Mr Obama hopes to create a global consensus on greenhouse emissions
US President Barack Obama has invited figures from the world's 16 major economies to Washington for a meeting on climate change at the end of April.
The event will be the first meeting of what the White House styles "the Major Economies Forum on Energy and Climate".
It will focus on increasing the supply of clean energy and cutting greenhouse gas emissions, the White House said.
It was announced as millions worldwide observed Earth Hour, turning off lights in a protest against climate change.
The Washington meeting is scheduled to take place on 27-28 April and the sessions will culminate in a July meeting in Italy.
The forum - which will bring together representatives of the 16 major economies and the UN secretary general - is designed to help broker a UN agreement on global warming, the White House said in a statement.
It aims to create dialogue between nations and "help generate the political leadership necessary to achieve a successful outcome at the UN climate change negotiations that will convene this December in Copenhagen", the statement said.
That pact that would take over from the Kyoto Protocol - an international agreement setting targets for industrialised countries to cut their greenhouse gas emissions.
Some 190 countries will be represented in the German city of Bonn on Sunday for talks on a new treaty on curbing greenhouse gases after 2012, when the provisions of the Kyoto Protocol expire.
The world's major economies include: Australia, Brazil, Canada, China, the European Union, France, Germany, India, Indonesia, Italy, Japan, Korea, Mexico, Russia, South Africa the UK and the US.