The Super-Hot Atlantic

By Chris Mooney | July 13, 2010 7:58 am

atlanticsst_ams_2010152-415pxAnd no, I don’t mean sexy.

This is a NASA image from the start of hurricane season, showing the sea surface temperatures in the tropical Atlantic and especially in the main hurricane development region.

I got the image from this great analysis over at the WWF Climate Blog, which is mainly devoted to summarizing a recent congressional briefing on why we very likely have a really bad hurricane year to look forward to.

Some observations that emerged from that meeting:

* We’ve never had a pre-season forecast of 23 storms before. Let’s hope that is an overshot, rather than an undershot.

* The Atlantic is even hotter than it was before the devastating 2005 hurricane season.

* Oh yeah, and there’s oil out there. (The title of the briefing was “Hurricanes and Oil Will Mix: Managing Risk Now.”)

How much of the Atlantic’s current, alarming temperature has to do with global warming? Well, listen to Greg Holland of the National Center for Atmospheric Research:

When asked about the degree to which rising greenhouse gas (GHG) concentrations in the atmosphere were contributing to the trend of rising  sea surface temperatures in the tropical Atlantic Ocean, Holland said the temperatures could not be explained without accounting for rising GHG concentrations.  He said that while some researchers thought the rising GHG levels might account for 60-80% of the temperature anomaly, he estimated that about half was due to rising GHGs.

I get the feeling we may have a summer for climate change coming, just as 2005 was, and just as 1988 was.

Comments (20)

  1. To put in another way, warmer oceans are like adding red bull to the season’s storms.

  2. ChrisD

    Chris, in the last sentence do you mean 1998 rather than 1988?

  3. FergalR

    Florida State University has a great site for current info on tropical storms:

    http://www.coaps.fsu.edu/~maue/tropical/

  4. Chris Mooney

    no i most emphatically mean 1988…

  5. Alex, for being “only” a CAT-2, was massive in terms of size, with it affecting pretty much the whole gulf with rain bands. Also, it’s central pressure was equivalent to a strong CAT 3. This does not bode well.

  6. CW

    Just to clarify – in many climate change discussions, is it predicted that climate change will only intensify storms, or both increase the frequency and intensity of storms?

  7. ChrisD

    no i most emphatically mean 1988…

    OK, so you’re not just talking about weather in this comparison.

    You’re talking about the overall prominence of climate change in the national discussion, as in “The Hansen Summer” and “The Hurricane Summer”.

  8. Chris Mooney

    ChrisD–yes.

    CW–at this point, I think it is really more intensify. frequency may decrease in some places, I believe, but I haven’t followed the science closely in the past year or more.

    Richard–Alex really, really got my attention too.

  9. Did you have some sort of personal experience in 1988? The year doesn’t stand out in the graph of number of storms (found at the bottom of this page):

    http://en.wikipedia.org/wiki/List_of_Atlantic_hurricane_seasons

    1995 looks like it was a bigger season.

  10. Chris Mooney

    1988 was the year that put global warming on the map. It wasn’t the most dramatic hurricane year ever but it had some hurricane drama.

    2005 was another year that caused global warming to get dramatic new levels of attention and concern. This was directly tied to Katrina.

    Needless to say both of these things were summer/very early fall phenomena due to temperatures.

    I’m saying, 2010 might be a 1988 or a 2005 in this sense.

  11. ChrisD

    @Tom Hill:

    Prior to 1988, there was a fair amount of science that said, “Global warming is coming, at some point.”

    1988 was the year Jim Hansen told Congress, “Global warming is here. Now.”

    It got everyone’s attention, whether they agreed with him or not.

  12. Nullius in Verba

    From your Greg Holland quote:

    “When asked about the degree to which rising greenhouse gas (GHG) concentrations in the atmosphere were contributing to the trend of rising sea surface temperatures…”

    One year does not constitute a trend. Weather is not climate. The Atlantic’s current temperature cannot be connected to global warming. Individual hurricanes, such as Katrina, cannot be associated with changing climate. More of that misleading scientific journalism…

    Incidentally, the climate models predict strongly increased Western Pacific tropical cyclones, but a slight decrease of activity in the Atlantic, due to increased vertical wind shear. (Vecchi and Soden, 2007.) If you’re inclined to believe the models, this is what 18 of the IPCC’s favourite ones said.

  13. George

    Fairly common for a la nina year for the Atlantic to warm up. Global SSTs are actually falling, though and at a fairly significant pace. But this is not going to be any 2005, that’s for sure. By this date in 2005 we were already up to the fifth named storm (Emily on July 11) and Franklin would form on July 18. So far this year we have seen one Atlantic named storm and there is currently no tropical weather activity in the Atlantic at all. In fact, a few days ago we had an interesting day with absolutely no tropical weather activity anywhere on the planet.

    This looks to be a rather strong La Nina event considering how rapidly the equatorial sea temperatures are falling in the Pacific.

