storage with capacity for multi-month usage.
Nuclear power
Nuclear power
Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by ...
could complement renewables for electricity. On the other hand, environmental and security risks could outweigh the benefits. Examples of these environmental risks being the discharge of radioactive water to nearby ecosystems, and the routine release of radioactive gases as well.
The construction of new nuclear reactors currently takes about 10 years. This is much longer than scaling up the deployment of wind and solar. And this timing gives rise to credit risks. However nuclear may be much cheaper in China. China is building a significant number of new power plants. the cost of extending nuclear power plant lifetimes is competitive with other electricity generation technologies if long term costs for nuclear waste disposal are excluded from the calculation. There is also no sufficient financial insurance for nuclear accidents.
Replacing coal with natural gas
Demand reduction
Reducing demand for products and services that cause greenhouse gas emissions can help in mitigating climate change. One is to reduce demand by behavioural and cultural changes, for example by making changes in diet, especially the decision to reduce meat consumption, an effective action individuals take to fight climate change. Another is by reducing the demand by improving infrastructure, by building a good public transport network, for example. Lastly, changes in end-use technology can reduce energy demand. For instance a well-insulated house emits less than a poorly-insulated house.
Mitigation options that reduce demand for products or services help people make personal choices to reduce their carbon footprint
A carbon footprint (or greenhouse gas footprint) is a calculated value or index that makes it possible to compare the total amount of greenhouse gases that an activity, product, company or country Greenhouse gas emissions, adds to the atmospher ...
. This could be in their choice of transport or food.[Patrick Devine-Wright, Julio Diaz-José, Frank Geels, Arnulf Grubler, Nadia Maïzi, Eric Masanet, Yacob Mulugetta, Chioma Daisy Onyige-Ebeniro, Patricia E. Perkins, Alessandro Sanches Pereira, Elke Ursula Weber (2022]
Chapter 5: Demand, services and social aspects of mitigation
i
Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change
Cambridge University Press, Cambridge, United Kingdom and New York, NY, United States So these mitigation options have many social aspects that focus on demand reduction; they are therefore ''demand-side'' ''mitigation actions''. For example, people with high socio-economic status often cause more greenhouse gas emissions than those from a lower status. If they reduce their emissions and promote green policies, these people could become low-carbon lifestyle role models. However, there are many psychological variables that influence consumers. These include awareness and perceived risk.
Government policies can support or hinder demand-side mitigation options. For example, public policy can promote circular economy
A circular economy (also referred to as circularity or CE) is a model of resource Production (economics), production and Resource consumption, consumption in any economy that involves sharing, leasing, Reuse, reusing, repairing, refurbishing, and ...
concepts which would support climate change mitigation. Reducing greenhouse gas emissions is linked to the sharing economy
The sharing economy is a socio-economic system whereby consumers share in the creation, production, distribution, trade and consumption of goods, and services. These systems take a variety of forms, often leveraging information technology and the ...
.
There is a debate regarding the correlation of economic growth and emissions. It seems economic growth no longer necessarily means higher emissions.
A 2024 article in Nature Climate Change emphasises the importance of integrating behavioural science into climate change mitigation strategies. The article presents six key recommendations aimed at improving individual and collective actions toward reducing greenhouse gas emissions, including overcoming barriers to research, fostering cross-disciplinary collaborations, and promoting practical behaviour-oriented solutions. These insights suggest that behavioural science plays a crucial role alongside technological and policy measures in addressing climate change.
Energy conservation and efficiency
Global primary energy
Primary energy (PE) is the energy found in nature that has not been subjected to any human engineered conversion process. It encompasses energy contained in raw fuels and other forms of energy, including waste, received as input to a system. Pri ...
demand exceeded 161,000 terawatt hours (TWh) in 2018. This refers to electricity, transport and heating including all losses. In transport and electricity production, fossil fuel usage has a low efficiency of less than 50%. Large amounts of heat in power plants and in motors of vehicles go to waste. The actual amount of energy consumed is significantly lower at 116,000 TWh.
Energy conservation
Energy conservation is the effort to reduce wasteful energy consumption by using fewer energy services. This can be done by using energy more effectively (using less and better sources of energy for continuous service) or changing one's behavi ...
is the effort made to reduce the consumption of energy by using less of an energy service. One way is to use energy more efficiently. This means using less energy than before to produce the same service. Another way is to reduce the amount of service used. An example of this would be to drive less. Energy conservation is at the top of the sustainable energy hierarchy. When consumers reduce wastage and losses they can conserve energy. The upgrading of technology as well as the improvements to operations and maintenance can result in overall efficiency improvements.
Efficient energy use
Efficient energy use, or energy efficiency, is the process of reducing the amount of energy required to provide products and services. There are many technologies and methods available that are more energy efficient than conventional systems. For ...
(or ''energy efficiency'') is the process of reducing the amount of energy required to provide products and services. Improved energy efficiency in buildings ("green buildings"), industrial processes and transportation could reduce the world's energy needs in 2050 by one third. This would help reduce global emissions of greenhouse gases. For example, insulating a building allows it to use less heating and cooling energy to achieve and maintain thermal comfort. Improvements in energy efficiency are generally achieved by adopting a more efficient technology or production process. Another way is to use commonly accepted methods to reduce energy losses.
Lifestyle changes
Individual action on climate change
Individual action on climate change describes the personal choices that everyone can make to reduce the greenhouse gas emissions of their lifestyles and catalyze climate action. These actions can focus directly on how choices create emissions, suc ...
can include personal choices in many areas. These include diet, travel, household energy use, consumption of goods and services, and family size. People who wish to reduce their carbon footprint
A carbon footprint (or greenhouse gas footprint) is a calculated value or index that makes it possible to compare the total amount of greenhouse gases that an activity, product, company or country Greenhouse gas emissions, adds to the atmospher ...
can take high-impact actions such as avoiding frequent flying and petrol-fuelled cars, eating mainly a plant-based diet
A plant-based diet is a diet consisting mostly or entirely of plant-based foods. It encompasses a wide range of dietary patterns that contain low amounts of animal products and high amounts of fiber-rich plant products such as vegetables ...
, having fewer children, using clothes and electrical products for longer, and electrifying homes. These approaches are more practical for people in high-income countries with high-consumption lifestyles. Naturally, it is more difficult for those with lower income statuses to make these changes. This is because choices like electric-powered cars may not be available. Excessive consumption is more to blame for climate change than population increase. High-consumption lifestyles have a greater environmental impact, with the richest 10% of people emitting about half the total lifestyle emissions.
