U.S. Climate Envoy Todd Stern (R) and U.S. Secretary of State Hillary Clinton (L) give a press confe
Enlarge Olivier Morin/AFP/Getty Images

Stern, with Secretary of State Hillary Rodham Clinton, earlier today.

U.S. Climate Envoy Todd Stern (R) and U.S. Secretary of State Hillary Clinton (L) give a press confe
Olivier Morin/AFP/Getty Images

Stern, with Secretary of State Hillary Rodham Clinton, earlier today.

Though he believes that "aggravating procedural wrangling ... led by the developing country group" has wasted valuable time, U.S. Special Envoy for Climate Change Todd Stern tells NPR that he still believes there's a chance negotiators will reach agreement by sometime tomorrow — when the U.N. Climate Change Conference Conference wraps up.

"It's going to be very challenging to get a deal done ... but I think it's still possible. ... It hangs in the balance," he told NPR's Richard Harris earlier today in Copenhagen:

More from Richard's conversation with Stern is due on today's All Things Considered. Click here to find an NPR station near you that broadcasts the show.

President Barack Obama is scheduled to leave for Copenhagen this evening.