More climate change denial in my local paper, via the letters page this time...Michael Maddock is wrong in his assessment of the evidence on climate change ('Exploding the myth on climate change', Bristol Evening Post Open Lines, 1 July). Climate change is not a myth as the headline suggests it is. In fact the (Nobel Prize winning) UN Intergovernmental Panel on Climate Change (http://www.ipcc.ch/) does exactly as he suggests scientists should. It continually looks at all the latest and most expert scientific research on climate change. It then periodically issues major assessment reports containing the best available evidence. There have been four assessment reports so far and its fair to say that each time a new report has come out the evidence has pointed out even more strongly the fact that human-caused climate change is real, serious, and requiring urgent action from everyone, lead by governments. What more could we all want than that??
Contrary to what Michael says, many scientists clearly do not state that climate change is not caused by carbon dioxide. If they did it would be in the IPCC reports. In fact what the scientists say is the complete opposite! Its not true to say that warming always happens first, followed by carbon dioxide rise. It has sometimes happened this way but it also, as now, happens the other way around, with carbon dioxide emissions rising, followed by warming. This is a natural feature of the tightly coupled systems that affect our climate. What it points to of course is that the warming we are causing now with our carbon dioxide emissions, will itself go on to cause even more warming on top of warming caused by further carbon dioxide emissions! There are several mechanisms by which it will do this eg warming melts ice/snow, which means the white area reflecting energy back into space is lower, which means more energy is absorbed, causing warming...This feedback effect amplifies human impact along with others.
Scientists will continue to question, investigate, and gather evidence as Michael suggests they should. What concerns me greatly is that Michael, and many others with him, are, despite the very strong evidence, in denial about climate change (see http://climatedenial.org/ ). The sooner we face up to the facts the better. Time is slipping away and it will get harder and harder to reduce the worst effects of climate change the longer we put off what we all know we have to do ie adopt efficient, renewable lifestyles that stay within environmental limits, something that will also make our lives more affordable as it means bigs cuts in our use of increasingly expensive oil.
