Stopping overpopulation is one way the dangers of climate change can be mitigated, according to two of the most prominent believers in global warming.

Former Vice President Al Gore and Microsoft founder Bill Gates said at the World Economic Forum in Davos that contraception is a key in controlling the proliferation of unusual weather they say is endangering the world.

"Depressing the rate of child mortality, educating girls, empowering women and making fertility management ubiquitously available ... is crucial to the future shape of human civilization," said Gore, who won the Nobel Peace Prize in 2007 for his work on global warming.

Gore said Africa's population is expected to surpass India's and China's by the mid-21st century and will be more than both combined by the end of the century.