Jeff Jacoby has taken the Media Nation challenge. On Dec. 24 I asked him to respond to some questions I had over a column he wrote that plays down global warming. Here is his answer, with my original questions to him in bold.
To: Dan Kennedy
From: Jeff Jacoby
Date: January 2, 2007
Thanks for reading my recent column on global warming alarmism. Here are my replies to the challenge you posted at Media Nation.
1. You make much of the fact that scientific predictions about the climate have changed considerably over time. For instance, you note that climatologist Reid Bryson, in the mid-1970s, predicted catastrophic global cooling.
Question: Do you believe science, and our ability to measure climate change, have advanced over the past 32 years? And if you do, don’t think you anything a scientist wrote in 1974 is utterly irrelevant?
Let me turn your question around: Do you really believe that it is never significant when scientists — unlike, say, politicians and journalists — say and do things that sharply contradict their previous statements and claims? It is true, as the mutual-fund disclaimers put it, that past performance is no guarantee of future results. But are they really “utterly irrelevant”? Surely the accuracy of yesterday’s predictions is one indicator of whether today’s new-and-improved prognostications ought to be taken seriously.
I am not a climate scientist, and can’t speak with expertise about the change in climate metrics since 1974. (More on that in a moment.) I agree that as a general rule, scientific understanding tends to advance over time. That doesn’t mean that it advances in every field, and it doesn’t meant that it advances at a uniform rate.
In any case, I didn’t quote Bryson’s alarmist 1974 warnings of the coming global freeze to disprove claims of global warming today; I quoted it to illustrate my point that while conventional wisdom undergoes 180-degree shifts, the gloom-and-doom fear-mongering never seems to change. The science may be more sophisticated now, but the Chicken Little squawking is exactly the same.
For an answer to the specific question of improvements in climate science since the 1970s, I turned to Richard Lindzen, the Sloan Professor of Atmospheric Science at MIT and a lead author of the Working Group I assessment report of the United Nations’ Intergovernmental Panel on Climate Change (IPCC), which focused on the science of climate change. He writes:
Actually, there has been almost no progress on crucial matters like climate sensitivity since the 1970s. The range of model results has not changed since Jule Charney’s report for the National Academy of Sciences in 1979. To be sure, the latest version of the IPCC Assessment does cut back the high end, but there is still no basis for relying on the range supplied by current models. The sensitivity of those models depends critically on the impact of the main greenhouse substances, water vapor and clouds. Models can’t account for these directly because they can’t resolve the effect clouds have on climate, and so modelers are forced to rely on formulas that date back to the 1970s.
Moreover, 30 years ago scientists were beginning to realize that major climate changes were characterized more by changes in the temperature difference between the poles and the tropics rather than by changes in the global mean temperature. With the current focus on global mean temperature and on a single global forcing term, it could be argued that the science of climate has actually regressed. As climate scientists in government agencies can tell you, financial support for climate research depends on heightened concern over global warming. This has undoubtedly discouraged attempts to actually understand climate.
Observation is an issue, too. The number of surface observation stations has decreased substantially over the past three decades. Of course, there are now satellite observations of atmospheric (rather than surface) temperatures. But these continue to show less warming than is found at the surface, even though greenhouse theory and the models say we should find more warming in the atmosphere.
These aren’t the only weaknesses in calculating climate sensitivity. For example, the models generate different (and frequently opposite) results for regional climate change. But these should be enough to demonstrate that progress since the 1970s has been pathetic at best.
2. Two words never appear in your column: “carbon dioxide.” Yet according to the National Oceanic and Atmospheric Administration, the level of atmospheric CO2 has risen from 280 parts per million to 370 parts per million since the start of the Industrial Revolution. “The concentration of CO2 in our atmosphere today, has not been exceeded in the last 420,000 years, and likely not in the last 20 million years,” according to the agency’s Web site.
Question: What evidence can you state for your apparent belief that rising CO2 levels have no effect on the climate?
I make no claim in my column about rising carbon dioxide levels, so I’m not sure how you detect my “apparent belief” that CO2 doesn’t affect climate. I am skeptical of the claim that the impact of human-generated CO2 on the planet’s climate can be determined with precision. And I am aware, as I hope you are, that global temperatures have varied over the centuries. A thousand years ago, the Northern Hemisphere was in the middle of the Medieval Warm Period, when temperatures then were high enough that the Vikings could cultivate Greenland — which today is covered with ice. By 1500, the climate pendulum had swung the other way. The next few centuries were so cold that historians call them the Little Ice Age. Oranges stopped growing in China. Glaciers engulfed French villages. Now in the 20th century, the world has started warming up again. In short, climate changes — and there appears to be more to the story than anthropogenic CO2 emissions alone.
