Emissions of greenhouses gases (GHG) from human activities disturb the radiative energy balance of the earth-atmosphere system. They exacerbate the natural greenhouse effect, leading to temperature changes and other consequences for the earth's climate. Land use changes and forestry also play a role by altering the amount of greenhouse gases captured or released by carbon sinks.
Climate change is of concern mainly as regards its impact on ecosystems (biodiversity), human settlements and agriculture, and on the frequency and scale of extreme weather events. It could have significant consequences for human well-being and socio-economic activities, which could in turn affect global economic output.
The indicators presented here refer to the sum of emissions of six GHGs that have direct effects on climate change and are considered responsible for a major part of global warming: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6).
They show total gross emissions expressed in CO2 equivalents as well as emission intensities per unit of GDP and per capita, and related changes since 1990. They refer to GHG emitted within the national territory and exclude CO2 emissions and removals from land use change and forestry. They do not cover international transactions of emission reduction units or certified emission reductions.
GHG emissions are still growing in many countries and overall, although at a slightly lower pace than CO2 emissions from energy use. CO2 remains predominant and determines the overall trend. Together with CH4 and N2O, it accounts for about 98% of GHG emissions. The other gases account for about 2%, but their emissions are growing.
Global GHG emissions have doubled since the early 1970s, driven mainly by economic growth and increasing fossil energy use in developing countries. Historically, OECD countries emitted the bulk of GHGs, but the share of the BRIICS in global emissions has increased to 40%, from 30% in the 1970s (OECD, 2012).
Individual OECD countries' contributions to the additional greenhouse effect, and their rates of progress, vary significantly. These differences partly reflect different national circumstances, such as composition and rate of economic growth, population growth, energy resource endowment, and the extent to which the countries have taken steps to reduce emissions from various sources.
Emission intensities per unit of GDP and per capita are decreasing in most OECD countries, though decoupling remains weak. Many countries have not succeeded in meeting their commitments under the Kyoto Protocol.
Reductions in national emissions may also be the result of offshoring domestic production and the associated emissions. Evidence of decoupling based on domestic emissions per unit of GDP or per capita, therefore, may reveal only part of the story.
The OECD Environmental Outlook projects that global CO2 and other GHG emissions will continue to grow over the next few decades. GHG emissions could increase by another 50% by 2050, primarily driven by a projected 70% growth in CO2 emissions from energy use.
These indicators should be read in conjunction with indicators on CO2 emissions, energy intensity, and energy prices and taxes. Their interpretation should take into account the structure of countries' energy supply and climatic factors.
Data on GHG emissions are reported annually to the Secretariat of the UNFCCC with 1990 as a base year but not by all OECD countries. They display a good level of comparability. The high per GDP emissions of Estonia result from the use of oil shale for electricity generation. Oil shale has a high carbon emission factor. The high per capita emissions of Luxembourg result from the lower taxation of road fuels compared to neighbouring countries, which attracts drivers to refuel in the country.
Latest year available: years prior to 2006 were not considered. The OECD total does not include Israel.