CLIMATE CHANGE

Is it just me that’s fed up with having it rammed down my throat that climate is changing due to the activities of man? (I refer to Chester City Council’s Draft Supplementary Planning Document Sustainable Development but more of that later.)  It was John Tyndall in 1861 who first pointed out that atmospheric CO₂ has a critical influence on temperature and climate because of its ‘greenhouse effect’.  A hundred years later on, it was known that human activities had raised the carbon dioxide content of the air by about 13% but it still took another 40 years or so for our politicians to realize that there was an obvious solution to the problem:  taxation.  Old Gaius must have been turning in his grave. 

But let’s put this in perspective.  We’re living on a planet which has experienced three major northern hemisphere glaciations during the last two million years, the most recent one of which (the Late Weichselian) ended about 9000 years ago.  During glacials, water becomes locked up in land-ice (and, to a lesser extent, sea-ice but that gets a little more complicated), so that sea level falls in response to the growth of ice sheets.  Conversely, during transitions into the wetter and warmer interstadials, the ice sheets melt and sea-level rises.  Since man did not start to cause the emission of significant quantities of greenhouse gases until the 19th century (i.e. the last 200 years out of a recent geological history spanning 10,000 times as long), humans cannot have been responsible for the increase in global temperatures which triggered the de-glaciations.  The calculated difference in relative sea-level height between glacials and interglacials is of the order of 100m but sea-level has only risen by about 40m since the Late Weichselian.  By my calculation, that means we’ve got another 60m to go.  Tax your way out of that one (but not from Westminster-under-Water).

Theoghinus Nuttors, 31 January 2009.