Follow Up On Landsea/IPCC

January 24th, 2005

Posted by: Roger Pielke, Jr.

Several news stories have come out flowing Chris Landsea’s "http://sciencepolicy.colorado.edu/prometheus/archives/science_policy_general/000318chris_landsea_leaves.html">resignation
from the IPCC last week. These news stories provide some additional
information that allows for some insight into the scientific dispute
between Landsea and NCAR’s Kevin Trenberth, as well as into the broader
political context of the IPCC.

The Scientific Dispute

Landsea wrote in his letter that he resigned from the IPCC, in part,
because “It is beyond me why my colleagues would utilize the media to push
an unsupported agenda that recent hurricane activity has been due to
global warming,” and one of those colleagues, Trenberth, was the Lead
Author for the IPCC responsible for writing the chapter on hurricanes to
which Landsea was to contribute. In an "http://www.washingtonpost.com/wp-dyn/articles/A29397-2005Jan22.html">article
in yesterday’s Washington Post Trenberth again asserted that the very
active 2004 hurricane season was influenced by global warming:

“Trenberth, who in an interview Friday called Landsea’s charges
“ridiculous,” said he participated last fall in a media conference call
organized by Harvard University professors “to correct misleading
impressions that global warming had played no role at all in last year’s
hurricane season.” He added he would have welcomed opposing views in the
assessment, even though he believes “if global warming is happening, how
can hurricanes not be affected? It’s part of the overall system.”"

And Sunday’s Boulder Daily Camera contained a similar "http://www.dailycamera.com/bdc/science/article/0,1713,BDC_2432_3491666,00.html">report:
“In a telephone interview with the Camera, Trenberth said the [Harvard]
press conference had been called to rebut statements by Landsea and others
who have said “global warming had nothing to do with hurricanes.”"

The scientific dispute between Landsea and Trenberth over whether or not
global warming played a role in the 2004 hurricane season is easily
addressed. Landsea writes that the assertion that the 2004 hurricane
season was linked to global warming was not supported by peer-reviewed
science, “All previous and current research in the area of hurricane
variability has shown no reliable, long-term trend up in the frequency or
intensity of tropical cyclones, either in the Atlantic or any other basin.
The IPCC assessments in 1995 and 2001 also concluded that there was no
global warming signal found in the hurricane record.” Yesterday’s Boulder
Daily Camera contains a similar perspective from MIT’s Kerry Emanuel,
another expert on hurricanes, “I think it’s extremely difficult to pin the
last season on global warming. That does not preclude that there may be a
global warming signal buried in there somewhere, but nobody in my field
thinks that we’ve seen it.”

It seems that Trenberth could easily respond to Landsea by producing a
single peer-reviewed study supporting his claims. While one such study
would not automatically overturn the many studies on hurricanes and
climate change (see RealClimate on this "http://www.realclimate.org/index.php?p=109#more-109"> general point),
it would provide a scientific basis for Trenberth’s statements, which
Landsea characterized as “far outside of current scientific
understanding.” For his part, Trenberth had earlier acknowledged that his
views on this subject are "http://www.ucar.edu/communications/staffnotes/0410/hurricane.html">controversial.
Absent at least one peer reviewed study to support Trenberth’s claims, it
would seem that he is, at best, a bit forward on his skis.

Why does peer review matter? As the folks at RealClimate have recently href = "http://www.realclimate.org/index.php?p=109#more-109">written
peer review is a “necessary but not sufficient condition” for the
production of good science. Consequently, “observers would thus be well
advised to be extremely skeptical of any claims in the media or elsewhere
of some new “bombshell” or “revolution” that has not yet been fully vetted
by the scientific community.” Presumably a good example of where such
skepticism would have been appropriate was in response to the "http://www.med.harvard.edu/chge/hurricanespress.html">news conference
held by Harvard Unveristy in October, 2004 – it was titled, “Experts to
warn global warming likely to continue spurring more outbreaks of intense
hurricane activity: Problem Tied to Rising Sea Temperatures From Trapped
Greenhouse Gases; Trend Portends More Storm Damage Costs for FL, AL, LA,
TX, NC and SC.” It was this news conference in which Trenberth and
colleagues asserted a link between global warming and the 2004 hurricane
season, but provided no peer-reviewed science to back up these claims.