  14. David

    Chris:

    Just a minor quibble. According to the NASA page, the image is not the surface anomaly. It is the sea surface temperatures on June 1, 2010.

    The anomalies image was the ugly, blocky one below it on the WWF page.

  15. Chris Mooney

    My bad. I will fix that.

  16. Michael

    There is a good side to the horrible devastation of the oil in the gulf: Hurricanes are fueled by evaporation, and an oil slick will reduce evaporation.

  17. David

    Michael:

    No, it doesn’t work that way. The amount of oil is not enough to change evaporation rates and also evaporation cools. It is heat that drives hurricanes. If it were enough coverage to change the weather, it would potentially make it even worse than it already is. The heat would build up even more than normal and put much more energy into the system. Even with millions of gallons of oil, it is a really big ocean.

    Thankfully we only have to worry about the toxic chemicals and the oil sticking to everything and smothering or drowning it. Isn’t that a relief?

  18. Here’s one way to think about the science of predicting AGW’s effects on hurricanes:

    Hurricanes are not supposed to happen. The distribution of equatorial heat towards the poles in water (the ocean) and air should be smoother and more efficient-looking than it is. But these pesky continents, embayments, funny ocean basin shapes, mountains, etc. cause glitches.

    Compare a set of Pacific hurricane tracks with Atlantic hurricane tracts, and in the Atlantic compare the northern hurricane season (summer/fall) with the southern hurricane season (the opposite time of year, but south of the equator). You’ll find that it is all rather mixed up. For instance, there IS NOT southern Atlantic season. The North Atlantic season happens because of the nature of the ocean basins and land masses. The Pacific and Atlantic hurricane patterns are very different, again, owing to the distribution of basins and continents.

    Asking “will higher SST in the Gulf and at the tropical convergence zone in the Atlantic cause bigger or more hurricanes or both?” is like asking “will an increase in poverty cause more robberies or bigger robberies or both?”

    Hurricanes are weird, quirky aberrant events.

    My guess is the following: The ramp-up to sea surface conditions conducive to transforming tropical waves into hurricanes after a storm has already dissipated that energy may end up being the key. But how much/quickly re-conditioning of the sea surface happens can cause bigger hurricanes if the reconditioning happens long before the next wave comes along, or it can cause more hurricanes if it happens such that more waves get transformed. That’s an oversimplified view, but it does suggest that in the absence of some kind of syncrhony between re-heating the Atlantic and Gulf surface waters and tropical waves, that some years we’d have a shitload of hurricanes of average to low intensity, and other years we’d have a few whopping big ones, depending on that timing, which probably can’t be easily predicted.

  19. Chris, I know from your book that you understand the scientific debate between tropical cyclone researchers who suggest examining year-to-year variability in the long-term record and those that believe secular SST increases are responsible for the Atlantic hurricane activity oscillations.

    I favor the former approach while not discounting the effects of SST increases due to GHG. Indeed, if you examine tropical cyclone ACE (analogous to Dr. Kerry Emanuel’s PDI) for the globe during the past 30-years, you see that there are huge swings up and down depending upon the phase of the PDO and ENSO in the Pacific Ocean. For the past 3-years, global ACE has fallen to record-low levels, where it sits currently today. While it is certainly possible that the Atlantic basin in the most susceptible or sensitive to global warming ocean temperature increases, it is instructive to see that the rest of the globe is NOT. This is in agreement with the new Knutson et al. (2010) consensus, which is cherry-picked by Dr. Holland in an egregious manner to tell the opposite story.

  20. Windy City Kid

    “This is in agreement with the new Knutson et al. (2010) consensus, which is cherry-picked by Dr. Holland in an egregious manner to tell the opposite story.”

    Maybe Chris could follow up with Dr. Holland as to why Dr. Holland would cherry-pick and twist Knutson et al. consensus findings. NOAA also provides a summary of the “Consensus Statements by International Workshop on Tropical Cyclones-VI (IWTC-VI) Participants” which highlights the following:

    1. Though there is evidence both for and against the existence of a detectable anthropogenic signal in the tropical cyclone climate record to date, no firm conclusion can be made on this point.
    2. No individual tropical cyclone can be directly attributed to climate change.
    3. The recent increase in societal impact from tropical cyclones has largely been caused by rising concentrations of population and infrastructure in coastal regions.

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About Chris Mooney

Chris is a science and political journalist and commentator and the author of three books, including the New York Times bestselling The Republican War on Science--dubbed "a landmark in contemporary political reporting" by Salon.com and a "well-researched, closely argued and amply referenced indictment of the right wing's assault on science and scientists" by Scientific American--Storm World, and Unscientific America: How Scientific Illiteracy Threatens Our Future, co-authored by Sheril Kirshenbaum. They also write "The Intersection" blog together for Discover blogs. For a longer bio and contact information, see here.

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