Hundreds of millions could be forced to migrate because of water shortages and crop failures in most of Africa, as well as in central and southern Asia and South America, the conference in London was told.
Rising sea levels could also cause havoc, with coastal communities in southern Asia, the Far East, the south Pacific islands and the Caribbean seeing their homes submerged.
The conference heard a warning from the UN High Commissioner for Refugees (UNHCR) that the developed world should start preparing for a huge movement of people caused by climate change.
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