Nearly 58,000 square miles of land, an area larger than Greece, are turned to desert each year, affecting more than 1 billion people and forcing many of them to flee their homes in search of food and work. Officials from more than 150 nations will try to address the problem this week at the U.N. Convention to Combat Desertification, being held in Brazil as a followup to discussions on the issue that took place at the Earth Summit in Rio in 1992. Desertification is attributed to logging, grazing, over-farming, population growth, and climate change. Delegates this week will try to get industrial nations to commit more funding to alleviate the problem; billions of dollars are needed to stop desertification and begin recovery efforts, specialists say.