Plants soak up greenhouse gas

PLANTS IN the northern hemisphere absorb about one-third of the carbon dioxide produced by fossil fuels, according to new research published today.

Contrary to previous lower estimates, scientists at the United States space agency, Nasa, have discovered that plant growth in the northern half of the Earth actually increased by 10 per cent between 1981 and 1991 - but they do not offer any data for southern countries, which have been more heavily affected by deforestation in the same period.

In a paper to be presented this afternoon at the American Geophysical Union meeting, Dr Christopher Potter, of Nasa's Ames research centre, says: "North American vegetation absorbs about one-third of the carbon dioxide being pumped into the air by burning fossil fuels" in the region. Determining that required analysis of thousands of data images of vegetation growth, taken by satellites.

But Dr Potter warned yesterday that the levels of carbon dioxide - one of the most important gases causing global warming - were still increasing. "Increasing the land covered by forests might be one means to decrease the amount of carbon dioxide in the air," he said.