Climate 'consensus': Is carbon dioxide the new cholesterol?
As some readers here know, I also follow the medical literature and what the writer below says is spot on. Moreover, that is not the only recent example of a reversed consensus in the medical literature. The wisdom on peanut allergy has also recently done a 180 degree turn, for instance -- JR
Imagine a public policy issue that could determine the course of millions of lives. Imagine the science concerning this issue was complex and confusing. Nonetheless, most scientists had reached agreement on certain aspects of it.
And imagine the Washington Post wrote an editorial stating, "Government agencies must constantly make recommendations on the basis of just this kind of incomplete but suggestive evidence, and there is a consensus on what to do."
That sounds like the current debate over climate change, doesn’t it? Nope. That editorial is from 1980. The issue was not levels of carbon dioxide in the atmosphere but levels of cholesterol in the diet.
In that case, the consensus was that the amounts of saturated fats and cholesterol in the diet are related to the levels of cholesterol in the blood and "that reducing the one will lower the other," the Post wrote.
That seemed to be the case at the time. But there were dissenters who claimed carbohydrates, particularly refined ones, were the more likely triggers for obesity and heart disease. That led the mainstream authorities to hold a "Consensus Conference" in 1984. The result was a national policy emphasizing low-fat diets as a means of combating obesity and heart disease.
Soon the market was inundated with low-fat foods. But they weren’t having the desired effect. By 2002, the cracks in the consensus were so evident that the New York Times Magazine ran a lengthy and well-researched article by noted science writer Gary Taubes headlined "What if it’s all been a big fat lie?"
"It used to be that even considering the possibility of the alternative hypothesis, let alone researching it, was tantamount to quackery by association," Taubes wrote. "Now a small but growing minority of establishment researchers have come to take seriously what the low-carb-diet doctors have been saying all along."
Last month, the prior consensus was turned on its head by a study published in the Annals of Internal Medicine. A meta-analysis of 76 studies and clinical trials showed no link between fat, even saturated fat, and increased heart-disease risk.
I discussed this yesterday with Meir Stampfer, who is a professor of epidemiology and nutrition at the Harvard School of Public Health. Stampfer said the move to low-fat diets might have actually increased obesity and heart-disease risk. That’s because people tended to substitute refined carbohydrates for fat in their diets, Stampfer said.
"Basically what happens is the refined carbs are very rapidly absorbed," Stampfer said. "Blood sugar goes up very rapidly and insulin is secreted so it plummets again."
That rapid fluctuation leads to an increase in triglycerides, which in turn can lead to weight gain and atherosclerosis, he said. So is there a new consensus that "Butter is back" as one op-ed piece in the Times recently stated?
Nope, said Stampfer. He and his Harvard colleagues disagree with those who are promoting saturated fats from dairy and red meat. The Harvard crowd argues that people would be better off consuming more olive oil and seafood.
But that’s a healthy disagreement. As for that prior consensus, the consensus is that it did not hold up.
"This is complicated and the policymakers tried to make it simple," Stampfer concluded. "But it’s better to be complicated and right than simplified and wrong."
It is indeed, and I would encourage my fellow journalists to keep that in mind in light of the highly touted "consensus" on the role of carbon dioxide in promoting global warming.
Climate science is infinitely more complicated than human physiology. Once all of the data are in, we may find that atmospheric carbon dioxide actually has the effect predicted by physicist Freeman Dyson of the Institute of Advanced Study in Princeton. The 90-year-old Dyson, whom many consider to be the smartest guy on Earth, argues that far from harming the planet, atmospheric CO-2 may have a positive effect by increasing plant growth.
Perhaps you disagree. Fine, but you’re disagreeing with a guy who calculated the number of atoms in the sun when he was 5 years old and who’s been at the institute since Einstein was walking the grounds.
Science requires taking the long view, said Dyson when I called him the other day. "Science of course is always correcting mistakes," he said. "That’s what it’s all about."
It is indeed. What it’s not about is consensus. That’s for editorial writers.
Posted by John J. Ray (M.A.; Ph.D.).