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Going cold on climate change

By Mark S. Lawson - posted Friday, 2 March 2007


When the fourth assessment report of the Intergovernmental Panel on Climate Change was released recently, the media and the IPCC functionaries concentrated on the point that part of the known increase in global mean temperatures in the past century or so is due to human activities. Quite so, although we did not need elaborate computer models - or intense scientific debate - to work that out, as this article will show.

The other side to all the recent screaming, however, and one that the environment industry which includes the IPCC is not keen to emphasise, is that part of the increase is due to natural climate cycles. That was the real change.

In previous years the IPCC has tried to blame all the warming on human activity, and was recently severely embarrassed in those efforts. The panel has never acknowledged this embarrassment and, tellingly, has never been seriously questioned over it, although the more recent report shows signs of preferring to keep within known science, rather than include last minute scare stories about ice caps melting and the like. This is welcome.

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In one sense all of this does not matter very much. If human activities are changing the climate then something should be done, no matter what the degree of change. This article does not address the issue of emissions, nor does it deny climate change (nor is the author in the pay of oil companies, which is a shame). Instead we will look at the issue of whether the IPCC predictions mean anything or whether they are of any use at all.

As is now well known, climate changes naturally. There are very large variations into and out of ice ages, which scientists seem to know something about, although there is still a lot of debate about the mechanisms involved. But there are also small scale changes over a few decades or a century or two which remain very mysterious.

In the most recent of those minor changes, it is known that up until about 1860 the world was in the grip of what has been called The Little Ice Age. The colder weather has been confirmed by everything from ice cores to surveys of cloud cover in Renaissance paintings (see Little Ice Age, Brian Fagan, Basic Books, 2000 - Fagan is a professor of Archaeology at the University of California). That Little Ice Age, in turn, had several sub variations of somewhat warmer and somewhat colder climate.

Scientists know that changes in solar activity have some hand in all this, but we can only guess at the interaction between the sun, the atmosphere, the ice caps, clouds, oceans currents, aerosols, water vapour, carbon dioxide (natural and man made), dust from volcanoes and heaven knows what else besides. The oceans, in particular, are proving vastly more complicated than scientists suspected until just a few years ago.

Scientists know that in 1860 average temperatures were low, so that at least some part of the 1C plus increase since then must be natural. They also believe that the upswing might have something to do with a general increase in solar activity.

However, the warming trend has gone on too long. There is no previous, recent period where warming has continued for as long as it has up to now (as far as anyone knows). Ergo, human activity might (90 per cent likely) be to blame, and never mind the battalions of IPCC scientists meeting in endless committees.

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The Little Ice Age book cited above gave that figure as accepted when it was published. The really tricky part is working out how much of the warming is natural and how much is artificial.

The IPCC, for its part, has fought bitterly against the suggestion that part of the warming may be natural with most of the fight being over a thing called the hockey stick graph - a piece of analysis done mainly by Michael Mann, a climatologist at the University of Virginia.

Distilled from readings of various ice cores and tree rings and the like, the graph showed temperatures rising exponentially and neatly in line with the rise of industrial activity. Perfect!

The panel and Mann (one of its leading scientists at the time) adopted the graph as dogma, declaring that the well established Little Ice Age pattern must have been a Northern Hemisphere thing, and got on with the lobbying. But then the analysis was severely criticised by two statisticians who alleged Mann had made a basic error.

That dispute was settled last year by a group of eminent statisticians who formed an ad hoc committee to the US Congressional Committee of Trade and Industry. They released the Wegman report (PDF 1.41MB) which found that Mann’s analysis indeed contained a major flaw. The Little Ice Age and the earlier Medieval Warming Period were restored.

So much for that diversion, but the really worrying point about the whole incident is that the IPCC is pretending it never happened. Its officials do not seem to have made any statement of any kind over the Wegman report, and the media has shown no interest in discussing the matter.

Mann’s name is not on the list of authors for the physical science section of the recent IPCC report - he continues to defend himself vigorously - and that is about all any outsider can say.

As for the Physical Science part of the IPCC report itself, which is, as yet, only available online in summary form, it notes the factors that affect climate change include greenhouse gases and aerosols and so on, and solar radiation. One can almost hear the panel scientists saying, through gritted teeth, “Oh alright! Part of the increase is natural”. (To be fair, the 2001 report also mentions solar radiation.) But how much of it is natural and how much due to human activity? While we are on the subject, how much warming can we expect in the future?