So even if Trenberth’s claims about a linkage between global warming and
the hurricanes of 2004 are proven correct through future research, public
pronouncements on science, particularly in highly politicized contexts,
will always be much stronger if they are backed by peer-reviewed
scientific knowledge. And right now there does not appear to be a
peer-reviewed basis for Trenberth’s claims. If the climate science
community wants to assert the importance of "http://www.realclimate.org/">peer review when evaluating the claims
of those scientists opposed to action on climate change (and quite
rightfully so in my opinion) then it seems appropriate that scientists who
advocate action on climate change should be held to the same standard.

Political Context

A second reason Landsea gave for resigning from the IPCC was the response
of IPCC officials to his concerns, “The IPCC leadership saw nothing to be
concerned with in Dr. Trenberth’s unfounded pronouncements to the media,
despite his supposedly impartial important role that he must undertake as
a Lead Author on the upcoming AR4.” In particular, it seems odd that the
head of the IPCC would assert that Trenberth’s statements accurately
reflected the work of the third IPCC assessment (in 2001), since they
clearly do not (and also by Trenberth’s admission as well). Landsea wrote
much of the IPCC conclusions on hurricanes for the 2001 report, so he
ought to know.

But more troubling than a lack of knowledge of the substance of the
science of the IPCC reports is the political stance on climate taken by
the head of the IPCC. The Independent "http://news.independent.co.uk/world/environment/story.jsp?story=603752">reported
yesterday
that the head of the IPCC recently called for deep and
dramatic emissions reductions to save humanity.

“Dr Rajendra Pachauri, the chairman of the official Intergovernmental
Panel on Climate Change (IPCC), told an international conference attended
by 114 governments in Mauritius this month that he personally believes
that the world has “already reached the level of dangerous concentrations
of carbon dioxide in the atmosphere” and called for immediate and “very
deep” cuts in the pollution if humanity is to “survive”.”

In taking such a political position in the highly charged context of
climate change, Dr. Pachauri has placed himself in a highly conflicted
position. If he were to have accepted Landsea’s complaint as valid, it
could be seen as admitting that an IPCC scientist is “overselling” the
science in support of a political agenda. This could harm the prospects
for advancing the political agenda that Dr. Pachauri advocates, so there
is a strong incentive for Pachauri to dismiss Landsea’s concerns. (We
have discussed politics and the IPCC on many occasions, "http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/000246politics_and_the_ipc.html">here
and "http://sciencepolicy.colorado.edu/prometheus/archives/author_pielke_jr_r/index.html#000234">here.)
These dynamics seem consistent with the "http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/000323a_third_way_on_clima.html">argument
made recently by Von Storch et al., “Judgments of solid scientific
findings are often not made with respect to their immanent quality but on
the basis of their alleged or real potential as a weapon by “skeptics” in
a struggle for dominance in public and policy discourse.”

So long as people within the IPCC leadership sees its role as political
advocate rather than honest broker, and acts accordingly, we should not be
surprised to see future controversies erupt in the IPCC. The solution is
not to retreat into the illusion that it can deal only with science, but
to openly confront the reality that its very existence is based on the
need to connect science with policy.

[Some disclosures: I know both Landsea and Trenberth quite well. I have
"http://sciencepolicy.colorado.edu/publications/index.html?newSearch=true&doSearch=Submit&selectedLists[]=1″>collaborated
with Landsea on a number of occasions, e.g., "http://sciencepolicy.colorado.edu/admin/publication_files/resource-76-1999.10.pdf">here.
I also have co-authored a "http://sciencepolicy.colorado.edu/homepages/roger_pielke//hp_roger/abstracts/hurricanes.html">book
on hurricanes (with my father, published by John Wiley, 1997)
, and on
pp. 186-188 you can see our views on hurricanes and climate change. And
you can find various other articles on hurricanes, climate change, etc.
that I have authored or co-authored "http://sciencepolicy.colorado.edu/publications/index.html?newSearch=true&doSearch=Submit&selectedLists[]=1">here.]

