UN Secretary-General Ban Ki-moon told the summit that securing a climate change deal in Copenhagen next month is crucial to fighting global hunger.

Ban Ki-Moon, UN Secretary-General said "There can be no food security without climate security. That is why next month in Copenhagen, we need a comprehensive agreement that will provide a firm foundation for a legally binding treaty on climate change."

The UN, says Africa, Asia and Latin America could see a decline of between 20 and 40 percent in agricultural productivity if temperatures rise more than 2 degrees Celsius. Sub-Saharan Africa is expected to be the hardest hit by global warming, as its agriculture is almost entirely dependent on rainfall. The number of hungry people in the world has topped one billion, for the first time this year due to the combined impact of the global recession and high food prices in poor countries.