“Stasists”? No. “Deniers”? Yes.

My previous post about the polar bear photo embarrassment, which Andy Revkin wrote about, gives me occasion to comment on Andy’s use of “stasists” for the people in opposition to the climate warming arguments. He favors that term, I gather, because it is more neutral than names like “denier,” and because he thinks it speaks to the goal common to the diverse camps of people on that side of the argument: to keep on doing things as we have been. Much though I appreciate Andy’s ongoing good-faith journalistic efforts to keep an even keel in these contentious discussions, after some consideration, I still disagree about the appropriateness of that label. (But then again, I’m no fan of the “pro-life” label for people who are objectively anti-choice, either.) First, let’s acknowledge that the terminology for both sides stinks. James Hansen, Stephen Schneider, Rajendra Pachauri, Al Gore and others warning about the evidence for anthropogenic global warming (AGW) are obviously not “warmists” in the sense of wanting more warming any more than Marc Morano and Bjorn Lomborg are "coolists" who want more cooling.

The problem is compounded by the range of nonexclusive reasons why (ostensibly) people are in the stasist/denier camp. First, there are the many who may start off with no particular opposition to the idea of AGW but who sincerely do not know or do not understand the evidence for it (I would like to think they constitute much of the U.S. public). Then there are the ones who outright deny the climate is changing; the ones who do not think human activity could affect the climate; the ones who recognize changes in the climate but insist it must be natural; the ones who concede the possibility of human influence but doubt the warming will continue; the ones who accept the fact of significant warming but doubt it will be disruptive; the ones who grant AGW could be bad but say responding to it in the future makes more sense than trying to prevent it; and the ones who simply argue that More Research Is Needed and refuse to act until their agnosticism is satisfied. And of course within each of those segments, one could split out still smaller shadings of opinion. (Baskin-Robbins doesn’t have as many flavors of ice cream as Andy’s stasists have flavors of opposition.)

Finding one name that honestly and accurately reflects all those points of view is difficult. Yet with the exception of those who can plead genuine ignorance (and who are almost never the ones publicly arguing against climate science or policy), pretty much all of those other positions involves some level of active denial or disagreement with copious scientific evidence or risk-management precedent. So at a purely existential level, they define themselves to my mind as the “uninformed” and the “deniers.”

(I suppose the latter could also be called “resisters,” but frankly, the dishonesty many of them exhibit in repeatedly using debunked arguments persuades me that the overtones of “denier” are more accurate. Moreover, since I suspect that many of them are simply committed a priori to rejection of the climate science and its consequences out of their own beliefs, the term “denialist,” with its creedlike associations, also makes considerable sense.)

But here is the crux of my argument: I think it’s a mistake when characterizing these people as deniers to try to homogenize what they think about AGW or climate science because they are all over the place on those. Rather, what they all deny is any need for a pro-active response to AGW.

Isn’t that essentially Andy’s argument for calling them stasists? It’s close but here is where I fault his terminology. First, these critics are not all calling for stasis in policies: those like Bjorn Lomborg are happy to see any number of policy responses but only after the damage of climate change is more evident. They simply don’t want anti-AGW activism to rock the boat now. Second, I think “stasist” is Orwellianly misleading as a label for a position synonymous with acceptance of massive change. Put it this way: would you consider someone a “biodiversity stasist” if he advocated continuing to cut down rainforests only at the current rate?

As so many climate scientists and others have already said, the time for action on global warming is already upon us. Let’s be clear, then, that the division in the arguments is between those committed either to climate action activism or to climate action denial (or resistance or opposition). Forget trying to find some neutral, anodyne term in the interest of reconciliation. The weight of evidence runs against most of the deniers' positions, so don’t hesitate to use a term that puts them on the defensive.

Polar Bear Pic was Bad... But So What?

