One of the biggest problems in the climate change debate is the fact that many people out there fail to understand the finer points of “scientific consensus.”

For an example of this misunderstanding, see Ron Rosenbaum’s recent article in Slate. (h/t Dot Earth.)

His article trots out one of the staples of the denial industry: Science has been wrong in the past, so how do we know that a scientific consensus on climate change is right? Because of this, reporters should report all sides of the argument.

So if you’re writing an article about climate change, you can interview one of the thousands of climate scientists out there who basically agree with the scientific assessment described by the IPCC reports, and then you can balance them out by quoting one of the the dozen or so credible scientific skeptics out there. After all, you don’t want to be biased.

To support this well-worn canard, he trots out the usual examples of scientific consensus being overturned, such as Ignaz Semmelweis, who recognized that proper hygiene could greatly reduce disease, and Einstein, whose theory of general relativity superseded Newton’s. Of course, the fact that the author had to go back more than a century to find these examples should give the reader pause. And never mind that Einstein’s theory didn’t overturn Newton’s, but extended it.

Why is this such a ridiculous argument? As all scientists know, the confidence in any “consensus” can range from low to very high. For some, such as the connection between cigarettes and lung cancer, or the observation that the Earth’s temperature is increasing, there is virtual 100 percent certainty that the scientific consensus is correct.

For the statement that humans are responsible for most of the recent warming, the consensus is slightly weaker. The IPCC estimates that there is about a one-in-ten chance that this statement is wrong.

For statements about changes in precipitation patterns under climate change, the consensus is weak. We think we know generally how precipitation will change, but no one would be surprised if it turns out to be substantially wrong.

Dissenting voices exist on just about every scientific question that touches the political sphere. For example, there are dissenters out there arguing that HIV does not cause AIDS, such as Kary Mullis, the 1993 Nobel Prize winner in Chemistry.

Because they are always out there, the existence of dissenting voices actually tells you nothing about the actual scientific strength of a position. I doubt that even Rosenbaum would argue that journalists writing an article about HIV should balance their work by providing the dissenting view that perhaps HIV does not cause AIDS.

Rather, journalists need to evaluate the strength of the consensus that they are reporting on. For confidently held scientific views, such as the connection between increasing greenhouse gases and climate change or the connection between cigarettes and cancer, it is highly unlikely that the scientific community is wrong.

What Rosenbaum fails to understand is that promoting uncertainty is a technique to forestall action. In other words, those opposed to action want the debate to focus on the science. As long as people are debating whether climate change is happening or not, and whether humans are responsible or not, then the debate will not be about what to do, and the status quo is maintained.

In these cases, providing balance is, in reality, bias.