We’ve all heard about the dire straits polar bears are facing if they lose their icy habitat to global warming. But just how many species may global warming drive extinct? One way to find out is to look over the mass extinctions of the past–and the picture there’s not pretty, as I explain in my new article, “Biodiversity in the Balance.” It appears today in the new publication Yale Environment 360, an online environment magazine from the Yale School of Forestry & Environmental Studies. They’ve already got some pieces from some big names, like Bill McKibben and Carl Safina. So check the whole place out.

[Photo: Marieke Kuijpers, Flickrunder Creative Commons License]

I’ve got a new conversation up at bloggingheads.tv. This time around I talk to University of Washington paleontologist Peter Ward about the mass extinctions that wiped out millions of species in the past, and how disturbingly difficult it is to rule out the possibility that we’re sending ourselves into another great die-off.

[Update 10/18 8:30 am: Honestly, when I wrote this post last night, I could only access the first couple paragraphs of the op-ed in question. But now the link takes you to the full text. Could it be that my cries were heard?? Doubt it, but open access is always nice.]

In today’s Wall Street Journal there was a very provocative op-ed by ecologist Daniel Botkin. He argues that the evidence of potential harm from global warming is overblown. Here is what you can see for free…

Global warming doesn’t matter except to the extent that it will affect life — ours and that of all living things on Earth. And contrary to the latest news, the evidence that global warming will have serious effects on life is thin. Most evidence suggests the contrary.

Case in point: This year’s United Nations report on climate change and other documents say that 20%-30% of plant and animal species will be threatened with extinction in this century due to global warming — a truly terrifying thought. Yet, during the past 2.5 million years, a period that scientists now know experienced …

…experienced…what? Well, you’ve got to pay to find out, or know somebody who subscribes to WSJ.

Botkin does make some cheap shots. He singles out the fact that the glaciers on Mt. Kilimanjaro are not melting due to global warming, and claims that “the paper is scorned by the true believers in global warming.” I so wish that op-ed writers were required to footnote their pieces. Who is doing the scorning? Perhaps, instead, they are looking at the melting of glaciers in many other parts of the world and see a pattern that is partly natural, but strongly influenced by recent human-driven warming.

But Botkin is not a crank. He accepts the reality of global warming. And he makes a lot of good points about the potential impact of warming on biodiversity. I talked to Botkin earlier this year to report an article in Science on the models used to make extinction projections, and he was in accord with lots of other people I spoke to that these models are incredibly crude.

I’m not totally convinced by the evidence he offers that there won’t be many extinctions. For example, he makes a big deal about the fact that over the past 2.5 million years, the climate has swung violently without major extinctions. But this particular swing is different. When the climate warmed at the end of each ice age, glaciers retreated, exposing lots of new territory to colonize. Our current increase in temperature is beginning from a warm period between Ice Ages. We may well end up with a temperature higher than anything seen in a long, long time. So perhaps one shouldn’t be too complacent about what happened in the past.

Still, no one should consider this debate settled, by a long shot. I’ll be sure to talk about his column at my lecture tomorrow. But, please, Mr. Murdoch, scrap that subscription model.

If you live anywhere near my home town of Guilford, Connecticut, I’d be delighted if you could join me Thursday at 7:30 at the Guilford Free Library for a talk, “Will Global Warming Redraw the Map of Life?” (flyer pdf) I’ll be discussing extinction projections, assisted migration, and more.

I’ve got a story in the current issue of Science about the challenge of predicting how many species (and which) may become extinct due to global warming. You can read the article here on my web site. I blogged about some of the early material in the article back in 2004 here. For a good summary of the qualms many scientists have about the power of current models, check out this recent review in the journal Bioscience: pdf.

[Update: If for some reason you have trouble reading my article on my web site, the link to the story at Science is here.]

A bit of journalistic irony. Last week I groused that a new paper on methane from plants was getting very little attention in the press, despite the fact that it refutes a 2006 paper published in Nature that got lots of press. I wished aloud that the situation would be set right. Well, five days later, a few more sites have published the press release, but I’ve only seen one new piece of original reporting.

It appears in the news section of today’s issue of Nature. Hats off to Nature for making room for some uncomfortable news.

