Readers letters
"It was Leo Tolstoy who wrote” The simplest concept cannot be made clear to the most intelligent man if he is firmly persuaded that he knows already, without a shadow of doubt, what is laid before him.” I was reminded of this quotation by the letter from Peter Gibbs (PE February). I don’t know about the chattering classes, but over 1000 climate scientists and researchers do have considerable doubts about the contribution of CO2 to so called climate change.
Even a casual study of the climatic history of the earth shows that it has warmed and cooled significantly in the distant past without prior of changes in atmospheric CO2. The present warming dates back to the middle of the 19th Century, the time of the end of the Dalton Minimum and the Little Ice Age. Man has clearly made a significant contribution to this warming; the world population has increased markedly and more and more fossil fuel has been consumed. Both generate increasing amounts of heat. But to lay the blame for the global increase in ambient temperature principally on the increasing amounts of CO2 in the atmosphere is to perhaps prejudge the case. Chemistry experiments have indeed shown CO2 to be a greenhouse gas, but we must remember that water vapour, another greenhouse gas, accounts for approximately 95%of the greenhouse gases in the atmosphere, whereas CO2 comprises just 3%.
Although the concentration of CO2 in the atmosphere continued to increase almost linearly between 1995 and 2010, there was no statistically significant increase in the global temperature over this period. Whilst 2010 has been measured as the warmest year on record, this attribution is made by just one of the 4 standard measurements of global temperature. Since the sea covers some 75% of the globe, somewhat surprisingly this standard takes no cognisance of sea surface temperatures. However, 2010 was still not statistically significantly warmer than the previous 14 years.
The fears over an increase in atmospheric CO2 causing an increasing and possibly runaway global temperature are based on modelling alone. These models, none of which are the same or give exactly the same answers, are derived from attempts to model past conditions and make a significant number of assumptions, not least that changes in sunspot activity have minimal effect (in spite of the evidence of the Maunder and Dalton Minimums) and feedback effects, which are the major unknown. The validation of these models has occurred principally since 1995, and the lack of any statistically significant increase in temperature over a period of 15 years indicates that they could be spectacularly in error. Any decision to dose the stratosphere with sulphur or to implement urban albedo enhancement based on these presently unproven models, as suggested by Colin Baglin (letters PE January), must be questionable.
In spite of the impression given in media reports, the average rise in global temperature per century is 0.7 degrees C, with a lower limit uncertainty of plus or minus 0.2 degrees C. Vegetation growth has increased and its area extended thanks to increasing atmospheric CO2. Artic sea ice extent and thickness have remained sensibly constant over the last decade and sea levels are rising at a rate of just 1.5 mm per year. Sea surface temperatures are decreasing and the sea is still alkaline, not acidic, falling from 8.2 pH to just 8.1 pH since the mid 18th Century. The annual number of cyclones has been decreasing steadily. In 2010, 66 cyclones of tropical storm force developed globally, the fewest since reliable records began in 1970. And be aware that sunspot activity in the current cycle is seriously on the wane, being predicted by NASA to be approximately 1/3rd of what it was during the previous cycle from 1998 to 2008 and approaching that during the Dalton Minimum.
Beware of media reports on climate change forecasts that include the words may, could or possibly; they are principally speculation. Better to read the hundreds of studies available on the internet, many of them peer reviewed, and form one’s own opinion on the validity of claims that we are in danger of a catastrophic increase in global temperature."
Geoffrey H L Glover, Dorset