More bad news for alarmists – no trend in global hurricane landfalls

This excerpt from Dr. Roger Pielke Jr. on his blog likely will cause Bill McKibben and the McKibbenites at 350.org to ramp up the rhetoric over the post Sandy “new normal” yet again, because as we’ve learned, new factual information doesn’t dent their resolve.

Pielke writes:

Earlier this year, Jessica Weinkle, Ryan Maue and I published a paper in the Journal of Climate on trends in global landfalling hurricanes (a PDF can be found here as well). At the global level the data is good from 1970. Our analysis covered through 2010. With 2012 almost in the books I recently asked Ryan if he could provide an initial tabulation of the 2012 data (note that the data could be revised from these initial estimates, and 2012 is still not quite over). [...]

Below is the dataset from 1970 first presented in our paper, updated with 2011 and 2012 included. In short, 2012 is just about an average year with 14 total landfalls (15.4 is average) of which 4 (initially, but could change, 4.6 is the average) characterized as major.

Here are some updated factoids summarized from the data: 

  • Over 1970 to 2012 the globe averaged about 15 TC landfalls per year (Category 1-5)
  • Of those 15, about 5 are intense (Category 3, 4 or 5)
  • 1971 had the most global landfalls with 30, far exceeding the second place, 25 in 1996
  • 1978 had the fewest with 7
  • 2011 tied for second place for the fewest global landfalls with 10 (and 3 were intense, tying 1973, 1981 and 2002)
  • Five years share the most intense TC landfalls with 9, most recently 2008.
  • 1981 had the fewest intense TC landfalls with zero
  • The US is currently in the midst of the longest streak ever recorded without an intense hurricane landfall
  • The past 4 years have seen 12 major landfalling hurricanes, very low but not unprecedented — 1984-1987 had just 11. The most is 35 (2005-2008).
  • The past 4 years have seen 51 total landfalling hurricanes, on the low end — the least is 41 (1978-1981) and the most is 80 (four periods, most recently 2004-2007).
  • There have been frequent four-year periods with more than 25 landfalling major hurricanes, or more than a 100% increase of what has been observed over the past 4 years.

Anyone who’d like to argue that the world is experiencing a “new normal” with respect to tropical cyclones is simply mistaken. Over the past 4 years, the world is actually in the midst of a very low period in tropical cyclone landfalls — at least as measured over the past 43 years.

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Read his full post here

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53 thoughts on “More bad news for alarmists – no trend in global hurricane landfalls

  1. Those aren’t factOIDS (‘like’ a fact) – rather, just plain old proper FACTS. Don’t sell the data short. ;-D

  2. I have and always have had a problem with this “new normal” term and way of thinking. 1. Those presenting such things are almost always ignorant of long time history, things like geologic time. 2. Those wishing to postulate a new anything tend to have no real clue what the old normal was/is. 3. This term and its use is simply more RP baffle gab without sufficient history it is meaningless. Time and time again people like Dr. Pielke Jr. point out the shortcoming but it apparently falls on the ears of the believers and gets rearranged by their cognitive dissonance.

  3. Bill McKibben, where are you?

    This article disputes your “new normal” meme. Better still, IPCC AR5 SOD also says you are wrong. Isn’t it about time you published a retraction? Or are you prepared to assert your opinion of the science in opposition to both the skeptics and the IPCC at the same time?

    Or will you just slink away in silence?

  4. Nevertheless, things tend toward the normal value, so one should expect that a period of low landfalls (like the one we are in now) will be followed by a higher rate -nearer to the normal or even above normal for some period of time. Just look at the chart and you can see it. But that will be normal too.

  5. If you search: Arctic Hurricanes Play Large Role in Climate
    you will see some additional information on how previous climate models have badly failed in some critical features of why the higher Northern latitudes warm or cool, and newer better models show a likely cooling period coming. Combining the lack of reasonable prediction of magnitude of solar effects (the new IPCC leak) and the lack of previous understanding of large Arctic Hurricanes effects on climate models make all previous models totally worthless.

  6. I hope that Gore et al continue with their extreme weather alarmism.

    It is so completely and unequivocally rebutted by the actual data, it can only destroy what is left of their reputation for honesty

    The temperature records are far less clear cut. I’m firmly in the skeptical camp but I recognize there is at least some scope for reasonable people to disagree over many details.

    Having said that, there’s really no data to demonstrate that the proposed remediation measures are an effective use of resources. And guess what? Joe Public is rapidly realizing this.

