Research station shows continuing rise in CO2 levels

Scientists have expressed concern about rising levels of carbon dioxide (CO 2) contributing to global warming, which have been recorded at the European atmospheric research station at Mace Head, near Carna, Co Galway.

Carbon dioxide levels have been increasing annually at Mace Head at a rate of 0.5 per cent since measurements began in 1992, an international conference on atmospheric science and global change heard in NUI, Galway, yesterday. However, the station's records also show international political efforts such as the Montreal Protocol are taking effect. The Mace Head measurements show a decrease in the rate of man-made chlorofluorocarbons (CFCs) which contribute to global warming, said Dr Peter Simmonds, of the University of Bristol.

The measurements document the changes in atmospheric composition of these substances and also demonstrate how effectively the EU has complied with the Montreal Protocol's terms, Dr Simmonds said. Most dramatic has been the decline in methyl choroform. Its atmospheric concentration is now lower than when the measurements were first taken in Ireland in 1978, he said. However, outputs of carbon dioxide, methane and nitrous oxide are, at an all-time historical high.

The strategic role of Mace Head was outlined by Dr John Miller of the World Meteorological Organisation, who paid tribute to its contribution to Global Atmospheric Watch. The Mace station, which dates back 40 years, picks up the first air travelling across the Atlantic on prevailing western winds. The relatively low levels of pollution carried by the Atlantic winds enable crucial baseline data to be set. It is a vital link in the WMO network, stretching from Ushuaia in Argentina to Ny Alesund on Spitsbergen. Not all pollution is a negative contributor to global warming, said Prof Gerard Jennings, of NUI Galway's atmospheric research group at the Department of Experimental Physics. There is evidence aerosol particles, derived from fossil fuels, urban sources and other industrial activities, have a cooling effect. However, such particles have adverse effects on health, causing respiratory problems.

Other natural phenomena, like the Pinatubo volcano eruption in 1991, have also demonstrated this theory. In Pinatubo's case, the atmosphere was cooled by about half-a-degree.