Eschenbach's Challenge

On the 31st March, Willis Eschenbach posted an informative item on WUWT in which he answered various self posed questions regarding climate change and his personal opinions on the matter. He also challenged other scientists to likewise answer the questions. I only noticed after Walt Meier from the NSIDC repsonded. I'm no scientist, and I rather doubt Willis or Wattsyor anyone else on WUWT has the slightest interest in what I think, so I'll just run through them and post my answers here. If nothing else it'll be interesting to see if my view change in years to come.

Preface Question 1. Do you consider yourself an environmentalist?

Yes, I certainly am and always have been. Indeed, why else would I be so against the despoliation of remote landscapes by windfarm developments? The great John Muir once said "Thousands of tired, nerve-shaken, over-civilized people are beginning to find out going to the mountains is going home; that wilderness is a necessity..." and I firmly believe that to be correct. We need the wilderness today. And those who follow will still need it tomorrow. Should we deny the wilderness to our children just so that we can waste more resources today?

Preface Question 2. What single word would you choose to describe your position on climate science?

Sceptical. As I hope all of a scientific bent are.

Question 1. Does the earth have a preferred temperature which is actively maintained by the climate system?

Clearly not, or else we would not be in an glacial/interglacial cycle. It could be argued that the current default position is glacial - and thus any warming is abnormal for this geological epoch.

Question 2. Regarding human effects on climate, what is the null hypothesis?

That the climate today in all parts of the world, and all observed changes in climate, would be and occur exactly the same had mankind never existed.

Question 3. What observations tend to support or reject the null hypothesis?

UHIs alone show that on a local level we must reject the null hypothesis. Changes caused by, for example, the drying up of the Aral Sea mean we must reject it on a regional basis. It's more complicated with regards a global basis, but my opinion is that local and regional chanages are themselves sufficent to effect a global change and thus we can reject the null hypothesis at all levels. The fact that atmospheric composition has also clearly changed due to human activity alone means that, if that change has any effect whatsoever on climate, then we have further rejection.

Question 4. Is the globe warming?

As Willis says, this is a trick question. On an annual basis, yes, but not significantly. On a centennial basis yes - this is I think indisputable. On a millenial basis I think no, we are in fact cooling as a result in subtle changes to Earth's orbit (this change set in around 5,000 years ago). It's probably not worth looking at longer time scales!

Question 5. Are humans responsible for global warming?

Yes. The question is by how much.

But I will also say the humans are respsonible for global cooling - through the likes are sulphate emissions, brown clouds etc, and indeed some landuse changes. This undoubtably balances out some of the warming so that the net increase is reduced.

Question 6. If the answer to Question 5 is “Yes”, how are humans affecting the climate?

By a variety of means, notably landuse change (which includes deforestation and urbanisation), but also from the likes of black carbon and from CO2 emissions.

Question 7. How much of the post 1980 temperature change is due to human activities?

An interesting question. What would the post 1980 temperature change have been had there been no humans on the planet (back to the mull hypothesis)? I'm not entirely sure that would have been any warming at all - in which case the answer is all of it. Further, would there have been an cooling? In which case it maight be argued the extent of warming due to human activity is greater than the extent of warming that has been measured.

Question 8. Does the evidence from the climate models show that humans are responsible for changes in the climate?

I do not consider climate models evidence of anything. What they show is how the climate may change in the future if certain assumptions are correct. I know it is argued that models cannot replicate late 20th century climate changes without increased CO2 having an effect - in my opinion this may be evidence for AGW only if we can be 100% certain that every possible factor - known and unknown - behind climate change has been taken into account. I do not think this is by any means the case.

Question 9. Are the models capable of projecting climate changes for 100 years?

Only for a given set of assumptions.

Question 10. Are current climate theories capable of explaining the observations?

Probably not, because it seems to me that if all theories are correct, there has not been as much warming as their should and therefore such theories must be missing some negative forcing or other factors.

Question 11. Is the science settled?

Insofar as there is always something new to learn and discover then science is never settled! But insofar as a general statement "humans are causing climate change" - which is the context in which I understand this statement should be taken - then yes, it is settled.

Question 12. Is climate science a physical science?

Yes. Although climate is about 'average weather conditions' it is necessary to understand weather and the forces which affect it in order to determine climate change cause and effect. There is some statistical element to it but in my opinion this is overstated by statisticans who have no understanding of the weather ... ;-)

Question 13. Is the current peer-review system inadequate, and if so, how can it be improved?

Having had no involvement with peer review, then I am not qualified to comment. However, in my opinion, if the peer review system is inadequate as far as climate science goes, then it must perforce be equally indequate in all other areas - some of which are often equally or even more contentious than climate change. I do also like Willis' suggestion

Publish the names of the reviewers and their reviews along with the paper. The reviews are just as important as the paper, as they reveal the views of other scientists on the issues covered. This will stop the “stab in the back in the dark” kind of reviewing highlighted in the CRU emails.

This seems quite reasonable to me - for all areas where the peer review process is used.

Question 14. Regarding climate, what action (if any) should we take at this point?

I believe our priorities should be to curb tropical deforestation and develop means for much more efficent use of the energy we generate. I do not consider CO2 emission reductions practical at this time. And carbon trading and 'green' taxation will not only make exactly nil difference but are certain to lead to resentment and greater rejection of the idea of human activity affecting the climate.