SCIENTISTS say the increase in the atmospheric concentration of methane -- a major greenhouse gas -- is fast levelling off (New Scientist, Vol 140, No 1991).

Evidence of a halt in methane rise comes from measurements of atmospheric gases made at 26 stations around the world. In the 1970s, the gas was increasing at a rate of about 1.1 per cent a year, it fell to 0.6 per cent a year in the 1980s, and has now come down almost to zero, according to observations.

Noting that the greatest change in methane levels has been recorded in the Northern hemisphere, researchers speculate the levelling off might be due to the decrease in wastage of natural gas in Russia and Eastern Europe.