Felix a category 5

[Scott Alister McKinley]

Hello all,

I realize it's not news to anyone on the Gulf Coast that there is a
Category 5 hurricane in the Caribbean. I'm just writing to express my
amazement that _every_ freakin' storm that gets in those waters is
immediately jumping to Cat 5 overnight.

This brings up something I've been wanting to get off my chest about
how common sense repeatedly gets trumped in the national media
narrative by conservatives' rhetorical tricks.

I am certain that if we're lucky enough that nothing makes landfall in
populated areas this year, the industry currently devoted to denying
that global warming is having an impact on storms will point to this
as "evidence" that things are no worse than they used to be.

In a rhetorical slight of hand, I repeatedly see people make the
argument that *global warming does not cause more hurricanes.* This
is true in that the location and direction of these systems are
determined by the configuration of air masses which are thus far
largely unaffected by atmospheric temperature changes. Reporters
faithfully parrot this characterization of the argument, when in fact
the issue is that *warmer Gulf and Caribbean waters DO cause storms
that enter this region to be outrageously stronger than 20 years ago.*

As a gentle reminder, many Louisianans recall 1985: a "vintage" year
for Gulf hurricanes.
http://www.wunderground.com/hurricane/at1985.asp

And look at Danny in particular.
http://www.wunderground.com/hurricane/at19854.asp

I insist that a storm with this same path now would be devastating.
There's no way it would stay that long in the Gulf in August and not
blow up to be a huge event.

To read a more scientific account of the issue, check out Kerry
Emanuel's now-famous letter in Nature, released July 31, 2005, less
than a month before Katrina.

ftp://texmex.mit.edu/pub/emanuel/PAPERS/NATURE03906.pdf

By linking the paper above I do not mean to say the issue is resolved.
I just want to say, never let the bad guys set the terms of the
debate. There is no denying that Gulf Coasters are dodging
ever-more-dangerous bullets.

-- Scott

[Ben Tuminello]

I share Scott's frustration with the rhetorical gymnastics displayed so unabashedly by politicians of all parties, and I would agree that the conservatives seem to have a particular knack for them. 

But independent of the political fray, I'm having trouble getting behind Scott's take on this issue.

First of all, by "every_ freakin' storm" being a Cat 5, you mean the last two, because there haven't been any others this year, none last year, and there were only three in 2004, regarded as the most active season in history.  Then there was exactly one in the five years before that.

Secondly, Emanuel's letter states the 0.5 degree increase in tropical ocean temperature should account for only a 2-3% increase in average peak wind speed, or an 8-12% increase in the average storm's power dissipation index (PDI), a function of both wind intensity and size of storm.  The actually observed increase in the North Pacific over the past 30 years has been 75%.  Even considering the 10% rise of surface temps in the North Pacific without a correlating increase in atmospheric temps would put the expected increase in PDI at only 40%.  So at worst, the Republicans and their Global Warming Initiative would only account for a little over half of the increase in intensity of tropical cyclones as a whole.

So yes, warmer waters equal stronger and longer lasting storms.  But to point to Felix (now a Cat 4 storm by the way) and say, "Look, it's global warming," seems to me to be grossly oversimplifying a science for which we've only barely begun gathering data.

Incidentally, I read somewhere that climate shifts over long periods of time since the ice age have caused the average Earth atmospheric temps to fluctuate as much as five degrees.  This seems to call into question the notion that greenhouse gases are the primary cause of the much more subtle temperature changes observed since the beginning of the industrial age.  But I am not very well versed in the scientific arguments on either side of the issue, and searching on the internet in this case can make you go cross-eyed.  Can anybody recommend some good sources on the science of global warming?

Ben

[Louis Jeansonne]

Ben,

http://en.wikipedia.org/wiki/Image:GCM_temp_anomalies_3_2000.jpg

This is the graph that convinced me. It overlaps actual observed
temperature with computer models of what the temperature should be doing
based on increasing levels of CO2. Since these models are based on pure
math, not observed temperatures, the fact that they match up so closely with
observed temperatures is, I believe, very convincing. This is the best
counterargument to the argument (which I used to make) that this century's
increase could just be a tiny upward blip in the overall long-term trend.
Wikipedia has some great articles on this topic.

So the answers to the questions of whether global warming is happening and
whether it is due to increasing CO2 levels are both definitely "yes." I
think conservatives make a big mistake by trying to dispute this, since it's
a fairly easy scientific question, not a political one.

The next question is "are we the cause?" I think the answer to this
question is probably "yes" as well. We know atmospheric CO2 is increasing,
we know we release a lot of CO2, and we don't have another source to account
for it (volcanoes don't release more than we do, despite what Rush Limbaugh
says).

The final question is "what will the effect of the warming be?" This is
where liberals exaggerate like crazy. As far as I can tell, no one knows
for sure what the effect will be. I can understand the argument that we
should try to prevent it just in case the worst-case scenarios are right,
but to say that we know that catastrophic changes will happen is not
accurate.

If someone has good data to the contrary, I'd like to see it. I'll believe
whatever the data says, since, as I said, this is a purely scientific
question. But from what I've read, the specific predictions of the future
(other than temperature increases and some amount of rise in sea level) are
pure speculation.

Scott, I agree with Ben that you can't just say "hey, seems like we've had
some bad hurricanes, must be global warming." Has there been an actual
statistically significant increase in the strength or number of hurricanes?
This is a very eqsy question to answer, although I don't know what that
answer is. Even if the answer is yes, you can't automatically attribute it
to global warming in the absence of a good model, since hurricane experts
expect that there will be cycles of good and bad hurricane seasons.