The Climate in Emergency

A weekly blog on science, news, and ideas related to climate change


Cowboys and Indians, Part 1

This is the first of a three-part series on the most recent Keystone pipeline protest in Washington DC. While this article focuses on the experience of being at the march, future articles will focus on the organization that lead the march, the Cowboy Indian Alliance, and on the media reaction to the Keystone issue.

Spotting two bald eagles while on the way to a protest in Washington DC has to be a good sign.

We, my husband and I, knew that various tribal groups were staging a protest against the planned Keystone XL pipeline. Its route crossed their lands, making the probability of eventual oil leaks a direct existential threat to them. We didn’t know who, really, had organized the protest, what the specifics of their concerns were, or what their other plans were. But we agreed with them that oil pipelines are bad and Native sovereignty is good, so we were happy to show up.

We drove as far as the first subway stop but used public transportation from there. It seemed the right thing to do, considering, although work being done on the track meant we had to go part of the way by bus. Once on the Mall, we had a little trouble finding the actual protest. Some tipis were evident–an unusual sight, and clearly related somehow, but we couldn’t see any crowd. What sounded like the notes of “Amazing Grace” floated up and out of the little group of peaked tents, played on what sounded like a musical saw. Nearby, a small group labored around a square event tent and a small stage, but nowhere were there any crowds. Nothing happening. So we walked on, towards the Washington Monument. The day was warm and sunny, the sky nearly cloudless, and tourists walked here and there just as though nothing special were going on. Had we gotten the day wrong?


The little encampment of tipis and the stage and the event tent and the few people around them were it. We returned there and joined the small, gathering crowd and wandered around for a while between the musicians on the stage (no musical saws among them) and a press conference conducted in front of one of the tipis and entirely hidden by a small, tight crowd. Most of the tipis were plain, or nearly so, though one was brightly painted. One had no covering at all, just a cone of bare poles. In among the tipis was a small wooden wagon with hoops of wood arching over its rectangular back. A covered wagon? Except it had no cover. It was elaborately carved but empty. There were no people available to explain these obviously meaningful objects, no sign whether any of these tipis were simply props or actually inhabited–were people camping on the national lawn? –or what the symbols on the tipi coverings or the wooden wagon were. Red-vested volunteers moved here and there and a modest crowd swelled slowly. Some of the people wore buttons bearing the letters CIA, referring, as we learned, to the Cowboy Indian Alliance. Others carried long bamboo poles hung with red flags printed with odd, angular symbols that turned out to be the brands of ranches along the proposed pipeline route. A man wearing a tuxedo and a pig mask carried a globe and a sign reading “Oil Pig.” We drifted towards the stage.

The speeches began around eleven, before we all stepped out on a short march to the Museum of the American Indian and back. The day finished back at the tipi encampment with more music and dancing.

It was curious, moving through an event created largely by Indians. The entire rally was subtly but definitely based on different cultural assumptions than I am used to. I felt somewhat out of place, not an intruder but a guest. That seemed about right.  Most of the people who spoke began and ended with a few phrases in languages other than English, and no one bothered to explain what they said or why because they were speaking largely to people who already knew. Curiously, a lot of people spoke with the same soft accent, whether they were Lakota, Dakota, Ponka, or Dineh-Athabaskans down from Canada where the tar sands are. Sage smoke drifted across the crowd.

I thought of asking questions, though I know some Native American cultures frown on questions. My husband thought I should ask, because anyone at such an event should be prepared to explain themselves, but I did not ask because I thought perhaps these people wanted to assert their right not to explain, to be the majority for once. One of the emcees politely asked anyone in the crowd wearing face paint to please wash it off. He said those designs are culturally specific; he said those designs are war paint and this was a peaceful gathering; he said you have to earn the right to wear those designs and not just anybody could do it.

The rally began with a prayer, as many events do. A man sang to the six directions (the extra two are up and down) while an older woman used a jar of water from the Oglalla Aquifer and a bucket of soil from the proposed pipeline in some small ceremony. The crowd turned to each direction as the singer addressed it and the song washed over and through us. The elm trees had just released their small seeds and the ground was busy with them. DC’s famous cherries were just leafing out, their flowers spent. I kept thinking I almost understood the words of the prayer-song, almost had it already memorized, since I heard it echo syllable by syllable in my mind. But of course I had no idea.

But the Cowboy Indian Alliance is not just Indians and the next man to offer an opening prayer was a Protestant Christian preacher, a white man and a farmer. He is part of a group called Pray No KXL and has committed to pray every day for God to direct the United States Government to do the right thing. He prayed in English, using the same kind of phrasing, the same rhythm, that my brother-in-law (also a preacher) uses to say table Grace, but this man’s version of Christianity seemed inclusive and almost animist. He assumed everyone prayed to the same God in their own ways and he spoke of God as the breath present in all our lungs, as the power that receives animals and plants when they die and creates them again. He spoke of repentance and thanksgiving and asking God to guide President Obama and Secretary Kerry.

Most of the farmers and ranchers who spoke were women; their men, as they explained, were back at home working, since it is branding season in Nebraska. As the “cowboys” of the Cowboy Indian Alliance, these women represented a culture far more alien to my experience than were the Native prayers. Farming is in my family, but not cattle. I’ve never been to the Great Plains, and I certainly haven’t studied their culture in school. These smiling, passionate women were a revelation. They spoke of living on the land for six generations now, of recognizing specific creeks as the source of their livelihood because that’s where the cattle drank, of building a barn inside the pipeline (could I possibly have heard that right?) to keep the oil from flowing. They spoke of trespassing surveyors, oil company representatives who lied, and a governor who threatened to call out the National Guard when the ranchers refused to let the pipeline cross their land.

In almost none of this did anyone mention climate change. Those few who did were not Indians and did not seem to be ranchers.

Climate change is inherent to the KXL pipeline debate, of course. The tar sands crude it is supposed to carry has a huge carbon footprint and there is enough of it that tar sands oil could keep the price of petroleum too low for renewables to be able to compete.  The pipeline is only one of the many routes that fossil fuel can travel from ground to sky and it isn’t even the only pipeline–other pipelines are already in operation carrying the same crude oil. But KXL has become something of a line in the sand for the anti-climate change movement, a rallying point for the nearly forty percent of the American population who passionately object to its construction. As a rallying point it is somewhat arbitrary, but then lines in the sand usually are. It’s just important to draw the line somewhere at last.

But for these cowboys and Indians, opposing Keystone is not arbitrary. It is not about climate change per se. For them, the issue is water.

The issue is that the pipeline route crosses rivers and streams that water their crops and their game and themselves. The pipeline crosses the Oglala Aquifer, the vast underground resource that feeds much of American agriculture. Pipelines leak; the pipelines that already exist are already leaking, some causing dramatic environmental disasters. Sooner or later, the Keyston XL pipeline, if built, will leak also, and if that happens it will destroy these peoples’ livelihoods, their health, and the health of the land that they love.

Climate change, of course, will be no picnic for the cowboys and Indians either. The central part of the United States is likely to become more prone to drought and that could hurt agricultural production there, especially since the current use of the Oglala Aquifer is already unsustainable. But for them, water pollution from crude oil is clearly the more immediate danger.

