How Much Is Known About Climate History?
Scientific papers on earth history can seem very erudite and confident, filled with jargon and named periods that appear carved in stone. Every once in awhile, though, a surprise discovery raises questions about how sound their timelines and models really are. Get a load of this opening to a review by Jacqueline Flückiger,1 an environmental physicist in Zurich, of a paper in Science2 that said major climate changes can occur much more rapidly than thought:
When Manhattan froze in a day in the movie The Day After Tomorrow as a result of an abrupt change in the Atlantic meridional overturning circulation, scientists emphasized the physical impossibility of this scenario. Now some might be stunned by how quickly climate can change. On page 680 of this issue, Steffensen et al. zoom in on three climatic shifts recorded in the NGRIP ice core from central Greenland… and show that the atmospheric circulation at mid to high northern latitudes changed within just 1 to 3 years.
In looking at the paper and the review, however, questions arise about how scientists know what they are talking about. The conclusions rely heavily on ice core data, and interpreting these rely heavily on oxygen-isotope ratios. We saw from the 07/29/2008 entry that assumptions underlying the use of oxygen isotope data can be drastically wrong.
Flückiger wrote matter-of-factly about several prehistoric climate periods, such as “Bølling-Allerød warm period (~14,700 years ago) and the onset (~12,850 years ago) and termination (~11,700 years ago) of the Younger Dryas cold period.” To the extent these periods, named after modern human beings who weren’t living at the time, are calibrated by proxy measurements based on questionable assumptions, how reliable are the conclusions?
The review waltzes past these questions with an air of certitude: “The high resolution of the records allows them to precisely define the duration of the shifts, and because all measurements were done along the same ice core, the sequence of events in different proxies can be compared without uncertainty in the relative timing.” In addition, she discussed correlations with other data sets besides the ice cores.
Actually, though, the interpretation of the data is heavily influenced by the consensus theories in which the models are embedded. The fact that both the reviewer and the research team were very surprised at the rapidity of major climate changes they interpreted from the ice cores should disturb the confidence placed in the pronouncements of the experts. In addition, they are dealing with very complex – almost chaotic – causes of change. In her ending paragraphs, Flückiger herself cast doubt on the confidence level of the outputs based on the complexity of the inputs:
Global coupled climate models provide one way to study the complex mechanisms that underlie climate shifts. Simulated climate shifts are, however, considerably slower than the observed ones, lasting a hundred to a few hundred years. This might be due to missing feedbacks, the wrong forcing of the abrupt shifts, or a misguided focus on changes in ocean circulation or temperature, rather than other aspects of the climate system. A closer look at wind patterns and atmospheric circulation in models will either reveal faster shifts and help clarify the underlying mechanisms, or tell us that better models are needed to study that question.
We should keep in mind that we only know the relative timing for three events so far, and that each of them looks somewhat different. Greenland ice cores offer the opportunity to study the 24 Dansgaard-Oeschger events of the last glacial period at a similar resolution. The data from all events, in combination with annually resolved records from other archives and improved models, will help to elucidate the dynamics of these events, revealing what they have in common, and what parts of the shifts are random.
The data reported by Steffensen et al. underscore the fact that the atmospheric circulation may shift from one state to another within just 1 year. With ongoing global warming, the climate system might therefore hold some surprises.
So the modelers are dealing with just a few inputs, without knowing what other inputs there are, or how relevant they are. Scientists may have a “misguided focus” on some data sets. Their models differ in resolution from real-time effects by orders of magnitude. They do not understand the dynamics of important events, nor what they have in common. Some inputs are admittedly random. The question no one seems to be asking is, based on these uncertainties, how do they know the timeline and named periods of which they speak confidently have any connection to the real history of the earth? Steffensen et al ended their paper saying, “Neither the magnitude of such shifts nor their abruptness is currently captured by state-of-the-art climate models…. If we are to be confident in the ability of those models to accurately predict the impacts of future abrupt change, their ability to match what we see in the past is crucial.” For more on problems with climate models, see the 02/05/2008 entry.
Another indication that global climate reconstruction and prediction is a dubious art showed up in a Science Daily story. Everyone has been hearing lately about the shrinkage of the Antarctic ice sheets and the disappearance of ice near the North Pole. Such announcements are usually stated in a tone of alarm, foretelling that the earth’s climate is in peril. Why, then, did this article state nonchalantly that Antarctica was ice-free 40 million years ago? Sure enough, a fossil “snapshot” from New Zealand “reveals a greenhouse Earth, with warmer seas and little or no ice in Antarctica.” Another article in Science Daily discussed warm-water fossils found in Antarctica and said it proved that the South Pole continent was ice free again 14 million years ago. The BBC News said the warm-water ostracod fossils show exceptional preservation in three dimensions.
