NAIROBI - Kenya could lose up to 3 percent of its $35 billion GDP annually by 2030 due to global warming, a donor-funded study on the impact of climate change on east Africa's biggest economy showed on Friday.

Like other countries on the world's poorest continent, Kenya has started to witness signs of climate change including the spread of diseases such as malaria and the movement of wild animals to areas where they were not present before.

Kenya is just emerging from a prolonged drought that choked growth and cut output in sectors such as agriculture, which accounts for nearly a quarter of its gross domestic product.

Climate impacts cost $0.5 billion per year now. Future annual climate change impacts equivalent to nearly 3 percent of GDP by 2030, said a summary of the British and Danish-funded report, entitled Economics of Climate Change in Kenya.

Although total carbon emissions by the country were low during the year-long study, it warned that they might double by 2030 in line with planned population and economic growth.

Poor nations want rich countries to cut emissions by 40 percent from 1990 levels by 2020 to avert the worst effects of climate change. But many industrialized nations fear such cuts are out of reach, especially in an economic downturn.

Ethiopian Prime Minister Meles Zenawi, Africa's most outspoken leader on global warming, has demanded that the West compensate the world's poorest continent for climate change.

The report found that Kenya's agriculture and transport sectors were its main sources of emissions, but said that full studies on low carbon options and the development of new strategies could mitigate against the effects of global warming.

There is a real reason for Kenya to start acting now, said Paul Watkiss, one of the authors of the study.

Some Kenyan companies such as electricity producer KenGen and sugar miller Mumias have developed Clean Development Mechanism project that will soon allow them to sell carbon credits on the international markets.

National carrier Kenya Airways has been planting trees in the Ngong Hills, near the capital Nairobi, which its planes fly over every day.

(Editing by Daniel Wallis)