Maybe this is why only about a thousand people showed up, in contrast to the tens of thousands we joined over a year ago–that protest had a clear focus on climate change and the support of big-name climate activists, like Bill McKibbon. I have not yet looked into the question formally, but my husband and I follow a lot of large environmental groups online and we don’t remember seeing anything about this week’s protest from most of them. Maybe they didn’t see this as their issue so they didn’t bother to get involved and get the word out?

If true, their reticence is a strategic mistake.

The atmosphere and its steadily rising carbon dioxide concentration is a problem for all of us; the climate warms for the just and the unjust alike. But by the same token, climate change is a bit abstract. It is hard to get angry about a problem that develops gradually, hard to organize a battle against a billion tiny tailpipes leaking poison all at once, especially when we also have rent to pay and kids to feed and other, more concrete, demands on our attention. The ubiquity of the problem saps our commitment and confuses our stratagems. Yet there are fulcrum points, places and people and events that hurry fossil fuel into the sky. The pipeline route is one of those critical places. And these people whose drinking water is threatened are the ones who will put themselves in front of the pipeline to stop it, even if all else fails.

If the rest of us show up when these people need it, they’ll be able to stop the pipeline for us. And maybe then the next group of people who find their homes and lives threatened will be willing to stand up and fight back, too, knowing that thirty thousand people will show up in DC to support them. And the next, and the next.

And we could win this.



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The Responses to the IPCC

This is the fourth installment of a four-part series of the Intergovernmental Panel on Climate Change (IPCC) and the report it is in the process of issuing. The first post in the series described the IPCC while the other two summarized the first, second, and third installments of the report (we still await the fourth installment, the Synthesis Report, due out later this year). This post addresses the media response to the report.

The world has not taken very kindly to the IPCC’s report, nor has its response, thus far, been particularly wise.

Generally, writers hand public figures have responded in one of three ways: by complaining that the report is alarmist and inaccurate; by complaining that the report is too conservative and does not raise sufficient alarm; and by accepting the report as true and complete and calling for a concerted effort to fight climate change.

First, let’s tackle the “deniers.”

Predictably, a number of commentators complained that the IPCC’s report is misleadingly alarmist. Let’s take this editorial in USA Today as an example.

The author’s basic argument is that not only is the IPCC wrong to raise the alarm, but that the experts actually know that the IPCC is wrong, and have said so, and that the IPCC continues to function only due to a kind of momentum. The article includes several short quotes to this effect (it is not clear that any of those quoted is a climate scientist) as well as a slightly longer excerpt from an editorial published in Nature.

However, the Nature article actually says something very close to the opposite of what the excerpt from it implies.

Joseph L. Bast, the author of the USA Today piece, quotes Nature as saying:

“Scientists cannot say with any certainty what rate of warming might be expected, or what effects humanity might want to prepare for, hedge against or avoid at all costs.”

He follows this quote up by a statement of his own that looks like a continuation of Nature’s critique but is not:

“Despite decades of research funded by taxpayers to the tune of billions of dollars, we are no more certain about the impact of man-made greenhouse gases than we were in 1990, or even in 1979 when the National Academy of Sciences estimated the effect of a doubling of carbon dioxide to be ‘near 3 degrees C with a probable error of plus or minus 1.5 degrees C.'”

Now, Bast’s statement, that “we are no more certain about the effect of carbon dioxide,” is true only in that we have been more or less certain about the effect of carbon dioxide on climate since 1896. Other aspects of the problem, like other greenhouse gasses, the role of aerosols, and various feedback loops, were less clear in 1979. Some, though not all, of those puzzles have since been solved.

Nature is correct that the rate of future warming is uncertain, but that doesn’t mean that scientists are totally clueless; a major source of uncertainty is that nobody knows what future greenhouse gas emissions will be. In any case, its editors’ main point is actually that the IPCC has done an excellent job, but that more reports on climate science as a whole aren’t necessary. They suggest that the IPCC produce smaller, more focused, and more rapidly compiled reports in the future.

Bast complains that the IPCC does not explain why “no warming has occurred for the past 15 years,” but in fact warming has occurred over this time frame. Warming did slow, for reasons the IPCC report did explain, but the so-called “pause” was an illusion born of creative misrepresentation of data.

He goes on to call on policy makers to listen to “other voices,” such as the NIPCC,  a group of “50-some scientists,” at least some of whom are associated with the Heartland Institute, a free-market advocacy group that receives significant funding from the oil industry.

For the record, 50 is a very small number of scientists for an international group on a major issues. The current  IPCC report has over 800 authors.

In any case, Bast himself is the president of the Heartland Institute.  Does a financial link to the oil industry mean a person can’t speak to global warming? Of course not. But the conflict of interest is certainly relevant.

I am not in a position to say that all high-level climate contrarians are in the employ of the oil industry or something similar. But at least a lot of them are. And while these critics typically present themselves as outsiders independent of Big Climate and its lucrative research grants, the fact of the matter is that there is no money in climate change.

The members of the IPCC serve without pay, most environmental scientists spent half their careers more or less begging for money, and the industries that are benefiting from increased awareness of climate change, like solar and wind power, have a fraction of the revenue and reach that traditional energy companies do. There is no Big Climate.

Any scientist who wants to earn money could earn more of it working in some more lucrative field. Any scientist who wanted prestige could win far more of it denying climate change, if there were some scientifically valid way to do it, than by sticking with the status quo–science lionizes successful iconoclasts.

So much for the contrarian critics.

However, the IPCC report also faces complaints that it does not warn enough. Glenn Scherer, of The Daily Climate, charges that the IPCC has had a consistent “conservative bias,” underestimating the threat in ways likely to influence policy. Although he does not name any sources (“scientists say” is generally the extent of attribution), Scherer, does offer several explanations for this bias, including the claim that the IPCC does too much to please climate deniers.

Scherer was writing in 2012, before any of the current report had actually been published. He was referring to earlier reports, on the occasion of the UN climate talks in Doha.

Now, he was correct that IPCC reports consistently underestimate global warming. Political pressure from climate deniers is possible, but it really isn’t necessary. These reports take a long time to write. By the time the full report is finally published, the information in it is already several years old. And since new climate news is almost always bad, consistent underestimation is to be expected.

That the IPCC kowtows to contrarians is just as unbelievable a charge as the idea that it is beholden to the monied establishment; if the Panel wished to be corrupt, wouldn’t they be better at it? If they wanted to avoid contrarian criticism, they clearly failed.

In any case, if the report does underestimate the amount of sea-level rise by a millimeter or two per year, or predicts an ice-free Arctic several decades farther down the road than reality, that doesn’t change the fact that climate change as described by the IPCC is a frightening, very serious problem that we should all do something about right away.

And yet, nobody has really done anything about it.

The third category of response to the report is approval, support, and a call to action. And that reaction is just as curious, because it is unclear whether many of the people who have it are actually doing anything to radically reduce emissions.

Despite all the efforts and raised awareness to the contrary, greenhouse gas emissions have not yet slowed.

We will see, over the next few years, whether the support of the IPCC is more than just talk.



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The IPCC: Summarizing the Summaries

This is the third post in a four-part series on the current report by the Intergovernmental Panel on Climate Change. The first post introduced the IPCC and the overall structure and purpose of its report. The second post described the first installment of the IPCC’s report. This post described the two other installments that have been released to date. The fourth post will discuss the critical reaction to the report.

