Watts vs. Bolt: Who's the Dumbest Denier?

You have to see this to believe it. Anthony Watts, perhaps the most influential global warming denier, just cited an article from 1989 to prove there's no global warming. You read that right: 1989. Check it out:

Here’s a blast from the past. Dr. James Hansen’s view in 1989 seemed a lot more temperate than it does today. Back then, he’s ready to accede to a study that says something counter to what his theory predicts, saying “I have no quarrel with it”. Today, he uses labels like “deniers” (see here) when such contradictory essays and facts are made public. What a difference 20 years makes...

Well yes, Anthony, actually it does, because over those 20 years, scientists have been accumulating data, and temperatures have been increasing. That's sort of how you become more sure of something: by collecting evidence over time. The fact that Hansen was "temperate" back in 1989, when the evidence for global warming was less unequivocal, would seem to prove that his current views are based on accumulated evidence rather than conspiracy.

Here's the beginning of the NYT article Watts cites:

January 26, 1989
U.S. Data Since 1895 Fail To Show Warming Trend

By PHILIP SHABECOFF, Special to the New York Times
Correction Appended

WASHINGTON, Jan. 25— After examining climate data extending back nearly 100 years, a team of Government scientists has concluded that there has been no significant change in average temperatures or rainfall in the United States over that entire period.

...

The study, made by scientists for the National Oceanic and Atmospheric Administration was published in the current issue of Geophysical Research Letters. It is based on temperature and precipitation readings taken at weather stations around the country from 1895 to 1987.

So Watts's logic is that 22 years of additional data should not allow James Hansen to become more certain of his conclusions?

This bit of boorishness follows right on the heels of another denier, Andrew Dolt Bolt of Australia, making the bizarre accusation that Apple is behind a new "answers to global warming skeptics" iPhone app. Here was his Twitter post:

Breaking News: Al Gore is funding iPhone apps to create secret new world order. First to be sent to the chambers - me. He must be stopped.

Even many of Bolt's commenters were able to squint through the fog and realize that Apple hosts, not develops, iPhone apps. No one's stopping skeptics from developing their own app.

So I propose a vote. What's dumber: Anthony Watts insinuating that a 21-year-old New York Times article disproves global warming, or Andrew Bolt claiming that Apple is nefariously developing global warming iPhone apps? I report, you decide.

Duds: a skeptic bombshell that never went off

Climate skeptics are having a field day with a new study on the earth's natural ability to absorb excess carbon dioxide (Knorr, W. (2009), Is the airborne fraction of anthropogenic CO₂ emissions increasing?). Influential skeptic and TV weatherman Anthony Watts calls it a "bombshell" (for more info on Watts, see "You're not a scientist, but you play one in real life"). Essentially the skeptic claim is this: “natural carbon sinks are soaking up human CO2 emissions at a faster rate than previously thought, which suggests that global warming will occur slower than models suggest. The science is not settled!” But is this an accurate interpretation of the study?

Here’s the story in a nutshell. Humans emit a lot of CO2, but only about 40% of that remains in the atmosphere (the airborne fraction, or AF). The other 60% is absorbed by natural carbon sinks, such as oceans, soil, and plants. As CO2 concentrations have increased, the AF has remained constant, meaning that carbon sinks’ ability to absorb CO2 is increasing in line with emissions. However, basic physics predict that eventually carbon sinks will begin to “fill up” with CO2, losing their ability to absorb more. When this happens, the AF will begin to increase exponentially, as carbon sinks absorb less and less CO2—a positive carbon cycle feedback.

The AF has remained constant for decades, but a few studies—Canadell et al (2007), Le Quere et al. (2007), and Schuster and Watson (2007)—have found signs that this carbon cycle feedback was starting to get underway. Canadell, for example, had found that the AF had increased from 40% in 1960 to 45% in 2007, which would signal that less carbon was being absorbed by the biosphere. The climate science website RealClimate notes:

There are uncertainties and caveats associated with each study, but taken as a whole, they provide convincing evidence that the hypothesized carbon cycle positive feedback has begun…

But then came the “bombshell” from Knorr (2009), who found that the AF has not, in fact, increased. The full study is behind a paywall, but you can read the abstract here. If Knorr is correct, it could mean that the studies from 2007 were premature in concluding that carbon cycle feedbacks have begun. The real question is, does this matter? If Knorr is right, does this cast doubt on the consensus view that greenhouse gas emissions from fossil fuels are causing global warming?

