A Way of Knowing

One of the first lessons a scientist learns is that 100 percent agreement on scientific matters is rare. And a consensus can be reversed. But that reversal won’t come from talk radio or TV pundits. It will come from those who publish under the stringent demands of scientific journals.

It is scientists’ right to disagree with the consensus in their field. I could even argue that it sometimes is their obligation. There are a small number of medical researchers who do not believe the HIV virus is the cause of AIDS. One is on the faculty at the University of California at Berkeley. I have a friend who knows him and who thinks his argument plausible. If he wants to overturn the dominant idea with data, power to him.

However, I don’t yet want a blood transfusion from someone who authorities tell me is carrying the HIV virus. I’ll stick with the overwhelming consensus of most scientists.

Which brings me to my most important message. I’m a geneticist, not a climatologist, and have no training in that discipline. But, because I hold to a scientific way of knowing, I accept the view of 99 percent of the men and women who publish in refereed journals on climate. What have they concluded? That humans burning fossil fuels — coal, oil, natural gas — are the major source of the carbon dioxide increase in the earth’s atmosphere. This is causing the planet to heat up, and for our health, and the planet’s, we must cut our fossil fuel consumption to 20 percent of what it is now long before century’s end.

Unfortunately, for purported balance, the media give disproportionate time to the 1 percent who are not convinced. But there are 2,000 scientists on the Intergovernmental Panel on Climate Change and the National Academy of Sciences, and among them the consensus is overwhelming.

I used to ask my students if they believed that Earth went around the sun or if the sun went around Earth. Of course, they all believed the former. I would then ask them why they believed that and if they ever stopped to check it out for themselves. They hadn’t. Few people have in our time.

How do I know the pancreas secretes insulin, that it isn’t the liver or the spleen or my femurs? How do I know that grinding plates of the earth cause earthquakes? That fire feeds on oxygen? These are only a few of countless conclusions we mostly accept because others devoted to a scientific way of knowing, in their particular fields, tell us it is so.

I have studied some of the arguments of the few climatologists who oppose their colleagues. I hope they are correct: Before me on my bulletin board as I type this are pictures of my grandchildren.

The question finally becomes, what is prudent? If 99 percent of climate scientists turn out to be wrong, what has been lost? If we act on the consensus and reduce fossil fuel consumption and turn out to be wrong, what is lost? But if the consensus is right and we refuse to respond, climate change is likely to present the greatest challenge to public health in the history of our species.

WES JACKSON is president of the Land Institute, Salina, Kan., and author of books including “Altars of Unhewn Stone: Science and the Earth.” His comment here is for the institute’s Prairie Writers Circle.