The IPCC is currently releasing its fifth Assessment Report in four installments over the course of just over a year. The first three installments are the reports of the IPCC’s three Working Groups, while the fourth is a final Synthesis Report. So far, the first three installments are out. No immediate release date has been announced for the fourth installment, though it will be sometime before this coming November. All these documents are publicly accessible, although they are also very large and very dry. The Summary for Policymakers for each Working Group’s Report is also available online for free. These summaries are very dry, but they are short enough to get through in an hour or so of reading, and most technical terms are explained.

Finding these downloads, or finding anything else relating to the IPCC’s report, is harder than it should be, though.

There’s no conspiracy, it’s just that nothing on the Internet is ever deleted and most of it is never updated. A search for IPCC AR5 WGIII (the rather awkward name of the third installment) therefore turns up articles on “recently” leaked drafts and anticipated publication dates, plus plenty of third-party commentary, but nothing that obviously includes the published report itself. Even the IPCC website still contains language that anticipates the release of the report and features download buttons for approved drafts of the Summary for Policy Makers. That the report has already been released is nowhere made clear, except that I remember when its release made the news last week. Probably, the IPCC actually has announced its release somewhere, but for whatever reason the webpage with the announcement has a much lower search engine ranking at present.

The Summary for the Second Working Group’s Report is much easier to find, but a search still yields a clutter of months-old announcements anticipating its arrival.

Let’s make this simple; here is a link to the Summary for Policymakers of the Second Working Group’s Report  and here is a link to the Summary of the Third Working Group’s Report. Go read them, if you want. They are each about 35 pages long, and then you will know what all the fuss and fevered commentary is about. In case you do not want to read them right now, or in case knowing what they are about ahead of time makes them easier to read, here is a brief summary of both summaries.

As with the first installment’s Summary for Policy Makers, the authors of these documents use language very deliberately, in ways that are sometimes slightly different from common usage. They explain their terms at the beginning. They also carefully explain how they gathered information, how they came to their conclusions, and which of their conclusions are basically certainties and which are still provisional. Without all this definition and context, quotes from the text might be misleading in places. With all that definition and context, the reports do seem a lot more reliable than critics on all ends of the political spectra suggest.

So, the Second Working Group reported on the impacts of climate change and on how well humans and the rest of the world can cope with these impacts. It is divided into three main segments: how things are now; what our vulnerabilities will be going forward; and what we can do to deal with these future risks.

So far, according to the report, climate change is mostly influencing ecological processes and has caused a few known extinction already. Climate change has also had some impacts on human societies, although it is difficult to determine how big those impacts are, because there are a lot of factors operating at once. Most of those impacts fall on the poor or otherwise disenfranchised, and most are negative. There are a few positive impacts, but whether the balance is positive for anybody is not clear. Generally climate change and other human problems (war, bigotry, etc.) make each other worse. A lot of countries are starting to adapt to climate change, or at least talk about doing so, but generally we are not ready and are vulnerable.

Assessing our risks going forward requires making some decisions about our values–what is important enough that the possibility of loosing it constitutes a high risk? The authors of the report outline the decisions they have made. While others are free to disagree with their decisions, because they have published what their decisions are, readers can use the report as a resource even if their values are different.

What the authors have to say is, in a word, scary. They do raise the real possibility of high emissions scenarios triggering sudden, irreversible changes due to the operation of certain feedback loops. The language is dry and a reader unfamiliar with these issues could easily miss the important paragraph, but basically the IPCC agrees that for some emission scenarios, the world as we know it could suddenly collapse.

That being said, their prediction of our future risks is nuanced and measured. Instead of predicting catastrophe across the board, the Second Working Group predicts various health problems, environmental problems, and economic problems, some of them sure and others uncertain, some slow and mild for the next couple of decades, others possibly severe.

The third section discusses only how we might better cope with climate change, not with how we might stop making climate change worse. Stopping our assault on the climate, which the report calls mitigation, is the subject of the Third Working Group’s Report.

The Third Working Group’s Report addresses what mitigation means, what opportunities for mitigation exist in various sectors (such as transportation and industry), and what the potential costs and benefits of various mitigation scenarios are. The authors of the report say that it is still possible to keep global temperature rise under 2 degrees C., but that doing so will become increasingly difficult the longer we wait before making serious changes. That we have not yet made serious changes in clear; while the authors note that a lot of mitigation policies and efforts exist, total greenhouse gas emissions are still going up.  Almost half of the total human production of greenhouse gasses since the Industrial Revolution began has been in the last 40 years alone.

The report addresses a lot of interesting points: that social justice and climate change policy are necessarily interrelated; that climate change mitigation could carry a lot of social and economic benefits; and that cost-benefit analysis have to take worst-case scenarios into account even if those scenarios are not likely to happen. If it has a weakness, it is the report’s definition of mitigation as an “intervention” by humans, phrasing that implies that global warming isn’t itself a human intervention already.

But perhaps the most important part is a single sentence:

“Effective mitigation will not be achieved if individual agents advance their own interests independently”

Translation? We’re going to fail unless we learn to help each other.




The Ghosts of White Birches

We will continue with our IPCC series next week; in the meantime, here is a follow-up to our series on climate change and extinction.

Early October, and half-frozen snow sugars the dark green firs and sifts down through the upturned wooden fingers of dead and dying birches in Franconia Notch, in the White Mountains of New Hampshire. The snow we expected; the dead birches were a surprise and a warning.

Early October is foliage season in the White Mountains, and my husband and I had joined my friend, Tom Wessels on the unofficial field trip he leads through blazing trees and unpredictable weather every autumn. Tom is a science writer and ecology professor, and he is the source of every statement of fact in this article, unless otherwise specified. I am no longer officially his student, and most of the grad students on the trip were strangers to me, but I do not pass up an invitation to walk in the woods with an expert.

Franconia Notch is the most dramatic of the three passes that cut through the famously rugged White Mountains. It is a narrow, foreboding glacial U. While the Whites are not tall as mountains go, they rise dramatically out of fairly low country and the turbulent storms that converge at their peaks make these mountains dangerous. Tree line here is only about 4500 feet, so a reasonable day hike can take in three different major ecological communities, one layered upon another, moving up the mountainside. We planned to tour all three, to start in hardwood forest and move through the spruce and fir-dominated subalpine layer and visit the exposed alpine tundra on the ridge top. From the trailhead in the Notch, we could see Cannon Mountain and Franconia Ridge sweep up above us into the clouds, almost parabolic in their steepness. The air, as we stepped out of our cars, was startlingly cold in comparison to the mild weather we’d left back home. There was no rain yet, but the day felt wet.

Tom had chosen a route that would take us up to Franconia Ridge, across three named peaks, and back down in a loop back to our cars. He had hiked the same trails before and was familiar with the route, but had not been this way in a few years. Though the trip was not associated with any particular class, part of the point of the hike was that Tom would take the opportunity to teach. His interest and his expertise lie in “reading” the landscape for its history. An oddly shaped tree or a shift in forest composition from one area to the next is a clue to what happened here decades, or sometimes even centuries, before. For those who can read the signs, events can cast a long shadow, shaping the growth and character of a place for generations. So as we hiked, every rest break became an opportunity for Tom to describe what was growing there and how the soil, topography, climate, and history of the place could all be seen in the identity of the forest at that spot.