7 Responses to “Follow Up On Landsea/IPCC”

    1
  1. Peter J. Wetzel Says:

    Roger ———–

    Your arguments are entirely sound. As the RealClimate piece on Peer Review indicated, science advances in slow measured steps. Peer reviewed papers are built on a foundation of previous peer reviewed papers which are cited in their bibliography.
    ———————-
    Unfortunately this slow process means that momentum shifts in science come only with difficulty. When someone like Dr. Trenberth proposes a hypothesis which has no previous history of peer reviewed publication, it is (rightly) very difficult to perform the rigorous analysis required to pass peer review.
    ———————-
    Nevertheless, momentum shifts do take place regularly. This is because good scientists do not close their mind to new evidence, nor to the possibility that their own conclusions might be overridden by this new evidence.
    —————–
    I think it is only a matter of time until peer reviewed papers emerge which support Dr. Trenberth’s position, which is now nothing more than a hypothesis. There is already a significant body of evidence that could serve as the basis for such a paper. I’d like to elaborate a bit:
    ———————–
    The evidence comes from climatology — the daily frequency of storms:
    ——————
    In the tropical North Atlantic the Tropical Storm Frequency (http://www.ems.psu.edu/~nese/f11_3_2.htm ) peaks sharply around 12 September. This corresponds with the time of peak heating at the latitudes (5 to 10 N) where tropical storms are spawned. One need only compare the frequency of hurricanes on 12 Sept with the frequency on 12 August or 12 October, for example, and ask what factors cause this difference. One of the primary factors is the heating and resultant sea surface temperature.
    —————————
    Similarly, one can compare the Atlantic basin with the Tropical Northwest Pacific. That part of the Pacific produces the most frequent and strongest hurricanes on Earth. An analysis of why this Pacific basin has more storms than the Atlantic basin is likely to point to the fact that Sea Surface temperatures are warmer there at the latitudes where Tropical Storms form. Since both basins experience the same solar input, but one produces warmer water (and higher air humidity) as a result of basin size and configuration, this provides further evidence that sea surface temperatures and air humidity cause the difference between the two basins.
    ————————-
    It is not unreasonable to conclude from this evidence that warmer sea surface temperatures (SST) and higher humidity cause a greater daily frequency of storms.
    ————————-
    So assuming that it has been established through other peer reviewed papers, that GHG warming will produce greater SST and humidity in the tropical northern ocean basins in early September, then one can fairly confidently conclude that there will be a greater daily frequency of tropical storms.
    ————————
    I believe that Landsea’s approach, of searching for a trend in storm frequency ignores the sort of climatological evidence I’ve cited above. Nevertheless, his methodology is sound, based on the data he used and the methods by which he analyzed them: The high year-to-year variability of storms produces a large “noise” level, above which a clear signal of Greenhouse warming has not yet emerged.
    ——————–
    What I predict will happen in the future is that a few papers will emerge that examine the evidence more from a climatological and process-study point of view: I’ve suggested the climatological approach above — process studies (regarding what makes hurricanes form and what sustains them) have already been done which rather clearly point to the fact that warmer SST’s and higher humidity do produce more and stronger storms. The result of putting the two ideas together provides strong **circumstantial** evidence that we can expect more tropical storms in a GHG warmed world.
    —————-
    It is entirely possible to get peer reviewed papers accepted which are based on strong circumstantial evidence, particularly when some direct evidence is also emerging (namely, the unusually high frequency of North Atlantic Tropical storms since the mid/late 1990’s, for example). As said, I expect to see these papers arriving at a peer reviewed journal near you — possibly even in time for the release of AR4.
    —————–
    – Pete Wetzel, Ph. D., 1978 Atmospheric Science, Colorado State University. Trained in the understandin of tropical storm processes by Dr. Bill Gray (http://typhoon.atmos.colostate.edu/ ). Specializing in the parameterization of land-atmosphere interactions for Global Climate, Regional Mesoscale, and Local Cloud Resolving numerical weather prediction models.

