Did Skeptic Magazine "Demolish" Objections to AGW?

UPDATE (June 22, 2012): Contrary to who I said in the first paragraph, Donald Prothero's article is not "recent." Rather, it was written in February of 2012. However, the article is currently displayed prominently of Skeptic Magazine's homepage and is the cover story of the magazine's current issue. 


I regret that my first substantive post is going to be contentious. I don't plan to make a habit out of ranting. But a recent article* in Skeptic Magazine titled "How We Know Global Warming is Real and Human Caused" demands a harsh rebuttal. This will be very long and detailed, since I'm planning on bringing it to the attention of Skeptic's editors. I promise that the vast majority of my posts will be much shorter and simpler than this one. The meatier stuff is actually below the dashed line.

The magazine introduces the piece with this heinously heavy-handed description:

"In this week’s eSkeptic, Donald R. Prothero addresses climate change denialism head on, demolishing deniers’ arguments and rebuttals, and clearly demonstrating how we know global warming is real and human caused."

Prothero, a professor of geology,  begins his article by sneering at the "Rupert Murdoch-owned" Wall Street Journal for publishing an "Opinion Editorial written by 16 people who deny the evidence of human-induced climate change." However, the editorial did not deny that humans affect the climate. At one point, it even said "it is likely that more [human-emitted] CO2 and the modest warming that may come with it** will be an overall benefit to the planet." The main message was:

"There is no compelling scientific argument for drastic action to 'decarbonize' the world's economy. Even if one accepts the inflated climate forecasts of the IPCC,aggressive greenhouse-gas control policies are not justified economically."

Prothero immediately points out that "Most of the authors of the editorial were not climate scientists." What he neglects to mention is that all "16 people" who signed the piece were indeed scientists of some sort, most of whom specialize in physics, the Earth sciences, or engineering. Since Prothero himself is a geologist (not a climate scientist), it is quite peculiar that he would try to diminish the value of non-climate scientists' perspectives on Anthropogenic Global Warming (AGW). 

Next, Prothero says, "one of two actual climate scientists of the group, Richard Lindzen, is a notorious global warming denier who also denies that smoking causes cancer." First, by "one of two," he is clearly trying to imply that only two of the contributors were climate scientists. I count at least 4 who deserve to be called climate scientists:

               Richard Lindzen: atmospheric physicist at MIT

               Henk Tennekes: Former director of the Royal Netherlands Meteorological Institute.

               Nir Shaviv: astrophysicist who has published several peer-reviewed papers on climate.

               William Kininmonth: former. head of climate research at the Australian Bureau of  Meteorology.                                     

Second, it is completely false that Richard Lindzen denies that smoking causes cancer. There is no evidence that he ever did, and when he was asked about it, he said:

"I have always noted, having read the literature on the matter, that there was a reasonable case for the role of cigarette smoking in lung cancer, but that the case was not so strong that one should rule that any questions were out of order."

Apparenty, Prothero does not recognize the difference between denying X and accepting the possibility that X might be false.

Then Prothero tells us about a “Letter to the Editor by 38 of the world’s leading climate scientists" that argued against the Op Ed. It's false that the letter was written/signed by 38 of the world's leading climate scientists - or at least it better be. There were 38 signatories in total. Below I've provided some of the signitories' credits as they appear in the letter. If you click the people's names, you can read more about them.

Camille Parmesan, Ph.D., Professor of Biology, University of Texas; Professor of Global Change Biology, Marine Institute, University of Plymouth, UK 

Gary Yohe, Ph.D., Professor, Economics and Environmental Studies, Wesleyan University, CT 

James J. McCarthy, Ph.D., Professor of Biological Oceanography, Harvard University 

William H. Schlesinger, Ph.D., President, Cary Institute of Ecosystem Studies 

Wolfgang Cramer, Professor of Global Ecology, Mediterranean Institute for Biodiversity and Ecology, CNRS, Aix-en-Provence, France 

Steven Running, Ph.D., Professor, Director, Numerical Terradynamic Simulation Group, University of Montana 

Terry L. Root, Ph.D., Senior Fellow, Woods Institute for the Environment, Stanford University

Barrett N. Rock, Ph.D., Professor, Complex Systems Research Center and Department of Natural Resources, University of New Hampshire 

If these people are really among the "leading climate scientists," then climate science is in trouble. A few of them, such as Parmesan and Root, really can't defensibly be called climate scientists at all.