One of the areas we walked through was the paper birch band. Paper birch, or white birch, is that pretty plant with the white, peeling bark. There are other birches that look vaguely similar, but paper birch is the most iconic and is famous as the source of birch bark canoes. It is a far northern plant, mostly native to Canada, and its small, light seeds allow it to colonize bare ground quickly. Around the turn of the last century the Whites Mountains were heavily logged for red spruce, another species adapted for cold, harsh weather. In Franconia Notch and several other places, paper birch moved in where the spruce had been removed, producing a distinct band at 2,500 to 3000 feet, the cheerful-looking shadow of clear cuts a hundred years old. So our trail took us through the birch band—and we found the birches were dying.

The birch band is temporary, as ecological time goes, since they belong to an early phase of forest development and paper birches are not long-lived trees, but these birches had not died of old age. They had not died alone, either. White birches are dying in many places across New England, pushed by a combination of factors including climate change.

Paper birch is a cold-weather species, capable of growing farther north than any other hardwood. It can cope with temperatures that would kill almost anything else, but it cannot withstand the rapid freeze-thaw cycles common in milder winters. The species is also struggling with a pair of relatively new diseases introduced several decades ago. Under the combined stresses of new diseases and a new climate, paper birch is already dying out of areas where the soil is not to its liking. The wood rots quickly, but the iconic bark is rot-resistant, and a New England nature lover can now easily find forests littered with broken trucks and hollow tubes of ghostly white bark. Some birch groves are hanging on, and of course trees farther north in Canada are still doing well, but the species could easily be the first tree the United States loses to climate change.

This bears repeating; anyone reading these words could well live to see the paper birches of New England become a memory.

This is not the first time we have lost a tree. The generation that logged the red spruces of Franconia Notch also watched the sweep of the chestnut blight. The American chestnut had been one of the largest and most common trees in eastern North America. In the South there were places where every other tree was a chestnut. The wood was strong, beautiful, and rot-resistant. The nuts were abundant and delicious to both human and beast. The blight, accidentally introduced from Asia, killed almost of these trees within a human generation. A few individuals survive, and a blight-resistant variety is being bred, but an experience of the forest that was utterly normal just decades ago is now completely lost. My generation will not live to know what a whole forest of chestnuts in bloom smells like.

The chestnut blight had nothing to do with climate change, but it does presage the same kind of loss that climate change could now be causing. Paper birch does not have the economic importance that the American chestnut did and its value as wildlife food is considered only moderate, but it is one of America’s most widely recognizable trees. Even people who know nothing else about trees can often recognize paper birch. In the movie “White Christmas,” paper birch and the similar-looking grey birch are used as visual cues of New England, even though the set does not otherwise look much like Vermont. This tree is part of the identity of one of the most beloved regions in the country and it is part of American’s cultural inheritance. And in another generation Americans will have to go to Canada to see it.

Tom knew all this when we hiked up to Franconia Ridge that day. He had been explaining it to students, including me, for years. But he had not known the birches in Franconia Notch were dying, specifically; last time he had hiked this route, they had appeared healthy. Now the canopy was open, broken, and bare. Almost all the birches were dead. They had gone from apparently healthy to dead in less than seven years. Our resident expert stood, turning in place, staring nearly slack-jawed at the rotting white trunks missing limbs and hanging at graceless angles, leaning on each other, bare to the grey sky.

Perhaps most hikers would not have noticed the difference. Most people, moving by, puffing with the effort and looking at their shoes, probably notice a few dead trees and think little of it. Maybe they chalk the damage up to an ice storm or confuse the dead birch band with a fir wave (a natural phenomenon that only affects firs), if they notice it at all. But to those who pay attention to trees and are familiar with this particular landscape, the damage glares like a neon sign. And it is moving astonishingly fast.

We continued hiking; summiting the peaks and circling back around, exhausted and finally snowed upon, but in good spirits, for the most part. It was a good hike. But from up near tree line in the stunted forests of dark firs and alpine shrubs we could look out upon the fins and coves of the mountains, rumpled like a giant blanket and partially obscured by blowing half-frozen snow, and we could see a line along the mountain sides where the autumn canopy below us was interrupted. Bare, white trunks, broken, marched their way in a distinct band as far as we could see. The sign of history, the paper birch band, standing ghostly now, ourselves witness to another turn in the story of the forest and a bauble of our children’s inheritance being stolen.


The Fifth IPCC Report: Just the Facts, Ma’am

This is the second in a four-part series on the IPCC’s fifth Assessment Report, which has been coming out in installments since last year. The first article in our series provided an overview on what the IPCC is, how it is structured, and how and why it produces this reports.

This past weekend, the IPCC, or Intergovernmental Panel on Climate Change, released an official summary of the third installment of its report. Before we get in to talking about this latest document, I want to take a step back and discuss the contents of the previous installments, beginning with the first one, the report from Working Group I, which was published last year.

I will not do a detailed summary, because the IPCC has already done that; you can download their Summary for Policy Makers (SPM) yourself. However, even the summary is dozens of pages long and dry as toast. If you aren’t familiar with sorting through this kind of report, or even if you are, learning about the document through bloggers and journalists seems more appealing. Reading other people’s perspectives is indeed a good way to draw on the experience of others, who may have been following the issue longer, and at more depth, than you have. But the problem is that commentators disagree with each other a lot and it is very hard to sort through their conflicting interpretations if you do not have a baseline understanding of what the report says and what that means.

So here (with apologies to Joe Friday), are just the facts, a summary of the Summary for Policy Makers, of the report by the Working Group 1 of the IPCC, which covers the basic science of climate change.

After a brief introduction, the report summarizes the observed changes in several different parts of the Earth: air, ocean, cryosphere (ice), sea level, and the carbon and other biogeochemical cycles. There are no real surprises here, although some of the details have either changed or become more certain since the last report. The broad, take-home message is that the air and water have gotten warmer, precipitation patterns have changed, the ocean has become more acidic and the patterns of its varying surface salinity have changed (because of changing precipitation across the ocean surface), levels of various greenhouse gasses have gone up, and the sea level has risen. The report describes each change in crisp, dense detail.

A short section on the drivers of climate change follows. Again, the broad, take-home message is familiar, but the report does make clear a number of factors that don’t normally make it in to the public discussion. In essence, there are multiple factors that influence, or force, our climate, both globally and regionally, and part of climate science is the study of these factors and how they interact. The various greenhouse gasses humans release are an example of positive forcing, because they act to warm the climate, but there are also non-human sources of forcing. Likewise, certain types of particulate pollution, or aerosols, plus natural aerosols from various sources, provide negative forcing,  or cooling. Cloud patterns, and changes in solar output can also influence our climate. These factors do not all cause the same amount of forcing, and scientists do not understand them all equally well. One of the reasons that climate models are still not completely accurate is that scientists don’t yet fully understand how the interaction of aerosols with clouds influences the climate.

One thing they are sure of now is that human activity is the dominant influence and has been since the middle of the 20th century.

The report does address each known cause of forcing, positive or negative, separately, discussing both how strong its influence is and how much we know or do not know about it.

Then there is a section on the strengths and weaknesses of existing climate models (which mostly do very well, now) and how these have changed since the last IPCC report, the AR4. Also, the report discusses how climate responses are quantified, that is, what exactly scientists measure when they measure the climate.

Then the report details exactly what humans have been doing to the climate; how much of the observed changes can actually be attributed to us and how sure scientists are that the attribution is correct (they’re pretty sure).

Finally, the report presents its predictions for the future, for the atmosphere, the ocean the cryosphere, and so on. Again, there are no great surprises in terms of the take-home message; global warming will continue, and will get more severe if we do not stop greenhouse gas emissions. Even when emissions stop, warming will continue for some time because of the emissions that have already occurred, but we do still have some control over how severe that warming will be.

