A final draft statement seen by Reuters News Agency made no mention of a trust fund for the contributions to be managed by the World Bank, this was a proposal put forward by the US in previous drafts.
The statement said the G8 summit kept a strong commitment to ensure adequate emergency food assistance.
G8 leaders have agreed to try to limit global warming to a 2C temperature increase following meetings with a group of major emerging nations.
The talks come on the second of a three-day Group of Eight summit in L'Aquila in Italy, with discussions broadened to include the heads of new economic powerhouses.
Those nations - Brazil, China, India, Mexico and South Africa -joined the expanded G8 summit this afternoon.
The five developing countries agreed with the big eight - Britain, Canada, France, Germany, Italy, Japan, Russia and the US - that they would oppose protectionism and push for a global trade deal.
The emerging powers, wary of shackling their growth potential through limiting their carbon emissions, also bowed to pressure from the industrialised democracies to agree climate change targets.
As late as last week, China and India opposed ambitious reductions targets, arguing the rich world should lead the way in fighting climate change.
But according to a diplomat and a draft copy of a summit communiqué, the Major Economies Forum - the 16 countries that between them produce 80% of the world's greenhouse gases - has come to a deal on a target.
The G8 countries, despite the reticence of Russia, had earlier agreed to cut their emissions by 80% by 2050.
Now the emerging economies appear to have accepted the principle of limiting the rise in the Earth's average temperature to 2C above its 18th-century level.
Clear differences remain however.
Brazil, for example, dismissed the G8's distant 80% emissions reduction target as 'not credible' without an earlier interim stage, echoing the position of Russia, which has dismissed the goal.
'We can't be satisfied with a single long-term objective without losing all credibility,' said Brazilian Foreign Minister Luiz Alberto Figuereido Machado.
Aside from climate, the summit in the earthquake-hit Italian town of L'Aquila focused on the world economic crisis, with the 14 major countries agreeing to resist domestic calls for protectionism.
Leaders from the G8, major emerging economies and some African nations will hold talks about food security tomorrow.
