SULPHATE aerosols are not all bad. Meteorologists now say tharsulphate aerosols help mitigate global warming.

Researchers from the UK Meteorological Office's Hadley Centre have developed a computer model that simulates the way in which aerosols mitigate Predicted (1860-2050) and observed the process of global warming. The scientists claim that the general Circulation Model replicates the observed temperatur ,e changes in the past 130 years and it "could be an important step forward in climate prediction science" (Nature, Vol 374, No 6522).

Previous studies by the International Panel on Climate Change reported that the temperature should have gone up by 0.6 to 1.3'c due to green-house gases, However, experiments based on the new model, which takes into account the emissions of natural and human-made sulphates, produced a simulated temperature rise close to the observed value of 0.5c.

Says David Bermetts of the Hadley Centre, "What we have done is reduce the uncertainties of the models. The important thing is that you can put the 71 aerosols in, and the model 1860 18801900 1920 1940 19601980 2000 2020 2040 appears to behave close to what is observed".

Scientists, however, acknowledge that more work needs to be done on the fact that regional calculations within the model show a greiner variability from observed temperature Changes than the global model.