This last section is difficult to read, because the authors provide no real context for their predictions. That is, they do not say whether and how these climate changes will hurt, or who will be hurt. That, of course, is a subject for a later installment of the report. A reader can, of course, mentally put the context back in and can tell, for example, that increased monsoon precipitation means a lot more flooding, especially in certain developing countries. The picture presented by the report is thus a colorless, extremely academic view of a future none of us actually want to arrive. And yet, there are no truly catastrophic predictions; the possibility of our crossing some kind of thresh-hold beyond which climate change will suddenly begin tearing apart life as we know it is never addressed.

That doesn’t mean such thresh-holds are not a possibility, only that they are not predicted by the current mainstream of climate science. Of course, it is the nature of such thresh-holds to be unpredictable.

Criticism of the IPCC report covers the spectrum; they are variously accused of either they are accused of under-representing the danger we face, or of over-representing it. Often there is the further accusation, overt or implied, that their mistakes are deliberate, motivated by some personal or political bias. I will address that at greater length in a later post, but deliberate bias in either direction is unlikely.

The best evidence that the IPCC is not biased in favor of alarmism is simply that they have not raised much of an alarm. As dire a picture as this report paints, it is much less severe than many credible scientists think it should be. They also lack credible motive to gin up fear of climate change beyond what is appropriate; IPCC members serve without pay and in any case there is very little money in global warming mitigation. Anyone inclined to lie for a buck could do much better in a different field.

It is slightly more plausible that they have caved to political pressure, but again, if these people have lied for political reasons they have done a very bad job of it. There is plenty in their report to offend climate deniers. Instead, their failure to acknowledge some of the scarier possibilities for our future is probably due to two features of the IPCCs structure. First, their mandate is to summarize the entire body of science on climate change, so ideas that are plausible but not yet full accepted by the mainstream tend to get lost in the crowd. Second, when preparing a report, the IPCC reviews only work published before a certain cut-off date. The time it takes to publish scientific papers adds further delay, so that IPCC reports are actually several years out of date even on the day they are published. Since climate change has been getting worse over time, and since newer discoveries tend to be ever more dire and frightening, we should expect out of date news to be comparatively rosy.

Out-of-date news is better than no news, of course, and the IPCCs job is to compile reports for the rest of us, who cannot spend our time reading and analyzing thousands upon thousand of scientific papers.

A few things stand out that make the Summary for Policy Makers much more reliable and more nuanced than brief quotes may suggest.

First, the use of language is very precise and in some ways different from the way we ordinarily write. For example, some phrases, such as virtually certain, are actually quantitative. That is, they refer to specific, mathematically calculated probabilities, which you could check if you wanted to. They don’t lack confidence, they are just talking about statistics.

Second, even in the Summary, the authors include notes on how they arrived at their statements, what methods they used. These notes not only ensure transparency, they also provide a lot of important context that might be left out by a journalist’s quotes.

Third, there is a lot of detail and nuance that a casual glance might miss. For example, the authors state that “It is extremely likely that human influence has been the dominant cause of the observed warming since mid-20th century.” That doesn’t mean that they have just now decided that humans are causing global warming–that has been clear for a long time. The first estimates of human potential to influence climate were made in 1896, based on the discovery of greenhouse gasses in 1859.  No, the key word here is dominant. They mean they are now pretty sure that human influence is stronger than all of the other things that also influence climate–a much more disturbing announcement.

The bottom line is that the first installment, officially known as A5 WG 1, summarizes what most of us have been hearing for years but, because it gives a complete picture, a lot of the points that have been taken out of context to generate debate are now back in context and readily accessible.

And the bottom line below that is that we shouldn’t have needed a 5th Assessment Report to begin with. We should have fixed this problem already, and it has gotten worse because we didn’t. Can we make a commitment to not require a 6th?


Who is the IPCC?

This is the first of a series on the 5th report from the Intergovernmental Panel on Climate Change, which is currently being released in several installments.

If you follow climate change-related news, you have probably encountered several stories over the past year on the release of the IPCC’s latest report. Certain corners of the internet have lit up of late with commentary both for and against. Predictably, some people insist the report is far too conservative while others label it alarmist.

But if you want to find out what the report is, or even what the IPCC is, you might have to go digging. There is not much in the way of simple, plain-language overview out there. So, in the name of being the change we want to see in the world, I offer the following.

“IPCC” stands for Intergovernmental Panel on Climate Change. It was founded in 1988, by two bodies within the United Nations, World Meteorological Organization (WMO) and the United Nations Environment Program (UNEP), in order to prepare a report for the General Assembly that could be used as a resource for international discussion of climate change.

The IPCC conducts no research of its own. Instead, its members collect and summarize the existing body of scholarship on the subject. A system of stringent rules require that the work of the IPCC be transparent, consensus-based, and apolitical. The idea is that its reports are a resource for creating policy, but do not dictate or suggest policy directly.

Those who serve on the IPCC are unpaid, uncompensated, for their work.

The first report was released in 1990. The current one being released is Assessment Report 5 (AR5). These reports have been very cautious, initially saying only that humans could be causing climate change or were likely causing climate change, even long after many individual researchers were sure. With AR5, the IPCC is finally sure; the phrase they used is “very likely,” but that’s only because scientists don’t like to make unqualified statements, ever. Each report reflects a fairly cautious version of scientific consensus, and as new information has come in over the years, the picture has gotten clearer.

Besides the Assessment Reports, the IPCC also produces other documents. Most of its publications are available publicly, through bookstores and other outlets. These things are not brief. Summaries of the reports are sometimes available for free online.

The IPCC consists of three Working Groups, a Task Force, several oversight bodies, plus other, short term groups that may be created to deal with specific issues. The Task Force works to facilitate international monitoring of greenhouse gas emissions. The three Working Groups create the Assessment Reports, with each group completing its own separate segment of the report.

AR5 consists of four installments, one for each Working Group, plus a Synthesis Report. Some of these are out already, while others are not. Since each installment is itself a report, written to stand alone, we’ve been in the confusing position of hearing that “the fifth IPCC report has just been released!” several times. Each such announcement has actually been either a new installment, a leaked draft, or a published summary.

The first installment, known by the awkward acronym, IPCC AR5 WG1 Report, was released on September, 27, 2013. The WG1 stands for the first Working Group, which covers physical science.

IPCC AR5 WG2 came out on March 28th, from the second Working Group, which covers the impacts of climate change and our ability to adapt to them.

The third installment, AR5 WG3, is due out later this month; its summary for policy makers is due out on the 13th. It will cover mitigation, or preventing climate change.

The fourth installment, the Synthesis Report, is due out sometime before November of this year.

As mentioned, the internet has exploded with commentary. Some people insist that the report is alarmist, presenting an inaccurately scary picture. Others insist that the report is not scary enough and is inaccurately mild in its warning. All the comments are interesting, and they keep coming as the reports keep coming out.

We have much to talk about.





The Good Fight

This is the final piece in a four-part series on the relationship between global climate change and mass extinction

Beneath all the scramble of detail about the relationship of global warming to species extinction, beneath all the attendant confusion of culture and money and worry, there is physics. Besides the physics of the greenhouse effect itself, which renders global warming impossible to deny, there is complex systems science and its own terrible, living clarity.