Dietary change
Some scientists say that avoiding meat and dairy foods is the single biggest way an individual can reduce their environmental impact. The widespread adoption of a vegetarian diet could cut food-related greenhouse gas emissions by 63% by 2050. China introduced new dietary guidelines in 2016 which aim to cut meat consumption by 50% and thereby reduce greenhouse gas emissions by 1Gt per year by 2030. Overall, food accounts for the largest share of consumption-based greenhouse gas emissions. It is responsible for nearly 20% of the global carbon footprint. Almost 15% of all anthropogenic greenhouse gas emissions have been attributed to the livestock sector.
A shift towards plant-based diets would help to mitigate climate change. In particular, reducing meat consumption would help to reduce methane emissions. If high-income nations switched to a plant-based diet, vast amounts of land used for animal agriculture could be allowed to Restoration ecology, return to their natural state. This in turn has the potential to sequester 100 billion tonnes of by the end of the century. A comprehensive analysis found that plant based diets reduce emissions, water pollution and land use significantly (by 75%), while reducing the destruction of wildlife and usage of water.
Family size
Projections of population growth, Population growth has resulted in higher greenhouse gas emissions in most regions, particularly Africa.[IPCC (2022]
Chapter 6: Energy systems
i
Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change
Cambridge University Press, Cambridge, United Kingdom and New York, NY, United States However, economic growth has a bigger effect than population growth. Rising incomes, changes in consumption and dietary patterns, as well as population growth, cause pressure on land and other natural resources. This leads to more greenhouse gas emissions and fewer carbon sinks.[IPCC (2022]
Chapter 7: Agriculture, Forestry, and Other Land Uses (AFOLU)
i
Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change
Cambridge University Press, Cambridge, United Kingdom and New York, NY, United States Some scholars have argued that humane policies to slow population growth should be part of a broad climate response together with policies that end fossil fuel use and encourage sustainable consumption. Advances in female education and Sexual and reproductive health, reproductive health, especially voluntary family planning, can contribute to reducing population growth.
Preserving and enhancing carbon sinks
An important mitigation measure is "preserving and enhancing carbon sink
A carbon sink is a natural or artificial carbon sequestration process that "removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere". These sinks form an important part of the natural carbon cycle. An overar ...
s". This refers to the management of Earth's natural carbon sink
A carbon sink is a natural or artificial carbon sequestration process that "removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere". These sinks form an important part of the natural carbon cycle. An overar ...
s in a way that preserves or increases their capability to remove CO2 from the atmosphere and to store it durably. Scientists call this process also carbon sequestration
Carbon sequestration is the process of storing carbon in a carbon pool. It plays a crucial role in Climate change mitigation, limiting climate change by reducing the amount of Carbon dioxide in Earth's atmosphere, carbon dioxide in the atmosphe ...
. In the context of climate change mitigation, the IPCC defines a ''sink'' as "Any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere". Globally, the two most important carbon sinks are vegetation and the ocean.
To enhance the ability of ecosystem
An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...
s to sequester carbon, changes are necessary in agriculture and forestry. Examples are preventing deforestation and restoring natural ecosystems by reforestation. Scenarios that limit global warming to 1.5 °C typically project the large-scale use of Carbon dioxide removal, carbon dioxide removal methods over the 21st century.[IPCC, 2018]
Summary for Policymakers
In
Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty
[Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, US, pp. 3-24. https://doi.org/10.1017/9781009157940.001. There are concerns about over-reliance on these technologies, and their environmental impacts. But ecosystem restoration and reduced conversion are among the mitigation tools that can yield the most emissions reductions before 2030.
Land-based mitigation options are referred to as "AFOLU mitigation options" in the 2022 IPCC report on mitigation. The abbreviation stands for "agriculture, forestry and other land use" The report described the economic mitigation potential from relevant activities around forests and ecosystems as follows: "the conservation, improved management, and restoration of forests and other ecosystems (coastal wetlands, peatlands, savannas and grasslands)". A high mitigation potential is found for reducing deforestation in tropical regions. The economic potential of these activities has been estimated to be 4.2 to 7.4 gigatonnes of carbon dioxide equivalent (GtCO2 -eq) per year.
Forests
Conservation
The Stern Review on the economics of climate change stated in 2007 that curbing deforestation was a highly cost-effective way of reducing greenhouse gas emissions. About 95% of deforestation occurs in the tropics, where clearing of land for agriculture is one of the main causes. One forest conservation strategy is to transfer rights over land from public ownership to its indigenous inhabitants. Land concessions often go to powerful extractive companies. Conservation strategies that exclude and even evict humans, called fortress conservation, often lead to more exploitation of the land. This is because the native inhabitants turn to work for extractive companies to survive.
Proforestation is promoting forests to capture their full ecological potential. This is a mitigation strategy as secondary forests that have regrown in abandoned farmland are found to have less biodiversity than the original old-growth forests. Original forests store 60% more carbon than these new forests. Strategies include Rewilding (conservation biology), rewilding and establishing wildlife corridors.
Afforestation and reforestation
Afforestation is the establishment of trees where there was previously no tree cover. Scenarios for new plantations covering up to 4000 million hectares (Mha) (6300 x 6300 km) suggest cumulative carbon storage of more than 900 GtC (2300 Gt) until 2100. But they are not a viable alternative to aggressive emissions reduction. This is because the plantations would need to be so large they would eliminate most natural ecosystems or reduce food production. One example is the Trillion Tree Campaign. However, preserving biodiversity is also important and for example not all grasslands are suitable for conversion into forests. Grasslands can even turn from carbon sink
A carbon sink is a natural or artificial carbon sequestration process that "removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere". These sinks form an important part of the natural carbon cycle. An overar ...
s to carbon sources.
Reforestation is the restocking of existing depleted forests or in places where there were recently forests. Reforestation could save at least 1GtCO2 per year, at an estimated cost of $5–15 per tonne of carbon dioxide (tCO2).[Stern, N. (2006). ''Stern Review on the Economics of Climate Change: Part III: The Economics of Stabilisation.'' HM Treasury, London: http://hm-treasury.gov.uk/sternreview_index.htm] Restoring all degraded forests all over the world could capture about 205 GtC (750 Gt). With increased intensive agriculture and urbanisation, there is an increase in the amount of abandoned farmland. By some estimates, for every acre of original old-growth forest cut down, more than 50 acres of new secondary forests are growing. In some countries, promoting regrowth on abandoned farmland could offset years of emissions.
