And atmospheric carbon dioxide enhances plant growth, which greenhouse gardeners have known for decades.

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The new centre will stand alongside the Eden Project's plant-filled biomes - large greenhouse domes, on the site of a former china clay pit near St Austell.

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Clearing land to plant food for biofuel releases the greenhouse gas carbon dioxide (CO2) through ploughing and can involve deforestation, which reduces the "carbon sinks" - the trees that absorb CO2.

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When Albert Lin, an American energy entrepreneur on the board of Future Fuels, a Texas-based power-plant developer, set out to find a gasifier for a pioneering new plant that is designed to spew less greenhouse gas, he figured that he would buy one from G.

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And over the next three decades, the clean energy from this plant will save 575, 000 tons of greenhouse gas emissions, which is the equivalent of removing more than 4, 500 cars from the road each year for the life of the project.

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Cellulosic ethanol uses non-food feed stocks with significant greenhouse gas emission reductions, and the first commercial-scale plant is being built today in Soperton, Ga.

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Effective July 1, 2011, any new source of greenhouse gas emissions that exceeds 100, 000 tons of CO2 per year or plant modification adding 75, 000 tons annually, will be subject to permit approval based upon undefined case-by-case "best available control technology" assessments.

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Couple such capability with new satellite measurements (America's Orbiting Carbon Observatory 2 is due to launch in a few years) and better measurements of the mass of plant life in forests and other ecosystems, and the planet's greenhouse-gas credits and debits will surely be understood far better.

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