    It’s a long, slow haul. But the truth will out!

  7. “Over the past 4 years, the world is actually in the midst of a very low period in tropical cyclone landfalls”
    =====
    So when it returns to normal, warmists will really think it’s the end of the world.

  8. But,.. but this is climatology, therefor users of empirical data that contradicts the models, are required to correct that data to match the gospel.
    The conclusions suggested by actual measurements can never be more correct than the modelling output.
    By UN-IPCC logic Bill McKibben is right, its reality that is mistaken.
    I love the failure of logic that has the activists babbling about weather, its as old as human speech and as transparent as Chicken Little.
    Ugh You bad, thunder come. Give me gift, chant and dance make lightning leave.

  9. I don’t want to rain on anybody’s parade, but…

    That link is to a line graph of Pielke’s data above I made with Excel, including 2011 and 2012. It plots only the number of “Intense” hurricanes (Cat 3,4 and 5) by year since 1970. Then I added the linear trend line in red.

    As you can easily see, there is a linear increase in the number of “intense” hurricanes over time just like that AGW alarmists say.

    The reason for the trend is that 2004-2008 had lots and lots of intense hurricanes. Though it is true that intense hurricanes are down over the last 4 years, the bottom line is that, in general, the alarmists are right on this one.

  10. azleader, is your conclusion correct though? We get told to expect this sort of thing as the “new normal,” yet the number of extreme events, while supporting the Alarmist meme from 2004 to 2008, has fallen off considerably from 2009 onwards. While the trend you plot is upwards, the data is highly inconsistent, which is not what we should be expecting from the “new normal,” while CO2 is ramping up like a bitch still.

    No, I don’t think you support the alarmists, but I just don’t think this data is saying anything other than we can see natural variability. The alarmists will see what they want to see, of course…

  11. So, what does the p value and r2 look like for your trend line? Since you don’t say, It probably isn’t statistically significant which means the trend is statistically indistinguishable from a zero trend.

  12. azleader

    hate to rain on your parade, but for the decade 1991-2000 I count 58 severe hurricanes (red) and for the decade 2001-2010 I count 56 huricanes, for a decrease of 2 major hurricanes compared to the previous decade. Now, tell us about that bottom line once again, please and thank you.

  13. Good question… I don’t know. :)
    All I know for sure is the trend line shows a growth of over 1 “intense” hurricane making landfall per year since 1970 and that includes the drop off over the last 4 years.
    TimiBoy says:
    December 17, 2012 at 11:49 am

    azleader, is your conclusion correct though?

  14. Also great questions… I don’t know that either. :)

    MattS, you are trying to make me actually understand stuff. LOL!!!!

    My math is very rusty. However, I was able to muddle through to calculate a p2 value of 0.064497 using Excel’s RSQ function for hurricane numbers and years. I’m not even sure what that result means.

    Excel has a TDIST() function to calculate the p-value, but I can’t figure out the input parameters and the tutorial I tried didn’t help. :(
    ————————————————-
    MattS says:
    December 17, 2012 at 11:52 am

    So, what does the p value and r2 look like for your trend line?

  15. “Bill McKibben, where are you?”

    Why do you care what he says other than to example him as a lunatic in a pseudo-scientific political cult? Once you start laughing at them and pointing at their denialism of the lack of temps change, therefore their pr firm-guided obsessions with measurements other than from thermometers, you win, they lose the “debate” that they really don’t want to have.

    If you really want to get under their skin, compare them to G. W. Bush’s economic policies–magical and insipid.

  16. azleader,

    The trend in intense landfalling global tropical cyclones is not significant at the 2-sigma level. The trend is 0.052 +- 0.031 TCs/yr with an R^2 of 0.064. It is just barely significant at the 90% level. The problem is that the data suffer from systematic issues. For example, the data start at a low point in the 60-year AMO cycle and end near a high point, so the trend is more likely an indicator of how much Atlantic TC activity affects global landfalling data.

    The trend in overall global landfalling TCs is not significant either: -0.011 +- 0.047.

  17. Mpainter… I hear ya, but here is the deal…
    Pilke’s own data creates a trend line of greater than +1 in “intense” hurricanes since 1970. That is 42 data points. I didn’t manipulate anything at all… it is what Excel produced.