Complex systems science is the same as chaos theory, but the newer name is closer to being self-explanatory. Complex systems are processes that cannot be precisely predicted, but at the same time are deeply ordered. Traditionally, much of science has focused on simple, wholly predictable systems, like clockworks, or the orbit of planets. Complex systems work by a completely different set of rules, and so seem exotic to scientists, yet complex systems are all around us. Actually, I am a complex system, and so are you. Human thoughts, feelings, movements, and bodily changes are unpredictable, yet we can maintain the same personality, the same regular bodily functions, even almost exactly the same body temperature, for decades on end. This incredibly durable order within almost complete freedom is the heart of what makes complex systems distinct.

The biosphere, which includes the atmosphere, is a complex system as well, so understanding the basics of complex systems science is a great way to get at the underlying principles of climate change-related extinctions. With this foundation of understanding, the sometimes confusing and contradictory whirl of environmental debate and advice comes together and makes a whole. For this reason, the writer and educator, Tom Wessels developed a course entitled Principles of Sustainability, which I was lucky enough to take. He has a book out, The Myth of Progress, which covers roughly the same material, and which I recommend, but for shear clarity and punch, nothing beats the progression of charts sketched on a whiteboard, the shifting mood of student response, the gradually changing light coming in through the windows on a cold, early spring day.

The major preoccupation of the class was the flow of energy through different patterns and forms. Sunlight is energy, movement is energy, heat is energy, and the power that binds atoms together in molecules is energy. As I write, a fire leaps in our woodstove, making the metal of the stove ping and knock with heat. One way to think about this fire is as a release of stored energy. Trees, over the course of many years, collected solar energy and bound it in carbon compounds. Whatever the plants did not use for their own metabolic processes they made into wood. Now, in our stove, the sunlight that the trees turned into wood is converted into heat and light and the sound of the woodstove pinging. It is therefore sunlight that is shining out of our stove and warming the grey cat who sits by the hearth. Virtually anything can be told as a story of moving and transforming energy.

Matter can be endlessly recycled. The wood of the tree becomes ash and carbon dioxide, which will in turn become another tree. The cat by the hearth built himself from cat food and someday his matter will become other life forms. Energy, however, cannot be recycled at all. Every time energy transforms, some of it is lost, dissipating and joining the thin background radiation of the universe. Eventually, all energy dissipates. The dissipation of energy is called entropy, and philosophers and physicists debate its implications. What we know is that any system that does not have an outside source of energy will eventually sputter to a halt. Fortunately, on Earth we do have an outside energy source in the sun.

Most people have probably heard some mention of energy and entropy in a high school science class, and never really thought about them again (if they did, the premise of the Matrix trilogy would have seemed distractingly unbelievable to more people). More to the point, sustainability would not be so confusing if more people were in the habit of thinking about energy. So Tom did not just explain complex systems science and the Second Law of Thermodynamics, he tried to get us to internalize them, leading us, over and over, along paths of thought until each became habit, became our own.

One particular day, Tom delivered a lecture on the relationship of entropy to complex systems. I don’t remember whether the class included anything but a lecture that day, but Tom’s lectures are never boring. He’s not the type to put on a show, not one of those professors who use a lot of bells and whistles to grab students’ attention, but the time never drags. He drew charts, used examples, or sometimes just sat backwards in a chair in the middle of the room and talked. Most of the examples and ways of explaining I use throughout this article are actually his. If I could remember clearly enough to quote that lecture word for word I probably would.

Entropy means disorganization. Order is an energetic state, which is why houses fill up with clutter when their occupants feel lazy. This is not a metaphor; a messy room is in a more entropic state than an orderly room is. Simple systems gradually fall into disorder as they run down. Clocks lose time and eventually stop. Castles settle into ruin. Complex systems, on the other hand, actively take in energy from outside and so they can fight entropy and win. We’re self-winding clocks. Living is a constant trick of falling upstairs.

Here, Tom drew a chart, a line curving up, rapidly at first, then leveling off, then sinking down again, like one of those glacial hills that are gentle on one side and steep on the other. The line shows the developmental stages of all complex systems, rising as the system gains in size and complexity, falling as it drops into decay. The height of the line is accumulated carbon, the physical weight of the system as a whole, and it varies, left to right, along the forward march of time.

In the beginning, a system, any complex system, takes in more energy than it needs and so it grows, gaining in size, complexity, and stability. Babies need hats even when adults don’t because their body temperatures are not yet stable, but they eat and grow and soon can shed their hats. Growing forests not only get taller, they gain species and soil biomas and they begin to resist the invasion of weeds better. Their temperatures, too, become more stable, since their leaves block both wind and sun.

Eventually the energy coming in is not enough for further growth, only enough for maintenance. The child becomes an adult and the forest reaches maturity. Mature forests do not just have big trees, they also have very complex microbial communities. Mature forests smell different than younger ones. The air is quieter, and on hot days the forest remains cool. There is shelter here. There is a fluid stability, a quiet, self-maintained order.

Later comes the entropic phase. More energy is used than can be taken in and the system shrinks, destabilizes and eventually ceases to exist as a distinct entity. A forest on fire is entropic, rapidly liquidating its energy assets as its diversity and structure unravel. A field of ash and charcoal is a very simple, spent thing, entirely subject to blazing sun and freezing wind. The entropic phase is illness, dying, because when it concludes, the complex system is gone. A corpse is a very simple thing.

The biosphere as a whole goes through these same phases. In the beginning, the biosphere was very small and simple. As plants took in sunlight that energy was stored in carbon compounds and distributed to other organisms through food webs. Life spread across Earth’s surface and the products of life, coal, natural gas, and petroleum, were buried layer on layer deep in the Earth, increasing the total size of the biosphere enormously. As biosphere grew, it also grew more complex and more species evolved to take advantage of ever more specialized ecological niches.

While the biosphere as a whole is too big to be weighed, its size at any given time can be estimated by the proportion of free oxygen in the atmosphere. Without life, free oxygen is soon bound up in other molecules such as carbon dioxide. Since life builds itself out of carbon that has been stripped away from oxygen by plants, the amount of free oxygen is an indication of how much carbon is in the biosphere, the same way the size of a footprint is an indication of the size of a foot. Over hundreds of millions of years, the amount of oxygen, and therefor the size and complexity of the biosphere, grew before it finally achieved a mature stability. The births of organisms and ecosystems were now balanced against deaths and extinctions elsewhere. With minor variations, the atmosphere was stable for hundreds of millions of years, until recently.

Planetary maturity has ended.

That the planet is dying and we are killing it is not a metaphor, it is physics. The current entropic state, triggered by the liquidation of our fossil fuel energy assets, is another version of the same process an organism goes through while dying. In both cases, more energy is being used than the system is taking in, causing the system to shrink, become less stable, and become simpler. That does not mean that the biosphere cannot recover; it has had close shaves before and recovered, and will probably recover again. But the question is do we really want to be culpable for this?

That we are in a planetary entropic state explains the current mass extinction as a systemic problem. Widespread extinction is what a shrinking, simplifying biosphere looks like. Whether a species is lost to climate change directly or to habitat destruction by logging, over-hunting, or pollution, the ultimate cause is still the entropic pressure destabilizing the system as a whole.
Climate destabilization, over-use of resources, and the production of toxic industrial byproducts are all aspects of part of the biosphere—us–using more energy than the biosphere as a whole can take in. That extra energy comes from fossil fuel, the stored energy assets of the biosphere. The first-world lifestyle requires this extra energy, and all energy must come from somewhere. And as long as we insist on using more energy than the sun gives us, the biosphere will remain in an entropic state and more species will go extinct. We can save some species through various creative and heroic means, but we will not be able to change the overall fact of mass extinction as long as we continue to shrink the biosphere that supports these species. That’s physics.

