Africa is turning to desert. Studies show that as much as two thirds of the continent’s arable land could become desert by 2025 if current trends continue. But a bold initiative to plant a wall of trees 4,300 miles long across the African continent could keep back the sands of the Sahara, improve degraded lands, and help alleviate poverty. Living on Earth’s Bobby Bascomb reports from Senegal.

Advances in computing are dramatically changing the field of chemical testing. And, as Living on Earth’s Ingrid Lobet reports, one day there may be far less need for scientists to use laboratory animals to test chemicals for health and safety.

The Environmental Protection Agency has proposed the first national standards to limit CO2 emissions from new power plants. Eric Schaeffer heads the watchdog group, the Environmental Integrity Project. He tells host Bruce Gellerman that the EPA’s rules have some loopholes but could be a big tool in fighting climate change.

Mesopotamia is believed to be the birthplace of civilization, but the extent of human settlement in this area is relatively unknown. Archeologists spend a lot of time scouring the ground for clues, but now some enterprising scientists are looking to the skies for help. Professor Jason Ur of Harvard tells host Bruce Gellerman about turning satellite photos into maps showing ancient cities, and why he digs this new technology.

Five nations in Africa have come together to create the world’s largest conservation area for wildlife. World Wildlife Fund’s Chris Weaver tells host Bruce Gellerman that the new preserve will allow migratory animals like elephants and rhinos to roam more freely.

The antibacterial agent triclosan is found in many consumer products like toothpaste, countertops and children’s toys. A coalition of environmental groups claims the chemical is an endocrine disruptor and toxic to the environment. But the U.S. Food and Drug Administration says there is no evidence of harm. Host Bruce Gellerman talks to Nichelle Harriott from Beyond Pesticides, the group leading the environmental coalition, and Shelly Burgess from the FDA.