    MattS makes a GREAT point about whether or not the result is statistically significant. That is what is important. If it isn’t then the trend line is meaningless. That part I don’t know. My rusty math skills aren’t good to figure it out yet.

    But this much I do know, it can be proven one way of the other.

    My sense is that a +1 when there is only a range of +8 “intense” hurricanes to start with over 42 data points sounds to me like it like it is probably statistically significant. That is yet to be determined.

  18. azleader;
    All I know for sure is the trend line shows a growth of over 1 “intense” hurricane making landfall per year since 1970 and that includes the drop off over the last 4 years.
    >>>>>>>>>>>>>

    That’s what happens when you try and cram a linear trend through cyclical data.

    I walk up the side of a hill, recording my altitude from the foot of the hill to half way up every minute. At the half way point, I draw a linear line through my data and conclude that I will be leaving earth orbit in about 2 weeks. At the crest of the hill, I draw a new line through all my data and it turns out itz 3 weeks, not 2. I cross the top of the hill to the other side, assess my data again, looks like orbit in 4 weeks not 3. But I’m still proving that I’m going into orbit. Half way down the other side, I draw yet another line, and discover that orbit is now 6 weeks away, not 4.

    At some point it may dawn on my that drawing a linear trend through cyclical data is just dumb. Unless I went to climaclownatology school….

  19. Compare and contrast:

    We say there are no significant trends in extreme weather & keep presenting the evidence.

    They say that the weather is getting more extreme.

    —————
    Keeping your eye on the thimble: they present recent weather events as evidence but shy away from presenting trends, especially long-term.

    Their message is not aimed at skeptics. It’s aimed squarely at the public, most of whom are unaware that they are being lied to.

    http://wattsupwiththat.com/reference-pages/climatic-phenomena-pages/extreme-weather-page/

  20. Thanks, Brian…
    I was verified your R2 value with Excel, so I trust your conclusion that Excel’s trend line is not statistically significant. I wondered about than before my original comment. However, I’m gonna have to dig a little deeper to understand it better for myself.
    —————————————————————-
    Brian says:
    December 17, 2012 at 12:38 pm
    The trend in intense landfalling global tropical cyclones is not significant at the 2-sigma level. The trend is 0.052 +- 0.031 TCs/yr with an R^2 of 0.064.

  21. Always need error bars on your trend line azleader. Random numbers will almost always show a trend also (it is unlikely that they will be exactly zero trend). It is the trend in comparison to the random variation that establishes if the trend is significant.

  22. This site could benefit from a set of reference pages on hypothesis testing with probability/likelihood estimates.
    The “p2″ metric, I believe, is the Pearson product-moment statistic, squared.
    That metric is generally presented and believed to be one way to say the amount of change in one measure that is accounted for by another. A p2 of .06 would thus say that six percent of the observed variation in number of intense hurricanes per year is explained by variance in year.

    Knowing that the trend is toward more hurricanes per year going from past to present, it means that there are more hurricanes as time goes forward, but that time as a predictor only explains six percent of the variation in the number per year.

    Either other factors account for the remaining variability, i.e., explaining why any one year has more or fewer than any other year, or the categorication of hurricane severity is not measured well enough to get a decent measure, or both.

    To consider this question, you are investigating a hypothesis: that severe hurricanes are getting more frequent across time. The contrary assertion would be: severe hurricanes are not getting more frequent across time. If the contrary were true, the Pearson correlation would be zero.

    Now, in reality, values rarely ever turn out to be zero. There are many factors involved, and the result, if there truly is a zero relation, most likely won’t be zero, but a number very close, which is so small it is just reflecting random variation, and not some genuine relation.

    That is where the significance test comes in. It uses variation in the number of severe hurricanes per year to see what numbers would be expected if there were only random variation around no changes from year to year, and tests how likely it is theat the obtained value shows a reliable difference from zero/normal variation, or is just normal variation around the usual annual number.

    If you take the data and put it in a histogram, it gets more easy to grasp this. You can use an image search to see what a “histogram” is, then imagine plotting the number of severe hurricanes each year on the histogram, then seeing where the data points are, in the histogram’s distribution, for the recent few years.

    If they are simply in the neighborhood of the rest of the points, you know you will not get a pearson r to be statistically ‘different’ from the rest of those data points.

    Brian has results of a test of the slope, rather than a test of correlation between each year and each year’s number of severe hurricanes.

    That tests whether the line, from left to right, is notably differently slanted or sloped upward, versus the “null hypothesis” of the line being flat.