We sat in stunned silence, the classroom beginning to darken in the late afternoon of a New England snowy spring. Nobody bothered to turn on a light. I, at least, felt slightly sick.

But there is still hope, because complex systems can change suddenly and completely, without warning. These bifurcation points, as they are called, are not random. They have identifiable causes, and the bifurcation points within well-studied processes, such as human embryonic development, are well known.

For example, you were once a hollow ball of cells, slowly growing bigger. Then, suddenly, you folded in on yourself and became an intricately crenulated tube and you have been an intricate tube ever since. There is no way an alien, unfamiliar with Earthly life, could have predicted you would do this. Based on all prior observation, it would have seemed reasonable to expect you to remain a ball, getting bigger and bigger like some monstrously round jellyfish, for the rest of your life. Your humanity, emerging suddenly from such simplicity, would be a complete surprise. And yet, every human being born has done it, and we all did it at exactly the same age. This paradoxical predictable unpredictability means that if you are watching a complex system go through something you’ve never seen before, there is no way to be sure what it will do. It can become something completely new on a dime.

The way it works is that complex systems are stable enough to actively resist change. The temperature of your room can drop ten, fifteen, twenty degrees, and yet your body will stay within a degree or two of 98.6 degrees Fahrenheit for as long as you have enough energy to keep shivering. The composition of Earth’s atmosphere can change radically and yet the forsythia still blooms in the spring. A ball of cells can create more and more cells and still remain a perfect ball. The system gives no sign at all of responding to the change until suddenly resistance gives way and a new order emerges. There is no way to predict, from prior conditions alone, when this shift will occur or what the new state will be. This works something like pushing on a stuck door; you push and push, and for a long time nothing seems to happen, until something gives way and the door suddenly swings open and you fall through to the other side.

These unknowable bifurcation points or tipping points are part of the danger of climate change. We can’t know when the next ounce of greenhouse gas might suddenly cause vast, horrible, and irreversible changes. But you are living proof that not all tipping points are bad. Sometimes, the thing that comes after is new and beautiful and wise.

The hopeful thing is that human societies are also complex systems. Our society as a whole may have done next to nothing about global warming so far, and obviously the hour is late, but we don’t know where the next bifurcation point is. It could be right here. If we keep pushing.

Tom, my teacher, spoke quietly into the deepening gloom;

“If you want a fight, this is a good one.”

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Predicting Extinction

This is the third in a four-part series on the relationship between global climate change and mass extinction.

In 2004, in an article published in the journal, Nature, Chris B. Thomas, Alison Cameron, and over a dozen of their colleagues asserted that some 37% of species, both animal and plant, could be “committed to extinction” by the year 2050. Over the past nine years, further research has added detail and greater clarity to the picture, but the prediction is still quite grim. Now, avoiding catastrophe usually requires knowing a bit about the threat, so, to this end, let us look more carefully at how Thomas et al. arrived at their prediction, what it means, and what it does not mean.

First, the phrase “committed to extinction” does not mean “extinct,” nor even “hopeless.” Instead, the phrase is an acknowledgement of the fact that extinction is seldom an instantaneous event. For example, say that a population is shrinking by 2% every year; eventually, this population will die out, unless something changes, but it could take many years. To be committed to extinction does not mean to be beyond hope, but it does mean that the process of extinction has begun, that the conditions the animal or plant needs to continue no longer exist.

Second, let us look at the methods these researchers used. At the heart of their work is the species/area relationship, a mathematically expressible law that states that the number of species in a distinct place (say, an island or a forest) is proportionate to its size. The law says nothing about which species will be present, only how many. Some species will die out locally and new ones will migrate in or even evolve over the years, but the total number of species at any given time will still hover right around whatever the size of the place dictates. So, if the place shrinks, if part of the forest is logged, say, a predictable number of species will die out. Usually, the lost species will come back as soon as the forest regrows, but if one of these species is endemic, that is, found nowhere else, it will be gone for good.

There are very large parks, supposedly protected in perpetuity for our grandchildren to enjoy, that are nevertheless slowly losing species. Once, these parks were just imaginary lines around land that was about the same inside as outside. They were part of islands of habitat that, for some species, covered most of North America or even beyond. Being very big, these areas had a lot of species, so to save the grandeur of that biodiversity, we made parks to protect them. But development or hunting pressure around those parks has cut them off, turned them into islands in an inhospitable sea. Even Yellowstone is not big enough to hold as many species as wild North America once did.

The species area relationship itself says nothing about which species will be lost, although educated guesses can be made based on other ecological principles. What this neat equation does instead is allow ecologists to be sure of themselves, within certain parameters. With this equation, Thomas et al. can be as sure of disaster as could a passenger on the Titanic who had counted the lifeboats.

The reason that the species area relationship matters for anticipating the impact of global warming is that one of the things climate change does is to shrink some habitats, polar ice caps being the most obvious, but hardly the only, example. By looking only at areas where species distributions and their climate parameters are fairly well known, and looking only at endemics, these researchers were able to calculate probable extinction rates for several different possible warming scenarios.

The scientists did not look at distinctly bounded places, however. Instead, they used anticipated changes in the distribution of particular species, either individually or as a group, in order to create a larger picture of extinction risk, using different permutations of the species area relationship equation. For example, if a forest were to shrink by half, than each species in the forest would lose an average of half its range. Therefore, if all the species under consideration lose an average of 50% of their range, then that is equivalent of the forest losing half its area and the number of species lost should be the same. They used three different methods to make the calculation so that minor potential flaws in each method would cancel each other out.

In all three methods, they looked at the climate that currently exists in the ranges of each of the species they studied and then looked at climate projections to see what the area of that particular climate type would be in the future. If the area is predicted to shrink, they assumed that the range of that species would shrink accordingly.

Each method was used to make several different predictions, based on different assumptions about variables that are impossible to actually measure. We do not know how much warming will happen and how fast because we do not know when, or if, society will really get serious about cutting carbon emissions. Therefore, the scientists considered three different possible warming scenarios and made a prediction for each one. Also, sometimes the climate conditions for a species expand in one area while shrinking in another, and species vary a lot in their ability to move to new areas. Since actually including each species’ ability to move in the calculation would make the whole study ridiculously complex, the scientists simply ran each calculation once under the assumption that none of the species could migrate and once under the assumption that all of them could. So for each of the three predictive methods, there are six predictions, one for each possible combinations of initial assumptions.

Additionally, the scientists considered a fourth, less precise method by applying expert judgment to make an educated guess. Then, they added in additional predicted extinctions due to other factors, such as habitat destruction by logging, and looked at specific extinction risk in particular ecological regions.

Naturally, the results for each region considered were different, and the results of each of the eighteen different simulations (three methods, three warming scenarios, and two dispersal scenarios) were also different. At first such a wide variety of answers to a single question might not sound helpful, but this is why scientists record and publish their methods as well as their results. With the methods in mind, a few interesting points can be drawn out.

