FAR FROM BEING BARREN WASTELANDS, THE DESERTS THAT OCCUPY ONE QUARTER OF THE EARTH'S LAND SURFACE COULD BE KEY SOURCES OF FOOD AND POWER, THE UNITED NATIONS SAID ON MONDAY, ACCORDING TO REUTERS. BUT THESE VAST OPEN SPACES, HOME TO RARE AND USEFUL PLANTS AND ANIMALS, ARE AT RISK FROM CLIMATE CHANGE AND HUMAN EXPLOITATION, THE UN'S ENVIRONMENT PROGRAMME SAID IN A REPORT PUBLISHED ON WORLD ENVIRONMENT DAY. DESERTS ARE PRIME POTENTIAL LOCATIONS FOR SOLAR POWER GENERATORS THAT DO NOT POLLUTE THE ATMOSPHERE WITH GREENHOUSE GASES, AND PLANTS THAT CAN THRIVE IN DESERT CONDITIONS COULD PROVIDE FOOD WHEN WATER RUNS SHORT. ONE SUCH, A PLANT CALLED NIPA FOUND IN THE SONORAN DESERT OF WESTERN MEXICO, PRODUCES A GRAIN THE SIZE OF WHEAT BUT IS DROUGHT RESISTANT AND EVEN THRIVES ON SEAWATER. "IT IS A STRONG CANDIDATE FOR A MAJOR GLOBAL FOOD CROP AND COULD BECOME THIS DESERT'S GREATEST GIFT TO THE WORLD," THE REPORT SAID. RAINFALL PATTERNS ARE CHANGING, GLACIERS THAT FEED IMPORTANT RIVERS ARE MELTING AS THE PLANET WARMS AND IRREPLACEABLE WATER FROM DEEP DESERT AQUIFERS IS BEING SQUANDERED.