Prothero says that this letter "pointed out the numerous lies, mistakes, and fallacies in the editorial." That's just not true. The letter was only 492 words long, and the only specific rebuttal to the Op Ed that the letter offered was a pathetic attempt to say the Earth has been warming for the past decade. The letter does not identify any "lies" in the Op Ed. 

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EVIDENCE

Ok, enough gossip. Now let's take a look at Prothero's bastardization of the actual evidence regarding AGW. 

HOCKEY STICK

He starts with a big fat Hockey Stick. Here's a screenshot from the article:

Prothero explains:

"Mann et al. (1999) compiled the past 900 years’ worth of temperature data from tree rings, ice cores, corals, and direct measurements of the past few centuries, and the sudden increase of temperature of the past century stands out like a sore thumb. This famous graph (see Figure 1 above) is now known as the “hockey stick” because it is long and straight through most of its length, then bends sharply upward at the end like the blade of a hockey stick."

Here's what Prothero does not tell us: 

1. The data analysis the produced the Hockey Stick contained numerous egregious errors.
2. The Hockey Stick was constructed using tree rings as indicators of past temperatures, a practice that has been called into serious question.
3. The Hockey Stick, particularly its indication that the Earth is currently substantially warmer than it was during the Medieval Warming Period (around 900 to 1300 A.D.), is contradicted by the vast majority of the relevant scientific literature. (Also check out this comprehensive peer-reviewed review).
4. Several peer-reviewed temperature reconstructions - which, unlike the Hockey Stick, have not been shown to have serious methodological or statistical errors - indicate that the MWP was approximately as warm as the present, or even a little warmer. 
5. A committee convened by the National Academy of Sciences said that Mann et al.'s Hockey Stick did not constitute compelling evidence that of the Earth's temperature history for the past 1,000 years. Specifically, the committee said:

 "The Research Council committee found the Mann team's conclusion that warming in the last few decades of the 20th century was unprecedented over the last thousand years to be plausible, but it had less confidence that the warming was unprecedented prior to 1600; fewer proxies -- in fewer locations -- provide temperatures for periods before then. Because of larger uncertainties in temperature reconstructions for decades and individual years, and because not all proxies record temperatures for such short timescales, even less confidence can be placed in the Mann team's conclusions about the 1990s, and 1998 in particular."

Despite all of these problems with the Hockey Stick's credibility, Prothero confidently refers to it multiple times to support his position that recent warming must be attributed mainly to human industrialization. He gives the reader no indication at all that the Hockey Stick has been seriously challenged.

RECENT TEMPERATURE RECORDS

Prothero also tries to refute the claim that the Earth has not warmed in over 10 years by insisting that "since 2002, the overall long-term trend of warming is unequivocal." He shows us two graphs as evidence: the first is too poorly marked to even consider, and the second is shown below:

I don't know where he got this data, and, frankly, I don't care. Notice that the last year shown is 2010. There was an El Nino that year, which pulled global temperature up. Here are several other constructions of the Earth's temperature over the past few decades. (captions and images provided by climate4you.com, except the last one, which which from drroyspencer.com):

Do these data look like they constitute "unequivocal" evidence of a warming trend since 2002? What was Prothero thinking?

TRENDS IN SEA LEVEL

Prothero wants to convince us that "the rate [of sea level rise] is accelerating" by telling us that "At present, sea level is rising about 3–4 mm per year, more than ten times the rate of 0.1–0.2 mm/year that has occurred over the past 3000 years." I'm not going to comment on the claim that sea level only changed at an average rate of .1 or .2 mm per year over the past 3,000 years. But I will propose a more straightforward way to determine the extent to which sea level rise is accelerating. Let's look at change in sea level that's occurred lately, and see if there's been acceleration:

Here's a The Colorado Center for Astrodynamics Research's record of global sea level since 1993:

It certainly doesn't look like sea level rise has accelerated since 1993. It even looks like it slowed down around 2005. Here's a graph from a peer-reviewed report depicting sea level from 1904-2003:

Certainly doesn't look like acceleration. That same report also included a graph with time on the x-axis and rate of sea level change on the y-axis. A rising line would indicate acceleration. Here it is:

But the line does not rise. It just wiggles more towards the right. The authors of the paper even tell us:

"The rate of sea level change was found to be larger in the early part of last century (2.03±0.35 mm/yr 1904 – 1953), in comparison with the latter part (1.45 ± 0.34 mm/yr 1954 – 2003)."

