Atmospheric scientist Ira Leifer installed special air sensors on a camper, then drove from Florida to California, measuring methane levels all along the way. More than 6,000 readings later, he found some noticeable spikes, especially around petrochemical plants and urban areas like Los Angeles.

Fish are moving away from the equator and toward the poles to maintain their preferred water temperature. That means, for example, that fishermen are seeing swordfish normally found in the Mediterranean swimming near Denmark. But in the tropics, there are no fish to replace the ones that are leaving.

The amount of carbon dioxide in the atmosphere has crossed the "psychological threshold" of 400 parts per million. That number is one of the clearest measures of how humans are changing the planet by burning fossil fuels.

Right now, solar panels make electricity. But a team of engineers in California wants to take solar energy one step further. They're trying to create a device that uses sunlight to make a liquid fuel that goes in our gas tanks.

Ken Caldeira is trying to come up with a big solution to the problem of increasingly acid oceans: antacids for coral reefs. That might keep the reefs from being destroyed by humans' use of fossil fuels. And that's not his only big idea. But even Caldeira admits that his audacious plan could fail.

Coral reefs are in trouble worldwide, from a host of threats, including warming ocean temperatures, nutrient runoff and increasing ocean acidity. A noted climate scientist from California has been conducting an experiment on Australia's Great Barrier Reef to see whether antacid could boost coral growth.

Scientists have been worried about coral reefs for years, since realizing that rising temperatures and rising ocean acidity are hard on organisms that build their skeletons from calcium carbonate. Researchers on Australia's Great Barrier Reef are conducting an experiment that demonstrates just how much corals could suffer in the coming decades.

A U.S. Senate committee held a confirmation hearing for Ernest Moniz on Tuesday, who has been nominated to be the U.S. Energy Secretary. Moniz says he will retire from MIT, where he's a professor of physics and energy systems. He would advocate for the Obama administration's "all of the above" energy strategy, which calls for continued fossil fuels development and supports nuclear energy, wind and solar.

The Environmental Protection Agency (EPA) proposed on Friday a rule to clean up gasoline. The new lower sulfur gas is already what California uses to reduce air pollution, and the EPA wants it to be used nationwide. The agency estimates that it would save lives while adding a penny a gallon to the cost of gas. The oil industry fears it will cost more.

The city of Gladstone is the world's fourth largest coal-export hub. It's also a jumping off point to the southern end of the Great Barrier Reef. But coal mining could eventually kill the reef that Australians revere.

There's some evidence that carbon dioxide we pump into the atmosphere has slowed the development of coral reefs. So researchers are adding antacid to the water in a tiny part of the Great Barrier Reef, to see whether the corals will grow faster if their water supply is less acidic.

Normally, the buff-breasted rail is a shy little creature. But on this island out on the Great Barrier Reef, it's become the avian equivalent of a weed. And the island is dotted with other pesky and sometimes (to visitors) menacing birds.

Seaweed might not be as flashy as coral, but it plays an important role on the reef. They compete for space, and rising carbon dioxide levels could someday tip the balance of power.

The tropical island set in turquoise water just off the Great Barrier Reef is the site of an experiment to see what will happen to coral reefs as the ocean absorbs ever more of the carbon dioxide and heat we've added to our planet's thin skin. The results weren't so pretty.

Scientists working with data from a large particle accelerator in Europe are now almost certain they have pinned down the elusive subatomic particle known as the Higgs boson.

It's not just the heat — it's the humidity. Health experts actually apply that principle to workers, soldiers and sportsmen who toil outside and in places that lack air conditioning. A study in Nature Climate Change says that global warming will noticeably reduce the amount of time people can spend working and playing safely outside.

Diplomats in Doha, Qatar, are working late into the night to hammer out a deal in the 18th round of U.N. climate talks. Expectations are low as the talks are part of a multiyear process to make a transition from the fading Kyoto climate treaty to something that engages all nations of the world.

The good news: Sea level has risen by just a half-inch in the past 20 years as a result of shrinking ice. The bad news: The melting is now speeding up. Over the next century, this could contribute to another 2- to 3-foot rise in sea level — enough to flood New York City every few years.

First came the news that Arctic sea ice is in sharp decline this year. Now, research indicates that springtime snow is melting away even faster than the ice. And that has profound implications for the Earth's climate.

Though summer melting is a yearly occurrence in the Arctic sea, this year set a new benchmark: Three-fourths of the ice melted away. Scientists say the effects of this unprecedented melting are likely to result in extreme weather changes throughout the Northern Hemisphere.