Planting new trees can be expensive and a risky investment. For example, about 80 per cent of planted trees in the Sahel die within two years. Reforestation has higher carbon storage potential than afforestation. Even long-deforested areas still contain an "underground forest" of living roots and tree stumps. Helping native species sprout naturally is cheaper than planting new trees and they are more likely to survive. This could include pruning and coppicing to accelerate growth. This also provides woodfuel, which is otherwise a major source of deforestation. Such practices, called farmer-managed natural regeneration, are centuries old but the biggest obstacle towards implementation is ownership of the trees by the state. The state often sells timber rights to businesses which leads to locals uprooting seedlings because they see them as a liability. Legal aid for locals and changes to property law such as in Mali and Niger have led to significant changes. Scientists describe them as the largest positive environmental transformation in Africa. It is possible to discern from space the border between Niger and the more barren land in Nigeria, where the law has not changed.
Soils
There are many measures to increase soil carbon. This makes it complex and hard to measure and account for. One advantage is that there are fewer trade-offs for these measures than for Bioenergy with carbon capture and storage, BECCS or afforestation, for example.
Globally, protecting healthy soils and restoring the soil carbon sponge could remove 7.6 billion tonnes of carbon dioxide from the atmosphere annually. This is more than the annual emissions of the US. Trees capture while growing above ground and Plant root exudates, exuding larger amounts of carbon below ground. Trees contribute to the building of a soil carbon sponge. Carbon formed above ground is released as immediately when wood is burned. If dead wood remains untouched, only some of the carbon returns to the atmosphere as decomposition proceeds.
Farming can deplete soil carbon and render soil incapable of supporting life. However, conservation farming can protect carbon in soils, and repair damage over time. The farming practice of cover crops is a form of carbon farming. Methods that enhance carbon sequestration in soil include no-till farming, residue mulching and crop rotation. Scientists have described the best management practices for European soils to increase soil organic carbon. These are conversion of arable land to grassland, straw incorporation, reduced tillage, straw incorporation combined with reduced tillage, Ley farming, ley cropping system and cover crops.
Another mitigation option is the production of biochar and its storage in soils This is the solid material that remains after the pyrolysis of biomass
Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...
. Biochar production releases half of the carbon from the biomass—either released into the atmosphere or captured with CCS—and retains the other half in the stable biochar. It can endure in soil for thousands of years. Biochar may increase the soil fertility of acidic soils and increase agricultural productivity. During production of biochar, heat is released which may be used as bioenergy.
Wetlands
Wetland restoration is an important mitigation measure. It has moderate to great mitigation potential on a limited land area with low trade-offs and costs. Wetlands perform two important functions in relation to climate change. They can Carbon sink, sequester carbon, converting carbon dioxide to solid plant material through photosynthesis. They also store and regulate water. Wetlands store about 45 million tonnes of carbon per year globally.
Some Wetland methane emissions, wetlands are a significant source of methane emissions. Some also emit nitrous oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or factitious air, among others, is a chemical compound, an Nitrogen oxide, oxide of nitrogen with the Chemical formula, formula . At room te ...
. Peatland globally covers just 3% of the land's surface. But it stores up to 550 gigatonnes (Gt) of carbon. This represents 42% of all soil carbon and exceeds the carbon stored in all other vegetation types, including the world's forests. The threat to peatlands includes draining the areas for agriculture. Another threat is cutting down trees for lumber, as the trees help hold and fix the peatland. Additionally, peat is often sold for compost. It is possible to restore degraded peatlands by blocking drainage channels in the peatland, and allowing natural vegetation to recover.
Mangroves, salt marshes and seagrasses make up the majority of the ocean's vegetated habitats. They only equal 0.05% of the plant biomass on land. But they store carbon 40 times faster than tropical forests. Bottom trawling, dredging for coastal development and fertiliser runoff have damaged coastal habitats. Notably, 85% of oyster reefs globally have been removed in the last two centuries. Oyster reefs clean the water and help other species thrive. This increases biomass in that area. In addition, oyster reefs mitigate the effects of climate change by reducing the force of waves from hurricanes. They also reduce the erosion from rising sea levels. Restoration of coastal wetlands is thought to be more cost-effective than restoration of inland wetlands.
Deep ocean
These options focus on the carbon which ocean reservoirs can store. They include ocean fertilization, ocean alkalinity enhancement or enhanced weathering.[IPCC (2022]
Chapter 12: Cross sectoral perspectives
i
Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change
Cambridge University Press, Cambridge, United Kingdom and New York, NY, United States The IPCC found in 2022 ocean-based mitigation options currently have only limited deployment potential. But it assessed that their future mitigation potential is large. It found that in total, ocean-based methods could remove 1–100 Gt of per year. Their costs are in the order of US$40–500 per tonne of . Most of these options could also help to reduce ocean acidification. This is the drop in pH value caused by increased atmospheric CO2 concentrations. The recovery of whale populations can play a role in mitigation as whales play a significant part in nutrient recycling in the ocean. This occurs through what is referred to as the whale pump, where whales’ liquid feces stay at the surface of the ocean. Phytoplankton live near the surface of the ocean in order use sunlight to photosynthesize and rely on much of the carbon, nitrogen and iron of the feces. As the phytoplankton form the Primary production, base of the marine food chain this increases ocean biomass and thus the amount of carbon sequestrated in it.
Blue carbon management is another type of ocean-based biological carbon dioxide removal
Carbon dioxide removal (CDR) is a process in which carbon dioxide () is removed from the atmosphere by deliberate human activities and durably stored in geological, terrestrial, or ocean reservoirs, or in products.IPCC, 2021:Annex VII: Glossar ...
(CDR). It can involve land-based as well as ocean-based measures. The term usually refers to the role that tidal marshes, mangroves and seagrasses can play in carbon sequestration.[IPCC, 2021]
Annex VII: Glossary
[Matthews, J.B.R., V. Möller, R. van Diemen, J.S. Fuglestvedt, V. Masson-Delmotte, C. Méndez, S. Semenov, A. Reisinger (eds.)]. I
Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change
[Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 2215–2256, doi:10.1017/9781009157896.022. Some of these efforts can also take place in deep ocean waters. This is where the vast majority of ocean carbon is held. These ecosystems can contribute to climate change mitigation and also to ecosystem-based adaptation. Conversely, when blue carbon ecosystems are degraded or lost they release carbon back to the atmosphere. There is increasing interest in developing blue carbon potential. Scientists have found that in some cases these types of ecosystems remove far more carbon per area than terrestrial forests. However, the long-term effectiveness of blue carbon as a carbon dioxide removal solution remains under discussion.
