April 8, 2009 -- A cardboard cooker which uses the sun's energy to boil water has won a global competition for the best innovation to tackle climate change.

The "Kyoto box" aims to save lives in poor countries by allowing people to boil unclean water without having to cut down trees or gather sticks for firewood.

The design, which costs five euro to make, also hopes to cut the number of people suffering from respiratory problems associated with smoke inhalation.

Its creator Kenyan-based Jon Bøhmer believes it could halve the need for firewood, saving two tons of carbon for each family that uses it per year.

He won 75,000 U.S. dollars in the FT Climate Change Challenge backed by the FT, HP and Forum for the Future, to develop his idea.

He beat other finalist entries including a feed additive from garlic which cuts the methane produced by cows, a cover for lorry wheels which reduces drag and fuel consumption and "evaporating tiles" which halve the energy use of air-conditioning systems.

The cardboard cooker consists of two boxes with a transparent acrylic cover to let in the sun's energy, black paint inside and silver foil outside to concentrate the heat, and straw or newspaper for insulation between the two layers.

Mr Bøhmer will use the prize money to run trials of his creation, which takes around one-and-a-half hours to boil water, in 10 countries including South Africa and India.

He has also designed a more robust, longer-lasting cooker in corrugated plastic, which he says can be manufactured just as cheaply.

He hopes to distribute the boxes and a package of other affordable low-carbon products free, with the costs covered by applying for them to be certified as carbon-saving measures which qualify for carbon credits. He said: "We're saving lives and saving trees. I doubt if there is any other technology that can make so much impact for so little money."