LONDON - Energy Secretary Steven Chu said on Monday he was still hopeful President Barack Obama would be able to sign a domestic carbon-cutting bill before a crunch global climate meeting in Copenhagen in December.

The prospective U.S. law is widely considered vital to allow the United States to take a firm stance in Copenhagen, and so unblock an impasse on targets to cut carbon emissions and funding to fight climate change at the United Nations-led talks.

Whether there will be a bill on the President's desk and he'll sign it, I'm hopeful it will be, he told reporters on the sidelines of a meeting on clean coal technologies in London.

It'll be tight (but) there's a good shot.

Chu's comments contrasted with the head of the U.S. Environmental Protection Agency Carol Browner who said 10 days ago she did not expect the U.S. Senate to act in time.

Democratic Senators John Kerry and Barbara Boxer introduced legislation that would cut U.S. industry emissions of carbon dioxide and other greenhouse gases by 20 percent below 2005 levels by 2020.

In the meantime, we're going to Copenhagen with substantive things, Chu said, referring to U.S. plans to spend some $80 billion on clean energy under economic stimulus spending, and a recently passed standard for auto emissions.

We are making progress on the domestic front, he added.

Chu would not comment on whether the U.S. could commit to a near-term carbon target in Copenhagen without the bill passed. We're not going to lay out plans B, C and D. It doesn't make any sense. We're going to try make plan A work, he said.

UN brokers have said that rich countries must commit to 2020 greenhouse gas targets to consider a Copenhagen deal a success.

The December meeting is meant to seal agreement on a new, tougher pact to extend or replace the existing Kyoto Protocol.

Chu said he had detected encouraging signs of new, serious global intent to tackle climate change.

If you look at the things going on, it's a different feel. Down in the trenches what you see are a large scale of activities, many countries, the U.S., of course Japan, Europe, but also China, India, Mexico and Brazil starting to go aggressively in this direction.

Regarding the timing of the U.S. energy and climate bill, Chu took comfort from collaboration outlined on Sunday/Monday between the democrat co-author of the Senate proposals John Kerry and Republican Senator Lindsay Graham.

In my discussions with Senators on both sides of the aisle I see a lot of recognition of the climate and energy problem, which is the climate, our dependence on foreign oil ... (and a recognition) there's an economic opportunity.

(Additional reporting by Michael Szabo; Editing by Sue Thomas)