The climate summit in Copenhagen could result in a one and a half degree deal according to the UN's climate envoy on Thursday.

Britain's Meteorological Office says uncontrolled greenhouse gas emissions could lead to an increase of global temperatures by 4 degrees centigrade or more by the end of the century.

Such a rise could see cereal crops diminish across most major regions in the world and average sea levels rising by up to 80 centimeters. The UN envoy says limiting the increase of global temperature to a one and half degrees may be possible if three conditions are met.

Yvo De Boer, Exec. Sec., UN Framework Coun. on Climate Change, said, "To get down to a maximum one and a half degree temperature increase is difficult, is quite a heavy lift and that's really only possible first of all if rich nations show a greater degree of ambition, secondly, if developing countries can do more to limit the growth of their emissions and thirdly - that is only going to happen if significant finance is mobilized here. But if all three of those conditions are met, then it's possible."