The cause of global warming remains unknown and the information being used to determine its effects is too recent to form a good basis for conclusions.

Outlining this at an event organised by the Fossil Fuel Foundation, Cape Peninsular University of Technology energy professor Philip Lloyd said that, contrary to widespread reporting, global temperatures were not rising excessively nor had there been recent indications of an acceleration in the rising of sea levels.

Statistics also prove that rare weather events were not on the increase.

University of the Witwatersrand school of geoscience professor Grant Cawthorn said it had still to be conclusively proven that carbon dioxide (CO2) was to blame for climate change, which retired former Wits University physics professor Dr Don Mingay described as being a natural phenomenon that had been present since the beginning of the earth.

“What we need to know is what’s causing global warming and the answer is: We don’t know,” said Lloyd, who formed part of the Intergovernmental Panel on Climate Change (IPCC) team that shared the Nobel Peace Prize in 2007.

The satellite record, which dates from 1979, showed a different truth to the thermometer record. It was seriously problematic that official data kept on being adjusted.

The temperature change between 1920 and 1940, which is not regarded as being CO2 driven, is very similar to the temperature change from 1970 to 2000, which the IPCC puts solely down to the effects of CO2.

Mingay postulated that there had been climate change in ancient times even though there was no evidence of ancient Egyptians and others having coal-fired power stations.

“You can’t deny the greenhouse effect, but probably 90% of it is water vapour and only 3% CO2,” said Mingay, who calculated that only 3.6% of greenhouse gas was CO2, of which 3.48% was natural and 0.12% Homo sapiens-driven.

Lloyd pointed out that the Dutch took fumes from nearby furnaces and ran their greenhouses at between 1 000 parts per million (ppm) and 2 000 ppm CO2 in order to stimulate plant growth.

“People work in there quite happily and plants do so well that they effect three crops every year,” he added.

Mingay saw no need to eliminate coal-fired power stations and pointed to the danger of declining global temperatures being far more dangerous to humans than rising global temperatures.