RALEIGH – The next time someone tries to sell global-warming alarmism to you by asserting the existence of an unassailable scientific consensus, don’t be tempted to buy it until the sales rep answers some questions of yours.
1. A consensus about what? There are many separate and important issues tucked into the climate-change cubby. Some are technical questions about the climate, its history and the effectiveness of models forecasting its future. Others are economic questions about the costs and benefits of taking government action to forestall predicting warming. Claims about expertise are often inconsistent here, as alarmists complain when social scientists comment on earth-science matters but express no concern when earth scientists comment on social-science matters (such as how best to expend inherently scarce resources to maximize human welfare).
2. Who says? Look at the results of two comprehensive, international surveys of climate scientists on point to key issues of global-warming policy. Both were conducted by German environmental scientists, in 1996 and again in 2003. Some 530 scientists in climate-related disciplines participated. The surveys did, indeed, find what could properly be termed a consensus on the most basic question. In the 2003 survey, 82 percent of respondents agreed that global warming is underway. But on other key matters, the “consensus” was less overwhelming. Only 56 percent agreed that “climate change is mostly the result of anthropogenic (man-made) causes.” This is a magnitude question, of course – a far larger percentage would say that anthropogenic causes are playing some role.
On the other hand, only 35 percent of the climate scientists agreed with the statement “climate models can accurately predict climate conditions in the future,” 41 percent said that the models adequately dealt with water vapor, 35 percent said they dealt adequately with precipitation, just 24 percent said they dealt adequately with cloud cover. The bottom line? When asked if “natural scientists have established enough physical evidence to turn the issue of global climate change over to social scientists for matters of policy discussion,” the respondents were split down the middle: 44 percent said yes, 46 percent said no, and 10 percent weren’t sure.
There are other indicators, of course. A number of scientific associations have released statements affirming certain propositions about global warming, including the anthropogenic cause of at least some of it. However, they do not typically endorse the wild exaggerations of Al Gore and other alarmists predicting sea level rise of 20 feet and such. And then there’s the Intergovernmental Panel on Climate Change. Doesn’t its recently heralded report settle the consensus question? Only if you want to know the consensus view among the handful of scientists, politicians, and regulators who wrote the summary documents that most reporters have fixated on. Hundreds of peer-reviewed, scholarly studies have questioned key elements of the alarmist story the IPCC summary report relates.
3. Do you always defer to expert consensus? This is an area particularly fraught with peril for left-wing activists who treat the global-warming issue as settled but agitate for many other public policies that run counter to the consensus opinion of experts. A good example would be trade policy and outsourcing. The vast majority of economists – by which I mean not just those from free-market schools of thought but everyone with graduate-level training in the field – agrees that the free trade of goods and labor confers net economic benefits and that recent free-trade agreements have advanced the interests of both America and its trading partners. There are many interesting disputes about how robust some of the effects are, for sure, but few serious economists believe that the inevitable laws of human action can be rewritten by legislation.
And yet, advocates of protectionism and labor-market restrictions routinely claim otherwise. They assert that raising labor costs will increase employment, that forcing consumers to pay higher prices for inferior goods will make them better off, and that increasing labor productivity by employing comparative advantage hurts the economy. These statements are more akin to the ravings of the Flat Earth Society than are skeptical comments about the net benefits of raising taxes and regulations to reduce greenhouse-gas emissions to 1990 levels.
I guess what I’m saying is that, when the usual suspects trot out the “global-warming consensus” argument in an attempt to shut down the debate, don’t let them browbeat or silence you. They are incorrect and inconsistent.
Hood is president of the John Locke Foundation.