Energy Secretary Steven Chu, Agriculture Secretary Tom Vilsack and White House Council on Environmental Quality Chairman Nancy Sutley will be going to the Mexico summit as the U.N.-led talks draw to their close, according to a State Department spokesman.

The three Obama administration officials are expected to be in Mexico for one day each, appearing at events underscoring their department’s work, the spokesman said. For Chu, that means low-carbon energy technologies. Vilsack will cover efforts to reduce greenhouse gasses via avoided deforestation. And Sutley is scheduled to discuss adaptation.

Obama was one of about 120 world leaders in attendance at last year’s U.N. climate negotiations in Copenhagen and played a big role in the closing hours to iron out the details of the voluntary “Copenhagen Accord” that allows countries to pledge emission reductions and make financial offers to help poor countries deal with global warming.

But Obama won’t be there this year. Besides his top three aides, the highest ranking U.S. officials will be State Department climate envoy Todd Stern and his deputy, Jonathan Pershing.

At a press conference Monday, Pershing said Obama officials have been trying to hash out agreements with China, now the world’s No. 1 emitter of greenhouse gases.

“I think that a success here will only emerge if we can both come to agreement,” Pershing said, according to Reuters. “We have spent a lot of energy in the past month working on those issues where we disagree and trying to resolve them. My sense is that we have made progress. It remains to be seen how this meeting comes out.”