September 20, 1990

Article at Reuters

International study confirms global warming trend


By Wilson da Silva

SYDNEY – An international scientific study confirms the Earth has grown progressively warmer in the past century, dispelling doubts cast by earlier studies, Australian researchers said on Thursday.

“This confirms the globe has been warming over the last 100 years,” said Bill Kininmonth, chief of the Bureau of Meteorology’s National Climate Centre in Melbourne, whose group contributed to the study along with scientists from the United States, the Soviet Union and Britain.

“There have been some very warm years in the last decade ... and a global warming trend in the last 100 years. But there needs to be a lot more research before we know if it is connected with the greenhouse effect,” he said by telephone.

The study, published in the September issue of the scientific journal Nature, analysed data from 1,219 weather stations in rural areas of the world over the past century.

Average world temperatures have risen by 0.5 degrees Celsius (0.9 Fahrenheit) in the period, the study found.

When compared with measurements taken from weather stations in or near urbanised areas, the study found no difference in most areas and a negligible difference in others.

“In none of the three regions studied here is there any indication of significant urban influence,” it said.

The findings counter research in the United States last year indicating weather stations in major population centres recorded temperatures 0.15 degrees Celsius (0.27 Fahrenheit) higher than rural areas. The Nature study says the U.S. data sets the upper limit of influence a city can have on temperature data.

The greenhouse effect is caused by a build-up of gases in the upper atmosphere which traps heat and acts like a planetary pressure cooker, causing the Earth’s surface temperature to rise.

The rise in temperature is believed to be caused by industrial pollution, but may also be a new natural fluctuation scientists have yet to understand. They warn that if it continues, sea levels could rise, and crop areas could be devastated by the changes.

The study, conducted for the United Nations International Panel on Climate Change, will be presented at a November meeting of the World Climate Conference in Geneva, Switzerland.

It was also carried out by Leningrad’s State Hydrological Institute, the Atmospheric Sciences Centre of the State University of New York, the National Climate Data Centre in North Carolina and Britain’s University of East Anglia.