Letter: Climate change debate

Just a quickie in response to Peter Street who questioned the broad range of temperature rises predicted to occur due to climate change.

The range is usually given as between two and six degrees because it depends upon how much carbon dioxide is added to the earth’s atmosphere between now and 2050 or the end of the century, whichever dates the prediction uses.

If we (the people of the world, not just MRMail readers) make large and immediate cuts to carbon emissions then warming is predicted to be limited to two degrees, but if things carry on with emissions rising at present rates then warming is predicted to reach six degrees.

So this broad range is due to the unpredictably of the human response to the threat of climate change, not due to the variability of the predictions.

Such predictions are not new , this is not a new-fangled science as many think - back in the nineteenth century when it was first realised that it was the blanket of carbon dioxide in our atmosphere that keeps the earth warm compared to the temperature out in space it was suggested that the global average temperature would increase by between five and six degrees if the carbon dioxide concentration in the atmosphere were doubled.

Historically the carbon dioxide concentration in the atmosphere was around 280 ppm, when I was born it was about 320 ppm, in October 2011 it was 389, in October 2012 it was 391 ppm. The rise is continuing, between 2 and 3 ppm per year and getting faster....

I suspect that Mike Stopper is simply trying to goad me when he suggests in his letter that we use shale gas for our future energy needs.

For the sake of future generations we need to accept and act upon the weight of scientific evidence which says that we need to reduce carbon emissions to stop adding to this blanket.

Surely that is the only moral thing to do, rather than to kid ourselves that we know better. If the evidence changes or new technologies become available then we can exploit the shale gas later - it has been there for thousands of years, it will wait.

Peter Sanderson