Saturday, June 18, 2011

What are climate sceptics actually saying?

They are shy of making any statements that are actually testable, so in a spirit of helpfulness, I will deduce them for them, by mirroring the scientists' case:

Essentially, climate sceptics are putting forward one or more of these key statements:


1 CO2 is not a greenhouse gas.

This would be very difficult to sustain, given that the effect is demonstrable in the laboratory, but one sceptic tweeter  (@TertiusIII) has already suggested that it is not, in fact maybe the opposite. I have challenged him for evidence, and no answer has been given.


2 CO2 has not increased since 1800

Again, this would be difficult to sustain, since there is a wealth of observational data to show that it has.

3 The climate sensitivity to CO2 is less than 1.5*C
It seems that this is emerging as their thesis, though Peiser was unwilling to actually state it. 
It probably is their key position, and the debate should therefore centre on this point.

Climate sensitivity is the degree of change in global temperature that will result from the doubling of any input factor - natural (solar, volcanoes, ocean currents) or man-made.

The IPCC states:
The equilibrium climate sensitivity is a measure of the climate system response to sustained radiative forcing. It is defined as the equilibrium global average surface warming following a doubling of CO2 concentration. Progress since the TAR enables an assessment that climate sensitivity is likely to be in the range of 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values. {WGI 8.69.6Box 10.2SPM}


Note the "Very unlikely to be less than 1.5*C".

So the challenge for the global warming skeptics is for them to try to defend their thesis that CO2 sensitivity is at that level or less.

The debate now gets pretty technical, but the skeptics claim to understand climate science, so the first approach would be to lock a few climate scientists and skeptics in a room together for a few days and see what they come up with.


One way of testing their thesis would be to put CO2 sensitivity of, say, 1*C into all the models, and see how good the match that produces is for observed temperatures.

On this point, their response might be that they want to disallow any computer models. The question then becomes, would they accept it if calculations were made by hand, with pencil and paper as they were in the early years of climate science? That seems pretty absurd.



 Or are they against calculation of any kind?

In the latter case, they would be not just anti-science, but also anti mathematics! Clearly an absurd position.



More:
What is the point of debating with sceptics?
Correspondence with a leading sceptic
Summary of the correspondence

12 comments:

Phil said...

I'm sure they'd be happy to have someone else do the calculations by hand, as that fits in very nicely with their delayer tactics.

DocRichard said...

That would be pointless, since if the results went against them, they would say that they fiddled the figures.

Therefore it must be the sceptics who must do the calculations by hand.

Phil, thanks for taking an interest in this initiative. It is getting a bit of attention - 48 hits so far on all the posts.

I've been corresponding with Roger Harrabin. He seems to be slipping over to the Dark Side...

@jessecusack said...

Perhaps they think the climate models themselves are incorrect, in which case it might be worth asking what aspect of the model is incorrect.

As mentioned in that nature article I linked to in a previous comment, the models are known to be very solid when it comes to calculating average temperatures. It is when you try to focus in on temperature variations on scales smaller than a few hundreds of km that things fall down.

So it follows that for large scale objects, say Greenland ice sheets (being many thousands of km in scale), average temperature calculations are not in doubt, thus consequences of such variations are not in doubt either (melting ice sheets, sea level rise).

AGW deniers really don't have a leg to stand on... even if the model is not accurate down to the size of the back garden.

GIDEON MACK said...

The IPCC is a joke and not worthy of quoting.

Who says we have the ideal climate now?

The planet is going into a cooler sun spot phase (yawn) - i.e. I don't know - you don't know - the IPCC doesn't know.

More fresh water from the glaciers would be much appreciated by 1 billion people.

DocRichard said...

Hi Gideon
The IPCC has made a couple of mistakes, and it is a pity that Pauchauri is still in post. But if the IPCC didn't exist we would have to invent one.
The disrupted weather patterns we are seeing are consistent with GW predictions.

I am pleased to say that I posted a prescient piece on a solar minimum 18 months ago.

Glacier melt could be caught for a bit, but no glaciers = no rivers. It is the old story - do not use your capital as income.

What about the core argument - is my guess right?

Phil said...

And if they did those calculations by hand, they'd take their time, insist on triple checking them, all so they could delay....

DocRichard said...

Keep 'em busy for a few centuries...

john said...

Since the global climatic regime is driven by the second law of thermodynamics [ http://en.wikipedia.org/wiki/Second_law_of_thermodynamics ] no sums are neccesary if the polar regions are warming the globe is warming, everything else is b------- . Both poles are warming, though there are far more straws for sceptics to clutch at and argue about in antarctica. In the arctic the warming continues, [ http://nsidc.org/arcticseaicenews/ ] and, I believe has passed the tipping point, we have entered a period where the arctic ocean has passed from being a continental sized arid frozen desert and are watching its transformation into an open temperate ocean which shifts the arid 'cold sink' point south to greenland and the area west of greenland, and/ or to siberia. These will be the late summer default centers of high pressure systems and will both tend to draw the atlantic drift deeper into the arctic and towards siberia. [ incidentally reducing the temperature of western europe by 5-15C The one to the west of greenland will have the unfortunate effect of drawing prodigious blizzards out of the arctic and dropping them over the usa all the way down to texas quite possibly rendering everywhere north of st louis uninhabitable. If it wasn't for the present[10 years and counting] cool phase long predicted by peirs corbyn and recently announced by nasa I think this would have already kicked off but with the ice in retreat is still on the brink.
The trouble is although this is blindingly obvious to me it has to be wrong because it spells the end of world dominance by the Usa and its nato lackeys, and it seems to be their spokesmen and dupes who are driving the denial/obfuscation machine.
So what explanation do they have for the retreating ice and what consequences do they forsee? Or is the current obscene concentration of wealth a sign of preparation and the abdication of care by the elite.

DocRichard said...

John
I fear you may be right. Which is why, paradoxically, I find myself wishing that the skeptics could be right, or even part right. I hope that if we are going into a solar minimum it has a bigger cooling effect than the scientists expect.

To get political change, we need to refute the skeptics' case. This involves concentrating on the q of climate sensitivity, and that is why I am focusing obsessively on it at present. I wish the Green Party and others would join in this, but no dice so far, on the only GP discussion forum I can find.

Anyone know what happened to GP email discussion lists? cannot find a link to them on the members site.

weggis said...

http://lists.greenparty.org.uk/cgi-bin/mailman/listinfo

Am I arguing with you?

DocRichard said...

Weg, a) thanks
b) I dunno. Are you?

DocRichard said...

Weg,
I found the lists soon after I poured out my bitter spleen at the unfairness of not being able to find them. I've rejoined the GP Climate Change list.

2Peter 2:22