Considering these questions and issues about scientific certainty when dealing with complex phenomena, it seems ironic that Nature, in a book review this week,3 took a jab at politicians. Jan Witkowski (Cold Spring Harbor Laboratory) reviewed a new book about the tragic story of how Stalin elevated Lysenko, a charlatan, and murdered Nikolai Vavilov, a noble-minded scientist sincerely trying to help feed the Russian people through good genetic research. Lysenko’s misguided policies resulted in the death of millions of people from starvation. Instead of aiming his moral lesson at communism, however, Witkowski seemed to have Washington on his mind: “Even now, politics continues to trump good science, as is evident from the delays in reducing global carbon emissions,” he said. “Pringle’s very readable account is a timely reminder that public policies must be based on rational decisions drawn from the best data available.” Does he really think that is what is going on at the U.N.?
Update 08/04/2008: The paper on the Antarctic fossils came out on PNAS today.4 The authors found moss tissues that were “freeze-dried” and unfossilized – i.e., the actual moss tissues were intact. Based on radiometric dating of ash falls in the area, they claim these delicate tissues, along with detailed parts of beetles and ostracods, have persisted in this dry valley for 14 million years. PhysOrg reported the story, too, and Live Science quoted a researcher who said, “We knew we shouldn’t expect to see something like that.”
On the same day, Science Daily reported claims that an abrupt climate change occurred in Western Europe 12,700 years ago. The “extremely rapid” cooling occurred “long before human-made changes in the atmosphere.”
1. Jacqueline Flückiger, “Climate Change: Did You Say ‘Fast’?” Science, 1 August 2008: Vol. 321. no. 5889, pp. 650-651, DOI: 10.1126/science.1159821.
2. Steffensen et al, “High-Resolution Greenland Ice Core Data Show Abrupt Climate Change Happens in Few Years,” Science, 1 August 2008: Vol. 321. no. 5889, pp. 680-684, DOI: 10.1126/science.1157707.
3. Jan Witkowski, “Stalin’s War on Genetic Science,” Nature 454, 577-579 (31 July 2008) | doi:10.1038/454577a.
4. Lewis et al, “Mid-Miocene cooling and the extinction of tundra in continental Antarctica,” Proceedings of the National Academy of Sciences USA, published online before print August 4, 2008, doi: 10.1073/pnas.0802501105.
One of the scientists in the Antarctic-moss story quickly used the data for a global warming sermon: “You have to understand where these thresholds are, because, if human beings are unfortunate enough to push climate over one of these thresholds, it could be a total catastrophe.” Instead of repenting over his evolutionary timeline have just been falsified, he got self-righteous about what humans should do.
One thing you learn pretty quick in the science reporting business (that is, if you think independently and don’t follow the Darwiniac parade) is that the same people pushing evolution-only in the schools are the ones pushing ruining the economy over global warming in the UN: i.e., leftist radicals and secular-progressive liberals. These, furthermore, are the same people with a high-and-mighty attitude about their scientific consensus being too urgent for free speech and democracy. Their views must be imposed on the public by the elite, through the World Court if necessary.
A number of ironies appear here. Witkowski rightly accused Stalin of politically-motivated policies that killed millions based on bad science, but thinks killing millions today based on bad science is rational and good. (Global warming is typically off-topic in these pages, but if countries implement what the IPCC and Kyoto recommend, the consequences will be brutal on the most vulnerable people in the world.)
Another irony is that he knows humans could not have caused the global warming that supposedly occurred 14 and 40 million years ago, but we must slash our wrists today over our ecological sins. (The papers above reveal that drastic climate change has apparently occurred surprisingly fast without man’s help, enough to melt the poles, and life got by in spite of it. That includes all the mammals, birds, Galapagos tortoises, penguins, tuataras and other endangered species that apparently got through the warm periods just fine.)
A third irony is that Witkowski (with Nature’s blessing) called us to make rational decisions drawn from the best data available. But the book he was reviewing was about genetics and farming, not climate change. You can grow plants in real time in the lab. You can test what makes plants and crops grow best and watch the results in weeks or months. Climate modelers, however, have to deal with chaotic and complex inputs, using proxy measurements, based on questionable assumptions, with unknown numbers of factors with unknown dynamics and unknown relative importance, confounded by feedback effects that are poorly understood, about prehistoric phenomena that cannot be directly observed. Indeed, their models look more like the convoluted theories of Lysenko than the experimental science of Mendel and Vavilov.
If Witkowski meant to impugn today’s communist countries instead of Washington, we forgive him, but experience teaches us that when Nature and Big Science accuses “politics” of trumping “good science” it means another conservative-bashing party is in progress. Let the reader beware (see previous entry, 08/02/2008).
Our readers know that good science is highly regarded here. We are unmerciful, though, against dogmatists employing the good name of science wrongfully. It’s hard sometimes to look past the arrogance in the papers for the kernels of truth in raw data, but respect for science demands it. The rare scientist who shows humility, who recognizes he could be wrong, who shows honesty and integrity and a desire to serve humankind through science, and a willingness to be corrected and learn from other points of view, is like a ray of warming sun in a blizzard of fogma.*
*See 05/14/2007 commentary.