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What's Causing The Hurricanes? (yahoo.com)

An anonymous reader quotes AFP: Hurricane Irma, now taking aim at Florida, has stunned experts with its sheer size and strength, churning across the ocean with sustained Category 5 winds of 183 miles per hour (295 kilometers per hour) for more than 33 hours, making it the longest-lasting, top-intensity cyclone ever recorded. Meanwhile Jose, a Category 4 on the Saffir Simpson scale of 1 to 5, is fast on the heels of Irma, pummeling the Caribbean for the second time in the span of a few days. Many have wondered what is contributing to the power and frequency of these extreme storms. "Atlantic hurricane seasons over the years have been shaped by many complex factors," said Jim Kossin, a NOAA hurricane scientist at the University of Wisconsin. "Those include large scale ocean currents, air pollution -- which tends to cool the ocean down -- and climate change"...

Some think a surge in industrial pollution after World War II may have produced more pollutant particles that blocked the Sun's energy and exerted a cooling effect on the oceans. "The pollution reduced a lot of hurricane activity," said Gabriel Vecchi, professor of geosciences at Princeton University's Environmental Institute. Pollution began to wane in the 1980s due to regulations such as the Clean Air Act, allowing more of the Sun's rays to penetrate the ocean and provide warming fuel for storms. Vecchi said the "big debate" among scientists is over which plays a larger role -- variations in ocean currents or pollution cuts. There is evidence for both, but there isn't enough data to answer a key question...

The burning of fossil fuels, which spew greenhouse gases into the atmosphere and warm the Earth, can also be linked to a rise in extreme storms in recent years. Warmer ocean temperatures yield more moisture, more rainfall, and greater intensity storms. "It is not a coincidence that we're seeing more devastating hurricanes," climatologist Michael Mann of Penn State University told AFP in an email. "Over the past few years, as global sea surface temperatures have been the warmest on record, we've seen the strongest hurricanes -- as measured by peak sustained winds -- globally, in both Southern and Northern Hemisphere, in both Pacific and now, with Irma, the open Atlantic," he added. "The impacts of climate change are no longer subtle. We're seeing them play out in real time, and the past two weeks have been a sadly vivid example."

15 of 442 comments (clear)

  1. Man made climate change.... by Anonymous Coward · · Score: 2, Informative

    for the feeble minded.

  2. Re:Why even bother quoting Michael Mann? by Anonymous Coward · · Score: 2, Informative

    Thoroughly debunked by the distinguished scientists at Mark Steyn Enterprises? We should all be so lucky.

  3. El Nino by Dripdry · · Score: 2, Informative

    Apparently it's actually due to the lack of an El Nino. The formation of the hurricane started 6 months ago and grew be because there wasn't a lot of wind sheer to stop it from forming. Maybe the better question is why wasn't there an El Nino?

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    1. Re:El Nino by mikael · · Score: 3, Informative

      Because El Nino / El Nina is a long-term oscillationg due to a build up of heat in the Pacific. A lot of these ocean and air currents operate like air conditioner thermostats. When heat builds up, ocean and air currents start gaining speed. Eventually they start cooling the water faster than it gains heat, then the currents slow down. Then the heat builds up again. This can take a decade to complete one cycle.

      The Sun is delivering 2 kilowatts of energy onto every square meter of the ocean every hour.

      --
      Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
  4. Re:Reversion to the mean by Maxo-Texas · · Score: 3, Informative

    Thank you for highlighting the issue.

    without a LANDFALL.

    The number of atlantic tropical storms and hurricanes is increasing very obviously just by eyeballing the charts at this point.

    The crap shoot is whether we have a weak or strong high over the northern atlantic. If it's strong, they land- if it's weak they don't.

    Likewise, it depends on whether El Nino is going- because it weakens hurricanes.

    Trust me , we had plenty of AGW foes posting about every year of the lack of landfalls.

    Tropical storm + hurricane graph (not just landfalls) here.
    http://policlimate.com/tropica...
    The cycle is obvious- but so is the trend. More tropical storms. More severe hurricanes.

