Climate Change

Point and Counterpoint

In #articles

In this post, I am reacting to a very interesting and well researched post where a liberal argues that the climate science is not as settled as we hear. I agree with many points and am critical of other points. The overall message I think is a good one, however.

This is a lot to go through so my initial thoughts may be a bit scattered as I go through pieces of this document.

Let's start with some critique. The argument that temperature causes CO$_2$ to increase in the past and not vice versa is a pretty terrible argument. The physics is known - they each influence each other. In the past it has been temperature that has changed due to the orbital changes, and that consequently drove increases in CO$_2$. But you can just as easily change CO$_2$ directly as in burning fossil fuels and affect temperature. It's not an either-or situation so this argument is misleading.

As for whether the earth was warmer a thousand years ago, I am somewhat agnostic. The tree ring data and other proxy data in my view is extremely noisy and hard to make concrete conclusions. So the uncertainty around the medieval warming period is something to be concerned about. If it was warmer 500-1000 years ago, many of the stronger claims, about climate change and how unusual the modern time period is, collapse. The statistical arguments that lead to the hockey stick are not convincing to me and are vulnerable to confirmation bias.

The solar connection to temperature is weaker than what the author presents here. The recent inactive sun should have led to an actual cooling not a leveling off if the solar connection was really as strong as they are saying in this article. The correlation is really somewhat weak especially in modern times. It's still there, though, and needs to be dealt with but it is in fact dealt with in many, if not all, of the models already so this is not a strong argument.

One thing where I agree with the article concerns a number of the predictions that have been made in the past concerning global warming. Many have not really come to fruition. Things like the polar bear population dropping and the increase in hurricanes and tornadoes are examples of this. These just haven't turned out to be the case. In addition, it happens that more people die from cold spells than do from hot spells which means there is at least one benefit of global warming (and there may be more). I'm not saying that it is necessarily a good thing when the climate changes or that it is overall a benefit that we are affecting the climate with our behavior. However one has to look at both the costs and the benefits of any change when trying to assess what to do about it.

I find many environmentalists, although well-meaning, are one-sided and do not look for the benefits of a perceived problem. The best example I can think of is pollution. What are the costs and benefits of pollution? Environmentalists are quick to point out the costs - namely the health damages. They are not so keen on pointing out the benefits. In fact if you ask an environmentalist what the benefits of pollution are they will often look offended as if the answer is obvious… None! I'll admit that when I first heard that phrase from an economist it was a little puzzling until it was explained that the meaning of the phrase "benefit of pollution" is what is the "benefit of the thing that is giving you the pollution". So if you look at cars for example we can see that the air pollution the cars give us has a cost - the pollution's impact on health and property - but it also has some clear benefits, even for health. Namely, with cars it is easier to access healthcare, there are more rapid transportation options than with horses, etc... Ironically the advent of cars while increasing air pollution, also produced a huge reduction in water pollution due to the reduction in animal carcasses (especially in cities) and the fertilizer used for animal feed. In the same way there are both costs and benefits of climate change and we need to be clear about which they are.

The Arctic ice dynamics do seem to be decreasing although the Antarctic ice seems to be increasing somewhat. Some of the predicted consequences have been overblown, however. The fact that polar bears for example, have been around for 200000 years and there have been ice free times in the arctic it during that time means that ice cover alone does not drive polar bear population declines.

"According to Bob Tisdale, a researcher I respect after reading his book Climate Models Fail, the IPCC models simply aren’t skillful. They failed to predict the past twenty years, they don’t realistically model the cloud response, and there is simply too much uncertainty about the inputs to get decent outputs."

I wholeheartedly agree with this paragraph. The reason the "pause" is called the "pause" is because none of the models predicted it, even if you see it as a couple-decades long variation in the overall increase, none of the models predicted it. It lies outside of the uncertainty range given for these models. This just shows that the models have a great deal of uncertainty which is not accurately characterized.

The biggest place where uncertainty plays a role it seems is in the climate sensitivity. Namely how much should we expect the temperature to change given an increase in carbon dioxide, given all of the Earth feedbacks (both positive and negative feedbacks). It seems as if most of the estimates that are done for theoretical reasons disagree with those empirically measured and always in the same direction - the theory predicts a bigger sensitivity than observed. This means that the climate sensitivity assumed in the models doesn't match the actually measured climate sensitivity. There is still a lot of uncertainty in this topic, mostly due to potential negative feedbacks like cloud cover.

"we should switch to renewable sources of energy, but for the right reasons at the right price."

I agree with this entirely. While it may be the case that carbon dioxide is causing climate change, the uncertainty surrounding the issue makes it a harder sell in my opinion than, for example, reducing fossil-fuel use for national security. If we can wean ourselves off of fossil fuels then we might be able to remove ourselves politically from those struggles in the Middle East that seem to cause so much grief. Unfortunately the only long-term solution is nuclear power which is another discussion altogether.

The section of the article which describes whom you should trust and whom you shouldn't trust smacks to me of conspiracy-theory thinking. I think you should look at all of the data and look at competing views and see for yourself on particular issues which side seems to be making more sense. Which side posts the data, and the analysis, so that you can reproduce it? What are the types of criticisms and counter arguments are presented? Look for cherry-picking and ad hominem attacks as a sign of a bad argument.

I agree with most of the skepticism the author communicates and with his recommendations for reading the "protagonist" side, as he calls them. People like Judith Curry and Steve McIntyre, for example. However he includes people like Michael Crichton, whose novel discussing climate change is really an exercise in cherry picking. We go through the actual data in a classroom exercise and the pattern is pretty clear.

So, look at all sides of an argument, examine the evidence, and look at the arguments. In addition, try to go in assuming that people intend the best - make the most charitable reading, and avoid attributing motives to the side you disagree with. On any complex issue, those that disagree with you are probably right on some level no matter what side of the argument they are on.

Finally, I want to add that I can be convinced of any reasonable position - just present the evidence. So please do!