They account for the vast majority of the world population and are responsible for roughly 95 percent of emissions driving dangerous levels of climate change.
The voluntary pledges -- dubbed Intended Nationally Determined Contributions or INDCs -- will help cap global warming at two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels, the UN-endorsed goal. They begin in 2020, with a few running to 2025 and the rest to the end of the decade.
But they are inadequate to meet the 2C target, and place the world on track for warming closer to 3C, several analyses conclude.
Among the top 10 emitters, here`s who has promised what:
- China envisages a peak in emissions "by around" 2030, and reducing carbon intensity (CO2 emitted per unit of gross domestic product) by 60-65 percent by 2030 compared with 2005 levels. The world`s most populous nation will boost the share of non-fossil fuel in primary energy consumption from 11.2 percent in 2014 to 20 percent, and boost the volume of CO2-absorbing forest by about 4.5 billion cubic metres (159 billion cubic feet).
- The United States has pledged a 26-28 percent reduction in emissions from 2005 levels by 2025. Power plants are to cut carbon dioxide pollution by 32 percent from 2005 levels by 2030.
- The 28-member European Union intends to cut emissions by at least 40 percent by 2030 over 1990 levels, and has set 27 percent targets for renewable energy supply and efficiency gains.
- India plans to reduce carbon intensity by 35 percent by 2030 from 2005 levels, and to generate 40 percent of its electricity from renewable sources by the same date.
- Russia has proposed cutting emissions by 25-30 percent by 2030 from 1990 levels, conditional on the pledges of other "major emitters".
- Japan has pledged a 26 percent reduction in emissions from 2013 levels by 2030, with nuclear energy -- offline since the 2011 Fukushima disaster -- providing 20-22 percent of electricity by then. Renewable electricity production, including hydro power, would be expanded to a 22-24 percent share, from 11 percent in 2014.
- Brazil will cut emissions 37 percent by 2025 from 2005, and 43 percent by 2030.
- Iran has made an unconditional pledge to reduce its greenhouse gas emissions in 2030 by four percent compared with a "business as usual" scenario. In addition, Tehran said it would reduce emissions another eight percent if it receives financial and technology support, and if what it describes as "unjust sanctions" were lifted.
- Indonesia envisages a 29 percent cut in emissions by 2030 compared with what the level would have been without any action. With financial and other help, this could be raised to 41 percent.
- Canada will seek to cut emissions by 30 percent from 2005 levels by 2030.