Warmer Oceans linked to Stronger Hurricanes

linguizic writes "According to Scientific American, global warming could be creating stronger hurricanes: 'Since the 1970s, ocean surface temperatures around the globe have been on the rise--from one half to one degree Fahrenheit, depending on the region. Last summer, two studies linked this temperature rise to stronger and more frequent hurricanes. Skeptics called other factors into account, such as natural variability, but a new statistical analysis shows that only this sea surface temperature increase explains this trend.'"

Comments

This can't be true

[Anonymous Coward]

Global warming is a Liberal Myth. Rush and Sean said so!

Um. . .Duh?

[Limburgher]

Didn't we already know this? Was it a total mystery that having a patch of water over which hurricanes generate, say, the Gulf of Mexico, will serve to strengthen them? Was it a total mystery that climate change might bring about nasty consequences?

Ok, well, for some people it was. :)

Re:Um. . .Duh?

[GooglePlexity]

and even if global warming was not mainly caused by human activity, that doesn't mean we shouldn't do everything possible to slow its rate.

Re:Um. . .Duh?

[Coryoth]

There is extremely good evidence that the process is substantially if not entirely natural.

And in practice there is a lot more damning evidence that a significant portion of the warming is anthropogenic. Here's a rief summary of some of the most quickly explained information:

Atmospheric carbox dioxide correlates very well with temperature. We know this by many methods, but the one with the longest historical record is that of ice-cores, which provide data on historical CO2 levels and historical temperature going back 650,000 years. Over that time span there is an extremely close correlation of atmospheric carbon dioxide and temperature.

More recently there is, again, very good correlation between the recent rapid (and accelerating) rise in temperature and recent rises in the levels of atmospheric carbon dioxide. By recent I mean the last 150 years or so.

Correlation, of course, does not prove causation. However we know from completely independent study that, based on its absorption spectra, atmospheric carbon dioxide will tend to trap heat. We therefore not only have very powerful correlations, we also have very good reasons to expect and anticipcate causation.

Further studies of the change in ratio of different carbon isotopes in atmospheric carbon dioxide shows that the recent (last 150 years) spike in carbon dioxide is almost entirely caused by humans.

Based on all of that we would certainly expect human carbox dioxide emissions to be a factor in recent global temperature increases. When models attempting to predict the rise based on historical data are run the expected warming trend is remarkably well accounted for.

The sun has gotten brighter and in particularly it has also been much more electrically active in the last few years.

Solar variation gets brought up often, and certainly there is solar variation and we can expect it to have some impact on global temperatures. The observed solar variation alone is, however, not sufficient to properly account for the observed warming. The IPCC claims that around 30% of the observed warming can be accounted for by solar variation, but the remaining warming is almost entirely accounted for by human factors, particularly human CO2 (and other greenhouse gas) emissions. So yes, solar variation most certainly matters. To the best of our knowledge however solar variation is not the primary factor - anthropogenic factors are.

Jedidiah.

Re:Um. . .Duh?

[codguy]

The fact of Global Warming isn't really in question.

Let me applaud you on getting this correct because some still deny it is even occurring.

There is extremely good evidence that the process is substantially if not entirely natural.

But I won't let you get away with this because it is simply incorrect. The vast majority of the scientific community that has studied this has reached the conclusion that it is related to human activity. Even George W. Bush finally admitted before the start of the G8 summit last year that global warming was linked to human activity.

Science, not just climate science, is overall a very conservative discipline. For the majority of the scientific community to have arrived at the conclusion that our planet is warming related to anthropogenic activity is not simply because a couple of scientists or even hundreds or thousands of scientists have said so. It is because an overwhelming amount of evidence from every corner of the globe has led them to this conclusion.

Yes, there are still some climate scientists, by far a small minority, that still claim that either global warming is not occurring, or if so, it is not related to human activity. That's ok, that's part of the scientific process, and everybody has a different understanding of reasonable doubt. But as evidence continues to pour in day after day from around the globe, I think eventually even that small majority will have a change of opinion.