    --
    She was like chocolate when she drank... semi-sweet at first and then increasingly bitter.
  5. Global warming and Atlantic hurricanes by Anonymous Coward · · Score: 5, Informative

    The problem with linking global warming to Atlantic hurricanes is that hurricane activity isn't necessarily predicted to increase in the Atlantic from global warming. In the north Pacific, sea surface temperatures will warm and vertical wind shear is predicted to weaken. This favors an increase in hurricane activity in the north Pacific. While the water in the north Atlantic basin is predicted to get warmer due to global warming, vertical wind shear is expected to increase. It's not entirely clear which of these opposing factors will have the greater impact, so it's not certain that hurricane activity will increase in the north Atlantic.

    There is a naturally occurring wave called the Madden Julian Oscillation (MJO) that can either enhance or suppress tropical convection. The phase of the MJO has likely helped to enhance Harvey, Irma, Jose, and perhaps even Katia. La Nina also enhances convection in the north Atlantic basin, generally results in a moister atmosphere, and weakens the vertical wind shear. All of these are favorable for hurricane activity. It's also the peak of the Atlantic hurricane season, when the waters are warm and vertical wind shear is still rather weak.

    The main reason Harvey produced so much rain over Texas and Louisiana was that it sat over that area for several days. It's not that the rain rates were souch more extreme, but that it just sat over the same area. While rain rates might be enhanced a little due to global warming, the main reason Harvey was so extreme was because it was almost stationary for days. That is not a consequence of global warming, just an unusual weather event.

    I also tend to view Irma and Jose as another unusual weather event, but not necessarily linked to global warming. It just doesn't match up with the predictions for the north Atlantic, and so I hesitate to blame global warming for those storms. It's possible that when the shear abates due to the weather, warmer water might result in stronger Atlantic hurricanes at those times. However, the overall increased shear will likely limit hurricane activity more at other times. One hypothesis is that global warming might result in fewer Atlantic hurricanes, but the storms that do occur will tend to be stronger. I understand the logic of that, but I'm just not convinced that Irma and Jose are significantly linked to global warming. There just isn't enough scientific evidence to support that link.

    1. Re: Global warming and Atlantic hurricanes by Anonymous Coward · · Score: 2, Informative

      How is my post a conspiracy theory? Do tell.

      It's not clear that Atlantic tropical cyclone activity should increase as a result of global warming. That's not a conspiracy theory. It reflects the current state of climate science, based on NOAA research that has been included in recent IPCC assessment reports. In fact, here are some links to information about it:

      https://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-5-3-6.html
      https://www.gfdl.noaa.gov/global-warming-and-21st-century-hurricanes/

      I didn't readily find a link to the IPCC AR5, but the AR4 is still credible science. And the NOAA link has been updated within the past year, so it reflects the current state of the science.

      Climate predictions are done on a regional basis with climate models. They're integrated forward just like weather prediction models, just over much longer periods of time. While it definitely isn't possible to predict the weather on a day to day basis beyond a week or, perhaps at most, three weeks (the theoretical limit), the statistical moments of the climate models (averages and extremes) have merit. The models aren't perfect, but they do a good job, and they're the best tootool we have for making regional climate predictions decades in advance. Here's what the models predict for the tropical north Atlantic: warmer sea surface temperatures, but stronger vertical wind shear and less humidity. The warmer sea surface temperatures would be favorable for increased tropical cyclone activity. However, stronger vertical wind shear and a drier atmosphere will suppress hurricane activity. Climate science isn't able to make a definite prediction about Atlantic hurricane activity because some of the factors would favor increased activity while others would favor a decrease. This isn't a conspiracy. It's the current state of the science.

      Why would you say that stronger Atlantic tropical cyclones be associated with global warming when the current understanding of climate science does not predict that global warming will increase Atlantic tropical cyclone activity? Your position is illogical.

      If you said that stronger typhoons and more typhoons in the northwest Pacific were a sign of global warming, I'd have no problem with that. The models do suggest that tropical cyclone activity will increase in that region, and I believe the science. But that's not what's currently being predicted for the north Atlantic basin.

      I'll go a step further and say that making claims about global warming that aren't supported by the science is irresponsible and undermines the credibility of the scientists. If you're going to make claims about global warming impacts and insult people, make sure your posts are factually correct.

      By the way, there are typically six factors cited as being necessary for tropical cyclone formation, unlike your list:
      1) Warm water temperatures, typically at or above 26 degrees C
      2) Non-zero Coriolis (you don't get hurricanes at the equator; you need to be several degrees north or south)
      3) Weak vertical wind shear
      4) Weak static stability
      5) High low- and mid-level humidity
      6) Low-level convergence (like a tropical wave)

      Those are the six ingredients for tropical cyclone formation. It is predicted that some of those factors will become less favorable for tropical cyclones in the north Atlantic despite the increase in sea surface temperatures.

