The cold truth about climate change

Deniers continue to insist there's no consensus on global warming. Well, there's not. There's well-tested science and real-world observations.

By Joseph Romm

Read more: Environment, Politics, Science, News, Global Warming

Feb. 27, 2008 | The more I write about global warming, the more I realize I share some things in common with the doubters and deniers who populate the blogosphere and the conservative movement. Like them, I am dubious about the process used by the U.N. Intergovernmental Panel on Climate Change (IPCC) to write its reports. Like them, I am skeptical of the so-called consensus on climate science as reflected in the IPCC reports. Like them, I disagree with people who say "the science is settled." But that's where the agreement ends.

The science isn't settled -- it's unsettling, and getting more so every year as the scientific community learns more about the catastrophic consequences of uncontrolled greenhouse gas emissions.

The big difference I have with the doubters is they believe the IPCC reports seriously overstate the impact of human emissions on the climate, whereas the actual observed climate data clearly show the reports dramatically understate the impact.

But I do think the scientific community, the progressive community, environmentalists and media are making a serious mistake by using the word "consensus" to describe the shared understanding scientists have about the ever-worsening impacts that human-caused greenhouse gas emissions are having on this planet. When scientists and others say there is a consensus, many if not most people probably hear "consensus of opinion," which can -- and often is -- dismissed out of hand. I've met lots of people like CNBC anchor Joe Kernen, who simply can't believe that "as old as the planet is" that "puny, gnawing little humans" could possibly change the climate in "70 years."

Well, Joe, it is more like 250 years, but yes, most of the damage to date was done in the last 70 years, and yes, as counterintuitive as it may seem, puny little humans are doing it, and it's going to get much, much worse unless we act soon. Consensus of opinion is irrelevant to science because reality is often counterintuitive -- just try studying quantum mechanics.

Fortunately Kernen wasn't around when scientists were warning that puny little humans were destroying the Earth's protective ozone layer. Otherwise we might never have banned chlorofluorocarbons in time.

Consensus of opinion is also dismissed as groupthink. In a December article ignorantly titled "The Science of Gore's Nobel: What If Everyone Believes in Global Warmism Only Because Everyone Believes in Global Warmism?" Holman W. Jenkins Jr. of the Wall Street Journal editorial board wrote:

What if the heads being counted to certify an alleged "consensus" arrived at their positions by counting heads?

It may seem strange that scientists would participate in such a phenomenon. It shouldn't. Scientists are human; they do not wait for proof. Many devote their professional lives to seeking evidence for hypotheses, especially well-funded hypotheses, they've chosen to believe.

Less surprising is the readiness of many prominent journalists to embrace the role of enforcer of an orthodoxy simply because it is the orthodoxy. For them, a consensus apparently suffices as proof of itself.

How sad that the WSJ and CNBC have so little conception of what science really is, especially since scientific advances drive so much of the economy. If that's what Jenkins thinks science is, one would assume he is equally skeptical of flossing, antibiotics and even boarding an airplane.

(Note to WSJ: One reason science works is that a lot of scientists devote their whole lives to overturning whatever is the current hypothesis -- if it can be overturned. That's how you become famous and remembered by history, like Copernicus, Galileo, Newton, Darwin and Einstein.)

In fact, science doesn't work by consensus of opinion. Science is in many respects the exact opposite of decision by consensus. General opinion at one point might have been that the sun goes around the Earth, or that time was an absolute quantity, but scientific theory supported by observations overturned that flawed worldview.

One of the most serious results of the overuse of the term "consensus" in the public discussion of global warming is that it creates a simple strategy for doubters to confuse the public, the press and politicians: Simply come up with as long a list as you can of scientists who dispute the theory. After all, such disagreement is prima facie proof that no consensus of opinion exists.

So we end up with the absurd but pointless spectacle of the leading denier in the U.S. Senate, James Inhofe, R-Okla., who recently put out a list of more than 400 names of supposedly "prominent scientists" who supposedly "recently voiced significant objections to major aspects of the so-called 'consensus' on man-made global warming."

As it turned out, the list is both padded and laughable, containing the opinions of TV weathermen, economists, a bunch of non-prominent scientists who aren't climate experts, and, perhaps surprisingly, even a number of people who actually believe in the consensus.

But in any case, nothing could be more irrelevant to climate science than the opinion of people on the list such as Weather Channel founder John Coleman or famed inventor Ray Kurzweil (who actually does "think global warming is real"). Or, for that matter, my opinion -- even though I researched a Ph.D. thesis at the Scripps Institution of Oceanography on physical oceanography in the Greenland Sea.

What matters is scientific findings -- data, not opinions. The IPCC relies on the peer-reviewed scientific literature for its conclusions, which must meet the rigorous requirements of the scientific method and which are inevitably scrutinized by others seeking to disprove that work. That is why I cite and link to as much research as is possible, hundreds of studies in the case of this article. Opinions are irrelevant.

A good example of how scientific evidence drives our understanding concerns how we know that humans are the dominant cause of global warming. This is, of course, the deniers' favorite topic. Since it is increasingly obvious that the climate is changing and the planet is warming, the remaining deniers have coalesced to defend their Alamo -- that human emissions aren't the cause of recent climate change and therefore that reducing those emissions is pointless.

Last year, longtime Nation columnist Alexander Cockburn wrote, "There is still zero empirical evidence that anthropogenic production of CO2 is making any measurable contribution to the world's present warming trend. The greenhouse fearmongers rely entirely on unverified, crudely oversimplified computer models to finger mankind's sinful contribution."

In fact, the evidence is amazingly strong. Moreover, if the relatively complex climate models are oversimplified in any respect, it is by omitting amplifying feedbacks and other factors that suggest human-caused climate change will be worse than is widely realized.

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