Thursday, November 30, 2006

Royal Society Alert 451

Comment this week:
Comment by Royal Society Policy Analyst, Dr Jez Weston
Scepticism is an intrinsic requirement for science to progress. It helps us
ask the right questions to test our theories. However, many questions
continually arise in scepticism about climate change. To some extent, these
arguments qualify as memes, in that they propagate and proliferate and as
memes, they resist disposal by answers. So what are some examples?

"The effect of human-produced greenhouse gases is tiny in comparison to the
warming effect of water vapour". This is true, but irrelevant. The amount
of water vapour in the atmosphere changes on a daily basis and is not
within our ability to influence. Water vapour multiplies the effects of our
own changes to the climate.

Another meme is the uncertainty of our predictions. Uncertainty is inherent
when studying a complex system like climate. The scale of response to
increases in greenhouse gases is governed by a host of feedback mechanisms,
some of which interact with each other. Hence the IPCC's 2001 warming
predictions of somewhere between 1.4 and 5.8 C. This uncertainty makes it
difficult to work out the optimum response to minimise climate change, but
it is not an excuse to pretend it isn't happening.

Other memes lie outside the bounds of scientific debate. The oft-repeated
claim that "global warming stopped in 1998" is an example of cherry-picking
of the data. 1998 was the warmest year on record. By definition,
temperatures have been cooler since the record-setting year. The global
temperature record has fluctuations because the climate has fluctuations
but the long term trend is upwards and it is long term trends that matter.

The meme that "climate change prediction depends upon obscure computer
modelling" is just plain wrong. I advise everyone to read Svante Arrhenius'
1896 paper "On the Influence of Carbonic Acid in the Air Upon the
Temperature of the Ground". Made with a pencil and paper, his predictions
are within a factor of two of the IPCC predictions, on a global scale. What
computers are needed for are the detailed calculations of impacts on a
local scale.

A final meme runs "scientific truth is not determined by consensus so the
fact that most scientists agree on climate change doesn't mean that climate
change is happening". It is true to say that science does not depend upon
consensus. I'd go beyond that to say that scientists hate consensus. It is
boring. We scientists are trained to argue with each other, over every tiny
little point. We love a good bust up. When we start agreeing it's because
we understand what's going on.

Hard to disagree with that...
The dabate has moved on from 'if' to 'what' i.e. what, if anything, should we do about our influence on climate? A viable option (albeit one i don't subscribe to) is to do absolutely nothing and let our children figure it out.
Putting your options on the table though assumes a reasonable debate and as JW's meme's comment points out - climate change 'debate' more closely resembles the "cute little baby seals" emotive campaigns of Greenpeace in yesteryear than a hard-headed political, financial and technological risk analysis.
NB please note that i think Greenpeace will be on the right side of history on that campaign, even though i disagree with everything they've stood for since the late 80's


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