The short answer is no. I don’t have the scientific training to figure out which study is correct, but I do understand logic, and here’s what you need to know about carbon cycles.

First, the study's conclusion makes no claims about FUTURE carbon cycle feedbacks—it simply finds that carbon sinks' ability to absorb CO2 has not declined in the PRESENT. Claiming that Knorr casts doubt on models predicting accelerating future growth in CO2 concentrations makes the logical fallacy of extrapolating future trends from current results—the same error that led financial firms to conclude that housing prices would always increase.

Second, keep in mind that the current climate consensus is summarized within the 2007 IPCC report. On the other hand, the studies that Knorr critiques were published AFTER the IPCC report came out; therefore, if Knorr is correct in proving these studies wrong, his findings cannot logically have any bearing on the accuracy of the IPCC’s conclusions. At worst, Knorr simply returns us to the state of science when the IPCC report was written. In other words, skeptics are attacking a straw man.

Let me elaborate. For the Knorr study to make a dent in the armor of global warming theory, the findings it attacks would have to be included in, and critical to, the most widely accepted climate models. This is not the case. Studies like Canandell cannot have been included in the models on which the consensus is based, since they were published AFTER those models were created.

Moreover, while these studies gave us reason to believe global warming could occur faster, no one claimed they were certain, so it is inaccurate to claim that Knorr is throwing a bomb at the consensus. RealClimate, for one, emphasizes the difficulties with modeling carbon cycle feedbacks, because there are multiple physical processes that work in opposite directions. For example, as CO2 concentrations increase, the ocean’s ability to absorb CO2 also increases. At the same time, rising temperatures decrease the ocean’s ability to absorb CO2 (think of a warm soda can losing its carbonation). So the trick is to figure out when one process begins to dominate the other, and that’s hard to do:

We have to keep in mind that it is a tricky business to invert the atmospheric CO₂ concentration to get sources and sinks. The history of this type of study tells us to wait for independent replication before taking this result to the bank… I guess it’s fair to say that models are not decisive in their assessment about which of these two factors should be dominating at present.

In other words, none of these findings had been independently verified, and certainly not risen to the level of consensus. In fact, before Canandell, most models apparently predicted a declining airborne fraction, meaning that Knorr’s study is actually in line with IPCC models:

Carbon cycle models (13 of them, from the SRES A2 scenario) also predict that the atmospheric fraction should increase, but not yet. For the time period from 1960 to 2000, the models predict that we would find the opposite of what is observed: a slight decrease in the atmospheric fraction, driven by increasing carbon uptake into the natural world. Positive feedbacks in the real-world carbon cycle seem to be kicking in faster than anticipated, Canadell et al conclude.

In any case, according to Jones et al (2007), it is incorrect to conclude that a constant AF disproves carbon cycle feedbacks (don’t ask me why—I’m just copying and pasting to prove that the consensus supposedly being attacked by Knorr is a straw man):

It is commonly assumed that no change in airborne fraction implies no change in the carbon cycle. This is not true. It is also commonly assumed that if AF is rising, this implies we’ve detected a climate feedback on the carbon cycle. This is also not true. In reality, the AF depends not only on this years emissions and natural fluxes, but the time history of the carbon cycle, which in itself depends on the time history of the emissions. A different rate of emissions will imply different response of AF. This is true regardless of any feedbacks from climate.

The bottom line is that while Knorr (2009) may cast doubt on the conclusion that carbon cycle feedbacks have already begun, that conclusion is hardly pertinent to the consensus on global warming. The most far-reaching conclusion a skeptic could logically draw is that global warming is as bad as we thought (and not worse than we thought).

In other words, Anthony Watts isn’t a scientist, but he plays one in real life.

NOTE: Obviously I am not a scientist, and have probably gotten some points wrong (and probably left some out as well). If you ARE a scientist with expertise in the area, please leave a comment, and I can send you a link to a Google Document that you can edit.

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The cold logic of hockey sticks

The cold logic of hockey sticks

It's fitting that so much of the "debate" over global warming concerns a sport played on

ice: hockey sticks, to be precise. For the non-initiated, "hockey stick" in climate-speak means any temperature reconstruction that shows relatively steady temperatures for 1000 years, followed by rapid warming in the last 100 (the "blade" of the hockey stick). We've been over this before, but global warming deniers just can't criticize hockey sticks enough.