Re:Wouldn't it be nice?

[saforrest]

It sure would be nice if people could discuss science and not politics, especially for something so important. But I'm not holding my breath.

Uh, is climate change not a political issue? Should we avoid political discussions whenever an issue is "important"? Seems like a strange idea to me.

I think what you mean to say is that we should avoid political discussions that consist of braindead mudslinging (e.g. "Everyone who drives a car is a guilty of ecological genocide!", "If you criticize car culture, you're with the terrorists", etc., etc.).

Re:This isn't Global Warming

[linguizic]

Quote from the SciAm article: "Her team will now focus on clarifying the mechanisms at work in the North Atlantic by separating out the 75-year natural cycle and climate change. "The last peak was in 1950, the next is in 2025," she adds. "We're only halfway up [the cycle] and we're already 50 percent worse [in terms of storms]. To me, that's a compelling issue that needs to be confronted." Though no one can yet claim that the 75 year cycle isn't responsible for Katrina et al, Dr. Curry there seems to think that this new data presents the possibillity that Katrina et al cannot be explained by the Atlantic cycle.

Re:Uh, isn't this obvious?

[SLOJava]

Interesting theory, especially since the viscosity of sea water *decreases* with temperature. See: http://www.marine.maine.edu/~jumars/classes/SMS_48 1/Viscosity.pdf

A meteorologist replies

[ctwxman]

OK - this is what I do for a living - forecasting the weather. I've been doing it for better than 25 years.

Most operational meteorologists I know feel human induced global warming is a bad theory, based on really bad modeling. The equations are incomplete as is the data set. Maybe we're worried because we use numeric weather prediction models on a daily basis and understand we can't always get the temperature right to within 2-3 degree over 24 hours, much less 24 years!

Academicians and theorists seem to support the idea in great numbers. These are people who haven't had to answer for a bad forecast in the supermarket.

Surely, human induced global warming is a political argument. Ask yourself, why have I never heard even one positive influence from global warming? In science, you should hear the good and the bad. In this argument, it's only the bad that gets publicized. If everyone in the Northern Plains, Northern Europe, New England, Canada and other cold weather climates get a longer growing season with lower winter heating costs, shouldn't that be weighed against tidal rises on Vanuatu?

Recently, after Katrina and the others, there has been a chorus trying to connect more hurricanes with global warming. Here's what Dr. William Gray says (he's the guy you hear quoted every year with seasonal hurricane predictions):

There is absolutely no solid evidence that the recent US hurricane disasters of 2004-05 and of Japan in 2004 are 'directly' attributed to the impact of global warming. Landfalling major hurricanes have occurred in earlier periods when the globe was cooler. The two scientific papers in Nature and Science have been largely discredited by myself and others.

Most of the warming of the last 30 years (1975-2005) cannot possibly be due solely to greenhouse gas increases. Although CO2 amounts have gone up by about 378 ppm/330 ppm = ~15% during this period, the net energy forcing (of about 0.65 w/m2) from this CO2 increase is considerably less than the other energy forcing changes of long wave radiation (LW), evaporation-precipitation, and ocean thermohaline circulation change that have been measured by the reanalysis data over the last 30 and 55 years. For instance, various rainfall measurements indicate there has been a small global average rainfall decrease of 0.5-1.0 mm/d. This is equivalent to global evaporation decreases of 1.5-3.0 w/m2 - 2 to 4 times than that can be attributed to CO2 increase. There are similar energy variations in the last 30 years in OLR and in the global thermohaline circulation. I believe that the global surface warming of the last 30 years is largely due to a small decrease in ocean surface evaporation cooling brought about by ocean deep water circulation changes.

Blaming all the warming of the last 30 years on CO2 requires that one believe that all the other larger energy source-sinks sum to zero. It is naive to think this is the case. Most warming of the last 30 years has to be of natural origin.

You can read more of Dr. Gray's thoughts in this excellent paper "Global Warming and Hurricanes."

I have posted this late. Positive modding to make it more visible would be appreciated.