Here’s a story that should be getting lots of press but apparently isn’t: a new study indicates that plants don’t release lots of methane gas.

You may perhaps recall a lot of attention paid to methane from plants back in January 2006. A team of scientists (mostly from the Max Planck Institute for Nuclear Physics)reported in Nature that they had found evidence that plants release huge amounts of the gas–perhaps accounting for ten to thirty percent of all the methane found in the atmosphere.

The result was big news for several reasons. It was a surprise just in terms of basic biology–scientists have been studying the gases released by plants for a long time, and so it was surprising that they could have missed such a giant belch. Making the matter of pressing interest was methane’s ability to trap heat in the atmosphere. Suddenly plants became a much bigger player in the global warming game.

Many news outlets covered the paper, and many made a muddle of it. Their wording implied that the scientists were claiming that plants, not humans, might be responsible for the recent rise in the global average temperature. The Max Planck Institute Society released a press release clarifying that plants are not to blame, and the Guardian and National Geographic published corrections.

Some pundits didn’t heed the scientists, though. At Foxnews.com, columnist Steven Milloy declared that deforestation ought to reduce global warming. “Our understanding of global climate system is woefully insufficient to support the rush-to-judgment advocated by celebrity-backed global warming alarmists,” he claimed. The folks from the Wall Street Journal editorial page declared that “this is causing big problems for the tree-huggers.” Rush Limbaugh sarcastically said, “Well, hot damn. God is to blame for global warming.”

Fast-forward eighteen months. A group of Dutch researchers put the Max Planck team’s conclusions to the test by tracing radioactive carbon isotopes through plants. Their conclusion: “There is no evidence for substantial aerobic methane emission by terrestrial plants.”

The paper went online today, published in the journal New Phytologist. (It’s free here.) The publisher sent out a press release, but my search has turned up almost no news coverage. There were three stories that were nothing more than cut-and-paste copies of the press release. I found just one piece of original reporting, at a site called Chemistry World, which I now intend to read regularly. The article casts the new paper as the first in a series of new publications that support both sides of this methane vs no-methane debate.

I do not expect that Rush Limbaugh will bother mentioning this paper. The world of punditry leaves me generally baffled. But as a science writer, I’m disappointed that this paper is not getting reported more in the press. If the original paper was so important that it should go on newswires and appear in newspapers and magazines, then what makes this new one less so?

Two forces are at play here. One is that the huge premium in the science writing world on stories about new ideas. It was such a shock to think that methane was churning out of plants, particularly with global warming becoming such a hot topic. The science writing machine is much worse at follow-up. Does the editorial unconscious say, “Hey, we’ve already written about that. Let’s move on”? Or perhaps it would look bad to say, “Remember that story with the big headline a while back? Well never mind, looks like it may have been wrong.” But ignoring these follow-up papers does a disservice to science. Science is not about single major discoveries, but about the flow of research, of debate and hypothesis-testing.

The other problem dwells, I’d suggest, within the scientific community. I like New Phytologist a lot, but it’s not a high-profile journal. The scientific community tends to present bold new claims in high-profile journals like Nature, while the essential follow-up ends up relegated to more specialized journals that attract less attention. I for one stumbled on this paper by chance. So scientists themselves may be contributing to the distorted view people have of the scientific process.

It’s always possible that I’m mistaken, and that the discovery of the missing methane will bubble up more into the mainstream media in the next few days. Prove me wrong, fellow scribes, and I’ll be happy.

Check this out. An international team of climate experts has been looking into the impact of climate on ecosystems, food production, and other aspects of the natural and human-controlled world. They’ve just come out with the executive summary of their contribution to the Intergovernmental Panel on Climate Change‘s fourth assessment report. Heavy rains likely in some places, heat waves in others. Some parts of the world may enjoy a better climate for producing food, but for how long is unclear. Other places face serious threats to food.

They consider the threat of extinction (which I’ve written about here, here, and here) particularly dire. “Approximately 20-30% of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5-2.5 degrees C.”

