I’ve largely stayed out of the “hockey stick wars” lately (by this I’m referring to climate science, not the resumption of NHL play). But some new stuff published in GRL (by von Storch and Huybers ) rather seems to undercut the criticisms that have been raised by McIntyre and McKitrick of the old Mann et al. hockey stick paleoclimate reconstructions.

The statistical questions raised by MM are somewhat arcane for the general blog-reading audience. In the first case, MM argued that the methodology used by Mann et al. essentially produces “hockey sticks” artificially out of random noise. Von Storch (who one of the M’s loves to quote approvingly, and who is one of the deans of climate statistics) disputes this assertion. Huybers argues that MM’s criticism of the Mann et al. choice of statistical significance tests is wrong. Suffice it to say, for purposes of the policy discussion in which MM have been invoked, that the responses by von Storch and Huybers suggest that the MM statistical criticisms of the hockey stick reconstruction are not as bone-headedly obvious as Michael Crichton wants to believe.

Climate scientist Roger Pielke Sr. took the Washington Post’s Juliet Eilperin to task a few days ago for an Oct. 13 story suggesting “that 2005 is on track to be the hottest year on record.”

Pielke’s contention is that, while surface temperature data may support the claim, the surface thermometer record “is not … the most appropriate metric to evaluate global warming.” And from a climatological view, of course, he is absolutely correct. Various layers of the atmosphere behave quite differently, and a complete picture requires looking at all of them, which, as Pielke notes, paint a much more complex picture of warming than a simple “warmest ever” headline.

Pielke also gives an important nod to regional anomalies, which he rightly argues “are what we should be focusing on in terms of long-term climate trends, rather than surface globally-averaged temperature trends.”

But this is a newspaper story for a national audience, where you really get to say one clear thing that has to communicate with people everywhere. If it were for a regional audience (like, say, mine) it could focus on a regional anomaly. But whoever is going to be reading this is living on the planet’s surface, so that’s the temperature number that’s going to matter to them.

Last month, I blogged about a talk I heard a few years back by Roger Pielke Jr. on hurricane damage. Roger’s case study was in significant part hurricane Mitch, which killed so many people in Central America because a) it was a very strong storm, and, more importantly, b) because the folks it dumped on were poor.

Keep that in mind as Filed under climate variability

I’m fascinated by climate and weather extremes, so this from this morning’s NHC discussion of hurricane Wilma caught my eye. (The old record was Gilbert in 1988 at 888 mb. Wilma’s unofficially at 881 – 884. This like golf – lower pressure equals more powerful hurricane.):

AN AIR FORCE RECONNAISSANCE PLANE MEASURED 168 KNOTS AT 700 MB AND ESTIMATED A MINIMUM PRESSURE OF 884 MB EXTRAPOLATED FROM 700MB. UNOFFICIALLY…THE METEOROLOGIST ON BOARD THE PLANE RELAYED AN EXTRAPOLATED 881 MB PRESSURE AND MEASURED 884 MB WITH A DROPSONDE. THIS IS ALL IN ASSOCIATION WITH A VERY SMALL EYE THAT HAS BEEN OSCILLATING BETWEEN 2 AND 4 N MI DURING EYE PENETRATIONS. THIS IS PROBABLY THE LOWEST MINIMUM PRESSURE EVER OBSERVED IN THE ATLANTIC BASIN AND IS FOLLOWED BY THE 888 MB MINIMUM PRESSURE ASSOCIATED WITH HURRICANE GILBERT IN 1988. HOWEVER…ONE MUST BE VERY CAREFUL BEFORE IT IS DECLARED A RECORD MINIMUM PRESSURE UNTIL A FULL AND DETAILED CALIBRATION OF THE INSTRUMENTS AND CALCULATIONS IS
PERFORMED. SO PLEASE DO NOT JUMP INTO CONCLUSIONS YET…BE PATIENT.

Before I slipped away for vacation last week, I was able to write this (sub. req.):

New Mexico’s massive pi?on die-off of 2002 and 2003 might be a harbinger of life here in a warming world, new research suggests.

High elevation forests that had survived previous droughts saw as much as 90 percent pi?on mortality, a team of researchers led by University of Arizona ecologist Dave Breshears reported Monday in the Proceedings of the National Academy of Sciences.

“Across a whole landscape, this system got whacked,” Breshears said in a telephone interview.

Drought weakened the trees enough that bark beetles could kill them, but warmer temperatures appear to have played a key role, the scientists found.

The temperature difference? 1 to 2 degrees Fahrenheit above the long-term average? might not sound like much. But the scientists say it made the difference, leading to tree death in areas relatively unaffected by the drier drought of the 1950s.

“This is a different kind of response than we saw following the 1950s drought,” said Breshears, who has been studying pi?on woodlands since the 1980s. “This drought was hotter.”

Breshears, in an interview, was careful not to blame the 2002 die-off on human-caused global warming, saying no one event can be unequivocally linked to the planet’s long-term rising temperature trend.

But he said the dramatic drought-induced changes in the Southwest’s landscape since the turn of the 21st century are consistent with global climate change projections.

“We’re more likely to get more frequent, more intense droughts,” Breshears said.

For those of you not in the U.S. southwest, the pi?on/juniper woodland is a dominant middle-elevation forest type that was decimated a few years back – whole hillsides turned from their usual green to a frightening greyish brown. Like dwindling snowpacks, it’s a warming effect that you can see on the ground, now, but until Breshears et al. did this work, no one had established the link. It’s still a controversial link, as the comments from Julio Betancourt in my story suggest. (Betancourt, a terrific scientist who I respect on these issues and who probably knows the drought of the 1950s better than anyone, believes we don’t enough about 50’s dieoff to be sure the current dieoff is worse.) But caveats notwithstanding, it’s nevertheless important work of the sort that matters – climate science helping us understand impacts on the ground.