Andy Revkin, on his Dot Earth blog, has already done a fine job of summarizing the self-defeating gaffe of Science publishing the new letter from 255 National Academy of Sciences members, which rebukes the misleading political assaults on climate research and its investigators, with a Photoshopped image of a polar bear on an ice block. Because of this frustrating error, the attention that the authoritative scientific statement deserves is instead diverting to the flawed rhetoric of its presentation (a mistake introduced by the publication, not by the NAS). The incident has become a perfect cameo of the larger climate-change issue: scientists speak out on the state of the research with facts and substantive arguments, and opponents jump on any small defects in what’s said to argue, honestly or otherwise, that the climate science is wrong, corrupt or both. Of course, the irony of us criticizing Science’s use of the polar bear artwork is we forget that in the eyes of the people most incensed by it, literally no effective image would have been acceptable. I’m not arguing that the polar bear picture wasn’t a particularly bad choice: it was, because it made the critics’ job much too easy. But what images would have been above reproach? Photos of shorelines racked by hurricanes or floods? Icebergs calving off polar glaciers? As individual incidents, none of those can be pinned definitively to global warming, so the critics will always call the images sensationalizing. How about a photo of a polar bear on a larger ice sheet? The critics don’t think polar bears are endangered, wouldn’t really care if they were, and don’t accept that global warming is the real reason for their problems. Ditto for any other climate-endangered species. Care to show photos of people whose livelihoods are jeopardized by climate change? Surely then you are ignoring the flexibility and ingenuity of human economies.

How about just a presentation of the scientific data, then? Maybe, say, a nice hockey-stick graph of rising temperatures over the past millennium? Hmm, apparently that’s not acceptable either, no matter how well vindicated its conclusions might be. Or maybe something showing the rapidly rising levels of CO2 in the atmosphere? But surely then you’ll be ignoring the fact that CO2 levels were higher during the Carboniferous, and if it was good enough for Apatosaurus, it will be good enough for us, too.

No, none of those is beyond controversy. Here’s what you need to show to keep the critics happy: Big, empty photos of the sun. Photos of scientists pulling ice cores out of the ground or otherwise engaged in bland, unintelligible, wonkish busywork. Maybe a big group photo of those 255 NAS members standing on the steps of a building in Washington. Photos of the IPCC reports (riveting!). Maybe some artwork of a thermometer creeping into the 90s with a big question mark beside it (awesome!).

Face it: to the people committed to rejecting your message, no image that helps you sell your message persuasively will ever be acceptable—because accepting it would be tantamount to conceding some point in your favor. And if the climate deniers have proven anything, it’s that they are willing to oppose the global warming issue at every possible level, from denying the fact or possibility of global warming right up through dismissing the possibility or desirability of responding to it proactively.

By the way, just as an experiment, consider if the shoe were on the other foot. Suppose 255 scientists released an official statement dismissing global warming as a sham. Are there any images they could use to illustrate that argument forcefully that would elicit an equal sense of outrage and disappointment from others on their own side? Somehow, I doubt it; these are people who have embraced “Al Gore is fat!” as a rallying cry.

Blood Simple: Mammoths, mice, malaria and hemoglobin

Oh, the allure of a misleading headline. When I saw this story on BBC news, “Mammoths had 'anti-freeze blood', gene study finds,” I thought for a moment that scientists had discovered those Ice Age behemoths had secreted some glycerol-like compound into their tissues to prevent freezing. Such a finding would have been genuinely astounding because, as far as I know, that trick is seen only among certain polar fish and overwintering insects; it would have been a first among mammals. In reality, the surprise is not that the mammoths’ blood resisted freezing but rather that it cleverly continued to do what blood vitally must do: transport oxygen to needy tissues, even at low temperatures. Kevin L. Campbell of the University of Manitoba and his colleagues reached this conclusion through a nifty piece of paleogenomic molecular biology, as they reported in Nature Genetics. Their technique’s fascinating potential to help biologists learn about the physiologies of extinct creatures has already drawn considerable attention, but the mechanism of the hardiness of the mammoths’ blood also helps to highlight a common way in which evolution innovates.

Mammoths display obvious features that must have helped them stay warm in the brutal subzero temperatures of the Pleistocene ice ages, such as long, shaggy coats and small ears. They may well also have had less obvious ones, too, like the arrangement of blood vessels in the legs of caribou that allows countercurrent exchange to minimize the loss of body heat from their legs while they stand in snow. Nevertheless, Campbell had wondered about whether the mammoths’ blood might have been adapted, too, because of hemoglobin releases oxygen into tissues only sluggishly at low temperatures.

By extracting the hemoglobin gene from DNA in well-preserved mammoth remains and inserting it into bacteria, Campbell and Alan Cooper of the University of Adelaide were able to replicate samples of the mammoth’s hemoglobin. And sure enough, in subsequent tests, the resurrected hemoglobin proved to release oxygen much more consistently across a wide range of temperatures—even glacially low ones.

