Restaurants usually pay about $100 a month to dispose of used oil from deep-fryers, but mechanical engineer James Peret of Massachusetts invented a way to turn that oil into energy savings. A small generator called the Vegawatt sits outside the restaurant, filtering out the old bits of food and pumping the clean oil into a system that can cut about $1,000 from a restaurant's utility bill. Guy Raz talks to Peret as part of our series on some of the great inventions of 2009.

The tugboat was working to prevent another oil spill in Alaska's Prince William Sound. The Coast Guard said two of tug's tanks — containing an estimated 33,500 gallons of diesel fuel — were damaged and there was a fuel sheen on the water about 3 miles long and 30 yards wide.

Despite 25 years and billions of dollars spent on cleanup efforts, the Chesapeake Bay remains one of the country's most polluted waterways. With waste of all kinds, each of the almost 17 million people living in the watershed contributes to the pollution.

As the Copenhagen talks neared collapse last week, President Obama cut a last-minute deal with leaders from China and three other nations to curb greenhouse gases. It's unclear how they'll do that, but one thing is clear: The U.S. and China have become leaders that may shape the new climate diplomacy.

'Tis the season for images of snowflakes. Unfortunately, many artistic renderings of snow crystals show an eight-sided structure — something that can't occur in nature. So this year, one scientist decided to set the record straight.

The federal government has been fighting pollution of the Chesapeake Bay, the nation's largest estuary, for 25 years. But harmful nutrients, particularly nitrogen and phosphorus, continue to flow into its waters — and they're often traced to nearby fertilizer- and manure-laden farms.

President Barack Obama hailed the last-minute accord at the U.N. climate summit in Copenhagen as a breakthrough. But many delegates left disappointed. NPR science correspondent Richard Harris talks about what was and what was not achieved in Copenhagen.

Four small quakes have been centered near New Madrid in southeast Missouri in the past week, according to the U.S. Geological Survey. In the early 1800s, the New Madrid fault line created some of the most violent earthquakes in U.S. history.

It was just before Christmas last year when a massive coal ash retention pond gave way near Kingston, Tenn. An estimated one billion gallons of the gray material spilled into a river and inundated acres of sparsely-populated land. One year later, clean-up is going slower than expected and it's more expensive too.

A biologist reflects on an awe-inspiring experience in Africa, when a group of baboons united in some kind of amazing "mystical" moment.

Michigan asked the U.S. Supreme Court on Monday to sever a century-old connection between the Great Lakes and the Mississippi River system to prevent Asian carp from invading the lakes and endangering a $7 billion fishery.

Much of the U.S. continues to dig out from a massive snowstorm that snarled traffic and travel plans. When the forecast is bleak, or a promised storm never shows, weathermen often take the blame. NBC meteorologist Tom Kierein explains just how accurate a forecaster can be.

The deal brokered in Copenhagen "lays the foundation for international action," the president said. The challenge now is to build momentum in the U.S. for a clean energy economy. The first part of that effort is legislation waiting in the Senate.

The climate change deal negotiated late Friday night in Copenhagen almost didn't happen. And for some, it's still too little, too late. The deal was brokered in the final hours of the conference. And it all hinged on one particular sentence.

President Obama is back in the U.S. after helping pull together a last-minute agreement at the climate change conference in Copenhagen. The president has said the deal is a breakthrough, but adds that it still falls short in some areas. Host Scott Simon talks to NPR's David Kestenbaum for more.

World leaders reluctantly agreed to a global effort to limit the effects of greenhouse gases.

After several rounds of last-minute diplomacy at the climate change talks in Copenhagen, President Obama announced that he had reached a "meaningful and unprecedented breakthrough" with the key developing nations of China, India, South Africa and Brazil. The countries say they will work to limit global warming to no more than a 2-degree Celsius increase over the next decade.

A senior Obama administration official says the U.S., China, India and South Africa have reached a "meaningful agreement" on climate change. The official characterized the deal as a first step, but said it was not enough to combat the threat of a warming planet.

Melissa Block checks in on a story about an ambitious expedition NPR reported earlier this year. Pascal Lee was leading a team to drive a Humvee 1,000 miles across the Northwest Passage in the Canadian Arctic.

Secretary of State Hillary Clinton says the U.S. will contribute to a $100 billion fund to help developing countries adapt to climate change related disasters such as floods and crop failures. But a binding agreement from the conference remains as elusive as ever.