    Same logic applies. If there truly is no trend, your actual slope from almost any data will not be exactly zero point zero zero zero zero, but some insignificant number very close to zero, and the trend line, when graphed, may not be impressively sloped.
    The floor in my home, we would all say, is not perfectly flat. If we measured it enough, we might find it slopes up from north to northwest, or something like that, but maybe by only a fraction of an inch across 40 feet. That rise is so small it is irrelevant.

    Worse yet, the rise could be error in measurement.

    My floor could actually be sloping the oher way, and msmt error is greater than the actual trend.

    The likelihood test essentially asks this question, and declares how likely it is that the obtained data reflects a departure from the value of no-trend.

    At or beyond two sigmas is fairly impressive, if the measures are good. That means the obtained data will be observed only about five percent of the time. That suggests that the trend would be notably divergent from flat – worth worrying about; otherwise, as Brian notes, the obtained data would be expected ten times of every hundred, so not very uncommon.

    All of that is “internal” likelihood math.
    At the same time, it is likely that, since the data start in 1970, tehse storms have been detected more reliably. If the likelihood of detecting a severe hurricane has increased across time, such as due to more consistent and better technology, better infrastructure, etc., then there is a surveillance bias that would make it appear as if more are occurring across time – we are looking more, hence we find more.

  23. IPCC consistently projects no trend in hurricane frequency. That view is not contradicted by the ‘alarmist’ milieu in general. The point of this article is premised on a falsehood.

    The metric that may trend higher, according to the IPCC, is hurricane intensity. Not frequency.

    This distinction has been made again and again in the climate debates. It is disappointing to see this mistake republished – yet again – at WUWT.

    REPLY: The mistake is yours, I posted it not to direct at IPCC, but at wild eyed alarmists like Bill McKibben, who coined the “new normal” phrase related to hurricanes and extreme weather. Reading comprehension failure on your part – Anthony

  24. I was going to add something similar: Unless the numbers are exactly divisible by 43 (years), then it is not even possible to have an “average” (arithmetic mean) year. “Hurricanes” is an integer variable…

  25. Are we able to cut through the alarmist’s “purposefully mendacious” [Anthony reply to post] dance and declare their is no trend in anything?

  26. A few typos…

    “simply mistaken” = “sadly mistaken”

    “intense” and “major” = “extreme”

    No need to thank me…:-]

  27. “The metric that may trend higher, according to the IPCC, is hurricane intensity. Not frequency”

    So is there any data supporting this at all?.

  28. I look at hurricanes and the procession of NE storms up our New England coast as a most painfully obvious temperature transport mechanism involving the latent heat of the phase changes of water. The more the temperature differential between the tropics and the temperate zone the more “mixing” is likely to occur and the more emphatic the correction. Entropy! It is not the absolute temperature it is the delta across the system a that controls the potential for work. Go a few miles inland from Homer Alaska in the winter and experience 150? feet of snow fall.

    Therefore in the [Medieval] Warming period, if the global temperature was more uniform, one would expect to see less intense rather than more severe storms. If the cooling trend is predictable then the land cools quicker than the oceans …….with a cool continent and warm ocean, mother nature is going to work very hard to strike a new thermodynamic balance. Exactly where and how did she manage to get enough energy to evaporate and precipitate a mile high ice sheet? Lake effect from an open Arctic? Maybe some, but insufficient volume. Notice that the NW sector of a low or a hurricane is the wet sector?

    Several weeks before Sandy there was an absolutely massive low that stretched across the continental US. It was not very intense just BIG. Sandy was not very intense in wind velocity but BIG. Sandies track and this track brought the wet quadrants over the areas that in the past accumulated continental glaciers and the NE SE sectors were over the ocean where water vapor was available to be entrained. This is just a theory on our predictably wild ride into the next glacial cycle.

  29. thelastdemocrat says:
    December 17, 2012 at 1:27 pm
    This site could benefit from a set of reference pages on hypothesis testing with probability/likelihood estimates.
    ======
    Quite a bit of statistics relies on the assumption that the data is normally distributed. That is, it has a constant mean and a constant deviation. For something like a coin toss, this is true because the nature of the coin does not change from toss to toss. Much of our theory of statistics is derived from this, because it has a very valuable application in gambling.