Perhaps it sounds surprising that something so fundamental to mammalian physiology as its hemoglobin chemistry would be subject to evolutionary revision. Surely the mammoths might have survived the cold just as well by evolving more hair or thicker insulation. Yet hemoglobin chemistry is actually a feature particularly well suited to modification—and that has been modified many times throughout evolutionary history. The key is that the genes making the globin proteins have leant themselves to frequent duplication throughout evolutionary history, which opens up the opportunity of variation among the copies and specialization in their activities.

Humans, for example, have several different types of globin genes (designated alpha, beta, gamma and so on) on chromosomes 11 and 16 that may be used in various combinations to manufacture variant forms of the tetrameric (four-chain) oxygen-transport protein in red blood cells. For our first 12 weeks or so in utero, our bodies make embryonic hemoglobin, then switch to fetal hemoglobin, which can continue to be a major component of newborn babies for six months. Mammalian fetuses need hemoglobin that takes up oxygen very avidly because they need to steal it away from their mothers’ blood as it circulates through the placenta (see graph). So fetal hemoglobin does not respond to a chemical (2,3-bisphosphoglycerate) that reduces the oxygen affinity of adult hemoglobin.

Fetal hemoglobin has actually been the salvation of many adults who suffer from sickle-cell anemia. These people make a defective form of adult hemoglobin that distorts their red blood cells into the elongated, sickle shape that gives their condition its name; these sickle cells can clump together and block blood vessels, leading to painful and frequently fatal complications. A treatment for sickle-cell anemia, however, is to give a patient hydroxyurea and recombinant erythropoietin, which stimulate the body to begin making fetal hemoglobin again, alleviating some of the problems.

Of course, sickle-cell anemia is itself the result of a mutant variation in the copies of the genes that make the beta subunit of hemoglobin. As is well known today, the genetic trait for sickle cell seems to have originally taken root in populations in sub-Saharan Africa and other parts of the world where mosquito-borne malaria is endemic: people who are carriers of the trait are somewhat more resistant to malaria infection. The prevalence of sickle-cell genes in those populations therefore may represent an adaptive, evolved response—albeit it a cruel one—to the harsh burden of malaria. Indeed, the genetic blood disorders called thalassemias, which are prevalent in many Mediterranean ethnic groups, may similarly represent the result of natural selection for improved survival against malaria (although unlike sickle-cell anemia, which involves an abnormal hemoglobin, thalassemias are caused by underproduction of a normal hemoglobin).

Looking outside the human species, one finds that the globin proteins have a staggeringly wide range of forms and chemistries, representing an incredible amount of evolutionary experimentation that long preceded the development of our species’ own tidy system. Horseshoe crabs aren’t aristocrats but they are literally blue bloods, with a blood pigment that carries copper instead of iron. Sea squirts have a green blood pigment based on vanadium.

Many animals (including humans), in addition to some form of hemoglobin, also have myoglobin, a large globular protein that helps muscle tissue hang onto the oxygen it needs while working. (Myoglobin is the reason that meat is red, my fellow steak lovers.) Some dopaminergic neurons and glia in the brain also seem to contain hemoglobin, possibly to insure the brain’s own access to oxygen under suffocating conditions. And hemoglobin itself also seems to have functions quite apart from oxygen transport: its antioxidant properties and interactions with iron seem to be used by cells in the kidneys and immune system.

All this variation suggests that hemoglobin genetics might not have been such an odd target for natural selection in the evolution of mammoths: it is an extremely malleable protein with diverse capabilities, and because organisms often contain multiple copies of it, variants can creep into a population and survive long enough to be tested by selection.

In fact, another example not unlike the mammoths was reported in the scientific literature last year. Jay Storz of the University of Nebraska-Lincoln and an international team of collaborators reported last August in the Proceedings of the National Academy of Sciences on their genetic comparison of deer mice living in lowland prairies and in the mountains. The mice were identical in every respect except for just four genes—all of which boosted the oxygen capacity of the mountain mice’s hemoglobin.

Mammoths and deer mice may be at opposite ends of the spectrum for mammalian size, but similar principles of evolution applies at all scales.

Principled Rightwing Absurdity

Nothing I could write could better capture the preposterous incoherence of current U.S. conservatism than this passage by Digby at Hullaballoo:

Next time someone in a tri-corner hat starts waving the constitution in your face, ask them about today's Senate Homeland Security hearings, where the conservatives had a complete fit at Mayor Michael Bloomberg's complaint that people on the terrorist watch list can buy any gun they like and there's nothing anyone can do about it --- while at the same time they all thoughtfully pondered whether or not we should strip them of their citizenship.

