COPENHAGEN, Denmark - As President Obama prepared to visit the historic climate conference here, there were signs yesterday of a break in the impasse between rich and developing nations.

The United States and Japan agreed to make major contributions to the developing world to keep a deal alive. And the leader of a bloc of African nations said they would accept a smaller - though still sizable - package of financial aid in return for going along with an agreement.

But tear gas hung in the air outside the conference center as protesters demanding faster and more stringent cuts in greenhouse-gas emissions clashed with police. And inside, talks were slowed by disagreements within the developing world, which has proved an unexpectedly powerful and fractious force.

Some environmentalists expressed hope that Obama's appearance tomorrow, the final day of the 12-day talks, could help conclude these two chaotic weeks with a global deal.

"If the pieces are here, President Obama is the only person who can pull them together into an agreement," said Fred Krupp, president of the Environmental Defense Fund. "We expect him to do so."

Even before the United Nations-led talks began, it was clear they would not deliver what environmental groups had initially hoped for: a global treaty on climate change, with high-emitting countries formally pledging to reduce their greenhouse-gas emissions in the coming decades.

Instead, the goal was to sign a "political agreement," in which nations would pledge to tackle emissions but without making a binding commitment under international law. The understanding was that a formal treaty would come in 2010. That goal still seemed within reach yesterday, a day before Secretary of State Hillary Rodham Clinton arrives to take part in the negotiations.

White House press secretary Robert Gibbs told reporters that it was typical of global conferences that some differences remain when heads of state arrive. Obama, who has made phone calls this week to the leaders of developed nations such as Germany and France and developing countries such as Bangladesh and Ethiopia, will join 118 other world leaders in the Danish capital.

In a moment that distilled the diplomatic dance in Copenhagen, Ethiopian Prime Minister Meles Zenawi, who is representing all of Africa here, unveiled his proposal for a system in which rich countries would provide money to poor ones to help deal with the effects of climate change. These effects might include rising sea levels, droughts, and changing rainfall patterns.

Zenawi said he would accept $30 billion a year in the short term, rising to $100 billion a year by 2020, for poor countries worldwide. This was seen as a key concession by developing countries, who previously spurned that figure as too low.

"It is no exaggeration that this is our best, and perhaps our last, chance to save our planet from destructive and unpredictable change," Zenawi said. "If we fail to rise above the current challenge of climate change, we will then have proved that global economic progress is based on a fundamentally dysfunctional political system."

Also yesterday, Japanese officials said their country would provide $15 billion over the next three years to help impoverished countries adapt to climate change and lower emissions. But that offer would be good, Japanese officials said, only if a global agreement is reached this week.

The United States has yet to say how much money, if any, it will offer to poor countries for this purpose. Agriculture Secretary Tom Vilsack announced $1 billion in U.S. funding aimed at helping developing countries preserve their forests.

Yesterday's progress was mainly concerned with just one of the conference's sticking points: how much the rich should pay the poor.

On other questions, including to what extent industrialized and major developing countries should reduce their emissions, and how to include these pledges in a global pact, the talks only inched forward.

Talks Slow on Deforestation

Negotiators moved closer

to a deal to protect the world's forests with a pledge from the United States and five other countries to spend $3.5 billion over three years to slow their destruction.

The plan to reduce and eventually reverse deforestation in developing countries is a key component of the climate pact being negotiated in Copenhagen, Denmark.

The burning or cutting

of trees to clear land for plantations or cattle ranches is blamed for about 20 percent of

global emissions. That's

as much carbon dioxide

as all the world's cars, trucks, trains, planes, and ships combined.

Progress has been slowed by a lack of funding commitments from developed countries. The nations with rain forests want billions more from wealthy nations.

The United States pledged

$1 billion from 2010 to 2012, with Australia, France, Japan, Norway, and Britain providing

the rest.

Delegates said several hurdles remain, including setting benchmarks for deforestation. Early targets of 50 percent reductions by 2020 and an end to deforestation by 2030 have been dropped.

About 32 million acres of forests are cut each year, an area about the size of New York state, and the emissions generated are comparable to those of China and the United States, experts say.

- Associated Press

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