Yet the world's poorest continent has the lowest levels of carbon dioxide and other greenhouse gas emissions, scientists said at a conference in Nairobi.

"Poor developing countries are least developed to adapt to climate change, although most of them play and certainly will continue to play an insignificant role in causing it," said Shem Wandiga, chairman of the climate change research group System for Research Analysis and Training (START).

Extreme weather patterns, caused by climate change and leading to drought, will trigger deepening food shortages in Africa where most people rely on rain-fed crops to survive, Wandiga said.

"Climate change will exacerbate hunger, which now affects about 50 percent of our population," he said. "Above all, climate change will worsen poverty on the continent."

In the long term, climate change will force foreign donors to pay more to feed Africa's hungry and add to the current $6 billion spent by humanitarian agencies, Wandiga said.

A United Nations official said Africa's many conflicts also had a dire impact on the environment.