    However, there is a large body of evidence that says that most time series do not behave like a coin toss. In effect, most of the time we are playing with a coin that changes each time we toss it, and the change is unpredictable. So when we try and apply statistics to the stock market or to climate forecasting, we often get nonsense results. The results may appear very reliable statistically, but the future refuses to co-operate with the odds.

    So when someone talks about the “new normal”, the problem is in their assumption that the “old normal” was indeed normal.

  30. halftiderock
    l also have been thinking along the same lines about the weather pattern set up need to form the last ice age. l got a big clue about it back in early Feb 2011 when a huge blocking high formed and extended right across northern asia. lt was just the sort of weather pattern that was needed to set up a huge block of cold air so the ice sheets could form. And as you say the other thing that is needed is area’s of large slow moving lows, so as to accumulate the amount of snow needed to form the ice sheets. lts was just this sort of set up that l think happened in the last ice age.

  31. http://metofficenews.wordpress.com/2012/12/14/2012-hurricane-season-comes-to-an-end/

    ‘It has been an unusual season in many respects. This is the third year in a row with 19 named storms, which is unprecedented in the historical records. Only one other season – 2005, which saw the devastating Hurricane Katrina – has experienced more named storms (28) since reliable records began in 1944.’

    Are we in the Apples and Oranges department again?

  32. Anthony, maybe you could post some links to where wild eyed alarmist have claimed an increase in the number of hurricanes making landfall since 1970.

  33. Cat 3,4,5 by decade:

    1970-79 38 storms
    1980-89 41 storms
    1990-99 55 storms
    2000-10 58 storms

    It’s not a downward trend.

  34. The last period in my prevous post is 2000-09 an not 2000-10. 59 cat 3,4,5 storms is correct for the 10 year period. Sorry for the error.

  35. A graph that starts in 1970 only covers 42 years. There seems to be a cycle of (very roughly) 60 years, in New England at least. In 1954 three hit and in 1954 two hit. If you start a graph in 1970 you miss that period, (which I have been expecting to reoccur for the past decade.) Irene and Sandy were only to be expected.

    The problem with cycles is that the storms are individuals. They are very different from each other. It is very interesting to study the storms during 1893.

    Even when a storm takes a track very much like a storm did sixty years earlier, it can be hugely different if it’s track is only 75 miles east or west of the earlier storm. 75 miles east, and it is a “fish storm” only surfers notice, while 75 miles west may put it over land or cold shelf waters that make it far weaker.

    The one hurricane we haven’t seen repeated is the sort that rushes north at fifty or sixty mph, like the 1938 hurricane or Connie in 1954. They come north so swiftly they don’t weaken as much, and tree damage is at its worst in New England, especially on hilltops.

  36. REPLY: The mistake is yours, I posted it not to direct at IPCC, but at wild eyed alarmists like Bill McKibben, who coined the “new normal” phrase related to hurricanes and extreme weather. Reading comprehension failure on your part – Anthony

    Thanks for the reply, Anthony.

    Could you provide a link or cite to where ‘wild eyed alarmists’ claim that there has been/will be an increase in the number of hurricanes making landfall? I searched 350.org (never visited the website before) and checked out the mcKibben articles in Rolling Stone and Environment360 kindly linked by CodeTech. Far as I can make out Bill McKibben has not made a claim about increased hurricane landfall, nor has any other wild eyed alarmist.

    • @barry McKibben claims that AGW will increase the number of hurricanes, so it follows that there’s an increased statistical probability of increased hurricane landfall. Here’s the relevant quote from McKibben:

      “The fossil fuel industry is causing the climate crisis, leading to more extreme weather events like Hurricane Sandy,” McKibben said. “We’re calling on Big Oil to stop spending millions to influence this election and donate the money to disaster relief instead.”

      Source: http://ens-newswire.com/2012/10/30/superstorm-sandy-is-what-global-warming-looks-like/

      And yes he’s a wild eyed alarmist. I stand by that definition of his bloviation on things he only feels, but doesn’t fully understand.

  37. @ barry

    They claim more frequent blocking patterns to keep hurricanes from harmlessly turning out to sea, hence more landfalls.

    http://green.blogs.nytimes.com/2012/10/30/did-global-warming-contribute-to-hurricane-sandys-devastation/

    My colleague on the opinion side of The Times, Andrew Revkin, posted an analysis from Dr. Francis this week in which she noted that an atmospheric blocking pattern over Greenland — possibly linked, in her view, to the loss of sea ice in the nearby Arctic Ocean — had helped force the storm to make a left turn into the United States mainland.

