U.S. Secretary of State Hillary Clinton tells the U.N. climate summit that the United States is prepared to join other rich countries in raising $100 billion in yearly climate financing for poor countries by 2020. The U.S. declaration could give a boost to the deadlocked Copenhagen talks.

In a new world, electric companies and manufacturing plants will have to control their greenhouse gas emissions. Congress is debating setting up a cap and trade system to cut global warming pollution across the whole economy. Meanwhile, the Environmental Protection Agency has announced it plans to regulate emissions from big polluters. Companies are comparing the impact of the two approaches to decide which one would work better for them.

World leaders are nearing the end of the climate meeting in Copenhagen. President Obama arrives Friday. There's a certain irony to the talks aimed at reducing greenhouse gas emissions. By just having the summit — all the airplane flights, hotel rooms and taxi rides — generates a lot of carbon.

Negotiators at the Copenhagen climate summit are facing an uphill task in their attempt to come up with a political agreement on global warming. Listeners ask how a developing nation is defined, about efforts by some countries to become carbon-free, the difference between global warming and climate change, and what to expect from the summit.

China has emerged as the world's top producer of solar panels, and Western companies are eager to cash in on the country's urgent drive for renewable energy resources. It has the Obama administration worried.

Climate negotiators in Copenhagen may snatch a small victory from the jaws of defeat Wednesday as they put the final touches on a deal that would pay countries to save carbon-absorbing forests.

As world leaders streamed into Copenhagen, disputes have left big issues unresolved just two days before participants hope to sign a historic accord to fight global warming. Meanwhile, hundreds of protesters tried to disrupt the conference, and police said more than 200 were detained.

The biggest stumbling block at the U.N. Climate talks in Copenhagen appears to be China's refusal make a legally binding commitment to reduce its green house gas emissions. The U.S. refuses to accept any deal that is not in writing. China has said it wants to see more action from rich nations before it signs on.

Children in Britain are driving the environmental agenda. They're forcing their parents to walk them to school, buy green products and watch the family's carbon footprint. But skeptics say their youthful enthusiasm will have little real impact on Britain's contribution to the climate crisis.

African leaders staged a boycott at the U.N. climate talks in Copenhagen to stress that their countries contribute the least to global warming, but stand to suffer the most. They seek concessions from the industrialized world, but many Africans are more worried about daily survival.

Theodore Cross has spent the last 40 years watching and photographing birds — and water birds are his favorite. He says the water birds have a "courage and beauty" that outshines others. A collection of his photos and stories are collected in a book called Waterbirds.

Bjorn Lomborg, author of The Skeptical Environmentalist, is roaming the halls of the U.N. climate talks in Copenhagen. While Lomborg believes climate change is real, he thinks the approach being taken to fight it is doomed to failure. Lomborg also famously led a team of economists who ranked climate change low on a list of priorities when compared to things like combating disease. Needless to say, Lomborg is not a popular figure at the talks.

For years, critics accused Brazil of emphasizing development over the environment. Rampant deforestation made Brazil a major producer of greenhouse gases. But in one town, farmers are now replanting native vegetation in a new initiative that could be replicated across the country.

Climate scientists say Colombia's glaciers could disappear within 15 years. Wet highland areas that provide much of the country's fresh water are getting warmer and drier. And each year, flooding becomes more severe. The coastal area of Tumaco has become an example of how environmental and security pressures are undermining previously stable communities.

With the help of powerful gene chips, geneticists are able to distinguish between northern European populations.

Treating multimorbidity — when people suffer from multiple health conditions — is a growing challenge for doctors.

A crew of six people in Moscow will be isolated for 105 days on a simulated flight to another world.

For people over 55, there may be benefits in a daily cocktail.

Leg ulcers are notoriously difficult to treat, but a new study suggests that patients may benefit from live maggots.

The conventional wisdom about breast cancer screening is coming under sharp attack in Britain.