United States: President Barack Obama has pledged cutting emissions by 17 percent from 2005 levels by 2020. That represents a 3.5 percent cut from 1990 levels, the benchmark used by most countries. Aims to reach a 41 percent reduction by 2030 and 83 percent by 2050. Requires that Congress passes complex climate legislation.

European Union: Has already agreed to cut emissions by 20 percent to 2020, compared with 1990 levels. Willing to increase target to 30 percent if other developed countries make comparable commitments.

Japan: Has set goal of cutting greenhouse gas emissions by 25 percent from 1990 levels by 2020 if other developed countries make similar commitments. Vague about how it will achieve the target.

Australia: Wants to slash greenhouse emissions by up to 25 percent below 2000 levels by 2020.

Russia: Has signaled to EU that it is ready to slash emissions by as much as 25 percent by 2020 if other developed countries do the same. Previously Russia has said it is willing to cut emissions by 10-15 percent from 1990 levels.

Canada: Plans to reduce emissions by 20 percent compared with 2006 levels by 2020. That is roughly a 3 percent cut from 1990 levels.

New Zealand: 10-20 percent cuts in emissions below 1990 levels by 2020.

Norway: Offering to cut emissions 30-40 percent below 1990 levels by 2020.

China: Has pledged to cut "carbon intensity", a measure of carbon dioxide emissions per unit of production, by 40-45 percent by 2020, compared with 2005 levels.

India: Plans to reduce the ratio of emissions to production by 20-25 percent compared with 2005 levels by 2020.

Indonesia: Has said it will reduce emissions 26 percent by 2020 compared with current trends, and up to 41 percent if it receives an unspecified amount of financing.

South Korea: Announced last month it would cut greenhouse emissions 4 percent below 2005 levels by 2020.

Brazil: Voluntary emissions cuts of 36-39 percent by 2020, largely by slowing deforestation in the vast Amazon region.