This article has been updated in some very minor ways. A dagger (†) appears next to each change to remind people to see the footnote at the end for an explanation of the update.
Even a Conservative Look Ahead is Scary
Noah Diffenbaugh, assistant professor of environmental Earth system science at the Woods Institute for the Environment at Stanford University, was interviewed by Tom Ashbrook last Thursday on NPR's On Point about a recently released Stanford University study that concludes that heat waves could be commonplace in the US by 2039. If you missed the interview, you can click here to listen. It was a very interesting discussion. The study findings are also discussed in Scientific American.
... We've looked at both the hottest season that occurred in the second half of the century at each location in the United States and we've also looked at the longest heat wave that occurred also in the second half of the twentieth century and then we've looked forward over the next three decades and we've found that both of those measures increase substantially with relatively modest global warming over the next thirty years.
So you're looking at the summers, you say, for example, the hottest heat waves between 1951 and 1999. I mean, those are the heat waves that just make people kind of want to lay down and just die, and sometimes literally do that, as tens of thousands did in Europe in 2003. I was there, saw that. You're saying those could be—what—every other year? Even more than that, in parts of the country?
Yeah, for most of the country, by the decade of the 2030's, so the period between 20 and 30 years from now, our projections indicate that most of the country could see five of those summers every--within that decade. So what was the hottest summer of five decades occurring five times in a single decade. And much of the country actually could see even greater intensification. In the western United States, we see values up to nine times in a single decade.
What's worrisome to me about these quoted remarks is this phrase: “both of those measures increase substantially with relatively modest global warming.” If you're not used to reading dispassionate words by scientists, let me help you out here because he's just trying to read off the data calmly and not be all alarmist:
First, he is talking about a substantial effect—what may be some pretty dire situations occurring in a pretty near timeframe.
But I think the phrase “with relatively modest global warming” is the real key to interpreting these remarks. This can be read as if he had said “I'm basing this on the most conservative a quite conservative† projection of temperature change I can find†. That is, some argue,† this is the mininum badness you should expect. These substantial effects involving increased heat wave intensity and frequency may well be a best-case scenario—what you can hope for if all goes well.” My personal feeling is that you should not expect us to be lucky enough to get this minimum little † effect, so I personally read this as “expect worse, and expect it sooner.”
At one point in the interview, he was pressed more about that issue:
You're anticipating extreme heat events but you're not basing this on an extreme greenhouse gas scenario. You're talking about a one degree Celsius rise in temperatures or about 2 Fahrenheit, which is not considered the extreme of where we may go globally.
No, this is actually a moderate global warming and in fact some people argue that this is a committed warming over the next 30 years that given the emissions of greenhouse gases that have already occurred, given population growth and industrialization, that there is basically no way to avoid that level of warming over the next three decades or so, and that's really why we were interested in looking at that period, kind of changing directions a little bit. Instead of looking at really extreme global warming, asking for the global warming that is likely to occur in the relatively near term and, in fact, it's within the envelope that international governments are currently considering as part of the Copenhagen accord. ...
The Everpresent Skeptic
In the modern media environment, no show about science is ever complete without an outspoken critic to explain “the other side.” In this case, Ashbrook invited Bjorn Lomborg, academic and environmental writer and author of Cool It: The Skeptical Environmentalist's Guide to Global Warming. Although Lomborg made a few common sense observations about the need to “cool our cities” and get off of fossil fuels, he almost made my blood boil with these ridiculous comments:
The US is much less vulnerable to heat waves than, for instance, Europe is because there's much more prevalent use of air conditioning. And that's certainly the short term way to fix many of the problems for people in heatwaves. ... I am saying we have to remember that there's also many cold deaths that will be avoided from global warming and we cannot just talk about this issue only saying there's going to be more heat deaths without also recognizing there's going to be fewer cold deaths and very clearly if you look at the last half century most Americans have very clearly said they would actually prefer to go places that are warmer. People don't move to Wisconsin when they retire. ...