    “While it’s impossible to say how this scenario might have unfolded if sea-ice had been as extensive as it was in the 1980s, the situation at hand is completely consistent with what I’d expect to see happen more often as a result of unabated warming and especially the amplification of that warming in the Arctic,” Dr. Francis wrote.

  38. @ Caleb

    I did my own amateur analysis of “hurricanes” hitting north of Chesapeake Bay, including Atlantic Canada, for the years 1851-2011. There does seem to be a correlation with the AMO, or at least a couple of the quite periods coincided with a negative AMO. No significant trend in my “index” yet. Just thought you might be interested as New England is included in this “analysis”.

    https://sites.google.com/site/climateadj/home/noreast-pdi

  39. Anyone who’d like to argue that the world is experiencing a “new normal” with respect to tropical cyclones is simply mistaken. Over the past 4 years, the world is actually in the midst of a very low period in tropical cyclone landfalls — at least as measured over the past 43 years.

    False, of course. It IS the new normal: lowered landfalls. Get used to it; brace yourself for Hurricane Deprivation!

  40. Anthony Watts says:
    December 18, 2012 at 3:42 pm

    @barry McKibben claims that AGW will increase the number of hurricanes, so it follows that there’s an increased statistical probability of increased hurricane landfall. Here’s the relevant quote from McKibben:

    “The fossil fuel industry is causing the climate crisis, leading to more extreme weather events like Hurricane Sandy,” McKibben said. “We’re calling on Big Oil to stop spending millions to influence this election and donate the money to disaster relief instead.”

    Source: http://ens-newswire.com/2012/10/30/superstorm-sandy-is-what-global-warming-looks-like/

    McKibben’s comments are in line with the mainstream projection of increasing intensity of hurricanes – for which there is some observational evidence based on Ryan Naues data sets (co-author on the paper you cited).

    Eg, for North Atlantic storm intensity; http://policlimate.com/tropical/north_atlantic_ace.png

    If the number of storms stays constant but the intensity increases, as it may have over the last 40 years or so, then McKibben is not much out of the ball park in saying we’ll get “more extreme weather events” like Sandy. Whether or not he means landfalling hurricanes, the point is the same. The frequency may remain constant or even drop, but greater intensity would mean “more extreme wether events.” Aside from that, his language is couched in the unscientific absolutes of the activist. Well, that’s his job and you can find plenty of people using rhetoric to persuade on all sides of the debate.

    In the article you cited, there is one person who directly (and incorrectly) states that more frequent storms are a likely potential, and that is the spokesperson from the Surfrider Foundation.

  41. John West:

    They claim more frequent blocking patterns to keep hurricanes from harmlessly turning out to sea, hence more landfalls

    No, one researcher tentatively hypothesises the possibility of changed storm tracks due to loss of sea ice.

    While it may be tempting to headline every maverick view and treat it as if it is mainstream, this only adds to the confusion. (Not a bad thing if that’s what one hopes for). Someone elsewhere posted an article where some guy predicted a possible 4.5 billion deaths from global warming by 2012. A singular bit of barminess, but also treated as if it was a middle of the road view for ‘alarmists’. Can’t we do better than this?

  42. Barry,

    You are not correct, either in your interpretation of what McKibben and others mean, or in what the data say. “More extreme weather events” means an increase in the number of either intense hurricanes or hurricanes in general. McKibben then gives Sandy as an example. As we know, Sandy was not even a hurricane at landfall, so it certainly doesn’t qualify as in intense hurricane. McKibben and many others believe that everything about weather will get worse because that’s what they believe about global warming–EVERYTHING has to get worse.

    There are no data supporting the notion that hurricanes, landfalling or otherwise, are getting worse or more numerous. Here’s a statement from the Maue’s site, which you linked above:

    “Statement concerning Irene made on August 27, 2011: The mainstream media has wondered in many recent articles if “global warming” is making hurricanes stronger or perhaps made Irene stronger. As Dr. Kerry Emanuel pointed out — that question is irrelevant. It is the number of intense hurricanes that actually make landfall that is societally important. However, from a scientific point of view, it is a good idea to recognize that the population of “major” global hurricanes has not increased since 1979. Thinking of the Figure as a stock market ticker, there are always ups and downs, recessions and depressions in activity. But, the overall trend is flat proving conclusively that there is NO “overall” global increase in hurricanes, minor or major. Since natural variability such as El Nino and La Nina is the primary driver of global hurricane variability, any discussion of “climate change” impacts on TCs is woefully incomplete without acknowledging the effects of ENSO on global TC activity. The North Atlantic basin is seemingly special — in that the current “active-period” since about 1995 has not necessarily manifested itself elsewhere — and scientists are still unsure of why. Tropical cyclone and climate change science is far from settled, and any conjecture about global warming impacts can be argued from both sides of the aisle in a civil manner without resorting to personal, political attacks.” (Bolding is mine.)

