The “Left” Does It Too

One of my arguments against Chris Mooney’s thesis (“The Republican War on Science“) is that all disputants in scientized political debates cherrypick. Chris has argued from the specific – Well-documented examples in which conservatives have done this. – to the general – The problem is that conservatives do this.

My view is that we have a different problem to cope with: the fact that both sides in most interesting science-politics-policy debates do this, and we’ve got to call bullshit on it wherever it happens. With that in mind, I’ll call bullshit on this:

Oceans worldwide are projected to rise as much as three feet this century, and much higher if the Greenland ice sheet melts away. (emphasis added)

It’s from an op-ed in the Washington Post by Mike Tidwell of the U.S. Climate Emergency Council, “a nonprofit organization dedicated to rigorous grassroots action in the fight to stop global warming and promote a clean energy future.”

People who want to do what Tidwell is advocating – use climate change science as a basis for energy policy action – can, if they are careful, speak from the high ground, basing their call to action on a strong scientific consensus on climate science. But as soon as they cherry-pick science that goes beyond the consensus, they are implicitly justifying all such cherry-picking, and we devolve into a he-said she-said argument with the Roy Spencers of the world.

So what’s the best available consensus statement on the subject of sea level rise? From the IPCC:

Global mean sea level is projected to rise by 0.09 to 0.88 metres between 1990 and 2100.

As you can see, Tidwell has picked the most extreme sea level rise scenario identified by the IPCC (“.88 meters” ~ 3 feet). This is epistemologically identical to picking the other end of the IPCC range and arguing that sea level rise will be negligible and can therefore be ignored. Sea level rise is a significant issue, and it’s important to incorporate the best available science in underpinning the discussion, including a recognition of the genuine uncertainties. As soon as Tidwell picks an outlier on one extreme, he sanctions his political opponents’ choice of the opposite, and gridlock is ensured.

(Hat tip Roger Pielke Jr. for the link, with a lot more interesting discussion there.)


  1. Well, he does say *as much as* 3 feet.

    I’m more worried about the “and much higher if the Greenland ice sheet melts away”. It’s true, of course. *If* the entire Greenland ice sheet melts away in the next century, then sea level rise will exceed 0.9 m. That’s a big “if” he’s hurrying past, though.

  2. John, as you know, that TAR range is widely considered to be on the low side at this point, so I don’t think it’s reasonable to insist it still be held it up as the gold standard. As well, people like Jim Hansen and Richard Alley are very worried that Greenland in particular, while it’s at no risk of melting outright that quickly, could be making a hefty additional contribution to sea level rise this century. The AR4 is out of date on this before it’s ink is even wet. So, no, there is nothing at all objectionable about the captioned statement.

    Also, pleasant though it would be to contemplate a Pielkean world where a shift in rhetoric could break the gridlock on getting meaningful action on global warming, I’m afraid it’s much more a matter of entrenched economic interests defending their perquisites.

  3. If I may expand on Steve’s nice comment, rather than saying “we should call BS“, I’d rather say:

    “Don’t give the denialists anything to grasp on to”.

    I think that’s much more accurate to my mind.



  4. John, on this topic and your opinion, we agree.

    Reading the op-ed made me wonder if it was a climate skeptic’s plant intended to discredit those who believe and publicize the coming impacts of global warming and the need to decarbonize the global energy system.

    I have been an environmental activist for nearly four decades. The quality of discourse, serious examination and national-level political advocacy environmental groups and spokespersons apply to the global warming concern sadden and anger me.

    Tidwell’s piece was a high volume rap rendition of what has been phrased in the more sensible, believable tone of the US Climate Assessment Report — similar conclusions minus the rhetoric and sensationalizing.

  5. John-

    From a more general view, a general rule is that all advocates use good rational arguments when they have them. When they don’t, then they use inaccurate arguments, anecdotes and stories, invocation of powerful symbols, appeals to emotion or prejudice …

    In the AGW debate, the side advocating GHG reductions is not morally superior: they don’t cherrypick because they don’t have to. The scientific evidence is on their side, so they can make a strong rational argument w/o cherrypicking. Those opposed to GHG reductions do not have that advantage, so they MUST resort to cherrypicking or lose the debate. If the scientific evidence were on the other side, then you’d see advocates in favor of GHG reductions cherrypicking.


  6. Andrew – I think you’re right for the wrong reasons (or, more likely, reasons left unsaid). It’s not a matter of morals. The decision-making body at large may decide to accept the validity of the risk and ignore it anyway. That is a perfectly valid political/policy-making response, preferable or not to advocates (or us). Since non-action is what the “objectionists” (used very loosely) want, they would be better served to admit the science, acknowledge the risk and then say, “So what — let’s just adapt instead.” That would at least be intellectually honest, and not immoral.

  7. Andrew,

    I usu. agree with your POV. But in my experience folk who use inaccurate arguments, anecdotes and stories, invocation of powerful symbols, and/or appeals to emotion or prejudice either don’t have command of the facts, can’t argue well, are engaging in advocacy/mendacity, or some combination of the three. I expect to see this kind of stuff in the Murrican mass media.

    That is: I expect accuracy from technicians or scientists, but I don’t from folk who are, say, travel writers turned advocates.

    So I don’t necessarily lump this guy in with ‘lefties’ unless I want to make it easy on myself and categorize someone.

    I’d rather…uh…ensure my BS detector has fresh batteries when I read something in the media, as my expectation in most instances is that the media product is dumbed down to the LCD for consumption by those most likely to buy the advertiser’s products.