Energetically Batty

A recent discovery about the evolutionary origins of bats relates, at least indirectly, to a problem causing the extinction of many bat species throughout North America.

As they reported in the Proceedings of the National Academy of Sciences, Ya-Ping Zhang of the Kunming Institute of Zoology and colleagues have found evidence that mitochondrial genes in bats, which are responsible for their metabolic use of energy, have been under heavy selection pressure since early in their evolutionary history. Such a conclusion makes considerable sense on its face because bats’ way of life is highly energy intensive.

Nevertheless, the finding also helps to sketch in some of the mysteries of the evolution of bats. Bats are hard to look at in fossil record because they don’t fossilize well; they suddenly appeared in Eocene strata from about 50 million years ago looking fairly much as they do now, which left cryptic some of the steps up to that point.

Over the past decade, several discoveries have helped to firm up the view that the ancestors of bats spent their lives leaping and hopping through vegetation before they could fly; that the evolution of their wings seemed associated with key changes in certain genes for digits; that their ability to echolocate seems to have emerged after their capacity for flight; that the larger bats called Megachiroptera are indeed descendants of the smaller Microchiroptera and not the convergently evolved cousins of primates. The place of the metabolic changes in that scheme, though, were largely speculative. The demands on bats’ mitochondria could have emerged only once they started flying, but instead it seems that their ancestors made a living as an extra hyperkinetic group of insectivores leaping through the trees and shrubs.

All that energy expenditure comes at some cost to the bats, however. Most obviously, they need to eat colossal numbers of insects to satisfy their energy needs. During the cold winter months when insects become more sparse, bat species that don’t migrate to warmer climes must overwinter in caves, suspended in a state of torpor with their metabolisms at a crawl.

Unexpectedly, those energy demands may also figure into the catastrophic epidemic of white nose syndrome that has been killing bats in North America in recent years. The bodies of the dead bats studied by researchers have commonly been marked by heavy accumulations of this fungal infection, which in severe cases can damage the overwintering animals' skin and wings, leaving them unfit. Yet the observed level of infection and the timing of the bats' deaths suggest that this obvious explanation isn't adequate: in many cases, the fungus should have been only about enough to pose an itchy nuisance, maybe akin to aggressive athlete’s foot in humans.

That benign comparison may break down when applied to bats in torpor, however. Bats going into hibernation carry stockpiles of fat to sustain them, but those stockpiles are often just sufficient to get them through the winter season. Moreover, the bats do not consume those fat reserves at a consistently slow pace: every two or three weeks throughout their hibernation, the bats wake out of torpor, excrete, groom themselves, settle into genuine sleep for a while, then slow down their metabolisms again. These periods of activity seem to be essential to hibernating mammals, perhaps because they help to reinvigorate their immune systems. Eighty percent or more of the energy that the bats consume during their hibernation is spent during these brief intervals.

One theory therefore being investigated by researchers such as Craig Willis at the University of Winnipeg is that the fungus makes the animals rouse from torpor more often to groom themselves, and in the process makes them burn through their crucial fat reserves too quickly. Long before winter is over and insects are plentiful again, the bats starve.

North American bat species may be more vulnerable to white nose fungus than their European counterparts are because they roost in far larger colonies and so may transmit the fungus more widely throughout their population. It’s entirely possible, however, that the smaller European colonies are in fact an evolutionary consequence of white nose fungus (or some equivalent affliction) selecting against larger gatherings in the distant past.

This is only my own speculation, but if a highly amped metabolism has long been an adaptive feature of bats and their immediate ancestors, then perhaps for as long as these creatures have been using torpor to survive the cold months, something like white nose fungus has been cropping back colony sizes periodically. Unfortunately, given the difficulty of finding good bat fossils, verifying such a hypothesis may never really be feasible. But who’s to say what other deductions might yet be possible from the DNA record?

(For the information about white nose syndrome and its possible mechanisms, I'm indebted to science writer Erik Ortlip, now of Environmental Health News, who wrote about this subject while he was my student in the Science, Health and Environmental Reporting Program at the Arthur L. Carter Journalism Institute of New York University. Thanks, Erik!)