Wednesday, June 24, 2009

Only certainty about the climate is that it will change.

Unpublished letter sent to the sydney Morning Herald 17/06

Matthew England (How noisy naysayers led Fielding on a false path, 17/6 takes great pains to explain one of the great contradictions of the theory of anthropogenic global warming: that global temperature has flat lined over the last decade despite constantly rising green house gas emissions. England rightly puts this down to natural variability in the climate system. He points to the warming trend revealed by surface temperature data over the last 150 years as evidence that the warming will continue and even accelerate. What he fails to to mention is that this temperature record is but a snap shot of global temperature that has varied more markedly over much longer time scales both up and down. For instance over the last 1000 years the earth has moved from relative warmth during the Medieval Warm Period to the relative cold of the Little Ice Age, intriguingly under virtually constant greenhouse gas concentrations. Modern temperature records begin during the later natural low point and it is little wonder that temperatures have risen since then as the earth has naturally warmed again. Likewise that we have seen a cluster of warmer years over the last decade is no mystery and merely reflects the fact that we started recording temperature accurately when the climate was much cooler.

One wonders if medieval weathermen were as concerned about climate change as we are or did they recognise the warming as a portent of better times to come that would eventually see the Vikings settle in Greenland, bring bumper crops to Europe and wine making to northern England?

Matthew England is right about one thing; change in the climate system will affect us all. However as there is little we can do about it we are better to spend our limited resources adapting to both positive and negative changes as they arise, rather than sit on our thrones by the sea shore and command the climate to stop. The only certainty about the climate is that it will change.