Has the climate change debate reached a tipping point?

Now you're starting to sound ideological. You are misinterpreting scientists' inherent caution not to overstate their conclusions as talking "like lawyers." All data have inherent uncertainties and no one can be absolutely certain about their conclusions. However, there is a scientific consensus that represents the best understanding we have at this time. The consensus is growing stronger as the data, models, and computing power get better. The implications of the consensus are raising serious concerns. We can't wait for a "smoking gun" before we act, because it will be too late at that point. I am not an expert, just well-read on the subject. I have directed you to a number of books that can help you to understand the way this scientific consensus has developed. It's now up to you to do the hard work of absorbing the data and understanding the consensus. Neither the scientists at Scripps nor I can do that learning for you. It's time for you to stop asking questions here and start reading. You need to understand both the process of science and the results. The answers to your questions are in the books I've recommended. How can I possibly describe all the details and the many examples in those books in this blog? This dialogue has run its course. Please do not reply. Just go read if you really want to understand. Fred Bortz -- Science and technology books for young readers (www.fredbortz.com) and Science book reviews (www.scienceshelf.com)

... however stubbornly you stick to it :)

That's an ideological statement, which is why I added the "smiley."

But it is not ideological to respect a scientific consensus that has built up over decades. Some of the weather and climate books reviewed on my Science Shelf website have an ideological bent, but most focus on the evidence and the growing scientific consensus.

Nonscientists who know how scientists build consensus now recognize that there may be huge problems ahead. Not acting can have serious consequences.

In the religious realm that plays out this way: Many scientists and nonscientists espouse conservative religious faiths that place the stewardship of the planet as an important aspect of doing "God's work." Others, such as members of my liberal denomination, include "repairing the world" as one of their central good deeds. That repair is social as well as physical. The sentiment is not ideological, even when ideologues happen to hold it.

If you're having problems accepting the scientific consensus, I suggest that you click the link earlier in this reply and select reading material from the titles you think are least ideological.

I'm afraid that you remain unconvinced because you wish things were different from the way they are. It's almost "magical" thinking, and few things are more dangerous than relying on magic instead of acting on fact.

Fred Bortz -- Science and technology books for young readers (www.fredbortz.com) and Science book reviews (www.scienceshelf.com)

Thanks for your comment, which is provocative and ideological but respectful. I will answer in the same spirit. Sagan deliberately did not follow the criterion which is now often quoted, "Extraordinary claims, require extraordinary evidence." But I wouldn't go so far as to call Nuclear Winter a fraud. It was a worst case but plausible scenario that made people rethink their advocacy of the Mutually Assured Destruction theory of the arms race. It was an important factor, though hardly the only one, in the movement toward arms reduction treaties. Hansen and others speaking of the tipping point in climate change are careful to state that their worst case scenarios are not definite predictions but rather plausible outcomes with consequences too dire to be ignored. Some people on the left-wing side of this argument might agree with your statement that "Sagan sold out," but they might view the sellout as giving credit to religion, as Billions and Billions does. You might also be interested in my comparative review of two Sagan biographies. Both of those discuss his reasons for promoting the Nuclear Winter hypothesis. He was the least important of the scientific contributors of the paper usually denoted as TTAPS for its five authors, but certainly the most active in promoting its conclusions. It has always puzzled me why religious conservatives have not spoken up about their concern for the planet. Could it be that they decided not to push the issue because it went against the interests of their big-business political allies on other social issues (abortion, gay marriage, etc.)? I'm glad they are finally speaking out on this. Preserving a viable planet is not a liberal or conservative issue. It is based on a scientific consensus that is no longer disputed except by those with vested interests in the status quo. (Though everyone denies vested interests.) Thanks again for opening this thread of discussion. I hope others will join in. Fred Bortz -- Science and technology books for young readers (www.fredbortz.com) and Science book reviews (www.scienceshelf.com)

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:
2005
Climate Crash: Abrupt Climate Change and What It Means for Our Future by John D. Cox
The Republican War on Science by Chris Mooney

2003
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

2002
A Matter of Degrees: What Temperature Reveals About the Past and Future of Our Species, Planet, and Universe by Gino Segre

2001
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

1999
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 (www.fredbortz.com) and Science book reviews (www.scienceshelf.com)

These are precisely the kind of questions that good, skeptical scientists have been asking. Their research has led to a stronger and stronger consensus that human activities are having an effect, and it appears to be quite substantial. The debate, among scientists with perspectives such as yours (and mine) but far more expertise and in-depth knowledge of the research than we have, is now moving to a different level. Now they are asking if we may be on the verge of a tipping point in climate, and if so, what actions can we take to avoid it. (If human activity is moving us in one direction, the presumption is that the trend can be reversed by changes in our actions.) I'll be reading new books on that issue soon, and you may wish to visit The Science Shelf and subscribe to receive alerts of new reviews, but the older books I've cited above and in another discussion on this blog will help you understand the current consensus and how it has been reached. To understand why so many well-intentioned people are still giving so much credence to the doubters, read The Republican War on Science by Chris Mooney. I approached that book as a skeptic, but I came out persuaded that science is indeed under ideological attack in the U.S. today. The word "Republican" in the title transforms what I see as an ideological fight into a partisan one. I'm still debating that angle, though for now the Democrats do seem to doing a better job of interpreting science in order to propose political policies. Fred Bortz -- Science and technology books for young readers (www.fredbortz.com) and Science book reviews (www.scienceshelf.com)