Enhanced weathering
Enhanced weathering could remove 2–4 Gt of per year. This process aims to accelerate natural weathering by spreading finely ground Silicate mineral, silicate rock, such as basalt, onto surfaces. This speeds up chemical reactions between rocks, water, and air. It Carbon dioxide removal, removes carbon dioxide from the atmosphere, permanently storing it in solid carbonate minerals or ocean alkalinity. Cost estimates are in the US$50–200 per tonne range of .
Other methods to capture and store CO2
In addition to traditional land-based methods to remove carbon dioxide (CO2) from the air, other technologies are under development. These could reduce CO2 emissions and lower existing atmospheric CO2 levels. Carbon capture and storage
Carbon capture and storage (CCS) is a process by which carbon dioxide (CO2) from industrial installations is separated before it is released into the atmosphere, then transported to a long-term storage location.IPCC, 2021Annex VII: Glossary at ...
(CCS) is a method to mitigate climate change by capturing CO2 from large Point source pollution, point sources, such as cement factories or Bioenergy with carbon capture and storage, biomass power plants. It then stores it away safely instead of releasing it into the atmosphere. The IPCC estimates that the costs of halting global warming would double without CCS.
Among the most viable carbon dioxide removal methods considered alongside solar radiation modification, biochar soil amendment is already being deployed commercially. Studies indicate that the carbon it contains remains stable in soils for centuries, giving it a durable potential of removing gigatonnes of CO2 per year. Expert assessments place the net cost of removing CO2 with biochar between US$30 and $120 per tonne. Market data show that biochar supplied 94% of all durable CDR credits delivered in 2023, demonstrating current scalability. Stratospheric aerosol injection (SAI), by comparison, could reduce global temperature quickly by dispersing sulfate aerosols in the stratosphere; however, deployment at climatically relevant scale would require the design and certification of a new fleet of high‑altitude aircraft, a process estimated to take a decade or more, and ongoing operating costs of about US$18 billion for each degree Celsius of cooling. While models confirm that SAI would lower global mean temperature, there are potential side effect including ozone depletion, altered
regional precipitation patterns, and the risk of a sudden "termination shock" warming if the programme were interrupted. These systemic risks are absent from biochar deployment.
Bioenergy with carbon capture and storage (BECCS) expands on the potential of CCS and aims to lower atmospheric CO2 levels. This process uses biomass
Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...
grown for bioenergy. The biomass yields energy in useful forms such as electricity, heat, biofuels, etc. through consumption of the biomass via combustion, fermentation, or pyrolysis. The process captures the CO2 that was extracted from the atmosphere when it grew. It then stores it underground or via land application as biochar. This effectively Carbon dioxide removal, removes it from the atmosphere. This makes BECCS a negative emissions technology (NET).
Scientists estimated the potential range of negative emissions from BECCS in 2018 as 0–22 Gt per year. , BECCS was capturing approximately 2 million tonnes per year of CO2 annually. The cost and availability of biomass limits wide deployment of BECCS. BECCS currently forms a big part of achieving climate targets beyond 2050 in modelling, such as by the Integrated assessment modelling, Integrated Assessment Models (IAMs) associated with the IPCC process. But many scientists are sceptical due to the risk of loss of biodiversity.
Direct air capture is a process of capturing directly from the ambient air. This is in contrast to CCS which captures carbon from point sources. It generates a concentrated stream of for Carbon sequestration, sequestration, Carbon capture and utilization, utilisation or production of carbon-neutral fuel and windgas. Artificial processes vary, and there are concerns about the long-term effects of some of these processes.[The Royal Society, (2009]
"Geoengineering the climate: science, governance and uncertainty"
Retrieved 12 September 2009.
Mitigation by sector
Buildings
The building sector accounts for 23% of global energy-related emissions.[Rogelj, J., D. Shindell, K. Jiang, S. Fifita, P. Forster, V. Ginzburg, C. Handa, H. Kheshgi, S. Kobayashi, E. Kriegler, L. Mundaca, R. Séférian, and M.V.Vilariño, 2018]
Chapter 2: Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development
In
Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty
[Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, US, pp. 93-174. https://doi.org/10.1017/9781009157940.004. About half of the energy is used for space and water heating. Building insulation can reduce the primary energy demand significantly. Heat pump loads may also provide a flexible resource that can participate in demand response to integrate variable renewable resources into the grid. Solar water heating
Solar water heating (SWH) is water heating, heating water by sunlight, using a solar thermal collector. A variety of configurations are available at varying cost to provide solutions in different climates and latitudes. SWHs are widely used for ...
uses thermal energy directly. Sufficiency measures include moving to smaller houses when the needs of households change, mixed use of spaces and the collective use of devices. Planners and civil engineers can construct new buildings using passive solar building design, low-energy building, or zero-energy building techniques. In addition, it is possible to design buildings that are more energy-efficient to cool by using lighter-coloured, more reflective materials in the development of urban areas.
Heat pumps efficiently heat buildings, and cool them by air conditioning. A modern heat pump typically transports around three to five times more thermal energy than electrical energy consumed. The amount depends on the coefficient of performance and the outside temperature.
Refrigeration and air conditioning account for about 10% of global emissions caused by fossil fuel-based energy production and the use of fluorinated gases. Alternative cooling systems, such as passive cooling building design and passive daytime radiative cooling surfaces, can reduce air conditioning use. Suburbs and cities in hot and arid climates can significantly reduce energy consumption from cooling with daytime radiative cooling.
Energy consumption for cooling is likely to rise significantly due to increasing heat and availability of devices in poorer countries. Of the 2.8 billion people living in the hottest parts of the world, only 8% currently have air conditioners, compared with 90% of people in the US and Japan. Adoption of air conditioners typically increases in warmer areas at above $10,000 annual household income.[Davis, L., Gertler, P., Jarvis, S., & Wolfram, C. (2021). Air conditioning and global inequality. Global Environmental Change, 69, 102299.](_blank)
/ref> By combining energy efficiency improvements and decarbonising electricity for air conditioning with the transition away from super-polluting refrigerants, the world could avoid cumulative greenhouse gas emissions of up to 210–460 Gt-eq over the next four decades. A shift to renewable energy in the cooling sector comes with two advantages: Solar energy production with mid-day peaks corresponds with the load required for cooling and additionally, cooling has a large potential for load management in the electric grid.
