These are the words, published by the Royal Society, of a man who is said to support the proposition that there is a significant human contribution to global warming (in all the following quotations, any emphasis is added):
[In the pre-human era] Earth has undergone enormous variations in climate state with changes taking place over times ranging from decades to millennia and longer.But who concludes:
So now we come to the modern climate problem. We know that it is capable of remarkable changes without human intervention. We also know that it has elements with very long memory times (the ocean, the ice caps, and some land processes including the biota). There is the possibility of solar fluctuations about which we know very little. The instrumental record only goes back about 300 years (being very generous) and global coverage is only really available following World War II. In many cases, we have no direct evidence for the spatial structures of natural variations and so find it almost impossible to compare observed changes with those known not influenced by human activities.
Thus at bottom, it is very difficult to separate human induced change from natural change, certainly not with the confidence we all seek.
In these circumstances, it is essential to remember that the inability to prove human-induced change is not the same thing as a demonstration of its absence. It is probably true that most scientists would assign a very high probability that human-induced change is already strongly present in the climate system, while at the same time agreeing that clear-cut proof is not now available and may not be available for a long-time to come, if ever. Public policy has to be made on the basis of probabilities, not firm proof.The man is Professor Carl Wunsch, Cecil and Ida Green Professor of Physical Oceanography at MIT, and it's worth pondering his words carefully, not least because he is angry about the way he was persuaded to participate in the filming of the Channel 4 documentary The Great Global Warming Swindle. As The Observer put it yesterday, he felt the documentary:
was 'grossly distorted' and 'as close to pure propaganda as anything since World War Two'.Wunsch has published a statement on his website at MIT. It begins:
He says his comments in the film were taken out of context and that he would not have agreed to take part if he had known it would argue that man-made global warming was not a serious threat. 'I thought they were trying to educate the public about the complexities of climate change,' he said. 'This seems like a deliberate attempt to exploit someone who is on the other side of the issue.' He is considering a complaint to Ofcom, the broadcast regulator.
I believe that climate change is real, a major threat, and almost surely has a major human-induced component. But I have tried to stay out of the `climate wars' because all nuance tends to be lost, and the distinction between what we know firmly, as scientists, and what we suspect is happening, is so difficult to maintain in the presence of rhetorical excess.But later he states:
I am on record in a number of places complaining about the over-dramatization and unwarranted extrapolation of scientific facts. Thus the notion that the Gulf Stream would or could "shut off" or that with global warming Britain would go into a "new ice age" are either scientifically impossible or so unlikely as to threaten our credibility as a scientific discipline if we proclaim their reality.And concludes:
As a society, we need to take out insurance against catastrophe in the same way we take out homeowner's protection against fire. I buy fire insurance, but I also take the precaution of having the wiring in the house checked, keeping the heating system up to date, etc., all the while hoping that I won't need the insurance. Will any of these precautions work? Unexpected things still happen (lightning strike? plumber's torch igniting the woodwork?). How large a fire insurance premium is it worth paying? How much is it worth paying for rewiring the house? $10,000 but perhaps not $100,000? There are no simple answers even at this mundane level.If these are nuanced arguments, one thing is plain: Professor Wunsch is a painstaking and honest scientist, who is deeply critical of the terms in which the Anthropic Global Warming (AGW) argument is often put. He is at pains to show the huge problem with the theory that there is a significant human component in modern climate variation - that this is not provable. Not that it hasn't been proved, but that at the moment it is incapable of proof.
How much is it worth to society to restrain CO2 emissions--- will that guarantee protection against global warming? Is it sensible to subsidize insurance for people who wish to build in regions strongly susceptible to coastal flooding? These and others are truly complicated questions where often the science is not mature enough give definitive answers, much as we would like to be able to provide them. Scientifically, we can recognize the reality of the threat, and much of what society needs to insure against. Statements of concern do not need to imply that we have all the answers. Channel 4 had an opportunity to elucidate some of this. The outcome is sad.
I quoted Richard Feynman on cargo-cult science a few days ago:
There is one feature I notice that is generally missing in "cargo cult science"... It's a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty — a kind of leaning over backwards... For example, if you're doing an experiment, you should report everything that you think might make it invalid — not only what you think is right about it... Details that could throw doubt on your interpretation must be given, if you know them.Wunsch emerges from this test with great honour, but almost all advocates of AGW are shown in their true colours - as cargo-cult scientists. Anybody who waffles about scientific consensus or says "the jury's verdict is in" is a disgrace.
And let's note again that Wunsch is presented, and seems now in the wake of the C4 controversy to see himself, as a pro-AGW advocate. He isn't - he is a pro-science advocate. He does not retract any of the points he made to the benefit of the producers of the documentary in question. He does not address, though there is no reason why he should, the documentary's demonstration of the difficulties any dissenting voice has in getting researched and published. In this climate, it is easy to wonder what the picture might be with a more balanced research environment.
So where does that leave us?
The following points remain unaltered and unchallenged:
- Climate change scares have characterised the 20th century and are really just a form of millenniarism.
- There might be a significant human contribution to global warming, but nobody knows.
- The environmental movement in general and AGW debate in particular has been colonised by ultra-leftists who are trying to use it to impose Stalinist micro-management on every person on the planet
- This has affected public policy and society to an unprecedented and unwarranted extent
By a happy coincidence, there are answers at hand that would provide the Professor's recommended insurance policy, and also answer several other problems. Even if they are not globe-threatening, hydrocarbon pollutants are unpleasant. Our reliance on oil products is politically inconvenient, to put it mildly: a little less reliance on the benevolence of Russia, Venezuela, Iran and Saudi Arabia would be a good thing.
The rapid introduction of sufficient nuclear generating capacity for the whole of our immediate and foreseeable needs would be sensible. Additional resources should be devoted to nuclear fusion research. Alternative sources of power for vehicle engines are all but ready. Announce a phased-in ban on the sale of new vehicles with oil-based engines and let the market sort it out.
Technology shift is the answer. It always has been.