Hundreds of millions of citizens could be driven from their residences by invading deserts, chiefly in sub-Saharan Africa and Central Asia, a report says.  The study by the United Nations University suggests climate change is making desertification "the greatest environmental challenge of our times".  If action is not taken, the report warns that some 50 million people could be displaced within the next 10 years.  The study was produced by more than 200 experts from 25 countries.
This report does not pull any punches - desertification is an environmental crisis of global proportions, it says, and one third of the Earth's population are potential victims of its creeping effect.  It says that the over-exploitation of land and unsustainable irrigation practices are making matters worse. Climate change was also a major factor degrading the soil. The UN report suggests that new farming practices, such as encouraging forests in dry land areas, were simple measures that could remove more carbon from the atmosphere and also prevent the spread of deserts.