There are two types of George Will climate change columns. The first are simply wrong, usually through a combination of factual error, disinformation, and illogic. The second actually manage to get things exactly backwards.
Will’s latest piece of syndicated nonsense, “Climate change’s instructive past,” exemplifies the latter. In it, Will reviews two books that explicitly show how even modest regional changes in climate can have devastating impacts on human society. Will manages to ignore the authors’ long discussions of this point and instead conclude that because the climate changed in the past for reasons other than human-caused carbon pollution, we can’t know that carbon pollution will cause harmful changes in the future.
That is the kind of classic logical fallacy that helped make Will the “Media Matters Misinformer of the Year” for 2014. It would be exactly the same as saying that because people who didn’t smoke have died of cardiopulmonary disease and lung cancer, we can’t know that cigarette smoking also causes those diseases and is unhealthy. In fact, climate scientists now have the same degree of certainty that human-caused emissions are changing the climate as they do that cigarette smoking is harmful.
As leading climatologist Michael Mann wrote me, “George Will is known for grossly misstating the science of climate change, and his latest piece doesn’t disappoint.”
Both of these books make clear that the historical record should make one more concerned about what modern human-caused climate change will do to society, not less. Before joining the throng directly debunking Will’s column, as Climate Nexus does here, let me point out that it’s obvious Will has never talked to leading paleo-climate scientists, since they are, in my experience, much more concerned about human-caused warming than most scientists.
Why are they more concerned? Because the paleoclimate record is alarming: “The paleoclimate record shouts out to us that, far from being self-stabilizing, the Earth’s climate system is an ornery beast which overreacts even to small nudges,” climate scientist Wallace Broecker said in 1995.
Human activity has raised CO2 levels to 400 parts per million (from preindustrial levels of 280). A 2013 paleoclimate study in Science determined that the last time the Earth had similar CO2 levels a few million years ago, we saw sustained Arctic summer temperatures some 8°C [14°F!] warmer than today.”
The authors concluded, “this could tell us where we are going in the near future. In other words, the Earth system response to small changes in carbon dioxide is bigger than suggested by earlier models.”
This period of sustained Arctic warmth “coincides, in part with a long interval of 1.2 million years when the West Antarctic Ice sheet did not exist.” In fact, sea levels during the time were some 80 feet higher than today!
A 2009 paleoclimate study in Science looked at an even earlier time CO2 was at current levels, about 15 to 20 million years ago — and found similar results. As the lead author explained, back then “global temperatures were 5 to 10 degrees Fahrenheit higher than they are today, the sea level was approximately 75 to 120 feet higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland.” That study concluded, “this work may support a relatively high climate sensitivity.”
Climate change’s instructive past should move us to start rapid reductions in carbon pollution ASAP, not continue the self-destructive delay that Will and his fellow climate science deniers embrace.
Will’s piece discusses two books on the more recent record. One is “Global Crisis: War, Climate Change and Catastrophe in the Seventeenth Century,” which focuses on the century that “included the Little Ice Age (LIA), between the 1640s and the 1690s.” The other is “The Third Horseman: Climate Change and the Great Famine of the 14th Century,” which examines “the Medieval Warm Period (MWP), from the end of the ninth century to the beginning of the 14th, the Northern Hemisphere was warmer than at any time in the past 8,000 years — for reasons concerning which there is no consensus,” or at least this is what Will asserts.
But even though Will claims the MWP saw the warmest temperatures we’ve seen in 8,000 years, that isn’t even true for the Northern Hemisphere, as the latest science makes clear. In fact, as Mann pointed out to me, the notoriously cautious Intergovernmental Panel on Climate Change in its 2013 Fifth Assessment, concluded, “in the northern Hemisphere, the period 1983–2012 was likely the warmest 30-year period of the last 1400 years.”
Moreover, while Will quickly dispenses with the fact that the MWP was limited to the Northern Hemisphere, our concern today is global climate change. Recent research makes clear the MWP was not a global phenomenon. The most comprehensive reconstruction of the temperature of the past 2000 years done so far, the “PAGES 2k project,” made that crystal clear in 2013:
Figure: Green dots show the 30-year average (area-weighted mean over the continents) of the new PAGES 2k reconstruction. The red curve shows the global mean temperature, according HadCRUT4 data from 1850 onwards (also smoothed with a 30-year window). In blue is the original hockey stick of Mann, Bradley and Hughes (1999 ) with its uncertainty range (light blue). Graph by Klaus Bitterman.
