Global climate talks are deadlocked on how to share the financial costs of fighting climate change, as world leaders meet at a U.N. summit in New York on September 22.
G20 leaders also meet in Pittsburgh on September 24-25, partly to discuss climate financing.
Agreement on climate funds and who will pay is an important ingredient to get a global deal to fight climate change, as intended in Copenhagen in December.
Climate costs are calculated as the money needed to cut greenhouse gas emissions and also prepare for more droughts and floods -- called mitigation and adaptation respectively.
The World Bank's World Development Report published on September 15 said: The estimated $75 billion that could be needed annually for adaptation in developing countries dwarfs the less than $1 billion a year now available.
Europe will call next week on rich nations to find up to 7 billion euros ($10.3 billion) annually for the developing world from 2010-2012.
Estimates follow of climate funds needed, proposals on how to raise these, and offers so far.
HOW MUCH MONEY NEEDED
* $1.1 trillion per year extra, clean energy investment 2010-2050 for tough carbon cuts -- International Energy Agency
* that total would be reduced to $53 billion per year, after fuel, efficiency savings -- IEA
* 530-810 billion euros ($778-1,189 billion) per year extra investment 2020-2030 -- McKinsey
* $100-150 billion per year by 2030 globally for early weather warnings, flood prevention, irrigation -- International Institute for Environment and Development
* $75 billion per year by 2030 needed by developing countries alone -- World Development Report, World Bank
3. Climate funds rich should pay developing countries
* 100 billion euros ($147 billion) per year by 2020 -- European Commission
* $140 billion per year by 2020 -- Greenpeace
PROPOSALS ON HOW TO RAISE MONEY
1. Norwegian proposal
* Set quotas of greenhouse gas emissions permits for rich nations for 2013-2020 of which 2 percent would be sold to them to raise funds
* Could raise $15-25 billion per year
2. Mexican proposal
* Raise an international fund from all nations, based on their responsibility for causing climate change, national wealth and population
* Could initially raise $10 billion per year
3. European Commission proposal
* Expansion of carbon markets whereby rich countries earn rights to pollute by paying for emissions cuts in the South
* Could raise up to 38 billion euros per year
4. Least Developed Countries' proposal -- Levy on international jet and shipping fuels.
* Could raise $28 billion per year
CLIMATE FUNDS ALREADY ON THE TABLE
1. Germany -- Is raising about 120 million euros per year in climate funds for developing countries from selling pollution permits to industry
2. Global adaptation fund -- Raised from a 2 percent levy on the global carbon market. Valued at just 83 million euros so far
3. World Bank's climate investment funds for developing nations -- pledges of over $6.1 billion from rich countries
4. Norway funds to slow deforestation -- Will provide up to 3 billion crowns ($510 million) a year to combat deforestation. Has committed 700 million ($119 million) to an Amazon fund