Skepticism regarding Katrina/Climate Change link?

[sprunch]

I'm doing a presentation with a group on scientific evidence that suggests there is no correlation between Katrina (or the increased frequency/strength of hurricanes and tropicals storms) and global climate change for my Economics of the Environment course.

If anyone has any scientific sources that have evidence suggesting this, please let me know.

[LJP07]

Originally Posted by sprunch

scientific evidence that suggests there is no correlation between Katrina and global climate change

If anyone has any scientific sources that have evidence suggesting this,

The question is, Is there any sources/evidence that supports this?

[Zythryn]

From what I have read, there is no clear link between global warming and the number of hurricanes. However, there are some studies that draw a correlation between the water temperature and the strength of hurricanes.
Most likely it came from Scientific American, the journal Science or the journal Nature. I will see what I can dig up for references.

[Zythryn]

Fascinating! I love good questions like this as they inspire me to do more research.

All right, this is only one site, but it looks very well documented. The summary is that, for a number of reasons, our measurements are inconclusive and can't really show any trends one way or another.

The models (which have a high level of uncertainty) seem to indicate that as the sea level temperature increases, we will actually have slightly FEWER hurricanes, however the ones we get will be slightly stronger.

I'm going to read more in depth, the site I found is Global Warming and Hurricanes

[CraigD]

Originally Posted by sprunch

scientific evidence that suggests there is no correlation between Katrina (or the increased frequency/strength of hurricanes and tropicals storms) and global climate change

Originally Posted by LJP07

The question is, Is there any sources/evidence that supports this?

I agree with LJP07. Scientifically, the correct approach is to suggest climate/weather models in which a particular climate change, such as the best current predictions for atmospheric and ocean warming and current changes causes a change in hurricane formation and behavior, then assign estimated probabilities to your model’s assumptions, and those of the models it relies upon. Such a project seems an ambitious scientific undertaking.

Locating and interpreting information about an existing project in progress or completed, would still entail some effort, but, as sprunch appears already to have concluded, is likely more appropriate for a class assigned presentation. I’ll keep my eyes open for such info, as I’m sure will many interested hypographers, and bring back any useful info to this thread.

In the meanwhile, I think it’s helpful and interesting to take a high-level look at a climate/weather model for predicting changes in hurricane patterns.

According to the wikipedia article “Tropical_cyclogenesis”, several factors are believed to effect hurricane formation. Of these, two seem related to global temperature trends: surface ocean water temperature; and surface atmosphere humidity. Looking a little more deeply (and making a few guesses), we can see that this first factor, ocean temperature, is a heat engine factor – what’s really required is a large difference in temperature between the ocean and the air coming into contact with it, allowing heat from the ocean to transfer to the air, producing a strong convection updraft. With this in mind, we can imagine models in which global temperature increases effecting the air more than the ocean might actually reduce the likelihood and strength of hurricanes.

Clearly, a climate/hurricane model is a complicated thing, involving not only the Earths total amounts of heat, but the location and distribution of it.

My guess is that weather models that predict and increase in hurricanes as a result of increased worldwide heat do so based on predictions that this increase will cause melting of polar and glacial ice, resulting in cold, fresh water runoff into the oceans, resulting in changes in ocean currents, resulting in concentration of warm water near the ITCZ “sweet spot” for hurricane formation. Very simplified, more ocean heat in these zones should result in more and stronger hurricanes.

Sprunch mentioned that his research is for an Economics course. As such, a good approach to it might be risk assessment. In this approach, one proposes several alternatives outcomes (eg: greatly increased hurricanes, slightly increased hurricanes, little/no/decreased hurricanes), assigns probabilities to them, assigns monetary costs to them (how much damage would they cause) to arrive at a recommended amount of money that should be spent to prevent or prepare for them, Because an outcome in which hurricanes increase greatly is very costly, even if its probability is very low, one can still justify spending substantial money on prevention and preparation. As increasingly good scientific models allow better probabilities to be assigned to various outcomes, the goodness of this approach increases.

What should, IMHO, be strongly avoided, is an effort to use scientific data to reach a conclusion in which one outcomes’ probability is prematurely and inaccurately assigned a value of 1 – that is, inappropriately changed from an alternative to a presumed certainty. The instruction to find “scientific evidence that suggests there is no correlation between Katrina and global climate change” arouses suspicion in me that it is an invitation to such an effort. “Scientific evidence” is not a commodity to be used to produce false certainty. Science works best when it is mindful of the uncertainty of its predictions, informing scientists and the public of possibilities, not certainties.