It's a 106-degree Fahrenheit day in the Mojave Desert. Heat devils dance off chocolate-hued Clark Mountain on the horizon. Air-conditioned cars zip along Interstate 15 toward Las Vegas. And inside a chain-link pen covered to keep out predators are scores of rare, threatened, sand-colored desert tortoises. Their captivity helps show how complicated it is to combat climate change without collateral damage. The foot-long (30-centimeter) creatures are being removed from their burrows for a project to harvest solar energy in the California desert. Trucks groan down sunbaked roads, cranes pivot with 750-pound (340-kilogram) mirrors and mechanical post-pounders drive steel pylons into the packed desert floor, destroying their habitat.