Nairobi — Africa must act swiftly to reverse global warming or face hard consequences, Nobel laureate, Prof Wangari Maathai, has warned.

She said the Government and people who failed to heed her warnings had frustrated her conservation efforts.

As a result, said the Tetu MP, water sources are drying up, threatening millions of lives.

Maathai said it was useless to negotiate issues if no action was taken. "What will make the difference is not the negotiations; it is what we'll do when we go home," she told a discussion forum on the sidelines of the climate change talks.

Destruction of forests is threatening Tana River, which generates 70 per cent of electric power, she said.

Maathai said the Government was determined to keep the shamba system despite the destruction it causes on forests.