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.'"

This isn't Global Warming

[rapierian]

The Earth is getting warmer currently, but the primary cause of increased ocean temperatures in the atlantic is from the fact that we're entering the warm part of the 50 year cycle. If you want a very good write up of the study check out this:

http://www.tcsdaily.com/article.aspx?id=031606F [tcsdaily.com]

Re:Um. . .Duh?

[Anonymous Coward]

There were similar numbers of hurricanes in the decade of the 1890s, even though the global temperature was about 1 deg F cooler.

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 [maine.edu]

Re:I don't understand...

[Anonymous Coward]

Hogshead is a measure of volume not temperature. If you are talking about volume of water large quantities are traditionally measured in acre feet. None of these measuring systems are really adequate to calculate ocean volumes. A more important number would be how much energy it takes to raise that much surface water by one degree. That would give you some idea how much energy was being added to the hurricanes. One degree doesn't sound like much until you take into account the volume of water involved. I doubt the entire United States uses that much energy in a year and I'm just figuring the Atlantic not all the world's oceans.

Known vs. known to idiots

[CarpetShark]

Well, it was obvious to some of us. But most people are in denial about this stuff. Hell, most people haven't admitted global warming is a problem yet, due to greed or stupidity or plain old laziness, or probably a hundred other reasons.

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:Normal Cycle

[Anonymous Coward]

Remember, polar air is moving about 0 mph at the exact North pole, but will have to be accelerated to ( circumference of the earth/24 hours )MPH as it goes to the equator. We have a significant coriolis effect here.

I want whatever you're smoking. Polar wind is 0mph at the north pole? Huh? And the air molecules up there somehow get accelerated towards the equator? Double huh?

Re:Um. . .Duh?

[Red Jesus]

The sun has gotten brighter and in particularly it has also been much more electrically active in the last few years. There were 2 massive solar flares only a few days before Hurricans Katriana and Rita flared up. Wilma has a strong match to several solar flares.

Pardon? Solar flares? What's this "match" you're talking about? I can understand how human-generated carbon dioxide can trap heat in the atmosphere -- we've established the greenhouse effect. I can also understand how warmer water makes more intense hurricanes, given that hurricanes form as a result of moist air rising over the ocean. These results match the rest of science. But solar flares?

Lomnicky Coronal Index [noaa.gov]

Accumulated Cyclone Energy Chart [wikipedia.org]

The first chart isn't exactly solar flares... It's more along the lines of sunspots because I couldn't find a good solar flare chart. But at first glance, I don't really see the correlation. Maybe I'm looking at the wrong charts and maybe I'm not looking closely enough at the charts I have, but I think the warm ocean theory matches the data better than the solar flare theory.

RJ

Re:Kyoto

[Lars T.]

The Kyoto Protocol always was and always will be useless.

Yes - thanks to the watering down the US demanded.

Re:Um. . .Duh?

[Coryoth]

"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."

Simple math shows that we are over 75%, rather than "half way up" and so we also should be 75%+ up on the storms.

I don't know exactly how you did your math - perhaps a little too "simply", but my rough calculations run like this:

Peaks are at 1950 and 2025 with 75 years between the peaks. Assuming the cycle is roughly symmetric the trough - low point of the cycle - should occur half way between in 1987. Half way up the next peak is half way between 1987 (the trough) and 2025 (the next peak). That works out to be ... 2006.

We are 75% of the way through the cycle, but a cycle has troughs as well as peaks.

Jedidiah.

Re:Known vs. known to idiots

[ElectricRook]

Most of us with some years behind us, have seen worse environmental scares than this. In the 70's we were running out of oxygen don't you know that we will be dying off in the millions of low oxygen levels predicted to occur in the late 90's. Of course, this was going occur before the comming ice age. Yes, we were warned of the ice age, and the big crash too. No, not the stock market crash, but a meteor was going to smack the earth. Oh yes, I forgot about running out of food too. Yes, us old-timers have seen lots of disasters on a global scale. That all never seemed to materialized after the book sales slumped. This is just the next round, and we are hardened by the frights of the past.

Comment removed

[account_deleted]

Comment removed based on user account deletion

Re:Um. . .Duh?

[2marcus]

2) Direct CO2 forcing is responsible for 9 to 26% of radiative forcing depending on how you do your calculations (realclimate calculations [realclimate.org])

Warming due to CO2 will also lead to more water vapor in the atmosphere in a positive feedback.

3) I have no idea where you are getting your numbers. Please cite some sources? Again, realclimate [realclimate.org] has reprinted a figure showing 6 different temperature reconstructions of the past 1000 years. None of them have medieval warm periods that are even as warm as today's temperatures, much less your absolutely ridiculous 2 degree C number.

Finally: Yes, historically CO2 has not been the prime mover in Ice Age oscillations - that would be orbital variations (Milankovitch cycles). However, given that the forcing changes due to orbital wobbling are small, most paleoclimatologists believe that there was a nice positive feedback loop: slight warming leads to CO2 outgassing leads to more warming leads to ice sheet retreat leads to more warming leads to more CO2 leads to... you get the picture. And our evidence for the CO2-warming link is not just "mere correlation" - there is significant science that goes into measuring all sorts of forcing agents from volcanoes to aerosols to GHGs to solar variations - and studies using these forcings find it very, very hard to explain the last 40 years of warming without taking into account anthropogenic GHG changes.

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 [noaa.gov] 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." [confex.com]

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

Re:A meteorologist replies

[Burz]

Statistical models (used by climatologists) are bound to increase in accuracy as they deal with average temperature of the entire globe over larger time scales.

This is not about determining whether it will snow or rain in Peoria on Dec. 11, 2006.

Some links that may interest you:
http://www.guardian.co.uk/climatechange/story/0,,1 517946,00.html [guardian.co.uk]
http://www.begbroke.ox.ac.uk/climatebasics/?style= plain [ox.ac.uk]
http://www.realclimate.org/index.php?p=270 [realclimate.org]