Urban planning
Cities emitted 28 GtCO2-eq in 2020 of combined CO2 and emissions. This was from producing and consuming goods and services. Climate-smart urban planning aims to reduce urban sprawl, sprawl to reduce the distance travelled. This lowers emissions from transportation. Switching from cars by improving walkability and cycling infrastructure is beneficial to a country's economy as a whole.
Urban forestry, lakes and other blue and green infrastructure can reduce emissions directly and indirectly by reducing energy demand for cooling. Methane emissions from municipal solid waste can be reduced by segregation, composting, and recycling.
Transport
Transportation accounts for 15% of emissions worldwide. Increasing the use of public transport, low-carbon freight transport and cycling are important components of transport decarbonisation.
Electric vehicles and environmentally friendly rail help to reduce the consumption of fossil fuels. In most cases, electric trains are more efficient than air transport and truck transport. Other efficiency means include improved public transport, smart mobility, carsharing and hybrid vehicle, electric hybrids. Fossil-fuel for passenger cars can be included in emissions trading. Furthermore, moving away from a car-dominated transport system towards low-carbon advanced public transport system is important.
Heavyweight, large personal vehicles (such as cars) require a lot of energy to move and take up much urban space. Several alternatives modes of transport are available to replace these. The European Union has made smart mobility part of its European Green Deal. In Smart city, smart cities, smart mobility is also important.
The World Bank is helping lower income countries buy electric buses. Their purchase price is higher than diesel buses. But lower running costs and health improvements due to cleaner air can offset this higher price.
Between one quarter and three quarters of cars on the road by 2050 are forecast to be electric vehicles. Hydrogen may be a solution for long-distance heavy freight trucks, if batteries alone are too heavy.
Shipping
In the shipping industry, the use of liquefied natural gas (LNG) as a marine bunker fuel is driven by emissions regulations. Ship operators must switch from heavy fuel oil to more expensive oil-based fuels, implement costly flue gas treatment technologies or switch to Marine LNG Engine, LNG engines. Methane slip, when gas leaks unburned through the engine, lowers the advantages of LNG. Maersk, the world's biggest container shipping line and vessel operator, warns of stranded assets when investing in transitional fuels like LNG. The company lists green ammonia as one of the preferred fuel types of the future. It has announced the first carbon-neutral vessel on the water by 2023, running on carbon-neutral methanol. Cruise operators are trialling partially hydrogen-powered ships.
Hybrid and all electric ferries are suitable for short distances. Norway's goal is an all electric fleet by 2025.
Air transport
Jet airliners contribute to climate change by emitting carbon dioxide, nitrogen oxides, Condensation trails, contrails and particulates. Their radiative forcing is estimated at 1.3–1.4 that of alone, excluding induced cirrus cloud. In 2018, global commercial operations generated 2.4% of all emissions.
The aviation industry has become more fuel efficient. But overall emissions have risen as the volume of air travel has increased. By 2020, aviation emissions were 70% higher than in 2005 and they could grow by 300% by 2050.
It is possible to reduce aviation's environmental footprint by better fuel economy in aircraft. Optimising flight routes to lower non- effects on climate from nitrogen oxides, particulates or contrails can also help. Aviation biofuel, carbon emission trading and carbon offsetting, part of the 191 nation ICAO's Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), can lower emissions. Short-haul flight bans, train connections, personal choices and aviation taxation and subsidies, taxation on flights can lead to fewer flights. Hybrid electric aircraft and electric aircraft or hydrogen-powered aircraft may replace fossil fuel-powered aircraft.
Experts expect emissions from aviation to rise in most projections, at least until 2040. They currently amount to 180 Mt of or 11% of transport emissions. Aviation biofuel and hydrogen can only cover a small proportion of flights in the coming years. Experts expect hybrid-driven aircraft to start commercial regional scheduled flights after 2030. Battery-powered aircraft are likely to enter the market after 2035. Under CORSIA, flight operators can purchase carbon offsets to cover their emissions above 2019 levels. CORSIA will be compulsory from 2027.
Agriculture, forestry and land use
Almost 20% of greenhouse gas emissions come from the agriculture and forestry sector. To significantly reduce these emissions, annual investments in the agriculture sector need to increase to $260 billion by 2030. The potential benefits from these investments are estimated at $4.3 trillion by 2030, offering a substantial economic return of 16-to-1.
Mitigation measures in the food system can be divided into four categories. These are demand-side changes, ecosystem protections, mitigation on farms, and mitigation in supply chains. On the demand side, limiting food waste is an effective way to reduce food emissions. Changes to a diet less reliant on animal products such as plant-based diets are also effective.
With 21% of global methane emissions, cattle are a major driver of global warming.[Olivier J.G.J. and Peters J.A.H.W. (2020)]
Trends in global CO2 and total greenhouse gas emissions: 2020 report
PBL Netherlands
Environmental Assessment Agency, The Hague. When rainforests are cut and the land is converted for grazing, the impact is even higher. In Brazil, producing 1 kg of beef can result in the emission of up to 335 kg CO2-eq.
Increasing the milk yield of dairy cows has been shown to reduce emissions.
Other livestock, manure management and rice cultivation also emit greenhouse gases, in addition to fossil fuel combustion in agriculture.
Important mitigation options for reducing the greenhouse gas emissions from livestock include genetic selection, introduction of Methanotroph, methanotrophic bacteria into the rumen, vaccines, feeds, diet modification and grazing management. Other options are diet changes towards ruminant-free alternatives, such as milk substitutes and meat analogues. Non-ruminant livestock, such as poultry, emit far fewer GHGs.
It is possible to cut methane emissions in rice cultivation by improved water management, combining dry seeding and one drawdown, or executing a alternate wetting and drying, sequence of wetting and drying. This results in emission reductions of up to 90% compared to full flooding and even increased yields.
Industry
Industry is the largest emitter of greenhouse gases when direct and indirect emissions are included. Electrification can reduce emissions from industry. Green hydrogen can play a major role in energy-intensive industries for which electricity is not an option. Further mitigation options involve the steel and cement industry, which can switch to a less polluting production process. Products can be made with less material to reduce emission-intensity and industrial processes can be made more efficient. Finally, circular economy
A circular economy (also referred to as circularity or CE) is a model of resource Production (economics), production and Resource consumption, consumption in any economy that involves sharing, leasing, Reuse, reusing, repairing, refurbishing, and ...
measures reduce the need for new materials. This also saves on emissions that would have been released from the mining of collecting of those materials.