As noted, climate research is an area with vast uncertainties, but the IPCC is apparently of the belief that they know all they need to know about climate change, including both large and small scale changes, and have put it all into a computer model along with the effects from the human-generated greenhouse gases (which is completely new territory) to produce temperature forecasts that range from 1.1C to 6.4C over 100 years. Right!

Perhaps in an effort to convince themselves as much as anyone else that they have waved their computerised magic wand over the subject of climate change, in the 2001 report the panel printed graphs of its computer projections compared to the known historical data over 100 years. They matched, to the extent that they had roughly the same start and end points, and for the faithful, that may be all the evidence required.

In the real world, however, matching computer results with known data - especially data on a generally rising curve - means very little. The real trick is to get the major turning points, particularly unknown turning points.

There is no indication that the IPCC can match the known turning point in climate around the 1860s, or any of the other turning points before that, especially as, until recently, the panel did not even acknowledge that the turning points existed. In other words, it is possible that the computer models over which the IPCC scientists have been slaving are useless.

Various scientists without any part of their careers vested in these models have sounded warnings, which the panel has done its best to ignore:

“For example, we know that carbon dioxide represents about 2 to 3 per cent of the natural greenhouse effect whereas water vapour makes up the vast majority of the remainder. While we know why carbon dioxide is increasing, the physics of water vapour - in particular of clouds - is almost entirely unknown despite dominating the natural greenhouse effect.” Associate Professor Stewart Franks, a hydro climatologist at the University of Newcastle. An article in the Sydney Telegraph, February 16, 2007.

“The recently released IPCC 2007 Fourth Assessment Report Summary for Policymakers reminds us that aerosols remain the least understood component of the climate system. Aerosols are solid or liquid particles suspended in the atmosphere, consisting of (in rough order of abundance): sea salt, mineral dust, inorganic salts such as ammonium sulphate (which has natural as well as anthropogenic sources from e.g. coal burning), and carbonaceous aerosol such as soot, plant emissions, and incompletely combusted fossil fuel.” Juliane L. Fry, Postdoctoral Scholar Department of Chemistry, University of California, Berkeley. Posted on the Real Climate site.

“Many scientists therefore rely upon numerical models of the climate system to calculate (1) the nature of natural variability with no human interference, and compare it to (2) the variability seen when human effects are included. This approach is a very sensible one, but the ability to test (calibrate) the models, which can be extraordinarily complex, for realism in both categories (1) and (2) is limited by the same observational data base already described. Thus at bottom, it is very difficult to separate human induced change from natural change, certainly not with the confidence we all seek.” Carl Wunsch. A professor of physical oceanography at Massachusetts Institute of Technology.

“Deterministic computer models predict future climate according to the assumptions that are programmed into them. There is no ‘Theory of Climate’, and the potential output of all realistic GCMs (Global Climate Models) therefore encompasses a range of both future warmings and coolings. The difference between these outputs can be changed at will, simply by adjusting such poorly known parameters as the effects of cloud cover.” Robert M. Carter, James Cook University, Townsville. Professor Carter is a former Head of School of Earth Sciences at the University. (Statement (PDF 86KB) to the US Senate’s committee on environment and public works.)

Greenhouse proponents may try to wave away these criticisms but only one has to be even partially right for the computer climate models to fall into a gigantic heap. The models are, after all, trying to predict the results of an enormously complex physical system, and they are trying to do so a full century out!

A small error at the beginning could make a nonsense of the result at the end, and there is every reason for thinking that the errors are not small, but colossal.

If all that is not bad enough, the issue really moves from being simply absurd into a farce when one asks what the projections would be used for. No policymaker in his or her right mind would base decisions on computer projections that are so vague and, in any case, are simply computer projections.

Would Australian wineries start moving their vineyards because of the IPCC projections, for example? Would land owners in Britain start planting vineyards again as they did in medieval times, on the strength of computer projections? Of course they wouldn’t. With the possible exception of the issue of emissions, no one would do anything until some sort of trend for their region becomes evident.

About the only use for the IPCC report is as an exercise in conscious raising for climate change, and the need to reduce emissions. In that sense it has been highly successful, but it still seems a bizarre way to do it.

Nor are our diligent computer model makers likely to cease or desist in their activities any time soon. They have too much of their careers invested in the models. In any case, why change? The media fawns on them, they are given awards, sceptics are howled down and, thanks to the long time scales involved, they may be in honourable retirement before it is evident that climatic reality is paying no attention to their models. Or worse, they may be right for the wrong reasons. This issue has reached the stage of theatre.

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About the Author

Mark Lawson is a senior journalist at the Australian Financial Review. He has written The Zen of Being Grumpy (Connor Court).

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