Is there a scientific consensus on climate change?

The discussion of my last blog entry on the climate change debate, “Has the Climate Change Debate Reached a Tipping Point?” is interesting enough to bring it forward as a new thread of discussion. One of the readers questioned my assertion that there is a scientific consensus, compared it to other issues in the past where he thought there was consensus, and said he hadn’t heard of any polls on the question. I’ll repeat my reply verbatim here. If you need context, click the link to the previous entry.

Here’s what I wrote:

Scientific consensus is not determined by a poll but by a steady accumulation of data and by hypotheses that hold up to criticism. I suggest you look at the trajectory of the argument over the last twenty years. It went from numerous people speaking cautiously about what seemed to be hints of warming to an overwhelming collection of evidence that the average temperature was increasing.

It went from most people saying that it wasn’t clear how much human activity was contributing to broad agreement that human activity was a significant component of the cause.

Today, the argument is moving toward whether we are approaching a tipping point that could have catastrophic consequences. There is no consensus on that yet, but there is enough concern that policy makers ought to be paying attention.

As far as consensus of a coming ice age in the 1970s, no. There was not enough evidence, though some hypotheses had more supporters than others. That’s a far cry from the consensus that we have today.

As for oil, Hubbert’s theory of production peaks is holding up well. There was no consensus on when we would start to see economic problems, nor is there now. It’s not a question of whether we will use up a finite resource but when, and that involves human factors as well as geological ones. Most energy policy makers are weighing the best scientific data they have, but economic modeling is far less precise than resource modeling (which also has its limits). Many of them are legitimately concerned that we will see the end of the age of oil in the lifetime of today’s young adults. That’s not yet a consensus, but the hypothesis is quite credible at this point.

As noted in my previous comment, I have a number of book reviews on my website about weather and climate. At the end of this message is a list of some of them. Even when these books suggest policy, they draw their conclusions from the evidence. Follow the above link to see the full list and to find links to my reviews.

I’m planning to read two more books that lay out the science and its implications for the rest of this century. If you add yourself to my Science Shelf mailing list (links to subscribe on nearly every page), you’ll receive an alert when those reviews are published.

I suggest you try The Change in the Weather from 1999 as a starting point, then read the newer titles. Then you will understand that a consensus is forming based on science.

If you want to understand how ideology can get in the way, include The Republican War on Science on your reading list. Leave out the author’s partisanship and just look at the evidence for the ideological abuse of science by the people to whom we have entrusted our future.

The steady drumbeat from people like that is a major reason why many decent people doubt that there is a consensus, probably including you. Remember, just because there are two sides to an issue does not mean that they are equally valid. Honest reporting requires discernment, not equal coverage of those who still claim the Earth is fhe center of the universe.

Reading list:
Climate Crash: Abrupt Climate Change and What It Means for Our Future by John D. Cox
The Republican War on Science by Chris Mooney

The Earth Policy Reader by Lester R. Brown
Science, Money, and Politics: Political Triumph and Ethical Erosion by Daniel Greenberg
State of the World 2003 by the Worldwatch Institute

A Matter of Degrees: What Temperature Reveals About the Past and Future of Our Species, Planet, and Universe by Gino Segre

The Coming Storm: Extreme Weather and Our Terrifying Future by Bob Reiss
The Little Ice Age: How Climate Made History, 1300-1850 by Brian Fagan
Our Final Hour: A Scientist’s Warning; How Terror, Error, and Environmental Disaster Threaten Humankind’s Future in This Century On Earth and Beyond by Martin Rees

The Change in the Weather: People, Weather, and the Science of Climate by William K. Stevens

Fred Bortz — Science and technology books for young readers ( and Science book reviews (