The most recent spat comes from TV weatherman Anthony Watts, who claims that a recent study by some Canadian scientists, Rolland et al, proves all hockey sticks wrong. Watts asserts that according to the study, which uses insects called "midges" as proxies for temperature in a small region of Canada, we had more global warming between about 1100 and 1400 AD than we do today. Here's the temperature graph he shows:

If you just glance at the graph, it appears that the hockey stick is broken, and temperatures have been higher in the geologically recent past than today. Look a little closer though, and you realize the study says no such thing, as it refers only to summer temperatures in a single island in Canada, not global climate change. The study's conclusion states:

The paleolimnological study of this northern Southampton Island lake provides information and extends the spatial understanding of Northern Hemisphere climatic events(Medieval Warm Period and Little Ice Age) in the Foxe Basin region. Both chironomid-based August air temperature inferences and sedimentological assemblages suggest that Southampton Island was affected by a regional warming between cal yr AD 1160–1360 and a regional cooling between cal yr AD 1360–1700. These results compare well with both archaeological studies made on Southampton Island and paleoclimatic studies. (More about the medieval warm period can be found here.)

So the paper makes no claims about *global* climate. Rather, it was testing how accurately a certain method of analysis could estimate past temperatures. It was already well-understood that there was *regional* warming in parts of the northern hemisphere during the time period in question, and the authors' midge analysis confirmed previous findings. For Watts to wave it around triumphantly as if it's the "latest" crack in global warming is misleading.

In fact, if Watts had read the study, he would have seen this in the very first paragraph:

Evidence of rapid climate change at northern latitudes has focussed research efforts on arctic environments. Due to possible feedback mechanisms, such as snowand sea ice extent (albedo), these regions are believed to be particularly sensitive to global warming... Many studies have already shown that some arctic areas have undergone major modifications of their annual thermal budget during the second half of the last century. They specifically showed an increase of surface air temperatures during summer, and a drastic reduction of winter sea ice cover thickness and summer extent (Johannessen et al.,1995,1999; Dickson, 1999; Rothrock et al., 1999; Comiso, 2002). On the other hand, regions surrounding the Foxe Basin, the Hudson Bay, and the Hudson Strait are so far only slightly affected by such global warming effects.

In other words, the authors acknowledge the reality of "rapid" global warming, with the potential for large feedbacks, and were trying to understand why one region in the arctic might be anomalous to this trend. To infer from the study that the medieval warm period was a global warming trend equivalent to today's is to commit several errors of logic.

But for the moment, let's assume that Watts' assertion was true, and temperatures today are similar to the "medieval warm period." Would it matter?

The reason the "medieval warm period" is important to Watts and his ilk is that in their interpretation, it shows that today’s temperatures are not out of the ordinary. If temperatures were just as high in the past as they are today, what do we need to worry about?

But there's a fallacy in that reasoning – what matters is not how high today's temperatures are compared with the past, but rather how high they’ll be 50-100 years from now. It's not where we are; it's where we're going.

We know that increasing carbon dioxide in the atmosphere warms the climate (check here for the best explanation out there). We also know that CO2 is already at a higher concentration than during the medieval warm period - indeed, than at any point in the last 400,000 years, and likely the last 15 million; since it takes a few decades for temperatures to catch up with CO2 levels, we've still got a few degrees of warming in the pipeline even if we stopped emitting CO2 today. And if we keep going like we are, it won't stop there: we'll double the preindustrial level of CO2 by 2050, and triple it by 2090. In fact, the last time CO2 levels were as high as they were today, the earth was 5 to 10 degrees Fahrenheit hotter, sea level was 75 to 120 feet higher, and there was no permanent ice cap in the Arctic and very little ice on Antarctica and Greenland. And we're poised to triple that level.

So even if Watts proved that the earth was as warm 700 years ago as it is today, it is completely irrelevant, because we're about to get a whole lot hotter if we don't act now. Any time you hear someone "debunk" the hockey stick, just remember, it doesn't matter.

Medieval warm period debunking global warming? The only thing that's medieval is Anthony Watts's grasp of logic and science.

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