First and foremost, our position is very scary. Some of the simulations predict upwards of 50% of species lost. To get an idea of what this really means, make a long list of animals and plants (the list can be random, since this prediction did not identify which species might be lost), think carefully and fondly about each entry, and then cross off every other one.

Perhaps more useful than the pure impact of horror, though, is the difference between the three warming scenarios. For minimum expected warming, the range is anywhere from 9% to 31% of species lost. Mid-range warming would cause between 15% and 37% losses. The maximum expected warming would drive extinction up to between 21% and 52%. Although there is some overlap, there are also clear differences between these scenarios—a clear difference between what could happen if we do stop pumping greenhouse gases into the atmosphere (the first or, quite possibly second warming scenario) and what could happen if we don’t stop. This is not merely a warning; is a practical tip. It is clear evidence that what we do still matters.

It is true that this prediction has a lot of wiggle-room. It is dependent on a lot of assumptions and it is focused on very particular species and regions that may or may not be representative of the whole planet. Again, this is why scientists record their methods. All scientists make assumptions in the course of setting up their studies, because it is impossible to study everything in the entire world at the same time. The system works because they keep track of their assumptions and clearly identify what they know, what they are assuming for the sake of the study, and what they did and how. So under the circumstances described in the paper, the results reported in the paper are reliable. The species-area relationship is reliable, the warming scenarios are all possible, and so we know that these extreme extinction rates are likely for the systems described. This isn’t an alarmist supposition or a vague guess. It is a small, keyhole view of the workings of oncoming disaster, and while it is small, it is accurate. With this view in mind, we can confidently take action.

Now, is it true that one of those carefully documented assumptions could be so wrong that the entire prediction is wrong? Yes, it is possible—but it’s unlikely, and so far, when scientists have been wrong about global warming, it’s because they have underestimated the scope of the problem. So while it is in the realm of possibility that Thomas et al. are wrong, how about we not wait around to find out?

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The Anatomy of Global Warming-Related Extinction

This is a re-post of the second in a four-part series on the relationship between global climate change and mass extinction. I plan to post on the IPCC’s recent announcement later this week.

Most people, by this time, probably know that global warming means extinction for some species; if the arctic sea ice completely melts, the fate of polar bears is fairly obvious. Yet the link between global warming and extinction risk is rarely so direct. Understanding how global warming can lead to extinction is important for conservation scientists, who may be able to discover ways to minimize the damage. For the warnings from scientists to make sense to the rest of us, we have to understand the anatomy of climate-related extinctions as well.

One possible source of confusion is the distinction between ultimate and proximate cause. Basically, if someone trips over the edge of cliff, the ultimate cause of death is bad footing but the proximate cause of death is the hard landing at the bottom. Climate change could become the ultimate cause of a lot of extinctions, but the proximate causes will mostly be something other than warm temperature. Because we don’t hear much about this distinction, the clear risk of extinction from climate change might look like a confusing swarm of multiple environmental problems.

Sometimes the proximate cause is obviously connected to climate change, as when organisms suffer from high temperatures, high carbon dioxide concentrations, or habitat destruction through the melting of polar ice.

Hot water, for example, bleaches coral. Bleached coral isn’t dead, but it no longer has the algae that give coral animals their color and their food. Coral can survive occasional bleaching, but if bleaching events last too long or are too frequent, the coral will starve to death. If water temperature is too high too often across a particular coral species’ range, that whole species goes extinct. Rising carbon dioxide concentrations are making the oceans more acidic, thinning some animals’ shells. If acidification continues, their shells will dissolve completely and they will die.

But there are other, less direct and less obvious, mechanisms as well.

Some species use changing day length as a kind of calendar to predict the seasons. Animals who cannot recalibrate their calendars to the new, earlier springs are starting to have trouble breeding. Their habitat is still intact, but their timing is off now. Other species might die out because an ecological partner, such as a favored food source or an insect pollinator, dies out, or because warming temperatures bring in new pests. For example, moose populations in some places are crashing because the winters don’t get cold enough anymore to kill ticks. Unlike whitetail deer, moose haven’t evolved ways to de-tick themselves efficiently and they’ve been found dead, bled to death through anemia by ticks.

Some of these changes are not just indirect, they’re counter-intuitive.

Some species respond to warming temperatures by moving to an even warmer area; the temperature itself isn’t a problem for them, but drought is, and the wetter refuge might happen to be warmer. Climate change can even cause extinction by making conditions easier. For example, red spruce trees grow mostly in cold, snowy areas, but they do not actually grow well there. That species would grow better if their habitat warmed up, but they won’t get to because warm weather would let faster-growing hardwoods come in and shade them out. There are mountains in New England with hardwoods at the base and red spruce forests near the top. As the climate warms, the hardwoods will creep upslope, pushing the spruce out. If this goes on long enough, the spruce, and the Bicknell’s thrush, which only breeds in spruce/fir forests, will be gone from New England. A warm enough planet will lose all its red spruce and all the other species dependent on it, forever.

Now, changes in climate have occurred before without causing mass extinction events. Species shift their ranges or adapt to new conditions, and life goes on. What makes this change different (other than humans being its accidental authors) is time–time and, to a lesser extent, space.

For a species to adapt takes time. Even insects, which sometimes do change very quickly, still can’t eat most exotic plants, even species first imported hundreds of years ago. For evolution, “fast” usually means thousands or tens of thousands of years. Even just shifting a geographical range can take centuries for some species, like nut-baring trees. Global warming now causes ecologically meaningful changes in only decades. In comparison to change this fast, evolution essentially stands still.

Even those species that can move quickly might not be able to. Many of today’s animals and plants are now stranded in isolated parks. The built-up world around the parks is now completely inhospitable to them. Some species survive only in a few parks and preserves. If those parks cease being appropriate habitat, where are these animals and plants going to go?

Climate change does not threaten all species equally. As we have seen, which species are at risk is a complex and sometimes surprising thing. Yet there is something that links most of the species in danger; they are specialists.

Rapid change favors generalists. This is the same principle whereby people in a rapidly changing economy try to learn to do a lot of different things. When society is stable, it makes sense to take the time to become an expert in one thing. The idea is to stand out from the crowd and find a niche that no one else can occupy. But in a rapidly changing job market, locking yourself in to just one career is economic suicide. Ecosystems work the same way.

Human activity as a whole favors generalists, because human activity causes rapid change. This is part of the reason why built-up areas sometimes have coyotes but almost never wolves; wolves mostly hunt mostly large animals, while coyotes eat almost anything. Starlings, house sparrows, pigeons, and rats are ubiquitous in American cities and towns because they are all generalists. Generalists are usually small and unassuming. Many people find them boring. But they do survive major extinction events, because they can handle change and instability. When the large, specialized dinosaurs died out, mammals and birds survived, in part because we were generalists at the time.

The current major extinction event follows the same pattern. Underneath the details of which species are at risk due to which proximate cause, there is the deep, ultimate cause of rapid environmental change. And we know the type of species that will be lost facing this sort of problem. We stand to lose the large, the distinctive, the unusual—we stand to lose the specialists, among them many of the animals we care most about.

We may be able to save some, through captive breeding programs, carefully focused legal protections, and other extraordinary efforts, but the problem is not particular to this or that species. The problem is systemic. The Earth is changing, and the new version simply has less room in it for biodiversity and for specialization. Like a wet sponge wrung, the excess is going to drop out.

If you don’t like it, then stop changing the Earth so fast.