It is time to stop quivering in our boots in pointless fear of the future and just roll up our sleeves and build it.
- Ray Pierrehumbert

Wednesday, June 6, 2007

tropical storms and extreme climate change

Matt Huber and his student Ryan Sriver are onto some interesting ideas about tropical storms to say the least. Following on some ideas of Kerry Emanuel's they are arguing that there are no ifs or buts about it. If their argument, which looks pretty solid to me, is correct, increased tropical cyclone activity is inevitable in a warming scenario. If you have access to the May 31 issue of Nature you can look up the original article.

Matt also points me to this nice summary of the PETM climate crisis of 55 million years ago, including some of the implications of his work, so I thought I'd share.

6 comments:

Steve Bloom said...

My first thought upon reading Kevin Trenberth's hurricane post over at the new Nature climate blog is that in a sufficiently warm climate the Iberian Peninsula should get pretty well hammered. I wonder if anyone has looked for sediment evidence there for the more recent and much more extensive warmish periods?

A related question is what will happen to EPac hurricane tracks in a substantially warmer climate. Right now they very rarely get to L.A., but has anyone looked for evidence of past more northerly strikes?

Michael Tobis said...

I don't have specific answers about specific regions, and I doubt anyone else does either as yet.

It's conceivable to me that evidence of landfalling hurricanes might be hard to come by in some locations. That is, the record may be unclear.

Huber's ingenious approach looks at the global scale rather than at the local scale.

To me, the Brazil hurricane of a few years back and the Oman hurricane this week are at least anecdotal support for the idea that the range of tropical storms might increase. I don't know of any strong dynamical or paleoclimatological arguments that this will or won't happen, though.

It's entirely possible that hurricanes in some existing tropical storm region, for instance, North Atlantic hurricanes, will decline. There are regional controls emerging from the large scale flow (wind shear, specifically) that may consistently shift to protect some region or another. What Huber is saying is about the global total, which must go up to maintain an energy balance.

The news here is that tropical storms aren't just freaks of nature, but an important intrinsic part of the heat engine that maintains the climate system.

SCM said...

From New Scientist - a pointer to new research indicating that the increase in tropical storms seen thus far is within past variability as measured from coral cores.

Of course this doesn't invalidate the idea that warming will cause more storms, just that we can't be sure we've seen any evidence of it yet.

Coral reveals increased hurricanes may be the norm

The recent increase in the number of major Atlantic hurricanes may just be a return to the norm after a period of unusually low storm frequency, say researchers.

Johan Nyberg of the Geological Survey of Sweden and colleagues used marine sediment cores of coral samples from the northeast Caribbean to build a proxy record of wind shear and sea-surface temperatures since 1730, and from this they estimated hurricane activity since that time....

Michael Tobis said...

matthew huber in response to this blog entry:

"cool... btw, in response to the question there is a paper exactly on a hurricane record at the petm in spain by birger schmit.came out in the past year."

Steve Bloom said...

The Schmitz paper is here. Although it doesn't make a direct claim about tropical cyclones, I expect it's the case that it would be hard to get that kind of precipitation increase without them.

Regarding possible proxy records of TCs in more recent pre-Pleistocene warm climates, off-hand I can't think of any candidate lakes in SoCal. OTOH it's early days for this sort of study and perhaps there are other proxies that could be used. IIRC, e.g., there was a recent paper that used stalagmites from Puerto Rico.

Steve Bloom said...

Speaking of climate disasters, I thought this recent research was absolutely fascinating (to say nothing of scary). Considering how recent this event was and what a repeat of it would do to the U.S., I'm surprised it's gotten little or no press coverage. It seems like a tremendous paleo-modeling opportunity. (Also, have a look at the single comment to the linked post. It's a perfect illustration of a very common kind of denialism.)