The United Nations Convention to Combat Desertification released a report earlier this week warning that if global warming trends continue, nearly five billion people — including in most of Europe, parts of the western U.S., Brazil, eastern Asia and central Africa — will be affected by the drying of Earth’s lands by the end of the century, up from a quarter of the world’s population today.Despite two weeks of U.N.-sponsored talks in Saudi Arabia’s Riyadh, the participating 197 nations failed to agree early Saturday on a plan to deal with global droughts, made longer and more severe by a warming climate. Should Drought be tackled locally without the need for United Nations ?