The PAGES 2k researchers concluded that “there were no globally synchronous multi-decadal hot or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age.” But as climatologist Stefan Rahmstorf notes, the researchers “identify some shorter intervals where extremely cold conditions coincide with major volcanic eruptions and/or solar minima (as already known from previous studies).” Again, the IPCC concluded, “the medieval period [A.D. 950–1250] is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”
In fact, if you look inside the Amazon link Will provides, the author of the book about the MWP explicitly states on page 12 “the MWP’s effects were confined to the Northern Hemisphere — and especially to Europe” and “there is still little evidence of worldwide temperatures were, on average, warmer than today.”
Again, since the best evidence says the MWP didn’t involve global climate change, Will’s assertion that “human behavior did not cause this climate change” is just more specious logic. The MWP has little to say about our understanding of the causes of modern global warming. The book does make clear that regional climate change can cause staggering disruption in human societies — even in societies one with a vastly lower population than we have today.
The most comprehensive “Reconstruction of Regional and Global Temperature for the Past 11,300 Years” ever done reveals how dangerously wrong Will is. The Science paper Marcott et al. (2013) shows just how stable the climate has been — and just how destabilizing manmade carbon pollution has been and will continue to be unless we dramatically reverse emissions trends:
Temperature change over past 11,300 years (in blue, via Science, 2013) plus projected warming this century on humanity’s current emissions path (in red, via recent literature).
This study also reveals no significant global Medieval Warm Period and not much of a Little Ice Age (LIA). It does show that prior to 1900 we were in a long-term cooling trend and that the rate of warming since 1900 is 50 times greater than the rate of cooling in the previous 5000 years.
The book on the LIA, “Global Crisis,” by historian Geoffrey Parker does show, as Will writes, that “Unusual weather, protracted enough to qualify as a change in climate, correlated so strongly with political upheavals as to constitute causation.” Climate change can indeed upend societies and even destroy civilizations.
Will starts one of his paragraphs: “Whatever caused the LIA — decreased sunspot activity and increased seismic activity were important factors — it caused, among other horrific things…”
What Will is trying to obfuscate here is that scientists know what “caused the LIA.” They have found abundant evidence that the cooling came from the combination of two major causes — reduced solar activity and increased volcanic activity. Parker explains this at length in Chapter 1, noting that multiple lines of evidence, “confirm that the energy of the sun diminished between the 1640s and the 1710s, a condition normally associated with both reduced surface temperatures and extreme climatic events on earth.” The recent scientific literature strongly supports that conclusion.
Parker concludes that “the dust veils produced by 12 well-known volcanic eruptions around the Pacific between 1638 and 1644 (apparently an all-time record) combined with the sunspot minimum both to cool the Earth’s atmosphere and to destabilize its climate.” Will explains that “The last 12 of Parker’s 712 pages of text deliver a scalding exhortation to be alarmed about what he considers preventable global warming.”
But the blinkered George Will knows more than the authors. Will ends with one of the most laughably backwards statements in a career filled with them:
By documenting the appalling consequences of two climate changes, Rosen and Parker validate wariness about behaviors that might cause changes … Neither book, however, supports those who believe human behavior is the sovereign or even primary disrupter of climate normality, whatever that might be. With the hands that today’s climate Cassandras are not using to pat themselves on the back for their virtuous empiricism, they should pick up such books.
Huh? First, the books show that climate change has “appalling consequences” — and both the MWP and the LIA were smaller in magnitude regionally than what humanity faces in the coming century if we listen to the George Wills of the world.
Second, the LIA in particular shows that reduced solar activity and increased volcanic activity have a cooling effect — and we’ve seen both of those in recent decades! That’s a key reason the IPCC concluded in its latest assessment that “the best estimate of the human-induced contribution to warming is similar to the observed warming over this period.”
That is, the best estimate is that humans are responsible for all of the warming we have suffered since 1950 — because if humans weren’t warming up the planet, we’d have been cooling from the combination of lower solar activity and the volcanoes we’ve seen and the long-term cooling trend we were in for the past few thousand years (prior to 1900) driven by slow changes in the Earth’s orbit.
So I’d urge all climate hawks, Cassandras, and indeed the general public to pick up these two books (and put down Will’s column). They are a very sobering picture of the kind of turmoil humanity will inflict upon itself if we keep listening to climate science deniers like Will.