The emission reduction unit (ERU) is an emissions unit issued under a

Joint Implementation Joint Implementation (JI) is one of three flexibility mechanisms set out in the Kyoto Protocol to help countries with binding greenhouse gas emissions targets (the Annex I countries) meet their treaty obligations. Under Article 6, any Annex I coun ...

project in terms of the

Kyoto Protocol The Kyoto Protocol was an international treaty which extended the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits state parties to reduce greenhouse gas emissions, based on the scientific consensus that (part ...

. An ERU represents a reduction of

greenhouse gas A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), methane ...

es under the Joint Implementation mechanism, where it represents one

tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...

of equivalent reduced.

Description

To allow comparison between the different effects of gases on the environment, scientists have defined multipliers for gases that compare their greenhouse potency (

global warming potential Global warming potential (GWP) is the heat absorbed by any greenhouse gas in the atmosphere, as a multiple of the heat that would be absorbed by the same mass of carbon dioxide (). GWP is 1 for . For other gases it depends on the gas and the time ...

) relative to that of carbon dioxide. One example of a

project resulting in an emission reduction unit, is the production of

biogas Biogas is a mixture of gases, primarily consisting of methane, carbon dioxide and hydrogen sulphide, produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste and food waste. It is a ...

es by

landfill A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste materials. Landfill is the oldest and most common form of waste disposal, although the systematic burial of the wast ...

sites. These gases consist of mainly

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 relative abundance of methane ...

which escapes to the atmosphere if it is not collected. The main reason for dealing with methane is that it has a 100-year global warming potential multiplier of 25 compared to carbon dioxide (i.e. has 25 times the greenhouse potency). Collection of methane is usually accompanied by its combustion. Burning one tonne of methane produces nearly 3 tonnes of , thus reducing its

greenhouse effect The greenhouse effect is a process that occurs when energy from a planet's host star goes through the planet's atmosphere and heats the planet's surface, but greenhouse gases in the atmosphere prevent some of the heat from returning directly ...

by (25−3=22) ERU. In December 2012, ERU prices crashed to a low of 15 euro cents before recovering to 23c after news that EU’s Climate Change Committee was to vote on a ban of ERUs from countries that have not signed up to a second commitment period under the Kyoto Protocol. In January 2013, ''Bloomberg'' reported that emission reduction unit prices declined 89 percent in 2012.

References

United Nations Framework Convention on Climate Change Climate change policy Carbon finance Climate change treaties Emissions reduction {{climate-change-stub