    Best regards,


  8. John–

    That’s not really my argument, you know. Everybody knows that everybody misuses science to some extent. My argument is that this has become severe and systematic within the current GOP due to a constant need to appeal to two key constituencies (industry and the religious right) that are themselves extremely dependent upon attacking inconvenient science. This is of course amplified by the conservative/Republican think tank infrastructure (a counter-academia), the conservative media, and by the total GOP dominance of the government. None of this is currently duplicated on the left in this country.

    Anyway, hope you can come out to one of my two talks in New Mexico as I’m touring for the paperback next month:

  9. Andrew –

    But in this case, someone in favor of greenhouse gas reductions *has* cherrypicked. It is not uncommon (see Ross Gelbspan’s Katrina’s real name is global warming piece as an example). And it’s a problem.

    Chris –

    In titling your book “the Republican war on science” you single out one particular manifestation of a general problem. I think we need to confront the general problem.

    And yes, I’m looking forward to your visit, and hoping to find an opportunity to get together so we can hash all this over in person.

  10. Steve B –

    Richard Kerr, in his most recent summary of the state of things in Science[1]said this: “If the recent surge of ice to the sea continues, sea level might reach something like half a meter higher by 2100.”

    Patz et al., in Nature last November[2], continue to cite the IPCC, picking a mid-range number as realistic: “(A) rise in the sea level of 40 cm is envisaged by the 2080s.”

    Meehl et al., in Science in March 2005[3] also continue to cite the IPCC and offer ranges that, if I understand them correctly, lie within the old IPCC range.

    Raper et al., in Nature in January[4], published estimates pushing the numbers for the contribution of mountain glaciers and icecaps in the opposite direction – less sea level rise than the IPCC 2001 numbers.

    No doubt the Fourth Assessment Report will clarify this somewhat, but it’s hard for me to read the literature and conclude that Tidwell has done anything other than cherrypick an outlier.

    [1] Science 24 March 2006 311: 1698-1701 [DOI: 10.1126/science.311.5768.1698]
    [2] Nature 438, 310-317 (17 November 2005) | doi:10.1038/nature04188
    [3] Science 18 March 2005: Vol. 307. no. 5716, pp. 1769 – 1772 DOI: 10.1126/science.1106663
    [4] Nature 439, 311-313 (19 January 2006) | doi:10.1038/nature04448

  11. John,
    Sure, let’s confront the general problem…but I pick out by far the *worst* manifestation. Surely you can agree with that?

    Look forward to talking in NM.

  12. John, careful with those cites:

    [1] Overall, I would say the Kerr article was more alarmist than the Tidwell piece; consider e.g. the subhed: “Startling amounts of ice slipping into the sea have taken glaciologists by surprise; now they fear that this century’s greenhouse emissions could be committing the world to a catastrophic sea-level rise[.]” The 20 cm rise for 2100 was a straight-line extrapolation of the *current* rate, and is described as “substantial but not catastrophic” (compare to subhed).

    [2] Patz et al wasn’t even a sea level research article, and simply took the IPCC scenarios as a given in looking at AGW health impacts.

    [3] Meehl et al looked at what would happen with sea level if we stopped adding to GHG emissions as of 2000 (ahem) and ignored any contribution from glaciers or ice sheets (i.e., looked at the thermal expansion commitment only).

    [4] The Raper et al results are as you present them but seem to be in some dispute; I can’t see the details of the comment/response since I don’t have a GRL sub. In any case the argument seems to be over a few inches (relative to 2100) since only mountain glaciers and icecaps are involved.

    Also, note that in March Nature ran a piece essentially identical in tone to the Kerr article.

    Given all of this, the Tidwell op-ed seems pretty mainstream.

  13. Steve –

    I was careful with the cites.

    [1] The Kerr article discussed the “what ifs” associated with recent surprising new research and the directions the science therefore seems to be headed, noting that “the uncertainties are large.” “If the recent behavior of ice sheets is not fully understood, their future is largely a blank.” His discussion of what is known firmly, as opposed to what’s out on this changing frontier, includes the number I cited.

    [2] Patz et al. presumably chose the best available current estimates on which to base their analysis.

    [3] Reread the Meehl et al paper. They also ran simulations with concentrations held constant at 2100 values. See their figure 1 for the CO2 numbers and the sea level numbers. You are correct that the numbers in that figure are only for thermal expansion, but the paper also suggests “Contributions from future ice sheet and glacier melting could perhaps at least double the projected sea level rise produced by thermal expansion.” And cites the IPCC 2001. Again, someone writing in the literature looking for the best available current estimates citing the IPCC, and offering up new numbers that lie within the IPCC range.

    [4]The Raper paper says what it says. As soon as you conclude the paper pointing in the direction you don’t want things to go is “in dispute” while accepting those heading the opposite direction, you’re cherrypicking.

    I await the citations in support of your original assertion – that the TAR estimates are low and that therefore Tidwell was justified in citing a meter. I don’t know this field well. I just went out and read what I could find, and everything I found suggested Tidwell was cherrypicking.

  14. The problem is that no matter what emissionscenerio you use most of the sea level rise that HAS ALREADY BEEN COMMITTED TO occurs after 2100. A lot after 2100 if you follow the TAR, but there is increasing evidence that the TAR and maybe AR4 are much too optimistic. The issue is not emission scenerios but the dynamics of the ice caps, and the real problem is that by the time you figure out if the pessimists are right nothing can be done.


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