30 December 2010

Climate Roundup

Most of the commentary on the cold winter has been too stupid to discuss, so I haven't. Certainly, cold winters do not prove that the climate scientists are wrong, though it does suggest that alarm is overstated: not only is weather not climate, but climate variability is so dwarfed by weather variability that it is not remotely possible to actually notice whatever climate variation there might have been over the last hundred years. The actual weather changes in any given place from year to year or decade to decade are vastly bigger than any global climate change we have seen. As I say, that doesn't make climate change wrong, but it does make it less relevant.

But most stupid are the desperate attempts to claim that cold winters are caused by global warming. Not because that is impossible, but because there has been scant regard for facts. I have been informed by one earnest physicist that snowy winters here are to be expected, because global warming increases the amount of water in the air. That would be sound logic if English winters were normally cold and dry, but they are not - winter conditions here are normally that if there is a clear night, there is frost, but if there is cloud cover, that keeps the ground too warm for frost, and it rains. We have snow this year because it is colder, not because there is more moisture.

Some random genius on Twitter takes the biscuit for claiming that the cold winter is to be expected, because global warming has melted icecaps, changed ocean salinity, and diverted the Gulf Stream. Again, logically sound, but the ocean salinity has not changed and the Gulf Stream has not moved. Apart from that, good try...

Monbiot's theory, that warming at the pole has disrupted atmospheric circulations, bringing cold weather down, is at least not obviously contradicted by the facts. It might be true. But there was certainly no consensus predicting it.

What has made this issue worth mentioning for me is the excellent collection of articles gathered by hauntingthelibrary, of the climate mainstream explaining that mild winters in Britain are the result of Global Warming. We are all familiar, I am sure, with the classic UEA "snowfall a thing of the past", but he shows that that was not one random nutter.

* Less snow and rain for islands (Hadley Centre)
* Warmer and Wetter Winters in Europe and Western North America Linked to Increasing Greenhouse Gases (NASA,Nature)
* The recent warm winters that Britain has experienced are a clear sign that the climate is changing (James Hansen)

The point is not that they are wrong. The fact is that the climate system is so complex, and the climate signal is so faint against the weather background, that there is no possibility of being right. If global average temperatures really have increased by a degree or so over the last fifty years, and I cannot see that there is any way to tell whether they have, then what the results are is equally unknowable. Weather is just too big a thing to see around.

The other point is the sheer lack of restraint in putting forward ad-hoc climate theories without the slightest thinking-through in response to any weather. Journalists do journalism, but this kind of speculation is what scientists were traditionally so unwilling to do that, 25 years ago, there was a popular stereotype of the scientist who couldn't commit himself to anything because "the evidence is not yet complete". That change is the most significant element in climate science.

1 comment:

hauntingthelibrary said...

Hi,

I saw you'd linked to my blog post on this. I think the point you make about the silliness of trying to detect patterns of global warming against the weather is particularly cogent.

One of the reasons I started my blog is that I got so fed up with professional prognosticators, commentators and activist scientists claiming every single weather event as a "sign" of global warming that proved their theories.

In truth, we can expect little from a change in average temperature of only a few degrees. But then that boring truth doesn't make careers . . .