February 08, 2010
Droughtgate: Study Finds IPCC had Temperature - Drought Connection
Backwards
Marc Sheppard

Add another to the growing list of IPCC outrages.


As I mentioned in last week’s IPCC: International Pack of Climate
Crooks, in Chapter 9 of Assessment Report 4’s (AR4) Working Group One
(WG1) Report, the IPCC claimed that manmade CO2-driven higher
temperatures drive higher evaporation, and thereby cause droughts. As
readers are all too aware, droughts are favorite ingredients in most
alarmists’ recipes for manmade climate disaster. But a paper
published last month in Geophysical Research Letters lays out a
compelling argument that the IPCC has it completely backwards – that
droughts are actually causing warming, not the other way around.


In Section 9.1.2, the IPCC states that: [emphasis mine throughout]
[P]recipitation and temperature are ordinarily inversely correlated in
some regions, with increases in temperature corresponding to drying
conditions. Thus, a warming trend in such a region that is not
associated with rainfall change may indicate an external influence on
the climate of that region (Nicholls et al., 2005; Section 9.4.2.3).


That statement is attributed to the same Neville Nicholls who wrote in
his 2004 paper, The Changing Nature of Australian Droughts, that:
The relatively warm temperatures in 2002 were partly the result of a
continued warming evident in Australia since the middle of the 20th
century. The possibility that the enhanced greenhouse effect is
increasing the severity of Australian droughts, by raising
temperatures and hence increasing evaporation, even if the rainfall
does not decrease, needs to be considered.


Later in the paper, Nicholls concluded that “the warming has meant
that the severity and impacts of the most recent drought have been
exacerbated by enhanced evaporation and evapotranspiration.”


Not surprisingly, as with many other AR4 irregularities that have
recently surfaced, this too has a non-peer-reviewed World Wildlife
Fund link to it. Nicholls’ was an extension of the work of fellow
Aussie alarmist, David Karoly, whose 2003 WWF report, Global warming
contributes to Australia's worst drought [PDF], studied the 2002
drought in Australia’s Murray-Darling Basin and found that:
"This drought has had a more severe impact than any other drought
since at least 1950, because the temperatures in 2002 have also been
significantly higher than in other drought years (see Table 1 and 2).
The higher temperatures caused a marked increase in evaporation rates,
which sped up the loss of soil moisture and the drying of vegetation
and watercourses. This is the first drought in Australia where the
impact of human-induced global warming can be clearly observed."
So then, the basis for the claim that anthropogenic warming causes
droughts put forth in the IPCC’s AR4 was a WWF report and its follow-
up written the next year.


But that basis, conclude Natalie Lockart, Dmitri Kavetski and Stewart
W. Franks, authors of On the recent warming in the Murray-Darling
Basin: Land surface interactions misunderstood, is bogus. As stated
in its opening, their study “demonstrates that significant
misunderstanding of known processes of land surface – atmosphere
interactions has led to the incorrect attribution of the causes of the
anomalous temperatures, as well as significant misunderstanding of
their impact on evaporation within the Murray-Darling Basin.” And
after deconstructing the claims of both Nicholls and Karoly, concludes
that:


All presented results demonstrate that potential evaporation under dry
conditions is elevated not as a result of the air temperature, but as
a result of the lack of actual evaporation. This is accompanied by
increased sensible heat fluxes which increases air temperatures. This
is an entirely natural consequence of the dynamics of drought.
Importantly, it is shown that antecedent temperature increases do not
lead to insignificant increases in actual or potential
evapotranspiration.


As coauthor Stewart Franks explained to me in an email, “this is a
confusion of the well known physics of evaporation - as higher air
temperatures are driven by the lack of evaporation (as occurs during
drought).” He explained further in a subsequent correspondence:
Of course, when there is a deficit of rainfall, this tends to be
accompanied by less cloud-cover, hence more sunshine, which does
increase the energy available for evaporation, but as soil moisture is
low, the bulk of the energy goes into heating the near-surface
atmosphere and hence higher air temperatures.
But amazingly, the story doesn’t end with how wrong the chapter was.


Professor Franks also pointed out that Neville Nicholls was one of the
chapter’s Lead Authors, and David Karoly, whose work was also heavily
cited in WG1 Chapter 9, was its Review Editor.


Quipped Franks: “Hence they cite and review their own papers as part
of the clearly flawed IPCC process.”


Unbelievable.