Recently, Zytigon, a skeptic who comments on Debunking Christianity, noticed a comment on a anthropogenic global warming denial blog entry by a Johnathan Pearce, thought it was me, understandably. The spelling, though, is slightly different and this person was not me. I support the scientific consensus on global warming agreed by an overwhelming proportion of scientists in the relevant fields. Zytigon seems to claim that we should be skeptical of the claims, endorsing a strong skepticism. Of course, this raises interesting discussions about what skepticism is, and where we draw the line: should we be skeptical of skepticism itself?
So, anyway, without wanting to get on to that discussion here (though I will soon, no doubt), Andy did well to pick up on issues with Zytigon’s AGW scientific skepticism. The comments are worth looking over on the original piece:
Over to Andy:
Richard Dawkins book TGD is a work of genius but will only help you if you read it. New Ten Commandments p299 Never seek to censor or cut yourself off from dissent; always respect the right of others to disagree with you
That indeed is true. However, I see no need in evaluating the opinions of people who have demonstrated that they cannot be trusted. The Heartland Institute is very deceptive and just by reading the first pages of this report, I can see all the classical signs of denialism, for example:
Another reason for the IPCC’s unreliability is the naive acceptance by policymakers of “peer-reviewed” literature as necessarily authoritative. It has become the case that refereeing standards for many climate-change papers are inadequate, often because of the use of an “invisible college” of reviewers of like
inclination to a paper’s authors (Wegman et al.,2006). Policy should be set upon a background of demonstrable science, not upon simple (and often mistaken) assertions that, because a paper was refereed, its conclusions must be accepted.
This is typical for denialism – sowing doubt about the peer-review process, which is admittedly not perfect, but what is being attacked here is a complete strawman. No one argues that the conclusions of a paper have to be accepted “because it was refereed”! All conclusions are provisional and if the conclusions in a paper are controversial, there will be follow-up studies that will also be published in the peer-reviewed literature. And the charges of an “invisible college” of reviewers are completely absurd, I looked up the Wegman 2006 report that is cited here as support for this charge, and this report seriously claims that it is problematic if a climate scientist has amassed 43 co-authors in the course of his career who work in the same field. This claim is completely idiotic. I am a Biologist in a very early stage of my career and I already have dozens of co-authors from just a handful of papers! It is virtually impossible to be an active scientist and not have many co-authors because science is a collaborative effort. And just because I published a paper with someone doesn´t mean that we agree about everything (I know that as a matter of fact) and even if we did, the respective communities are MUCH larger than a few dozen people.
Further signs of denialism: the list of signatures that they refer to (the infamous oregon petition project: http://en.wikipedia.org/wiki/O… ) is standard procedure for denialists, try to find as many alleged academics that support your criticism and cheat to inflate the numbers. This list is completely worthless since institutional affiliations are not given and no one can check whether these people even exist (which led to absurdities like this “Approved names on the list included fictional characters from the television show M*A*S*H, the movie Star Wars, Spice Girls group member Geri Halliwell, English naturalist Charles Darwin (d. 1882) and prank names such as “I. C. Ewe”. “). Exactly the same kind of shenanigans that we are used to from dealing with creationists.
And this is just my impression from reading the introduction… So, while I agree with your statement that one should not shut himself off from criticism, I also believe that I can reasonably dismiss the Heartland Institute as an untrustworthy source without spending days to read their full report and fact-check every of their claims.
One hypothesis is that temperature leads CO2 level in atmosphere, another is that CO2 level leads temperature of atmosphere
It is both, an increasing concentration of atmospheric CO2 increases global temperature because CO2 is a greenhouse gas and increasing temperature causes an increase in atmospheric CO2 levels because more CO2 is released from the oceans (example: equilibrium between H2CO3 (carbonic acid) <-> H2O + CO2 is shifted to the right as temperatures increase). This is not controversial.
There is often a trade off between various priorities. Do we go for
increasing CO2 to 1000ppm for better crops or do we try to stick at
400ppm because we fear the world will end if it gets higher ?
Nobody claims that the world would end, but many species would go extinct and many densely populated regions would become uninhabitable.
We currently have the lowest level of CO2 in the atmosphere of any time in the last 500 million years.
If you calculate averages for intervals of *at least* 500 years, that claim would be true. But for annual levels, it is false – the concentration of atmosspheric CO2 is much larger today than it was some decades ago:
Re the last 500 million years – you are comparing apples with oranges, the biosphere 500 million years ago was *drastically* different compared to modern times. Just one example of what was different 500 million years ago: there were no land plants (and the evolution of leaves was one of the key factors in reducing CO2 levels).
Also, if you look at CO2 rates over geological timescales in a higher resolution, you´ll see several peaks, like the Paleocene–Eocene Thermal Maximum (~55 million years ago) and the Cretaceous peak (>70 million years ago), and these peaks are associated with significant increases in global temperatures. What is dangerous about that is not the raw increase in temperature but rather the speed of change. If this happens gradually (as it did for the cretaceous maximum where there was an overall increase of 5 degrees Celcius), this does not cause an above average rate of extinctions because there is enough times for species to adapt to changes in climate and because the Oceans don´t acidify when CO2 accumulates slowly. If the speed of climate change is faster (the speed of change leading to the Paleocene–Eocene Thermal Maximum was an order of magnitutde faster compared to the Cretaceous Maximum), this does cause extinctions because many species cannot adapt in time. And as it looks at the moment, the rate of change that we experience at the moment is much faster than both of those previous events. And again, it´s not the raw increase in temperature or CO2 that is dangerous, it is the speed of change that is dangerous.