Again, from Professor Lindzen:
No one claims that rising levels of carbon dioxide have no effect on climate. In fact, we understand the forcing of climate that arises from CO2 pretty well.
The normal heat balance of the Earth consists in about 200 Watts per square meter (W/m2) coming in as visible light and about 200 W/m2 going out in the form of infrared radiation. Doubling CO2 should produce a 3.5 W/m2 reduction of the latter — a perturbation of just under 2%. That in turn leads to warming of about 1 degree Celsius if everything else remains the same. The more alarming climate claims are based on the belief that water vapor and clouds amplify the warming caused by carbon dioxide. But their impact is not well understood — and may actually be the opposite of what the models assume.
It is also well known that the temperature effect of atmospheric carbon dioxide is logarithmic, not linear. That is, each added unit of CO2 causes less warming than its predecessor. It turns out that the current perturbation to the greenhouse forcing amounts to about 2.5 W/m2 (1.5 from CO2, 0.5 from methane, and the rest from N2O and fluorocarbons). According to the models, we should already have seen much more warming than we have. In order to match observations of global mean surface temperature, models have to cancel more than two-thirds of the greenhouse forcing. Many modelers claim the cancellation is due to aerosols. But scientists who specialize in aerosols maintain that their effect is essentially unknown. Thus, the cancellation is nothing more than an arbitrary adjustment.
A simpler, and more likely, reason for model overestimates is that the model feedbacks are incorrect, and the models are exaggerating the impact of the small CO2 forcing. Twenty years’ worth of satellite observations support this conclusion.
3. Most serious people who’ve looked at global warming believe we need to undertake technological steps ranging from developing renewable energy sources such as solar and wind to building a safer generation of nuclear power plants. That was certainly one of the messages Al Gore puts forth in his film “An Inconvenient Truth.” In other words, though there may be a few alternative-lifestyle types who believe global warming can only be reversed by living like the Amish, most of us want to innovate our way out of this mess — a very American approach, I might add.
Question: How did global warming become part of the culture war? And why on earth have conservatives like you adopted the denial of global warming as a pet cause?
Global warming became part of the culture war when it became another topic on which the left decided to stifle free speech and demonize dissenters.
I don’t speak for other conservatives, but global warming seems to me to be the latest weapon in the arsenal of environmental ideologues who warn that the earth and humankind are doomed unless we adopt sweeping policies that will radically change the way we live, generally by reducing freedom, limiting choices, and aggrandizing government. The particular threat they invoke changes over time — pesticides, overpopulation, resource depletion, nuclear winter, global warming — but the we-are-doomed-unless-you-do-what-I-say hysteria remains constant. In Al Gore’s words, “We must make the rescue of the environment the central organizing principle for civilization.”
Human beings were able to adapt and innovate their way from the Medieval Warming Period to the Little Ice Age and out again. They will probably be able to handle the global temperature increase of a degree or two that may be coming over the next few decades. And they will be able to do it more intelligently and successfully if they don’t shut down debate, discussion, and dissent — or let a Global Warming Czar tell them that the only way to make the world better is to make do with less energy and a lower standard of living.
Last words from Professor Lindzen:
The earth is always warming or cooling a bit. The latest fluctuation can be measured in tenths of a degree. Over the past century, the earth has probably warmed about half a degree Celsius (according to NOAA’s Climate Data Center) or as much as 0.7 degrees (according to other research centers). A jump in temperature was recorded between the late 1970s and the mid-1980s — but that may have been related to the closing of more than 1,000 observation stations in the former USSR during the same period.
The scientific issue is not whether there is warming or not. It is whether the level of warming is unusual, whether the analysis of the data (as well as the data itself) are adequate for the small changes being studied, and whether the change in global temperature is significantly related to increasing CO2. The interesting political question is not about “denial” on the right. Rather, it is this: Why does the left get so excited by what seems to be a natural phenomenon?
Media Nation responds: In the spirit of my invitation to Jacoby, I’m not going to attempt any sort of detailed response. I asked questions, he answered them, and there you have it. But I do find it interesting that he sought out Lindzen for back-up.
I will not engage in the sort of attacks against Lindzen that have become popular among some of his critics. I assume he received consulting money from oil companies in years past because of his views, not the other way around.
But I will say this: Lindzen is one of a very, very few qualified scientists who do not believe that human-caused global warming is a serious danger. Nearly all the evidence is stacked against Lindzen — and Jacoby.
Maybe 50 years from now we’ll learn that Lindzen was right and everyone else was wrong. But on what basis should we act today? That is the issue.