      My post wasn't a conspiracy theory or denying climate change. It reflects the current state of the science, that it isn't certain whether global warming will increase tropical cyclone activity in the north Atlantic.

  6. Re:One active season and now everything is differe by Solandri · · Score: 3, Informative

    We haven't had two Cat 4 hurricanes hit for more than a century. The increase in water temp is increasing the power of the storms, and we should expect this to continue. That doesn't mean every storm will be Cat 4/5 or that every season will be worse than the last. Just that the frequency of high-power storms will increase. Again, we haven't had landfall of two Cat 4 storms in 100 years, so Harvey and Irma are definitely unusual.

    The last time two Cat 4+ storms made landfall in the North Atlantic was 2008. Gustav hit Cuba as a Cat 4. And Ike hit Great Inagua Island and Grand Turk Island as a Cat 4. (Paloma hit Cat 4 just south of Cuba, but dropped to a Cat 2 before landfall.)

    If you mean landfall in the U.S., well the U.S. lies at the extreme northern edge of hurricane territory. So you're basically just counting outliers if you're only counting U.S. hurricanes. They're too infrequent and random to draw reliable stats from. With modern satellite coverage and flights into major storms to get precise measurements, there's no reason not to use the entire database of every storm that forms in the North Atlantic.

    And those trying to tie hurricanes in with climate change invariably focus on the North Atlantic because that's the storm basin whose recent history fits their desired narrative. Meanwhile, storm frequency in the East Pacific is flat. The West Pacific is mostly flat with a recent slight downward trend. The South Pacific is down, as is the North Indian Ocean.

  7. Re:Edit. by cbeaudry · · Score: 3, Informative

    Sandy wasn't a hurricane when it made landfall.

    Also, the only reason for the extensive damage was because it hit one of the most populated areas in the world.

  8. Water [Re:Deforrestation of the Amazon] by Geoffrey.landis · · Score: 5, Informative

    Massive deforestation is not being considered? Seriously.

    indeed. A fascinating image of carbon dioxide concentration in the atmosphere here: https://www.nasa.gov/feature/g...

    The thing to look at is not merely the carbon dioxide being emitted from the northern hemisphere-- it's fascinating to look at the plume of carbon-dioxide depleted air wafting off of the rain forests of south America.

    One unit of burnt coal or gas produces 1 unit of CO2 and one of H2O! Yes, water is a greenhouse gas.

    Indeed, water is a greenhouse gas. But.

    But water precipitates out of the atmosphere very very fast, so the water actually emitted by humans doesn't really contribute for very long. The carbon dioxide, on the other hand, sticks around for an estimated lifetime of about a hundred years. More to the point, the hundred and fifty million square miles of ocean surface evaporates so much water into the atmosphere that the amount emitted by humans really is, in this case, trivial-- the equilibrium water content of the atmosphere is driven by evaporation, not by direct emission.

    For the most part, the humidity in the atmosphere is driven by the temperature, not vice versa.

    --
    http://www.geoffreylandis.com
  9. Re:One active season and now everything is differe by Geoffrey.landis · · Score: 5, Informative

    You obviously don't know how science works. Here you go:

    1) When you have unusually hot or volatile weather, that's evidence of man-made climate change.

    No. One hot summer (in one place) or one warm winter (in one place) is not due to climate change. Say this over and over, this is important. Climate change is real, but it is global and it is long term.

    No single event, no single warm summer, is evidence of climate change (nor is a single cool summer evidence against it.)

    A continuous series of record breaking temperature, on the other hand, might be something to point at. But, again, even there, look for global temperatures-- regional temperatures (even regional temperature records) are just weather.

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    http://www.geoffreylandis.com
  10. Re:Stolen from twitter by hey! · · Score: 5, Informative

    Note you're taking a very US-centric view here. Not all hurricanes are Atlantic hurricanes, and not all Atlantic hurricanes hit the US. And your memory of US hurricanes must be spotty, since you don't seem to recall Hurricane Sandy.

    Let me fill in the some of blanks you've left.

    2007: Dean and Felix were both extremely deadly Category 5 Atlantic Hurricanes that hit Mexico instead of the US.

    2008: Gustav was a Category 4 storm in the Carribbean but dropped to Cat 2 by the time it hit Louisiana.

