UN panel shows emissions sources
The United Nations' expert panel on climate change is preparing a new report outlining cuts in greenhouse gases, mainly CO2 from the burning of fossil fuels, required in coming decades to keep global warming in check.
As a scientific body, the Intergovernmental Panel on Climate Change will not tell governments how to divide those emissions cuts - a crunch issue in negotiations on a new climate pact which is supposed to be adopted next year.
However, in a leaked draft of the report, the IPCC shows with graphs and tables which countries are responsible for the greatest share of emissions, using a range of accounting methods. These are some of the key facts on emissions:
:: Current total emissions
At the time of the IPCC's previous climate assessment, in 2007, the US was the world's top carbon polluter. It has since been overtaken by China, which now accounts for a quarter of global emissions because of its rapidly expanding economy.
The US is second with 17%, followed by India on 6.6%, Russia 5.1% and Japan 3.7%.
:: Historical emissions
If you count back to when the Industrial Revolution started in the 18th century, the US is the undisputed number one, accounting for nearly 28% of the world's cumulative emissions from energy and industry.
China's share is 9.9%, Russia's 6.9%, Britain's 5.9% and Germany's 5.6%.
Western countries rank high because they have been burning coal and oil for much longer than the rest of the world.
:: Emissions per capita
Putting emissions in proportion to population size also puts Western countries - and oil and gas-rich Gulf states - at the top of the table. In per capita emissions, Australians, Canadians and Americans exceed 20 tons of carbon per year - more than twice as much as the Chinese.
The draft report says: "Overall, per-capita emissions in the highly industrialised countries ... remain on average about five times higher than those of the lowest income countries."
:: Consumption emissions
The main way of counting emissions is by looking at where they are released, but some say you get a better picture of what is driving emissions by looking at consumption patterns. As the IPCC puts it: "A ton of steel produced in China but exported to the United States results in emissions in China when the fundamental demand for the steel originated in the US."
Accounting for emissions based on where a product is consumed rather than where it is manufactured still puts China at the top, but with a narrower gap to the US. China accounts for 21.9 % of global consumption emissions, while the US accounts for 18.1 % .
:: Emissions by sector
Energy production is the biggest source of emissions, representing about a third of the world total. Of the fossil fuels, coal generates the highest emissions, followed by oil and then natural gas.
Agriculture, forestry and other land use accounts for 24% of total emissions. Other big sectors include transport (13%) and buildings (7%).
:: Future emissions
The IPPC gives a range of trajectories for global emissions, but does not break them down by country. However, it notes that nearly all growth in emissions is expected to occur in developing countries, as their populations grow and they try to catch up economically with the industrialised world.
Developing countries say that is why they should not have to face as strict emissions targets in a new treaty as industrialised nations.
The latter say at least the biggest developing nations, including China, India and Brazil, must also make significant cuts. Both sides are likely to point to selected statistics and projections in the IPCC report.