LIMA, Peru -- Rays of sunshine in recent days broke through the blanket of smog that hangs over this bustling city of ancient adobe pyramids and chic fusion eateries. But diplomats and activists here for U.N. climate change talks say the brightening weather is inversely proportional to the gloomy mood descending over the negotiations.

Ministers arriving in the South American capital this week will find little trace of the cheer that marked the summit's opening days last week. Early excitement over an announcement by the United States and China to slash carbon emissions and an international infusion of nearly $10 billion into a global climate change fund has given way to familiar disgruntlement among poor nations that rich countries are still failing to do enough.

The appearance of U.N. Secretary-General Ban Ki-moon tomorrow and of former U.S. Vice President Al Gore on Thursday could still buoy the talks. But with the creation of a new international global warming agreement on the line, observers say there is serious concern about the direction the talks are taking.

"If we are at the end of next week and there's a really negative mood, having just moved some of the biggest barriers in climate action in the last 20 years, then there is a real problem with our ability in this process," said Jake Schmidt, international climate policy director for the Natural Resources Defense Council.

The decisions to be taken this week are expected to lay the groundwork for the new global deal, scheduled to be signed in Paris in 2015. If the United States and other industrialized countries have their way, it will look dramatically different from the current Kyoto Protocol. That 1997 treaty obligates only wealthy countries to cut carbon, while demanding that they pay poorer nations to take voluntary action. The new deal could see all nations make unilateral pledges to reduce greenhouse gas emissions in the years after 2020.

With governments expected to declare their pledges by the first quarter of next year, wealthy nations are under intense pressure to unveil not just carbon cuts, but also the dollar figures they will deliver to help boost clean energy and protect vulnerable nations from climate change.

The United States and Europe oppose the effort, saying it will distract from the overriding goal of cutting emissions. Activists argue that wealthy countries simply don't want to be held to financial promises.

How to weigh the scale of ambition?

"When you don't know what the scale of ambition is going to be ... it sounds like we are headed for a very weak agreement in Paris," said Meena Raman of the Third World Network nonprofit group.

Not all developing countries are on the same page, though. Saleem Huq, who works closely with a bloc of the world's least-developed countries, said their first priority is seeing that all countries themselves show how they will curb carbon. Wealthy countries certainly need to pony up more money, he said, but it doesn't necessarily have to be in the early pledge.

"The most important element is mitigation. All countries should be doing as much as possible, and we are prepared to do our part," Huq said.

As for financial pledges from developed countries, he said, "They don't have to promise it in a document. They just need to put it in a fund."

But there is little doubt here that the issue is fueling anger at developed countries, especially the United States. The Obama administration even appears to be losing the goodwill it gained by its joint emissions pledge with China.

Raman argued that the United States is getting praise it doesn't deserve and called President Obama's pledge to cut emissions 26 to 28 percent below 2005 levels by 2025 "weak." Combined with efforts to avoid specific financial promises down the line or allow the Paris deal to be legally binding, Paris is shaping up to repeat what she called the failures of the 2009 U.N. agreement in Copenhagen, Denmark.

"The last time we had leadership from the U.S., in Copenhagen, it was basically undermining a robust climate regime," Raman said. "With the U.S., it's their way or no way. The sad part of it all is that developing countries will follow ... but that architecture will not save the planet."

Paul Bledsoe, a former Clinton administration climate aide, argued that the U.S. targets are ambitious.

"The U.S. deserves real credit. What we have to make sure they do is actually deliver it," he said.

First, though, the Obama administration will have to prove that it on track to meet its current target of cutting emissions 15 to 17 percent by 2020. Countries will have a chance to grill the U.S. delegation this morning about whether executive authority under the Clean Air Act rules that the administration is depending upon in the absence of legislation can truly do the job.

Wait-and-see vs. action

"They get that the Obama administration is moving forward much more aggressively than it did before, and they want to be sure that it's not just smoke and mirrors," NRDC's Schmidt said.

But with post-2020 commitments taking up most of the negotiating focus, another major fight will be over what type of review process those emissions pledges should include. The United States has been urging that nations declare their targets far enough in advance of the Paris negotiations to allow what U.S. Special Envoy for Climate Change Todd Stern has called a "sunshine" period in which other nations and watchdog groups can weigh each nation's ambition.

Small island nations and a group of progressive Latin American countries, meanwhile, are pushing for a more structured review process, while China has opposed a review.

Adrian Macey, New Zealand's former climate change ambassador, said the past week of stalemate is reminiscent of the gamesmanship before Copenhagen. Countries, he said, are playing the "long game" and focusing more on Paris than on the Lima negotiations themselves.

"We've had a whole week of stating positions. There's been no negotiations," Macey said.

"If you have your eye on the endgame, you want to get into the text as much language as you can," he added. "Nobody is going to make any concessions, because why make them now?"

But former President of Ireland and U.N. Special Envoy for Climate Change Mary Robinson said countries can not afford to their usual wait-till-the-last-minute tactics. She noted that the world is on a dangerous path toward catastrophic climate change and said countries must commit to a "zero emissions, zero poverty" path.

"There is a lot to be done here in Lima in order to have a successful agreement in Paris," Robinson said. "I do think that there is a momentum. That's important, because we've got a lot to do, and it's incredibly urgent. I hope the discussion will continue in a positive manner, because we're running out of time."

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500