  2. 2
  3. Peter J. Wetzel Says:

    Sorry, the links didn’t work — try these:

    http://www.ems.psu.edu/~nese/f11_3_2.htm

    http://typhoon.atmos.colostate.edu/

  4. 3
  5. O. Linde Says:

    Trenberth´s hypothesis is absolutely reasonable. At the most basic level, Thermodynamics explains it all. We were expecting weird climate since many years. It is, unfortunately, possible a scientifically explanation of these severe events. Sometimes we don´t understand excellent scientists like Landsea ..
    Well.. maybe we are not experts in this particular extremely complicated Science. Climatology will have never the possibility to take into account in models all and every one of the million of real events that take place on the Earth (so many marginal, unknown ones which add a lot, maybe).
    I hope we have not to wait too much for papers suppporting Trenberth´s views being written.
    His point of view is much understood, at least empirically, by many Scientists and people with common sense.

  6. 4
  7. FuturePundit Says:

    Hockey Stick Climate Temperature Trend Theory Challenged

    A pair of Canadian researchers, University of Guelph Canada economist Ross McKitrick and Toronto-based mineral exploration consultant Stephen McIntyre, have a paper…

  8. 5
  9. garry culhane Says:

    May a layman comment briefly?
    One must regognize the value of peer review, but one can also notice that there is a lot of research that is part of the climate controversy where the “peers” are chosen by the research author or a very supportive editor,or even the owner and ideological dictator of a publication. A recent case was the von Storch blowup a year or so ago, followed by his resignation when the owner was not sufficiently impressed by his adverse views, and the journal seems to have sailed along since without benefit of improvement. Then there is the publisher of the M&M paper whose only apparent standard is whoever puts out a line she favors, and the ensuing climb down by Science which seems to have left it to reviewers to explain why nothing further should be done except that Mann should perhaps let the bad guys see all the data, so that apparently peer review does not include doing that, or even taking a close look at the study concerned if they are busy, as one reviewer complained. And then Science puts its bets on von Storch, who contributes a devastating attack on Mann (that Mann is not even given a chance to read prior to publication).

    Tell me of something nasty that the skeptics have done that is worse than all that. The only item I can think of is that the majority of climate scientists are the white hats and the skeptics are the black hats. Just look at their funding, their associations, and their often hilariously brainless arguments. We really do not need the help of statistical science to reach a conclusion on that one.

    Not that I am complaining about all this. The climate scientists are in the “happy” position that whatever modest conclusions they draw from their studies, supporting evidence is likely to land at their front doors with the morning media .

    I believe it is reasonable to say one must hope the scientists will insist upon maintaining high standards in their work. But they should form and stay loyal to alliances among themselves (IPCC), stop giving the rest of us these ego displays like we are seeing now between von Storch and Mann, and pour their venom instead into attacks on the enemy.

    Yes we do need good science. But we do not need wimps who panic and start to qualify themselves out the back door as soon as corporation funded academic whores start snarling. There will be no gentlemen in this fight. Garry Culhane

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  11. Colin MacDonald Says:

    So we have strong supporting evidence that hurricane intensity will increase with global warming,this being: hurricane frequency is greater during september than august/october. Well gosh that’s demolished the skeptics. Why not demolish them some more by comparing September to March. Perhaps if we were told the exact increase in frequency and the exact increase in hurricanes and the exact increase in sea temperature we could come to some useful conclusions.
    Meanwhile a simplistic counter-argument of my own. Given that vedlocity increases with the square root of energy (E=.5mv^2) my calculations show that a 1 C increase in average temperature gives .1% increase in average windspeed, ie unmeasureable. Highly simplistic I know! But so is saying that higher temperatures must increase storminess

  12. 7
  13. M Osment Says:

    A lot of these arguments represent tautologies. Hurricanes must become more frequent and stronger because of global warming. The fact that this past year had a number of strong storms proves that there is global warming. This is an unreasonable leap in logic. There is no evidence that there was a significant or unprecedented change in the number of hurricanes. Even the current, flawed GCM’s would not predict an increase in hurricane activity at this point in the global warming cycle. They would place such changes several decades in the future. The most crucial point is that there is no peer reviewed science that “proves” anthropogenic global warming exists. I suggest that anyone who is convinced should read up on the “Maunder Minimum” and the “Little Ice Age”.