It’s a bit frustrating to read a stark statement like that and not be able to jump directly to the sources on which it is based. I assume it’s based on studies like this one, but it’s worth bearing in mind that these extinction estimates are a subject of pretty stiff debate. See for example, this recent review. We’ll have to wait for the full report, I guess. But even if extinctions turn to to be just half of what’s projected here, it would still represent a major event, particularly when you bear in mind that species face many other pressures, from biological invasions to seawater acidification.

There’s nothing more grating for a science writer than see your work get cut and pasted to give people precisely the wrong impression. My latest irritation: “Ten Questions For Al Gore and the Global Warming Crowd”, which appeared Friday on the conservative web site Townhall.com.

The author is John Hawkins, who describes himself as a professional blogger who runs Right Wing News. Hawkins claims that he is skeptical that humans are causing global warming because, in his words, “‘the Earth-is-going-to-burn-us-alive’ crowd cannot answer the most basic questions about the theory that they haughtily insist is so beyond reproach that there should be no more need for debate.”

He then offers ten questions for the “global warming crowd,” claiming that “if the proponents of the manmade global warming theory can come up with good answers to questions like these, you can expect everyone, including me, to accept their theory.”

Questions seem inherently innocent–they’re just simple quests for knowledge, right? But in the hands of someone like Hawkins, they also have the potential to spread quite a lot of misinformation…

(more…)

Next week I’ll be heading to Utah. Southern Utah University asked me to be their Visiting Eccles Scholar, which means that I’ll be spending a couple days talking with students and faculty. I’ll also be giving two talks that are open to the public. The first, Wednesday evening, will be on global warming and extinctions, about which I wrote an article for the New York Times a couple months back. The next evening I’ll be talking about E. coli and the meaning of life. It’s the first time I’ll be speaking about my book in public, so I’m looking forward to sharing some of the stuff I learned while writing it. So if you’re anywhere in the vicinity of Cedar City, come on out.

SUU – College of Science: Zimmer Presentations

The Intergovernmental Panel on Climate Change is about to release its newest edition of its report on global warming. In this AP report, one of the scientists who co-authored part of the IPCC study promises that it will contain much more than a smoking gun. It will contain “a batallion of intergalactic smoking missiles.”

The IPCC has been strengthening its conclusions about human responsibility for the rise in global temperatures for a few years now. One thing that apparently will set this new edition apart will be a section that looks at the impact global warming is having on nature–plants blooming earlier, species moving towards the poles, and so on. (Here’s a sneak preview of sorts from Camille Parmesan at the University of Texas [pdf])

Global warming now raises a new, difficult question for conservation biologists. It may be shrinking the ranges of many species, pushing already endangered species towards extinction. In theory, at least, some species might thrive if they could somehow move far enough to find their old climate in a new habitat. But in some cases, they may not be able to get there unless people move them. Should we?

As I report in today’s New York Times I met some conservation biologists who are asking this question. In a time when global warming can trigger staggeringly fierce reactions, they have been surprisingly candid about their mixed feelings and the complexity of the debate they are trying to grapple with. Which is worse: the risk of creating a new invasive species through assisted migration, or just watching a species become exinct? The scientists have a paper coming out soon in Conservation Biology, but it’s not on the journal web site yet. Along with my own article, you can also check out Douglas Fox’s news article in the January issue of Conservation in Practice.

I always like to consider questions of the day from the perspective of deep time. How hot is it these days? Look back 1.35 million years, and you can see it’s pretty hot. Here’s a chart, published yesterday in the Proceedings of the National Academy of Sciences (free paper here). It combines historical records with geological evidence from the West Pacific to reach back 1.35 million years (kyr= thousands of years ago). The scale is telescoped near the right end, since recent warming has been so fast that it would be hard to make out its details otherwise. Two lines mark some average recent temperatures–the lower line is from 1870 to 1900, when recent global warming was just starting to kick in. The top line is from 2001 to 2005. As the record shows, the temperature has seesawed a lot over time, mainly due to the swing in and out of Ice Ages. The last time the Earth was this hot was about 400,000 years ago, and it will take a couple degree more to put us above anything that the planet has experienced in the past 1.35 million years. As the authors of the new study point out, projections based on “business-as-usual” rates of carbon dioxide emissions indicate that the planet will warm at least 2-3 degrees celsius by 2100. In other words, off the chart.