PresidentObama will attend negotiations in Copenhagen where he will promise 17percent emissions reductions below 2005 levels by 2020 and 83% by 2050,Obama administration officials said. These are the US’s most ambitioustargets to reduce climate change causing greenhouse gases.

The17 percent reduction range is consistent with a climate bill thatpassed in the House in June and is pending in the Senate, but belowwhat many scientists and political leaders say is needed from the US toavert the most catastrophic effects of climate change.

Developing nations have also indicated their willingness to engage domestic targets. As prime minister Manmohan Singhsaid in Washington after talks with the President on November 24, "BothPresident Obama and I have agreed on the need for a substantive andcomprehensive outcome, which would cover mitigation, adaptation,finance and technology," .

In fact, White House officials saidthat the President was buoyed by discussions with the leaders of Indiaand China. Those discussions left the president optimistic that hispresence in Copenhagen could seal a meaningful deal even if it is notlegally binding.

Reciprocal cycles of pressure are being exertedon the US and the developing world to get into line with effortsunderway in Europe and Japan. The White House’s announcement returnsthe onus to a world that was waiting for US action on climate changebefore taking steps of their own. Carol Browner,Obama’s assistant for energy and climate, said the administration hopesthe announcements will lead other nations "to put forth ambitiousactions of their own."

Obama will address negotiators December9, shortly after the opening of the two-week summit. half a dozen otherCabinet-level officials, including interior secretary Ken Salazar andenergy secretary Steven Chu, also will attend the talks, the WhiteHouse said. Yvo de Boer,the UN climate chief, called Obama’s attendance and a concretereduction target from the United States "critical" to the talks.

Indiaand China are showing signs of cooperation ahead of Copenhagen, butPresident Obama’s announcement that he will attend climate change talksin Copenhagen breathes new life into hopes for a global agreement oncurbing greenhouse gas emissions.