Climate concern

Quite why Professor Tony Trewavas, of Scientific Alliance Scotland (Letters, 30 September), should have wondered if he 
was reading the same 
Intergovernmental Panel on Climate Change (IPCC) climate report as was described in The Scotsman (28 October) is unclear.

Your article gave a fair summary of the report’s main points. Perhaps his organisation couldn’t find anything actually incorrect in your account but was just intent on spreading doubt.

Prof Trewavas went on apparently to query why the IPCC scenario predicting a temperature rise in the range of 2.6 to 4.8C could be described as “up to almost five degrees by the end of the century”.

The answer is that the 2.6 to 4.8C range refers to the average of the past 20 years of the 21st century, and is, moreover, only the “likely” range – it does not cover the extreme possibilities. To characterise that scenario as “up to almost 5C” by 2100 is thus entirely reasonable.

Prof Trewavas also described this 5C scenario as “very unlikely”, while warning against “unilateral imposition” of climate policies. But the whole point of the IPCC report is to encourage global agreement (hopefully at the Paris summit in 2015) to reduce CO² emissions.

It is only such an agreement that would make such a scenario unlikely. No-one suggests unilateral action by any country can solve this problem. That “up to 
almost 5C by 2100” scenario stands as a warning of what is a real possibility if the world fails to come to a common agreement in the near future.

That catastrophic future is made all the more likely by those who, against all the overwhelming evidence of science, refuse to accept that we have a problem that must be faced.

Roy Turnbull

Nethy Bridge

Inverness-shire