Hmm. Sea levels rose faster prior to industrialization (circa 1950) than they did afterwards. 

FUTURE SEA LEVEL PREDICTIONS

Prothero says that "most scientists predict sea level will rise 80–130 cm in just the next century." First of all, let me point out that that is a far lower estimate than what Al Gore is saying: Gore says we could reasonably expect about 6 m of sea level rise "in the near future." So, rather than frame this point as a refutation of the skeptical position, why not frame it as a refutation of Gore's hysterical alarmism?

But I don't even think it's true that most estimates are in the .8-1.3 m range. Prothero does not cite any sources on this. I'll give you some of my own, starting with the IPCC. Here is a table from the IPCC's 2007 Summery for Policy Makers:

Notice that the average estimate across the 6 models is about 0.3 m (which is about 1 ft.). Only one model has a upper limit as high as .59 m. The IPCC is certainly not an organization that tries to downplay the seriousness of AGW, yet none of the IPCC's models predicted a range of sea level rise that even overlap the range that Prothero attributes to "most scientists." What's (or should I say, "Watts") up with that?

Now of course, there are reports that do give predictions similar to the .8-1.3m range, like this one. But here's another paper that makes lower estimates, most of which are well under .8 m. So it's a bit puzzling that Prothero feels comfortable declaring that "most scientists" project between .8-1.3m. It would be nice if he bothered to show us how he got that impression.

POORLY CHOSEN POINTS TO ADDRESS

Prothero spends much of his article explaining things like how we know methane and volcanic activity are not driving climate change, and why the fact that a few recent winters have been very snowy do not constitute evidence against AGW. However, intelligent skeptics of AGW never emphasize these points. Prothero also devotes much space to comparing AGW "deniers" to "creationists," which is totally unproductive; and to scoffing at the climategate controversy, which was utterly uninformative. 

Prothero was so busy ridiculing skeptics with ignorant insults that he never got around to address several key issues. For instance he never mentions the issue of climate sensitivity: The words "sensitivity" and "feedback" both do not appear in the article. Everyone who actually follows the AGW debate knows that the fundamental disagreement between the two "camps" is over climate sensitivity: the extent to which feedback mechanisms (e.g. cloud formation) will exacerbate or diminish the effect on the Earth's temperature caused by the greenhouse warming from human CO2 emissions. The skeptics, unlike proponents, do not believe that the best available evidence justifies any confidence at all in the belief that the Earth's climate sensitivity is high enough to render CO2 emissions dangerous. 

Prothero also neglects to address trends in extreme weather. A serious point of contention between AGW-proponents (particularly of Al Gore's variety) and skeptics is whether or not hurricanes, droughts, floods, tornados, and extreme temperatures are increasing. There are many reports that compellingly show that the answer is no, or at least, "not really." 

CONCLUSION

Skeptic Magazine said that Prothero "demolish[ed] deniers’ arguments and rebuttals, and clearly demonstrat[ed] how we know global warming is real and human caused." I hope I've made it clear that Prothero did not even come close to demolishing skeptics' position. Did he make a compelling case that humans' CO2 emissions cause the globe to warm? Sure he did. That's easy to do, and the vast majority of skeptics accept that. But he also spread confusion about important data, and about what the debate is really about. I was glad to see that Prothero's article was very poorly received by the online readers of Skeptic Magazine, and I am optimistic about the magazine's likelihood of improving its coverage of the climate change debate.

Questions? Comments? Rebuttals? "Planet Murderer!!!"? Fire Away.

*You have to scroll down a bit to see the article

**The emphasis is my own, as will always be the case unless I say "original emphasis"