Methane responsible for hotter climate

Press, 24 February 1988, Page 41

Methane responsible for hotter climate

PA Wellington A team of D.S.I.R. scientists say they have broken new ground internationally with research into the sources of methane gas in the atmosphere. The build-up of methane and other gases is thought responsible for the "greenhouse effect” which is boosting temperatures throughout the world. The scientists, led by Dr Dave Lowe, at the D.S.I.R.’s Institute of Nuclear Science at Lower Hutt have determined that 30 per cent of methane comes from fossil fuels and 70 per cent from plant, soil and animal activity. "The contribution of fossil fuels to the build-up of methane in the atmosphere has not been measured before but was thought to be significantly lower than 30 per cent. The analysis of methane is part of the Institute

of Nuclear Science’s investigation into changes in the atmosphere which are believed to be altering the world’s climate. Methane, carbon dioxide and several other gases are building up in the atmosphere in everincreasing amounts, forming a dense layer of gases. Like glass in a greenhouse, the layer of gas is believed to be trapping more and more of the Sun’s warmth. By early next century, global temperatures are expected to rise between I.sdeg. and 4.5 deg., with sea levels expected to rise between 20cm and one metre. Research into climatic changes has become a priority for several countries, as scientists from many different disciplines work to refine predictions. Dr Martin Manning, a co-author of the institute’s methane study, said that five years ago it was

thought carbon dioxide was the only culprit in the warming process.

“But then scientists discovered that methane, nitrous oxide, chlorofluorocarbons and other gases were also part of the equation, together accounting for about 50 per cent of the warming effect.

Methane,’ the concentration of which in the atmosphere is rising rapidly, was thought to be responsible for about 30 per cent of the total effect.

Although scientists knew that greater consumption of fossil fuels was behind the rising concentration of carbon dioxide, they were not sure where all the extra methane was coming from, Dr Manning said. The D.S.I.R. team solved the mystery by developing a special technique and equipment to analyse air samples.