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Letter to the editor of The Hill Times

Date: March 22, 2004

Subject: Solar activity a downward cycle: scientist

My colleague and fellow paleoclimatologist, Dr. K. Gajewski, University of Ottawa, Department of Geography, correctly points out that there is close to a consensus in the scientific community that climate change is real ("Small, vocal group of scientists against Kyoto, "March 15, 2004), and is having impacts on the Arctic that are unprecedented in the past century.

However, I am compelled to disagree that there is a consensus of scientists who agree that this is the consequence of human activities. While the melting of permafrost, retreat of glaciers and waning of the permanent ice pack may be alarming, it is only alarming to those unfamiliar with past changes in climate in the North. Paleoclimatologists recognize such events as part of natural changes wholly unrelated to CO2 concentrations in the atmosphere. In fact, the waxing and waning of ice shelves, along with glaciers, ice caps and pack ice are largely related to changes in solar inputs.

Arctic paleoclimatologists are very familiar with the Holocene "Hypsithermal" event - a warm period some five to 10 thousand years ago caused widespread retreat of permafrost and changes in vegetation patterns. Indeed, we have shown that Arctic summer temperatures at that time were five to eight degrees warmer than today. Polar bears and those lower on the Arctic food chain survived, as they will with the current warming.

As for 20th century warming, climatologists and paleoclimatologists alike agree that we are observing a solar-driven climb out of the Little Ice Age. In fact, most of the modern warming trend began prior to any substantial increase in CO2. Recent glacier retreats, breakup of the Ward Hunt Ice Shelf on the north coast of Ellesmere Island, and permafrost degradation have been in the making since the end of this Little Ice Age. We know that the Little Ice Age was an artifact of solar variability, with key intervals of maximum cooling corresponding to historically documented minimums in solar activity when no sunspot activity was recorded. The cosmogenic isotopes, 10Be in ice cores and 14C in tree rings, are measures of solar activity, and they faithfully correlate with sunspots and with climate.

The return to warmer conditions began in the late 1800s (when ships managed to sail the Northwest Passage for the first time), and we find solar activity has greatly increased since this time, with sunspot numbers now at all-time highs. However, the scientific basis for climate change is poorly presented in the media. That The New York Times published rubbish about ice leads on the northern ice cap appearing for the first time in 50 million years is totally irresponsible (the Times was finally shamed into publishing a retraction). That portion of the scientific community that attributes climate warming to CO2 relies on the hypothesis that increasing CO2, which is in fact a minor greenhouse gas, triggers a much larger water vapour response to warm the atmosphere. This mechanism has never been tested scientifically beyond the mathematical models that predict extensive warming, and are confounded by the complexity of cloud formation - which has a cooling effect.

On the contrary, the role of solar activity on climate warming has been observed in real data sets collected at many different time scales. All are consistent in showing a relationship between changes in solar activity and temperature. Before spending futile billions on Kyoto implementation measures, perhaps we should pay more attention to the role that the sun plays. We know that it was responsible for climate change in the past, and so is clearly going to play the lead role in present and future climate change. And interestingly... solar activity has recently begun a downward cycle.

Dr. Ian Clark 
Professor, Department of Earth Sciences (arctic specialist) 
Isotope Hydrogeology and Paleoclimatology 
University of Ottawa 
Ottawa, Canada  

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