Workers ride past cooling towers at a coal-fired power plant on the outskirts of Beijing. Such power plants are at the center of a debate about the future of energy production in China and the U.S. Frederic J. Brown/AFP/Getty Images hide caption

itoggle caption Frederic J. Brown/AFP/Getty Images

The ring-tailed lemur is one of many pint-sized creatures on the island of Madagascar. Scientists have long noted that despite the great diversity of fauna on the island, there are few large beasts, like the lions and elephants found on mainland Africa. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Haitians watch the L.A. County Search and Rescue working at a collapsed building in Port-au-Prince. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

This decorative shell ornament, attributed to Neanderthals, shows signs of being painted with orange pigment. It's one of several examples of ornamentation that researchers have found in Spain, at sites that were used by Neanderthals as far back as 50,000 years ago. Courtesy of Joao Zilhao hide caption

itoggle caption Courtesy of Joao Zilhao

Mountaintop removal coal mining approaches a home on the Mud River in Lincoln County, W.Va. The mine site is part of the Hobet 21 mine. Courtesy of Vivian Stockman hide caption

itoggle caption Courtesy of Vivian Stockman

Soon, ranchers like this one might be able to use their land to offset carbon emissions. Some are excited that they could use the land to earn a profit, while others don't want to invest in the idea just yet. Charlie Riedel/AP hide caption

itoggle caption Charlie Riedel/AP

SkyFuel unveiled last year one of the world's highest-performance, lowest-cost solar thermal power systems, in Arvada, Colo. Concentrated solar power, in which a large array of collectors concentrates a beam of energy to heat a fluid and run turbines, is viewed as a more likely source of large-scale electric power. Jack Dempsey/AP/SkyFuel hide caption

itoggle caption Jack Dempsey/AP/SkyFuel

Sunlight shines through a grove of redwood trees at the Muir Woods National Monument in Marin County in Northern California. Eric Risberg/AP hide caption

itoggle caption Eric Risberg/AP