Science is about prediction and refutability

The recent Guardian editorial on climate change was a near-perfect encapsulation of everything I think is wrong with the current "scientific consensus" on climate change. Before I start panning parts of the article though, let me start by acknowledging that it does highlight that current temperatures have diverged from predictions, and that we really don't understand why - it doesn't even fall into the trap of translating post-hoc explanations as fact:

There is, however, a serious debate about why the observed temperatures have not kept pace with computer-modelled predictions and where the heat that should have registered on the global thermometer has hidden itself.
On the other hand, however, it fails to nail just how important is the failure of these past predictions to the climate change debate.

Science is about prediction and refutability. You use your best measurements and scientific theories to determine what you think is going to happen; you then make a public announcement and justification of this theory and associated predictions, and the criteria for measuring their success or failure in the designated timespan. We were fairly clear back in the late 90s that everyone was predicting steadily increasing global temperatures, based on the (objectively measurable) amount of carbon dioxide in the atmosphere and its effect as a greenhouse gas. Since then, reality has not dealt kindly with the predictions. There has been warming in parts of the globe, but not elsewhere; global temperatures have been basically flat over the past decade. There have been spikes and troughs, but nothing sustained. If carbon dioxide levels drive temperature rises, and atmospheric CO2 has been climbing steadily, where is the associated temperature rise that this theory would predict?

If reality does not match your predictions, you have to face the possibility that you do not actually understand the system you are modelling. What a lot of people are missing is that when "scientists" go back to tweak the failed computer simulations so that they then correctly model the past years they are not performing science. At best, it's a sanity test for their adjusted models, but it's not a verification in any form. The only way they can repair their reputation is to start over; produce and justify predictions for the next N years, set out success/failure criteria, and wait. I would say that five years is the minimum period for which we should demand a prediction, and ten years is more like it. Therefore we won't know until around 2020 whether the current theories and predictions are any good. Should we base major economic decisions on these conjectures?

I contrast the article's reports of current climate chaos:

Twelve of the 14 warmest years on record have occurred since 2000; the last two years have been marked by catastrophic floods in Australia and record-breaking temperatures in the US; and the loss of north polar ice has accelerated at such a rate that climate modellers expect the Arctic Ocean to be routinely ice-free in September after 2040.
with the reality of thickening ice in the Arctic blocking the Mainstream attempt to row the Northwest passage:
Severe weather conditions hindered our early progress and now ice chokes the passage ahead. Our ice router Victor has been very clear in what lies ahead. He writes, “Just to give you the danger of ice situation at the eastern Arctic, Eef Willems of “Tooluka” (NED) pulled out of the game and returning to Greenland. At many Eastern places of NWP locals have not seen this type ice conditions. Residents of Resolute say 20 years have not seen anything like. Its, ice, ice and more ice. Larsen, Peel, Bellot, Regent and Barrow Strait are all choked. That is the only route to East. Already West Lancaster received -2C temperature expecting -7C on Tuesday with the snow.”
and the lack of hurricanes in the Atlantic this year:
Seasonal predictions were for an above-normal season. The 30-year average is for 12 storms with winds of at least 39 miles per hour, the threshold at which they are named. Nineteen such systems formed in each of the last three years.
The Arctic ice is a particularly interesting case. It seemed very clear a few years ago that the Arctic ice was getting thinner and less expansive every summer, and an ice-free season seemed like a slam dunk. Now, suddenly, the ice is getting thicker again - a lot thicker, jumping back towards the 1998-2010 average. Why is this happening? We don't know, we didn't predict this. Perhaps there's a lot more about the Arctic that we don't understand.

It seems clear that the climate of the world is changing, and it may even be warming. But the degree, if any, of this warming is far from certain. If the world is indeed warming considerably, it's not clear whether we can (in practice) do anything to affect it. If we can do anything to affect it, it's not even clear that we should do anything - if Arctic sea ice melts completely then suddenly we can send a lot more shipping trade north of Canada, avoiding the bottleneck of the Panama canal. If we can't grown corn in the middle of the USA any more, we may be able to grow it far more north in Canada than we can currently. The current media clamour sounds awfully like the syllogism: "Something must be done! this is something, therefore we must do it."

The more I read of climate science, the more I realise that we know sweet F.A. about it. Confusing political propaganda with science is not helping. Mounting witch hunts against scientists sceptical of current orthodoxy ("denialists!") is not science, it's medieval conformism. If your theory is threatened by a few loudmouths then perhaps the problem is not with the loudmouths. True science welcomes debate and rebuttal. That is, after all, how we learn.

1 comment:

  1. I agree, there have been too many plugs in to the models to make them fit hind casting that the models no longer work.

    Alongside that is another problem that seems to have happened, although I have no real proof only an observation that a large consensus exists about a hugely chaotic system that we've only been seriously studying for 30 years or so. Every time a climate team produces a model that doesn't fit with the orthodoxy of the hockey stick they go back and fix their model rather than ask whether or not they were right. For as we know if you don't agree with the hockey stick you are denier.

    Its a shame because there is no doubt that the climate is changing, it always has and it always will, and that man is making a difference*. What we need is an honest debate about what we do know and what is speculation then we'll have a better chance of teasing out what is man made and what is "normal".

    * To paraphrase Bill Shankly, if man isn't making a difference what's he doing here.


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