26 February 2013

Hot topic

Last Friday I toddled along to a seminar on climate change conducted by the West Wales Eco Centre (WWEC).
As regular readers will know, I am a bit sceptical about anthropogenic climate change, formerly known as global warming.
It is my great misfortune to have spent three years doing hard sums at university, so I understand quite a bit of the science.
This is misfortunate because it prevents me accepting many of the fashionable "truths" that infuse the modern world.
I am fully conversant with the fact that Carbon Dioxide absorbs certain wavelengths of the light reflected from the earth and re-emits some of it back to earth, producing a warming effect.
I am also aware that basic physics leads to the conclusion that, all other things being equal, a doubling of the concentration of Carbon Dioxide in the atmosphere will raise global temperatures by approx 1 degree C.
After that it gets a bit tricky because the climate is, as the scientists like to say: a non-linear chaotic system, and some of the fancy figures bandied about in the press depend on what are known as positive feedbacks.
To take a simple example, the1degree C increase caused by doubling of CO2 will allow the atmosphere to hold more water vapour (not to be confused with clouds) and as water vapour accounts for some 70% of the greenhouse effect that effect will be correspondingly enhanced.
Add to that the fact that warm water can absorb less CO2 than cold water and the heating of the oceans caused by the doubling of CO2 will cause the out gassing of even more CO2 from the seas making the problem even more acute.
And before you know it the tundra will be melting releasing large quantities of methane - an even more powerful greenhouse gas than CO2 - which will cause global temperature to rise even further.
Inevitably, the ice caps will begin to melt (floating ice doesn't count, ask Archimedes) and sea levels will rise to the extent that New York will only be habitable above third floor level.
But there are scientists who say that the feedbacks will be negative.
For instance, the increased concentration of water vapour in the atmosphere will produce more clouds which will intercept the incoming heat from the sun and reflect it back into space.
Even the UN body the Intergovernmental Panel on Climate Change (IPCC) which draws together the science on the subject, admits that "the effect of clouds is poorly understood".
But to return to the seminar which kicked off promisingly with a slide showing a photo of of Einstein and a quote.
Not only was Einstein a great thinker but he was also a master of the philosophy if science.
It was, I think, Einstein who said that scientists don't set out to prove their hypotheses, but to test them.
The quote used by the WWEC's "education officer" was the following. "The supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience."
This was a promising start and when he went on to explain the difficulties in actually measuring global temperatures - urban heat islands, lack of reliable weather stations over large parts of the globe etc, etc - I was rather regretting my earlier doubts.
However, it wasn't long before the scales fell from my eyes when a "graph" flashed up on the screen showing global temperatures for the past 100 years.
This showed a steep rise from left to right.
Now, I should say a word or two about graphs at this point, because there are graphs and graphs.
To a mathematician, a graph is a pictorial representation of a mathematical function.
So, if you plot a quadratic equation on a sheet of graph paper you will get a parabola.
And the parabola will be exactly the same whoever plots it.
On the other hand there are graphs which are nothing more than diagrammatic representations of data.
And while mathematical graphs usually have the same quantities (numbers) on both axes this second type of graph does not.
That gives scope for squeezing and stretching the scales to give the desired effect.
For example, on the diagram below if you squeeze the time series, or stretch the temperature, or both, you can make the slope of the lines much steeper to give the impression that the temperature is projected to rise much faster.
And vice versa!

Graph

And the graph we were shown had been so manipulated to give a slope of roughly 45 degrees.
There was another interesting thing about WWEC's "graph" in that the time series ended in 2000 though the data is available up to the end of 2012 (see black line above).
The problem is that temperatures have remained flat since about 1998 and the Met Office says they are likely to remain so until at least 2017.
So I asked the "education officer" how Einstein's dictum about not leaving out a "single datum of experience" could be reconciled with the omission of the most recent 12 years.
An embarrassed silence followed.
Of course, one reason could be that no amount of stretching and squeezing of the axes can change the slope of a horizontal line.
And this latest pause in global temperatures strikes a serious blow at the the anthropogenic warming theory because CO2 levels in the atmosphere have continued to rise throughout the period.
So, at least, we can say that there is no linear connection between CO2 concentration and global temperature.
But, as I pointed out in an earlier post, that doesn't directly disprove the theory because there could be other things going on that are masking the warming effect of the extra CO2.
However, what it does show is that the computer projections on which much climate change alarmism is based are not very skilful in representing the climate.
In the graph above, the coloured lines represent the various scenarios generated by these computer programmes and, as can be seen, the actual temperatures; represented by the thick black line, have now dropped below the lower bound.
If, as the Met Office suggests, temperatures remain flat until 2017, the gap between the computers and reality will become even more pronounced.
And that leaves us with the question of whether we should prefer the computer simulations, or the data.
Anyone who is in any doubt about this might like to consider the difference between the forecasts for economic growth spewed out by the Treasury and Bank of England computers and the real data i.e. the amount of cash in their pay packet.
I am afraid that this educational exercise was propaganda masquerading as science.
And what made it even worse was that it was paid for by the taxpayer, as were the travelling expenses of all the members present.

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