Feature
Natural reactions
by Bryan Leyland and Chris de Freitas
The global-warming debate is far from settled.
With the Emissions Trading Scheme promising to add billions of dollars to the annual cost of electricity, transport and agriculture, there is no doubt that “climate change” is important. Sadly, some of Dave Hansford’s recent Ecologic columns seem intended to suppress debate and ridicule and denigrate sceptics of catastrophic global warming. The science is most uncertain; therefore, objective, unimpassioned debate is needed.
Global climate changes naturally, has always done so, and will continue to do so. Studies of past climate change show that when the world was warmer, civilisations prospered. Records from ice cores show the world was warmer during the Middle Ages when the Vikings settled Greenland and Polynesian explorers made voyages to Easter Island. It was also warmer in Roman and Minoan times. Cooling, on the other hand, is disruptive. During the Dark Ages and the Little Ice Age, famine, disease, malaria and plague were rife.
Research since the latest Intergovernmental Panel on Climate Change (IPCC) report was finalised in 2006 shows the world is no longer in the 23-year warming phase that started in 1975. Using the same data that the IPCC uses, we can see that the world’s monthly average surface temperature peaked in 1998 and there has been no global warming since 2002, despite an increase in atmospheric carbon dioxide (CO2) of more than 4%. None of the climate models predicted this would happen. In fact, none of their predictions have proved accurate.
Pronounced global cooling coincided with a rapid rise of CO2 in the atmosphere between 1940 and 1977. If greenhouse gases caused the warming observed between 1976 and 1998, the most pronounced warming would be in the upper atmosphere above the tropics. Climate models predict that greenhouse gases will warm the upper atmosphere, but observations show this is not happening. Therefore, CO2 cannot have been a major factor in the late 20th-century warming.
Other recent research shows that when the world warms, there are more low-level clouds. Low-level clouds cause cooling. The IPCC’s computer models assume that warming will increase high-level clouds that cause warming. If the models were corrected, they, too, would show that greenhouse gases have only a small effect on climate.
There is strong evidence that solar variations have some influence on global climate. Recent research shows temperatures correlate well with sunspots and cosmic rays. This correlation extends over thousands and millions of years. This is explained in a recent book called The Chilling Stars and is demonstrated by records from a stalagmite in Oman.
There are many similar examples that cast doubt on the hypothesis that burning fossil fuels causes dangerous global warming and show that the science is definitely not settled.
Common responses to the above include: “What about the Arctic ice? Or polar bears? Or glaciers retreating? Or sea level rise?” and so on. The facts are: the Arctic had less ice in the 1930s and it is now back to normal after a record rate of refreezing; Antarctic ice was at a record extent last winter; of the 13 populations of polar bears, 11 are increasing; glaciers have been retreating at the same rate for more than 100 years; and the sea level is still rising at about two millimetres a year – a rate that has been steady for more than 100 years.
There is widespread confusion about human-caused “global warming”. It has taken on a life of its own, driven by alarmist scaremongering based on speculation rather than sound science. Profits and careers have come to depend on it.
Now we know the world is no longer warming, the most sensible option is to convene a Royal Commission to hear – and question – experts on both sides of the argument. To do otherwise is to risk doing huge damage to the economy and the welfare of our citizens in what may be a futile attempt to solve a problem that does not even exist.
Bryan Leyland is an energy expert and Associate Professor Chris de Freitas is a climate scientist at the University of Auckland.
