George Will is citing past shifts in the climate to cast doubt on the scientific consensus that human behavior is currently driving global warming, despite the fact that those previous shifts actually demonstrate the need to take action on climate change.

On January 8, The Washington Post published Will's syndicated column, headlined “Climate change's instructive past,” in which he discussed two books about previous climate shifts -- the Medieval Warming Period and the Little Ice Age. Will asserted, “of course the climate is changing -- it always is,” and warned against “wagering vast wealth and curtailments of liberty on correcting the climate.”

Without explaining his reasoning, Will claimed the books do not “support those who believe human behavior is the sovereign or even primary disrupter of climate normality.” But Will ignored the overwhelming scientific consensus that human activity is the main cause of recent global warming. Further, Will's myopic view of history ignores the wealth of scientific evidence showing that greenhouse gases -- which are currently at record levels due to the burning of fossil fuels -- have been the principal factor in prior climate changes.

As Climate Nexus pointed out, Will actually missed the lesson from his historical examples -- that climate change left unchecked will have devastating impacts:

Contrary to [Will's] claim, past changes in our climate should be understood as a warning, but shouldn't be seen as evidence that current climatic change is naturally occurring, as he suggests.

The problem with this claim is that human-made emissions have increased exponentially since Will's historical examples. Science has clearly shown how current human-made climate change is very different from earlier slower natural changes, something Will failed to factor.

More accurately, historical climate change provides insight into problems we can expect in the future as greenhouse gases are increasingly amplifying variations in our climate. Historical trends should, instead, serve as a stark warning of what we can expect from the emission-driven warming we're experiencing now.

ThinkProgress' Joe Romm called Will's logic “exactly backwards.” Pointing out that climate change has occurred naturally in the past does not disprove the fact that it is happening unnaturally now, as Romm analogized: "[I]t would be exactly the same as saying that because people who didn't smoke have died of cardiopulmonary disease and lung cancer, we can't know that cigarette smoking also causes those diseases and is unhealthy." He added that “climate scientists now have the same degree of certainty that human-caused emissions are changing the climate as they do that cigarette smoking is harmful.”

Will is infamous for his climate misinformation -- over the past few years, other writers have called his misunderstanding of science “mystifying” and asserted that he is “helping to muddle our collective scientific literacy.” Will's misleading coverage of climate science in his columns sparked a petition in 2014, signed by more than 100,000 people, urging The Washington Post to exclude climate misinformation from its pages.