This will be a longer post about the new Iphone-App where skeptical and pro-AGW views are pitted against each other, with the pro-crowd winning. I will only focus on some of the criticism, because I don’t think all of this is genuine skeptic stuff, some is just Republican bull-sh*t.
One thing before we get started, I really like this app, though I don’t agree with everything. It is, however, a good place to start looking at the scientific background, because for every “skeptic” argument, there is a rebuttal with lots of links to science papers. I like it on a different point, too, it is an open debate tool and if there is anything that we need, than it is open debate. If you want the app, just search for it in the AppStore @Apple (name: Skeptical Science)
Since I’m not in the category of “It’s not happening”, which is the prominent first batch of Q&A in the app, I will continue with “it’s not us” and “it’s not bad”.
1. Global Warming is good:
This is actually a cost-benefit analysis, that is often done without the help of economists (which is bad, because scientists do have often not a good grasp on basic economics). First of most of the papers pro- and contra the issue make a simple mistake: They assume a certain change without a lot of checking on the certainty level.
There a good points for and against a certain change and often they only look at the effects of one change (f.e. higher temperatures in the Mid-West, which cannot necessarily concluded from higher average mean temperatures). So, the only good prediction we can do is actually deriving a prediction from history. How did people survive in different regions in the world since the first known settlements. And here, we have an interesting picture: Higher Temperatures are often linked to higher mobility and higher productivity. Lower Temperatures are especially linked to famine and death and diseases during the little Ice Age. Of course, both directions have one magic word in them: Adaption and Movement of civilizations.
I’d say that a mild warming of half a degree to a degree C is no problem for most parts. It has been that warm during the reign of the Roman Empire and they coped with it quite well. There are of course ramifications for several people living in already hot areas, but so has the idea to stop or cool the earth again.
2. Climate Sensitivity is low:
I’m not sure that the author completely understood the skeptics point on climate sensitivity. In short, he argues that sensitivity is calculated empirically from past temperature changes. The sensitivity is the result of several examinations of the distant past and is agreed on 3 °C. This is not entirely right, because we have to distinguish between the direct effect due to CO2 and the so-called feedback element. It is also untrue that the first estimations of climate sensitivity are derived from models. The first estimation of CO2 impact is actually the laboratory test of the CO2 re-radiation property of infrared rays. And these tests give us a sensitivity of 0.6-1 °C per century when CO2-concentration is doubled with the relationship decreasing the higher the CO2-concentration.
Some climate scientists also tried to derive sensitivity from the past climate temperature data. This is a difficult process, because:
a) Uncertainty is higher the father one goes in the past (see NAS panel)
b) Linkage of CO2 and temperature in the past is mostly reversed: Temperature changed and then CO2 changed.
There is however one interesting linkage, high-rates of CO2 change are the result of high temperature changes. This is crucial, because today's changes in temperature are not that different from others in the last 2000 years, which means that Earth can adapt to changes up to now pretty fast (within less than a century – Schwartz et. al.). Thus we still have a lot of time to geo-engineer something.
Problematic is the missing distinction between feedback and sensitivity, because they are interlinked, but also quite different. Feedback are effects that take place due to sudden temperature changes caused by CO2, thus not directly caused by an increase of CO2. These effects are highly debatable and are the reason for Sensitivity ratings higher than 1.2 °C.
3. Animals and Trees can adapt to global warming:
This is a difficult topic, because we can only derive knowledge from the past and most of those climate changes were only temporary. There were catastrophic events that eradicated a lot of species, there were also slow events that extinguished some species, but there were also numerous cases where species could adapt. Nowadays, the chances for some species are higher due to human development (cows, pigs, chicken etc. – everything we eat).
Of course, it will have consequences if there is a long lasting warming trend. However, there have been similar rises in temperature in the last 2000 years and they didn’t hurt the flora and fauna much. Also, ocean acidification isn’t the worst issue, because most shell-fish can adapt pretty well, as I have explained in another blog post.
4. CO2 is not a pollutant:
The explanation for CO2 as a pollutant is, that a pollutant is every kind of substance that changes the “pure” natural order. This could also include parasites, Ants, all kind of human construction etc. It is a bad and not very useful description of a pollutant. Water vapor has the same effect as CO2 and it is not yet a pollutant.
CO2 can’t even be considered to have undue effect on the climate system, because it has varied greatly in the past, too, without human influence. Yes it is a controlling variable, but not (unlike Sulphur-Oxid) a pollutant. Sadly, the rest of the entry in this category is just politicized demagoguery which has little scientific basis, beyond prediction studies that are very uncertain.
I have nothing to say on sea level rises, because I believe that technology and wealth can perfectly deal with them. You don’t believe me, but I think the people of Belgium and Holland might have to say something about this.
Now, I will be going on to the category “it’s not us”
5. Medieval Warm Period was warmer:
Actually, the defense here is weak, because even Dr. Jones now concedes that the MWP was higher than the assumptions made by Mann et. al. McIntyre clearly demonstrated this on his blog and I think he is on to something. He criticized the papers using proxies to establish the height of the MWP, because they used an algorithm that under-represented the bump artificially.
Also, anecdotal evidence of glacier free passes in Switzerland should give an impression of what the northern hemisphere looked like. The funny thing is that the southern hemisphere is actually pretty constant, even today. It is mostly the northern hemisphere that registers exceptional swings.
6. CO2 has been higher in the past/CO2 lags Temperature:
It is true that solar levels were lower, when CO2 was higher (nice trick by the Earth climate system), but so it is today. The solar cycle is in a hiatus while CO2 is pretty high. It was actually in a high during the 1900-1970s and its increase in CO2. Again it is rather the lag between temperature rises in the past and CO2 levels that should be investigated and is of interest.
The explanation to this lag of temperature is simplistic at best.If it were true that the rise in CO2 would amplify the temperature that much, than why did it swing back? All because of the solar cycle? In this case, the solar cycle could be used to reduce warming nowadays, too…