Lomborg portrays the problem of Climate Change in an almost cartoonish way, as if only people are affected by it, so that if those people go inside and switch on some air conditioning, the problem goes away. Unfortunately, all manner of problems are still occurring even as people stick their heads in the metaphorical sand.
The world is increasingly dependent on farming to work perfectly in order to support our still-growing population, but discussed elsewhere in this interview with some other participants were issues related to the effect of this heat on crops, for example. The issue isn't just one of gentle and even warming, but rather one of extreme and unpredictable weather that even with careful crop controls may yield more crop failures. In the metaphor of the stock market, we're more and more heavily leveraged and making the assumption that such leveraging will be allowed to go up and up and up. We're behaving like there's no possibility of a crash, and we should know better. We need to keep a close eye on the food supply because no matter how bad you think bank run is, a food run is going to be much uglier.
And speaking of the food supply, there's a whole food chain out there and a great deal of it depends on the coral reefs. Warming itself, as well as the increases in CO2 which are helping to drive it, are killing the coral reefs. A great deal of the food chain depends on fish that live in those reefs. It isn't like we'll see some coral dying from the heat but other coral that is presently freezing suddenly able to survive. It doesn't work that way. Corals take a long time to form and yet most of these climate effects are short-term. There may not be enough time for the ecosystem to adapt. History suggests that rapid change of the environment can be deadly.
To offer another example, it's conjectured that the ecosystem of various areas relies on cold to keep pest insects in check. In some places the cold keeps various insects away altogether. In other places the cold is enough to kill off large parts of the insect populations every winter. Warming may create circumstances that are more friendly to such insects. Invasive species may move in, while species already present may reproduce in unusually large numbers. That can pose big problems for forests, for crops, and even for people.
What's to be done?
Is there an obvious answer—something we should be doing? Diffenbaugh says at one point, “I think that there are trade-offs and I don't know that there is a clear silver bullet where there will be no costs and only benefits.” I think he's right about that.
But it's time for a vigorous public debate. It can't be postponed. It's time for this to take center stage. I know everyone's worried about jobs and the economy, but my personal take is that Climate Change is a bigger problem even than that. And, anyway, if we're going to have to retool our society anyway, we might as well do it in the knowledge of how we're going to confront these changes, so we can come up with a solution to our financial woes that isn't fighting whatever solution we need for the climate.
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† There is a “robust discussion” (some have used harsher terms) that followed the original publication of this article. You're welcome and encouraged to read the comments for a discussion of that. Some of the discussion is tedious in tone and length, but there is some substance to the disagreement, so I've tried to make a few small textual updates in the article itself to address that.
All changes made between the original and this update are clearly marked. In particular, all changes, including inserted words, have a light pink background (like the background of this box). All deleted words are explicitly marked with a line through them like this.
The disagreement seems to center on my the use of the words “most conservative” and “minimal” my interpretation of Diffenbaugh's remarks. There are different ways to define what might be adequately conservative, and it's not a matter of science but of human judgment which of these is best, so I've removed references that seem to suggest that only one interpretation is possible.
Moreover, in this article I am not interpreting his paper, but his remarks. There seemed to be some confusion about that—although I think I was quite clear that I was reporting on the interview. Diffenbaugh seems comfortable with his own characterization of the study parameters as being intentionally conservative, as illustrated by the fact that he volunteers the notion that some people argue it's “committed warming.” He also later emphasizes, in a response I didn't previously quote, that he was trying hard to be skeptical himself, which implies he thinks his approach is conservative:
... I think the science is so hard. And I think it takes so much personal and collective energy to do it objectively and as rigorously as we possibly can. For me personally, that's where all my effort goes, is to being as objective as possible and doing the most rigorous, skeptical science that we possibly can. ...
And yet, for all that rigor and skepticism, he chose these numbers and got these results. I would be remiss not to conclude that he thinks this is the very definition of a conservative projection. Others might make different studies or conclude different things. But it sounds to me like I've got his intent. And I've explained why. You can, of course, judge for yourself.
My thanks to Kanuk for helping me decide what specific correction to make here. He didn't get the last say on the precise wording, but his advice was quite specific and helpful.