In honor of the passing of the polar vortex, I’d like to review what I think we know about the state of climate science:
- The earth is warming, probably as a result of human carbon dioxide emissions.
- The amount the earth has warmed in modern times so far, although measurable, is negligible. The warming trend we see (as in the famous “hockey-stick” charts) uses a smoothing function, and is much, much smaller than the year-to-year variation.
- Thus, anyone who says this or that weather is the result of global warming, is a fool, a liar, or both. Generally climate scientists refrain from making such statements, but climate activists and politicians do not. (This problem seems particularly prevalent in Britain, where both parties’ leaders believe global warming is affecting current weather.)
- We can calculate the direct impact of increased carbon dioxide on the climate as a straightforward physics problem. The direct impact is small.
- Predictions of dire consequences are based on feedback loops. For example, warming causes ice to melt, which results in more clouds, which either increase or decrease warming depending on where and how they form. Climate scientists differ on whether positive or negative feedbacks will dominate, but the former camp (i.e., feedback leads to more warming) seems to be larger, and is certainly more influential and better funded.
- There is no way to test whether the positive or negative feedbacks dominate, and by how much, so climate scientists build models. Predictions of future climate are made on the basis of these models.
- Most climate scientists (at least the influential, well-funded ones) believe that the strong-positive-feedback models are more convincing.
- KEY POINT: However, there is no way actually to test the long-term predictions of these models without waiting for the long term. The short-term predictions of the models have generally not come true. (In fact, in 2005 Gavin Schmidt could only point to one instance in which a climate model made a prediction that was subsequently validated.)
- Consequently, we just don’t know what long-term effects increased carbon dioxide will have, scientifically speaking.
- However, we do know that cutting carbon dioxide emissions to a degree that would make a difference (according to the models) would not only be disastrous, it is literally impossible, barring an unforeseen technological advance.
- Thus, we ought to be looking at reasonable, cost-effective ways to limit CO2 emissions (e.g., nuclear energy, carbon sequestration), but not ridiculous ways (e.g., everything the left wants). We should also be looking at geoengineering in case the worst comes to pass.
Note that above I am not criticizing any of the work of any climate scientists. I simply don’t have the background to do it. Other people who do have the background have criticized their work (the media calls them “climate skeptics”), but I have no way to judge who is in the right. Thus, I’m relying on the consensus view (by which I mean actual consensus, not the consensus of just one side, which is how the media seems to use the term), and — in points 8 and 9 — my basic understanding of the scientific method.
One area in which I do have the background to criticize their work is in their programming. Much of climate science relies heavily on data sets that must be processed by computer. Unfortunately, it seems that their standards of programming is very low, at least if the story of HARRY_READ_ME.txt is typical. This means that the data they are using is suspect. (And, unfortunately, the raw data doesn’t exist any more!)
Worse, there is very good reason to worry that the academic process itself in climate science is badly broken:
- Climate scientists refuse to share their data, and actually delete their data when they might be forced to release it. (They also lie about it, and even break the law.) From scientists this is astonishing and horrifying, and it tells us that we simply cannot believe their results.
- Influential climate scientists have subverted the peer-review process. This corrupts their entire field, not just their own work.
- On occasion, they tell outright lies.
- Alas, there’s no indication that anything has improved in the field since all the above misconduct came to light.
So where does this leave us? Climate scientists have a tough job: they can’t run controlled experiments and their most important predictions can’t be tested. You can’t blame them for that. You can blame them for shoddy programming, and for academic misconduct.