Global Warming Cyclical..

A marine geologist from Australia claims carbon dioxide has prodcued a green revolution.

Carbon dioxide is not a harmful gas and has helped produce the "green" world agricultural revolution, according to an Australian climate expert.

Rob Carter, from James Cook University in Townsville, said the rising level of carbon dioxide in the atmosphere in recent decades had boosted agricultural crop yields.

"Carbon dioxide is the best aerial fertiliser we know about," he told the Victorian Farmers Federation in Morwell late last week.

Professor Carter, a marine geologist, is research professor in the university's Marine Geophysical Laboratory.

He said the Kyoto Protocol would cost billions, even trillions, of dollars and would have a devastating effect on the economies of countries that signed it. "It will deliver no significant cooling - less than 0.02 degrees Celsius by 2050," he said.

"The United Nations Intergovernmental Panel on Climate Change has been the main scaremonger for the global warming lobby . . . Fatally, the IPCC is a political, not a scientific body."

To understand climate change, it was necessary to look at the longer record, he said.
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Through an examination of material taken from deep below the ocean floor, marine geologists could study layers of earth's history similar to the way a tree's age could be determined by tree rings.

"We are in a relatively warm period today," he said. "But 20,000 years ago, it was as cold as it has ever been - that was the peak of the last glaciation."

Professor Carter said that over 2.5 million years there had been 50 glacial and interglacial periods. Of the past 400,000 years, the earth had been colder for 90 per cent of the time, with briefer warmer periods of about 10,000 years.

He said the earth was now at the end of a warmer period, and reputable climate-change scientists agreed that the climate was going to get colder. The debate was whether it would take tens, hundreds or even thousands of years to occur.

On a shorter time scale, Professor Carter said the earth had broadly got warmer in the modern period, from 1860 to 2000, although it had also been warmer in Roman and medieval times. There had also been a Little Ice Age between 1550 and the 19th century, when the Thames used to freeze over.

A cooling trend took place between 1940 and 1970, when temperatures began to rise again, reaching a peak in 1998. "This coincided with the biggest El Nino in the 20th century," he said.

However, research by the climate research unit at East Anglia University in Britain had shown that the average global temperature had declined since 1998.

Professor Carter said greenhouse gases such as carbon dioxide were not causing the earth to warm up. On both annual and geological (up to 100,000-year) time scales, changes in temperature preceded changes in carbon dioxide, he said. This was true even in the famous 1960-1991 graph showing rising amounts of carbon dioxide.

Professor Carter said that without the natural greenhouse effect, the average earth temperature would be minus 18 degrees Celsius, compared with the average of plus 15 Celsius that had nurtured the development of life and civilisation.

Water vapour made up about 95 per cent of the greenhouse effect.

Carbon dioxide was a minor greenhouse gas, responsible for 3.6 per cent of the total greenhouse effect, he said. Of this, only 0.12 per cent, or 0.036 degrees Celsius, could be attributed to human activity.