Of Polar Bears and Walruses

"Carbon dioxide is one of four principal anthropogenically-generated GHGs (greenhouse gases), the others being nitrous oxide, methane, and halocarbons. . . Since the start of the industrial era, the effect of increased GHG concentrations in the atmosphere has been widespread warming of the climate."

Greenpeace? Sierra Club? Al Gore? No, the quote is from the Bush Administration, page 28244 of the May 15, 2008 Federal Register.

Earlier this month, the U.S. Geological Survey reported what everyone has known for quite some time - that the summer extent of Arctic sea ice has decreased sharply over the past several decades. In a paper about the response of the Pacific walrus to sea ice loss, the Survey noted that in 6 of the last 9 months, the Chukchi Sea ice shelf was ice-free, with periods of no ice cover extending from one week to as much as 2 1/2 months. There had always been at least some ice over the Chukchi shelf in all of the previous 20 years of measurement (1979-98).

As most people who care about such things have probably heard by now, this week the U.S. Fish and Wildlife Service has finally gotten around to declaring the polar bear a threatened species pursuant to the Endangered Species Act. Most of the progressive press coverage of the listing declared "about time" and lamented that the ruling didn't call for regulation of greenhouse gases to preserve the sea ice upon which the bears depend, but I think that the press missed what was actually said in the Federal Register - there's some amazing stuff in there, especially coming as it does from the Bush Administration.

For years, the Bush Administration has denied the issue of global warming, declaring it the "greatest hoax ever perpetrated on the American people" in the infamous words of James Inhofe. Government scientists have long been silenced or otherwise censored when they've admitted to the science behind climate change. Julie MacDoanld, a high-ranking department official with no formal educational background in natural sciences, had pressured government scientists to alter previous findings on threatened species. Officials of the White House Council on Environmental Quality made more than 180 changes to a status report on global warming, virtually all of which had the effect of exaggerating scientific uncertainties and minimizing certainties. The official responsible for most of the changes, Philip Cooney, had come to the White House from the American Petroleum Institute and now works for Exxon Mobil.

This week's listing of the polar bear as endangered initially goes on at length about the biology and ecology of the bear and its habitat, and then addresses the observed changes in Arctic sea ice, diminished sea ice thickness, and changes in oceanic and atmospheric circulation. All of this leads the Wildlife Service to the unavoidable conclusion that global temperatures are rising and affecting polar sea water and ice, and the loss of sea ice is threatening the continued survival of the polar bear. The listing makes extensive use of the many climate models to support this case.

But the most interesting part to me was the Wildlife Services' published responses to comments on the draft ruling. Commenters threw about every argument that's ever been made against climate-change theory at the listing, and the Service patiently goes through each of these arguments one by one, until they eventually start to sound like none other than Al Gore in full Inconvenient-Truth mode.

The public comments are presented in the Federal Register ruling divided by issue, starting with polar bear populations and progressing through several other topics before getting to the science of climate change. Here, the first comment states, "The accuracy and completeness of future climate models are questionable due to the uncertainty or incompleteness of information used in the models."

I've heard that argument often. In response, the Service notes that the models and interpretation "represents a collaborative effort among climate scientists from around the world with broad scientific consensus on the findings." Quite a departure from the Administration's previous emphasis on uncertainty and claims of lack of consensus. The Service goes on and states that climate models have consistently improved over the years and now "provide credible quantitative estimates of future climate change, particularly at continental scales and above." This confidence comes from the foundation of the models in accepted physical principals and from their ability to reproduce observed features of current climate and past climate changes. Additional confidence comes from considering the results of suites of models rather than the output of a single model.

Other commenters provided a number of regional examples to contradict the major conclusions regarding climate change. Michael Crichton uses this argument extensively in his case against climate change. In response, the Service repeated the observation that the models provide their best results at global or continental-level scales, and are less accurate in projecting climate changes over finer geographic scales. However, the regional variability merely suggests to the Service that the future will also have a large variability, but does not negate overall climate trends.

