I have long been sceptical about global warming but last week I began to think that maybe it is true after all and maybe it is - to an important degree - the result of human activity.
I chaired a debate on climate change for a firm of lawyers. The main speaker arguing that global warming exists and is man-made was Professor Mark Maslin. He argued that the evidence was overwhelming and that none of 26 (?) computer models of climate change made around the world could make sense of the change that have occurred without assigning importance to CO2. But what made me veer towards believing that the 'warmists' could be right were the answers he and the other speaker on his side gave to the various objections that many people, including myself, have been aware of. These answers were during the debate and afterwards, at lunch.
The medieval warm period is a classic objection. If the earth got warm in medieval times when the human output of CO2 was tiny compared to now, then clearly other factors were more important. His colleague and he replied that the medieval warm period took place in Northern Europe but it does not appear to have occurred elsewhere on the planet. It was not 'global' warming.
It was objected that the earth had stopped warming in 1998. He and his co-speaker responded that this was taking just the land temperature. If you added in the ocean temperature, the rise in the temperature chart continued. He also added that taking 1998 was a bit of a trick on the part of the other side. That year was a sudden peak caused by particular factors (he mentioned them but I am afraid I forget what they were). If you exclude 1998, then the global warming shows a more continuous rise.
One thing is very clear. The issue is incredibly complex and none of us who are not specialists can ever hope fully to master it. It is fair to say that even he admitted some uncertainty about the behaviour of clouds. He also mentioned 'interesting' recent work on solar activity. Yet despite the complexity and some uncertainties, we are in the position of having to make major decisions on the basis of whether or not it is true. It is like having to choose a spouse without ever seeing her or him - relying instead on the supposed disinterested expertise of others who, themselves, cannot be 100% sure.
How do you make a decision in these circumstances as to whether to 'believe' or not? I guess that time and again I found his answers to objections plausible. One objection put to him was that scientists are shunned if they do not subscribe to warming theory. He said that on the contrary, if a scientist was able to prove man-made global warming wrong, he would make his reputation and win a Nobel Prize.
That rings true to me. Of course, as a lay-man, I do not think I am in a position to be dogmatic about man-made global warming, either way. I remain sceptical in the simple sense of being not sure. But I have changed my mind somewhat. I now tend to believe it could well be true whereas before I tended to believe it probably was not.
I put it to him that if man-made global warming is going on, there was an elephant in the room: the most effective way to cut it back would be to reduce the number of people in the world.
On this basis, you could answer that the biggest contribution to 'saving the world' had been made by China with its brutal 'one child' policy.
He commented that the production of CO2 per person in America was 22 times that of a person in China. So limiting population growth in China was not as important as it might appear. But he said that the Chinese certainly mention it in negotiations about climate change.
I then suggested that it followed from what he said that the biggest contribution that could be made in the short term to climate change would be a reduction in the population of America. He did not openly agree. I think he was holding back from reaching a conclusion which would appear so extremely illiberal!
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