The decarbonisation of cement production requires new technologies, and therefore investment in innovation. Bioconcrete is one possibility to reduce emissions. But no technology for mitigation is yet mature. So CCS will be necessary at least in the short-term.
Another sector with a significant carbon footprint is the steel sector, which is responsible for about 7% of global emissions. Emissions can be reduced by using electric arc furnaces to melt and recycle scrap steel. To produce virgin steel without emissions, blast furnaces could be replaced by hydrogen direct reduced iron and electric arc furnaces. Alternatively, carbon capture and storage solutions can be used.
Coal, gas and oil production often come with significant methane leakage. In the early 2020s some governments recognised the scale of the problem and introduced regulations. Methane leaks at oil and gas wells and processing plants are cost-effective to fix in countries which can easily trade gas internationally. There are leaks in countries where gas is cheap; such as Iran, Russia, and Turkmenistan. Nearly all this can be stopped by replacing old components and preventing routine flaring. Coalbed methane may continue leaking even after the mine has been closed. But it can be captured by drainage and/or ventilation systems. Fossil fuel firms do not always have financial incentives to tackle methane leakage.
Co-benefits
Co-benefits of climate change mitigation, also often referred to as ''ancillary benefits'', were firstly dominated in the scientific literature by studies that describe how lower GHG emissions lead to better air quality and consequently impact human health positively. The scope of co-benefits research expanded to its economic, social, ecological and political implications.
Positive secondary effects that occur from climate mitigation and climate change adaptation, adaptation measures have been mentioned in research since the 1990s. The IPCC first mentioned the role of co-benefits in 2001, followed by its fourth and fifth assessment cycle stressing improved working environment, reduced waste, health benefits and reduced capital expenditures. In the early 2000s the OECD was further fostering its efforts in promoting ancillary benefits.
The IPCC pointed out in 2007: "Co-benefits of GHG mitigation can be an important decision criteria in analyses carried out by policy-makers, but they are often neglected" and added that the co-benefits are "not quantified, monetised or even identified by businesses and decision-makers". Appropriate consideration of co-benefits can greatly "influence policy decisions concerning the timing and level of mitigation action", and there can be "significant advantages to the national economy and technical innovation".
An analysis of climate action in the UK found that public health benefits are a major component of the total benefits derived from climate action.
Employment and economic development
Co-benefits can positively impact employment, industrial development, states' energy independence and energy self-consumption. The deployment of renewable energies can foster job opportunities. Depending on the country and deployment scenario, replacing coal power plants with renewable energy can more than double the number of jobs per average MW capacity. Investments in renewable energies, especially in solar- and wind energy, can boost the value of production. Countries which rely on energy imports can enhance their energy independence and ensure supply security by deploying renewables. National energy generation from renewables lowers the demand for fossil fuel imports which scales up annual economic saving.
The European Commission forecasts a shortage of 180,000 skilled workers in hydrogen production and 66,000 in solar photovoltaic power by 2030.
Energy security
A higher share of renewables can additionally lead to more energy security. Socioeconomic co-benefits have been analysed such as energy access in rural areas and improved rural livelihoods. Rural areas which are not fully electrified can benefit from the deployment of Renewable energy, renewable energies. Solar-powered mini-grids can remain economically viable, cost-competitive and reduce the number of power cuts. Energy reliability has additional social implications: stable electricity improves the quality of education.
The International Energy Agency (International Energy Agency, IEA) spelled out the "multiple benefits approach" of Efficient energy use, energy efficiency while the International Renewable Energy Agency (International Renewable Energy Agency, IRENA) operationalised the list of co-benefits of the renewable energy sector.
Health and well-being
The health benefits from climate change mitigation are significant. Potential measures can not only mitigate future health impacts from climate change but also improve health directly. Climate change mitigation is interconnected with various health co-benefits, such as those from reduced air pollution. Air pollution generated by fossil fuel combustion is both a major driver of global warming and the cause of a large number of annual deaths. Some estimates are as high as excess deaths during 2018. A 2023 study estimated that fossil fuels kill over 5 million people each year, as of 2019, by causing diseases such as heart attack, stroke and chronic obstructive pulmonary disease. Particulate pollution, Particulate air pollution kills by far the most, followed by ground-level ozone.
Mitigation policies can also promote healthier diets such as less red meat, more active lifestyles, and increased exposure to green urban spaces. Access to urban green spaces provides benefits to mental health as well. The increased use of Green infrastructure, green and Blue space, blue infrastructure can reduce the urban heat island effect. This reduces Hyperthermia, heat stress on people.[IPCC (2022]
Technical Summary
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Climate change adaptation
Some mitigation measures have co-benefits in the area of climate change adaptation.[IPCC (2022]
Chapter 8: Urban systems and other settlements
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Chapter 4: Mitigation and development pathways in the near- to mid-term
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Cambridge University Press, Cambridge, United Kingdom and New York, NY, United States Examples in the urban context include urban green and blue infrastructure which provide mitigation as well as adaptation benefits. This can be in the form of Urban forestry, urban forests and street trees, green roofs and Green wall, walls, urban agriculture and so forth. The mitigation is achieved through the conservation and expansion of carbon sinks and reduced energy use of buildings. Adaptation benefits come for example through reduced heat stress and flooding risk.
Negative side effects
Mitigation measures can also have negative side effects and risks. In agriculture and forestry, mitigation measures can affect biodiversity and ecosystem functioning. In renewable energy, mining for metals and minerals can increase threats to conservation areas. There is some research into ways to recycle solar panels and electronic waste. This would create a source for materials so there is no need to mine them.
Scholars have found that discussions about risks and negative side effects of mitigation measures can lead to deadlock or the feeling that there are insuperable barriers to taking action.
Costs and funding
Several factors affect mitigation cost estimates. One is the baseline. This is a reference scenario that the alternative mitigation scenario is compared with. Others are the way costs are modelled, and assumptions about future government policy. Cost estimates for mitigation for specific regions depend on the quantity of emissions allowed for that region in future, as well as the timing of interventions.
Mitigation costs will vary according to how and when emissions are cut. Early, well-planned action will minimise the costs. Globally, the benefits of keeping warming under 2 °C exceed the costs, which according to The Economist are affordable.
Economists estimate the cost of climate change mitigation at between 1% and 2% of Gross domestic product, GDP. While this is a large sum, it is still far less than the subsidies governments provide to the ailing fossil fuel industry. The International Monetary Fund estimated this at more than $5 trillion per year.
Another estimate says that financial flows for climate mitigation and adaptation are going to be over $800 billion per year. These financial requirements are predicted to exceed $4 trillion per year by 2030.
