Editor’s note: This is the second of a series of discussions with Grove City College physicist Dr. Glenn Marsch regarding global warming. In the first Q&A we compared the articles that ran in the New York Times and the Wall Street Journal about how the Obama administration will pursue a U.N. international global warming treaty even while the science demonstrates, and the U.N. acknowledges, that there has been no global warming since just before the turn of the century.
V&V: Dr. Marsch, in our last climate discussion, you suggested that Americans “cool it” or wait and see what the science really has to say about global warming and humanity’s part in it. But what about computer models and their predictions? Some claim that we can speed up the political process of remediating CO2 by using computer models. They ask: Do we really need to wait for years or decades to see what science tells us? Wouldn’t it be faster and more efficient to make climate policy based on computer models?
Marsch: The computer models, which in many ways are the basis of the alarm about global warming, became famous in 1988. That summer, Sen. Tim Wirth encouraged climate modeler James Hansen to testify before Congress that global warming was real and was a national threat. I think he succeeded in creating alarm and he was a catalyst for doing something about it economically.
V&V: What about the global warming pause or hiatus (no global warming for the past 15-26 years) that we talked about in our last discussion? Did the models predict that phenomenon?
Marsch: Ninety-five percent of them failed to predict the pause, or the hiatus, that we’re experiencing right now. So there’s a lot about the effect of carbon dioxide that we’re unsure about. Now Richard Muller of Berkeley – who believes that humans are causing global warming but who is also cautious about climate computer modeling – thinks the past data suggest that the global temperature will increase in a stair-step pattern.
V&V: What does that mean?
Marsch: This hypothesis suggests that we’re going to have maybe a couple of decades of relatively stable temperatures; and then we’re going to get a fairly abrupt “stair-step” when temperatures increase. And then it will be stable for a couple of decades and then another stair-step increase. Some folks think that this pause, this hiatus of at least 15 years that we’re experiencing now, may just simply be that we’re on the stair and that we’re going to have a stair-step again and it’s going to ratchet up maybe another half degree or so.
V&V: Is that plausible?
Marsch: Yes, it’s a reasonable thing to say. It’s a perfectly reasonable interpretation of the past data and so what we have to do is look at future global climate temperatures and see if another temperature increase happens. It might happen.
V&V: So there’s risk in relying on models to make sweeping climate treaties? You say we have to “look at it and see if it happens.”
Marsch: Yes, there are too many climate variables to create computer models with enough certainty upon which to make international policies that could radically alter the global economy. I consider myself not a denier but a skeptic. I think the science is too complicated to make simplistic policy decisions right now. Climate science is a relatively new field and is far too complicated for us to use it to make overarching policy prescriptions.
V&V: It sounds as though the one certainty that we have from the models so far is that there’s much more work to do in modeling. We know this for certain: Modeling, at this time, cannot accurately predict climate change.
Marsch: Yes, I believe that’s correct.
V&V: Okay, so what’s the value of the Matthew Ridley article in the Wall Street Journal that we recently discussed?
Marsch: Well, he quotes a paper by Ross McKitrick, who is not appreciated by many in the climate science community, but who is an excellent statistician. It’s basically a lot of his work (along with the work of Steve McIntyre) that has cast doubt into some of the statistical analyses of climate data done by some in the global warming community. At any rate, McKitrick has looked at the hiatus – and depending upon what kind of data set he’s looking at, the hiatus is anywhere from 16 to 29 years. And the microwave satellite data show approximately a 17 or 18-year hiatus. Most computer models didn’t predict this outcome.
V&V: A “hiatus” means we’ve leveled off?
Marsch: We’ve leveled off. So, our freshman college students have essentially never seen global warming.
V&V: How many of them do you think are scared by it?
Marsch: Probably a lot. The computer models and the press they attract may have contributed to their fear and the fear experienced by a large segment of our population. The reality is that our freshmen have never experienced global warming in their lives. And, as I suggested in our last discussion, it’s not clear that if they were to experience global warming that it would be a bad thing. Climate science is important work and computer modeling is an important component of that work. Climate researchers have a lot more work to do.
V&V: Thank you, Dr. Marsch. We’re looking forward to discussing carbon dioxide levels next week.
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