    2009: Gustav is a powerful storm on the high end of category 4, but hits wind shear when it enters the Gulf of Mexico which weaken it to a category 1. Hurricane Paloma, the third strongest Atlantic hurricane on record, develops off Nicuragua and hits the Cayman Islands and Cuba; it weakens by the time it hits the US but it does drop 14 inches of rain.

    2010: a grand total of 12 full-fledged Atlantic hurricanes form, the second highest number on record. As usually happens in bumper-crop years most of the hurricanes were relatively weak, but Earl, Ivan and Julia reached category 4. Both Ivan and Julia turned away from the US, and Earl succumbed to wind shear before striking the US.

    2011: another extremely active year with 19 named tropical storms, most of them modest in intensity. Irene, was a category 3, but like most hurricanes that make landfall north of Cape Hatteras it had slowed to Category 1. Katia was a category 4 but moved up the Eastern Seaboard well offshore; Katia was similar Irene.

    2012: the third super-active Atlantic hurricane season in a row, with twenty named storms, including Hurricane Sandy , aka "Superstorm Sandy". You do remember that one?

    2013: An actual quiet year, with only two hurricanes which did not affect the US.

    2014: Another below average year with only one hurricane.

    2015: Thrid straight below average year -- again for Atlantic hurricanes. The most powerful was the Category 4 Joaquin, which hammered Bermuda and threatened the Eastern Seabord of the US. It turned north instead. It's also important to note that 2015 wa the year of Hurricane Patricia, which formed on the Pacific side of Mexico. Patricia was the second strongest storm ever recorded with peaked sustained winds of two hundred and fifteen miles per hour.

    2016: An active hurricane year with fifteen storms, seven hurricanes, four of them major, including the Category 5 Matthew, the Category 4 Nicole, and the Category 3 Gaston and Otto.

    Now to summarize:
    (1) The Atlantic Basin is not the *world*. Often quiet Atlantic years are not quiet at all elsewhere.

    (2) The US is not the entire Atlantic Basin.

    (3) It takes more than atmospheric energy for a powerful hurricane to hit the US. Think of energy being like gravity, and the hurricane being like a pachinko ball. Most of the time, hurricanes don't fall into one of our slots. Most hurricanes that do hit the US weaken, not for want of energy but because of wind shear; Cape Verde hurricanes ride the tradewinds across the Atlantic but then nearly always weaken substantially if they turn north to the US.

    --
    Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
  11. Re: Deforrestation of the Amazon and more by Anonymous Coward · · Score: 2, Informative

    Whilst coal is mostly carbon, it is not entirely so, hence coal used to be used to create town gas, a.k.a coal gas. Hydrogen is the second most abundant element in coal, after carbon.

  12. Re:One active season and now everything is differe by sfcat · · Score: 5, Informative

    And those trying to tie hurricanes in with climate change invariably focus on the North Atlantic because that's the storm basin whose recent history fits their desired narrative. Meanwhile, storm frequency in the East Pacific is flat. The West Pacific is mostly flat with a recent slight downward trend. The South Pacific is down, as is the North Indian Ocean.

    It should be noted that most climate change models currently don't predict a significant increase in the number of hurricanes in a season. This was not true in the past but we get better with modeling over time so its not surprising. Most do however predict that the storms will be larger on average. That part seems to be holding worldwide.

    --
    "Those that start by burning books, will end by burning men."
  13. It's Human-caused climate change. by Rick+Schumann · · Score: 3, Informative

    ..and you know what? I really don't even give a shit anymore. I got enough to worry about day-to-day without continually arguing with morons who INSIST that it couldn't possibly be their SUV and burning coal in power plants that's causing it, among other things. I've only got about another 30 or so years of life left; I'll be long DEAD by the time it's so bad that it can't be stopped, and you can't live with it anymore unless you move to the Arctic or Antarctica, so screw all of you deniers. I'll keep saying that it's our fault this is happening, but YOUR KIDS and GRANDKIDS are the ones who will suffer. Act accordingly. Oh, memo to you Dominionists: Jesus Chirst was just a MAN, there are no GODS of any kind, you're all DELUDED, I know what your plans and agenda are, and I hope you all get shot in the head for your trouble. Humans need to evolve past all this superstitious nonsense like religion and gods and ghosts and other nonsense. Seriously just get over it already.

    /rant