Following is a snapshot of the main players in the global climate talks, ahead of the December 7-18 conference in Copenhagen.
GROUP OF 77 AND CHINA
The bloc of developing nations insist rich countries - deemed responsible for today's warming and best placed to tackle it - commit to legally-binding reductions of their emissions by at least 40 percent annually by 2020 over 1990 levels.
They refuse to make binding emissions targets of their own, arguing that they need to keep access to cheap, plentiful fossil fuels to haul themselves out of poverty.
Some, though, have agreed to announce voluntary measures for braking their growth in emissions by 2020.
Developing nations are also clamouring for money to help shore up their climate defences and support the switch to low-carbon energy. Industrialised countries are being urged to earmark one percent of their gross domestic product (GDP) per year, or around 400 billion dollars (270 billion euros).
Within the developing world, high-population fast-growing countries are under pressure from rich nations to show earnestness in tackling emissions that started to surge at the start of the century.
Many analysts give high marks to measures that have already been announced, adding the caveat that these are voluntary measures that are unlikely to be policed by internationally enforceable compliance measures.
China, the world's biggest carbon emitter, says it will cut the intensity of its CO2 emissions per unit of GDP by 40 to 45 percent by 2020 from 2005 levels.
Brazil has promised a voluntary reduction of 36-39 percent by 2020, mainly from tackling deforestation in the Amazon, as compared to its forecast level of emissions in 2020.
Indonesia says it could reduce its emissions by 26 percent by 2020 from forecast trends mainly by tackling deforestation, which would deepen to as much as 41 percent, with international help.
South Korea, still categorised as a developing country under the UN Framework Convention on Climate Change (UNFCCC), has promised what it says is a 30-percent reduction by 2020 over "business-as-usual" trends.
India, like South Africa, has yet to put specific proposals on the table, but has taken a hard line on demanding Kyoto-style commitments for rich countries.
Rich countries are divided both in their offers for reducing greenhouse-gas emissions and their enthusiasm for the approach, enshrined in the Kyoto Protocol, for legally-binding emissions targets backed by tough compliance mechanisms.
- The United States, the world's richest country and No. 2 carbon emitter, remains outside the Kyoto framework and is pushing for an accord that would not have Kyoto's compliance teeth.
The US says that relative to a 2005 benchmark, it would reduce carbon emissions by 17 percent by 2020, 30 percent by 2025, 42 percent by 2030 and ultimately 83 percent by 2050.
The US target for 2020 means only a fall of four percentage points compared to 1990, the benchmark year widely used as the interim target in the UN process.
- The European Union (EU), which saved Kyoto after the US walkout in 2001, is unilaterally cutting its emissions by 20 percent by 2020 compared to 1990 levels, and offering to go to 30 percent if other industrialised parties play ball.
- Japan has offered 25 percent, but there are conditions.
- Canada sees a reduction of 20 percent by 2020 compared to 2006, equivalent to a fall of three percent compared to the 1990 benchmark.
- Australia's parliament is debating a bill for reducing carbon pollution by between five and 25 percent by 2020 from 2000, with the higher levels dependent on the outcome in Copenhagen. Experts estimate that a cut of 25 percent over 2000 equates to 24 percent over 1990 levels.
- Russia has yet to announce its pledges.
As for climate funds, rich countries have been hazy. The EU says developing nations would need 100 billion euros a year by 2020, but failed to set levels for Europe's contribution.