"Climate models do not adequately address naturally occurring phenomena," the commenters argued. "Atmospheric CO2 is an indicator of global warming and not a major contributor" and "Atmospheric CO2 levels are not greater today than during the pre-industrial time," they state. "Wrong," the Service in effect responds, "Wrong, and very wrong."

"Atmospheric concentration of carbon dioxide'" they note (page 28244), "has increased significantly during the post-industrial period based on information from polar ice core records dating back at least 650,000 years. The recent rate of change is also dramatic and unprecedented, with the increase documented in the last 20 years exceeding any increase documented over a thousand-year period in the historic record."

"The increases," they conclude, "are largely due to global increases in GHG emissions and land use changes such as deforestation and burning." CO2 levels have been increasing since the start of the industrial revolution due to man-made activities, and the most recent spike in concentration is an anomaly in the 650,000-year record. As will be shown later, the 650,000-year record goes back to before there even were polar bears on planet Earth.

One argument maintains that the current climate patterns are part of the natural cycle and reflect natural variability, not human influence. Considered on a global scale, climate is in fact subject to an inherent degree of natural variability. However, evidence of human influence on the recent evolution of climate has accumulated steadily during the past two decades.

After a while, the comments start to sound kind of desperate: "The world will be cooler by 2030 based on sunspot cycle phenomena." Almost not worthy of a response, but the Service did reply, gamely explaining sunspot science and how it was incorporated into the models. The conspiracy theorists weighed in too with, "The climate change analysis ignored information about areas that are cooling and made selective use of the available information" and "Evidence that does not support climate change was not included in the analyses."

At the risk of being accused of conveniently overlooking some important anti-global warming argument , I won't recount every comment and response here. Instead, I'll provide you with this link, and let you read for yourself the Administration's defense of every argument against climate change thrown at it. They repeatedly emphasize that they did not rely upon any single climate model or scenario in their listing, but instead upon suites of models and the broad consensus among scientists around the globe. Each contrary argument is carefully considered, addressed and shown to be without merit.

This is an amazing document to see coming from this Administration, and one hopes it's a harbinger of a more-reasoned approach to this global problem soon. I'm also encouraged by McCain's recent speech in Oregon about his suggested approach to climate change. While I'm always suspicious of campaign promises (Bush had promised back in 2000 to regulate CO2) especially considering that McCain was speaking in one of the greenest of states, I think he was correctly reading the changing mood of the American public. His proposal for a CO2 cap-and-trade system (a pragmatic approach of which I approve) could give his campaign much credibility.

Oh, one more thing. Earlier, I said that the listing goes on at length about polar bear biology and habitat. It does, and on the very first page it says "The polar bear is usually considered a marine mammal since its primary habitat is sea ice, and it is evolutionarily adapted to life on sea ice. . . Polar bears divereged from grizzly bears somewhere between 200,000 and 400,000 years ago." A few paragraphs later: "Polar bears evolved in sea ice habitats and as a result are evolutionarily adapted to this habitat," and "Polar bears evolved to utilize the Arctic sea ice niche."

What? Admission of evolution from the Bush Administration? Acceptance of evolution as the law of the land, published as it is in the Federal Register? I thought I'd never see the day.

The image of polar bears evolving out on the sea ice reminds me of a passage from Charles Darwin, brought to my attention by reading Richard Dawkins' The Ancestors Tale (and I still intend to blog about that book one of these days):

"In North America the black bear has been seen by Hearne swimming for hours with widely open mouth, thus catching, like a whale, insects in the water. Even in so extreme a case as this, if the supply of insects were constant, and if better adapted competitors did not already exist in the country, I can see no difficulty in a race of bears being rendered, by natural selection, more and more aquatic in their structure and habits, with larger and larger mouths, till a creature was produced as monstrous as a whale (Origin of Species, 1859, p. 184)."