Globally, limiting warming to 2 °C may result in higher economic benefits than economic costs. The economic repercussions of mitigation vary widely across regions and households, depending on policy design and level of international cooperation. Delayed global cooperation increases policy costs across regions, especially in those that are relatively carbon intensive at present. Pathways with uniform carbon values show higher mitigation costs in more carbon-intensive regions, in fossil-fuels exporting regions and in poorer regions. Aggregate quantifications expressed in GDP or monetary terms undervalue the economic effects on households in poorer countries. The actual effects on welfare and well-being are comparatively larger.[IPCC (2022]
Chapter 3: Mitigation pathways compatible with long-term goals
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Cost–benefit analysis may be unsuitable for analysing climate change mitigation as a whole. But it is still useful for analysing the difference between a 1.5 °C target and 2 °C. One way of estimating the cost of reducing emissions is by considering the likely costs of potential technological and output changes. Policymakers can compare the marginal abatement costs of different methods to assess the cost and amount of possible abatement over time. The marginal abatement costs of the various measures will differ by country, by sector, and over time.
Eco-tariffs on only imports contribute to reduced global export Competition (economics), competitiveness and to deindustrialisation.
Avoided costs of climate change effects
It is possible to avoid some of the costs of the effects of climate change by limiting climate change. According to the Stern Review, inaction can be as high as the equivalent of losing at least 5% of global gross domestic product (GDP) each year, now and forever. This can be up to 20% of GDP or more when including a wider range of risks and impacts. But mitigating climate change will only cost about 2% of GDP. Also it may not be a good idea from a financial perspective to delay significant reductions in greenhouse gas emissions.
Mitigation solutions are often evaluated in terms of costs and greenhouse gas reduction potentials. This fails to take into account the direct effects on human well-being.
Distributing emissions abatement costs
Mitigation at the speed and scale required to limit warming to 2 °C or below implies deep economic and structural changes. These raise multiple types of distributional concerns across regions, income classes and sectors.
There have been different proposals on how to allocate responsibility for cutting emissions.[ PDF version: IPCC website.] These include egalitarianism, basic needs according to a minimum level of consumption, proportionality and the Polluter pays principle, polluter-pays principle. A specific proposal is "equal per capita entitlements". This approach has two categories. In the first category, emissions are allocated according to national population. In the second category, emissions are allocated in a way that attempts to account for historical or cumulative emissions.
Funding
In order to reconcile economic development with mitigating carbon emissions, developing countries need particular support. This would be both financial and technical. The IPCC found that accelerated support would also tackle inequities in financial and economic vulnerability to climate change. One way to achieve this is the Kyoto Protocol's Clean Development Mechanism (CDM).
Policies
National policies
Climate change mitigation policies can have a large and complex impact on the socio-economic status of individuals and countries This can be both positive and negative. It is important to design policies well and make them inclusive. Otherwise climate change mitigation measures can impose higher financial costs on poor households.
An evaluation was conducted on 1,500 climate policy interventions made between 1998 and 2022. The interventions took place in 41 countries and across 6 continents, which together contributed 81% of the world's total emissions as of 2019. The evaluation found 63 successful interventions that resulted in significant emission reductions; the total release averted by these interventions was between 0.6 and 1.8 billion metric tonnes. The study focused on interventions with at least 4.5% emission reductions, but the researchers noted that meeting the reductions required by the Paris Agreement would require 23 billion metric tonnes per year. Generally, carbon pricing was found to be most effective in Developed country, developed countries, while regulation was most effective in the Developing country, developing countries. Complementary policy mixes benefited from synergies, and were mostly found to be more effective interventions than the implementation of isolated policies.
The OECD recognise 48 distinct climate mitigation policies suitable for implementation at national level. Broadly, these can be categorised into three types: ''market based'' instruments, ''non market based'' instruments and ''other'' policies.
* Other policies include the ''Establishing an Independent climate advisory body''.
* Non market based policies include the Implementing or tighening of ''Regulatory standards''. These set technology or performance standards. They can be effective in addressing the market failure of informational barriers.
*Among market based policies, the ''carbon price'' has been found to be the most effective (at least for developed economies), and has its own section below. Additional ''market based'' policy instruments for climate change mitigation include:
''Emissions taxes'' These often require domestic emitters to pay a fixed fee or tax for every tonne of CO2 emissions they release into the atmosphere. Methane emissions from fossil fuel extraction are also occasionally taxed. But methane and nitrous oxide from agriculture are typically not subject to tax.
''Removing unhelpful subsidies:'' Many countries provide subsidies for activities that affect emissions. For example, significant fossil fuel subsidies are present in many countries. Fossil fuel phase-out#Phase-out of fossil fuel subsidies, Phasing-out fossil fuel subsidies is crucial to address the climate crisis. It must however be done carefully to avoid protests and making poor people poorer.
''Creating helpful subsidies'': Creating subsidies and financial incentives. One example is Energy subsidy, energy subsidies to support clean generation which is not yet commercially viable such as tidal power.
''Tradable permits'': A carbon emission trading, permit system can limit emissions.
Carbon pricing
Imposing additional costs on greenhouse gas emissions can make fossil fuels less competitive and accelerate investments into low-carbon sources of energy. A growing number of countries raise a fixed carbon tax or participate in dynamic carbon emission trading (ETS) systems. In 2021, more than 21% of global greenhouse gas emissions were covered by a carbon price. This was a big increase from earlier due to the introduction of the Chinese national carbon trading scheme.
Trading schemes offer the possibility to limit emission allowances to certain reduction targets. However, an oversupply of allowances keeps most ETS at low price levels around $10 with a low impact. This includes the Chinese ETS which started with $7/t in 2021. One exception is the European Union Emission Trading Scheme where prices began to rise in 2018. They reached about €80/t in 2022. This results in additional costs of about €0.04/KWh for coal and €0.02/KWh for gas combustion for electricity, depending on the emission intensity. Industries which have high energy requirements and high emissions often pay only very low energy taxes, or even none at all.[IPCC (2022)]
Chapter 11: Industry
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While this is often part of national schemes, carbon offsets and credits can be part of a voluntary market as well such as on the international market. Notably, the company Blue Carbon (company), Blue Carbon of the UAE has bought ownership over an area equivalent to the United Kingdom to be preserved in return for carbon credits.
International agreements
International cooperation is considered a ''critical enabler'' for climate action while conflicts generally hamper it. Almost all countries are parties to the United Nations Framework Convention on Climate Change (UNFCCC). The ultimate objective of the UNFCCC is to stabilise atmospheric concentrations of greenhouse gases at a level that would prevent dangerous human interference with the climate system.
Although not designed for this purpose, the Montreal Protocol has benefited climate change mitigation efforts. The Montreal Protocol is an international treaty that has successfully reduced emissions of ozone-depleting substances such as Chlorofluorocarbon, CFCs. These are also greenhouse gases.
Paris Agreement
History
Historically efforts to deal with climate change have taken place at a multinational level. They involve attempts to reach a consensus decision at the United Nations, under the United Nations Framework Convention on Climate Change (UNFCCC). This is the dominant approach historically of engaging as many international governments as possible in taking action on a worldwide public issue. The Montreal Protocol in 1987 is a precedent that this approach can work. But some critics say the top-down framework of only utilising the UNFCCC consensus approach is ineffective. They put forward counter-proposals of bottom-up governance. At this same time this would lessen the emphasis on the UNFCCC.
The Kyoto Protocol to the UNFCCC adopted in 1997 set out legally binding emission reduction commitments for the "Annex 1" countries. The Protocol defined three international policy instruments ("Flexibility mechanisms, Flexibility Mechanisms") which could be used by the Annex 1 countries to meet their emission reduction commitments. According to Bashmakov, use of these instruments could significantly reduce the costs for Annex 1 countries in meeting their emission reduction commitments.
The Paris Agreement reached in 2015 succeeded the Kyoto Protocol which expired in 2020. List of Kyoto Protocol signatories, Countries that ratified the Kyoto protocol committed to reduce their emissions of carbon dioxide and five other greenhouse gases, or engage in carbon emissions trading if they maintain or increase emissions of these gases.
In 2015, the UNFCCC's "structured expert dialogue" came to the conclusion that, "in some regions and vulnerable ecosystems, high risks are projected even for warming above 1.5 °C". Together with the strong diplomatic voice of the poorest countries and the island nations in the Pacific, this expert finding was the driving force leading to the decision of the 2015 2015 United Nations Climate Change Conference, Paris Climate Conference to lay down this 1.5 °C long-term target on top of the existing 2 °C goal.
Barriers
There are individual, institutional and market barriers to achieving climate change mitigation. They differ for all the different mitigation options, regions and societies.
Difficulties with Carbon accounting, accounting for carbon dioxide removal can act as economic barriers. This would apply to BECCS (bioenergy with carbon capture and storage). The strategies that companies follow can act as a barrier. But they can also accelerate decarbonisation.
In order to decarbonise societies the state needs to play a predominant role. This is because it requires a massive coordination effort. This strong government role can only work well if there is social cohesion, political stability and trust.
For land-based mitigation options, finance is a major barrier. Other barriers are cultural values, governance, accountability and institutional capacity.
Developing countries face further barriers to mitigation.
* The cost of capital increased in the early 2020s. A lack of available capital and finance is common in developing countries. Together with the absence of regulatory standards, this barrier supports the proliferation of inefficient equipment.
* There are also financial and Capacity building, capacity barrier in many of these countries.
One study estimates that only 0.12% of all funding for climate-related research goes on the social science of climate change mitigation. Vastly more funding goes on natural science studies of climate change. Considerable sums also go on studies of the impact of climate change and adaptation to it.
Society and culture
Commitments to divest
More than 1000 organisations with investments worth US$8 trillion have made commitments to fossil fuel divestment. Socially responsible investing funds allow investors to invest in funds that meet high environmental, social and corporate governance (ESG) standards.
Impacts of the COVID-19 pandemic
The COVID-19 pandemic led some governments to shift their focus away from climate action, at least temporarily. This obstacle to environmental policy efforts may have contributed to slowed investment in green energy technologies. The economic slowdown resulting from COVID-19 added to this effect.
In 2020, carbon dioxide emissions fell by 6.4% or 2.3 billion tonnes globally. Greenhouse gas emissions rebounded later in the pandemic as many countries began lifting restrictions. The direct impact of pandemic policies had a negligible long-term impact on climate change.
Examples by country
United States
China
China has committed to peak emissions by 2030 and reach net zero by 2060. Warming cannot be limited to 1.5 °C if any Electricity sector in China#Coal power, coal plants in China (without carbon capture) operate after 2045. The Chinese national carbon trading scheme started in 2021.
European Union
The European Commission estimates that an additional €477 million in annual investment is needed for the European Union to meet its Fit for 55, Fit-for-55 decarbonisation goals.
In the European Union, government-driven policies and the European Green Deal have helped position greentech (as an example) as a vital area for venture capital investment. By 2023, venture capital in the EU's greentech sector equalled that of the United States, reflecting a concerted effort to drive innovation and mitigate climate change through targeted financial support. The European Green Deal has fostered policies that contributed to a 30% rise in venture capital for greentech companies in the EU from 2021 to 2023, despite a downturn in other sectors during the same period.
While overall venture capital investment in the EU remains about six times lower than in the United States, the greentech sector has closed this gap significantly, attracting substantial funding. Key areas benefitting from increased investments are energy storage, circular economy initiatives, and agricultural technology. This is supported by the EU's ambitious goal to reduce greenhouse gas emissions by at least 55% by 2030.
Related approaches
Relationship with solar radiation modification (SRM)
While solar geoengineering, solar radiation modification (SRM) could reduce surface temperatures, it temporarily masks climate change rather than addressing the root cause, which is greenhouse gases.[IPCC (2022]
Chapter 14: International cooperation
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Cambridge University Press, Cambridge, United Kingdom and New York, NY, United States] SRM would work by altering how much solar radiation the Earth absorbs. Examples include reducing the amount of sunlight reaching the surface, reducing the optical thickness and lifetime of clouds, and changing the ability of the surface to reflect radiation. The Intergovernmental Panel on Climate Change, IPCC describes SRM as a climate risk reduction strategy or supplementary option rather than a climate mitigation option.
The terminology in this area is still evolving. Experts sometimes use the term ''geoengineering'' or climate engineering in the scientific literature for both CDR or SRM, if the techniques are used at a global scale. IPCC reports no longer use the terms ''geoengineering'' or ''climate engineering''.
See also
* Carbon budget
* Carbon offsets and credits
* Carbon price
* Climate movement
* Climate change denial
* Tipping points in the climate system
References
{{Authority control
Climate change mitigation,
Biogeochemical cycle
Biogeography
Carbon, Cycle
Chemical oceanography
Climate change policy
Geochemistry
Numerical climate and weather models
Soil