    In fact, over the entire hurricane record (1851 – 2012), there are no significant trends either in the number of hurricanes or in their intensity. That is, no trends in number, number of Category 3+, ACE, PDI, etc. The few data trendlines that DO appear to give a significant trend are always capturing the increase from low to high AMO and other cycles (as in the graphs above). Whenever the fits are done over a whole number of cycles, the trends are no longer significant.

    It is true, of course, that some models predict increases in intense hurricanes, as well as decreases in overall hurricane number, but there is currently no evidence supporting any change whatsoever in hurricane activity, and there is not likely to be any such evidence for many decades, if ever.

  43. Brian,

    You are not correct, either in your interpretation of what McKibben and others mean, or in what the data say. “More extreme weather events” means an increase in the number of either intense hurricanes or hurricanes in general.

    His language is ambiguous – he doesn’t specify frequency of hurricanes in general, or increasing intensity in extreme hurricanes. The former postulate would be incorrect according to both observation and mainstream projections. The latter is correct according to mainstream projections, as you note.

    McKibben then gives Sandy as an example. As we know, Sandy was not even a hurricane at landfall, so it certainly doesn’t qualify as in intense hurricane.

    The language he used was “more extreme weather events.” In terms of size and damage done, Sandy was extreme, regardless of classification. Not the biggest or most costly, but definitely in the upper ranks.

    The social impact of Hurricane Sandy is what McKibben is really leaning on. He is an activist, after all.

    There are no data supporting the notion that hurricanes, landfalling or otherwise, are getting worse or more numerous….

    The data show a small downward trend regarding frequency, but I’m not sure about intensity.

    In fact, over the entire hurricane record (1851 – 2012), there are no significant trends either in the number of hurricanes or in their intensity. That is, no trends in number, number of Category 3+, ACE, PDI, etc. The few data trendlines that DO appear to give a significant trend are always capturing the increase from low to high AMO and other cycles (as in the graphs above). Whenever the fits are done over a whole number of cycles, the trends are no longer significant.

    Do you have a cite or links to some work on intensity (ACE, PDI) time series? From the charts on Maue’s cite, there is a definite trend in North Atlantic hurricane intensity (which he comments on), and seemingly a small trend for global tropical cyclones with wind speed of 96+ knots.

    Probably not statistically significant, but I’m curious about the longer term data. It should be possible to extrapolate intensity trends as a fraction of total observed (bearing in mind storm monitoring has improved over time).

  44. From Maue’s most recent paper on cyclone intensity.

    While the NATL accounted for about 14% of global ACE on average from 1979–2010, the calendar year proportion was highly variable (standard deviation of 8.5%) ranging between 2% and 32% (Figure S2). Indeed, the NATL contribution during 2010 of nearly one‐third of global ACE clearly beats out 1996 and 1999 for the highest percentage since at least 1979. Much of this observed dramatic increase in NATL ACE is associated with a strong upward trend in the frequency of deep tropical systems called Cape Verde hurricanes during the past two decades [Kossin et al., 2010]. Cape Verde origin storms typically have long lifecycles and peak at high intensities, thus contributing considerable ACE to the seasonal totals.

    Frustratingly, neither his paper with Pielke cited in the top article, nor in this one is there a focussed examination of long-term intensity trends, despite both papers dealing with intensity data. Maue has a new paper in the works,

    Maue, R. N. (2012), Are tropical cyclones becoming more intense?

    yet to be submitted/published. Looking forward to it.

  45. Hurricane strength is said to be increasing. This can likely be attributed to increasing satellite coverage and resolution, which tends over time to more accurately capture the hours when a storm is at maximum strength. A study that corrects for storm detection ability over time (Vecchi and Knutson 2011) finds no trend in Atlantic hurricanes over the period of 1878 to 2008. Studies of landfall hurricanes (Balling and Cerveny 2003) also show no trend. The last cat 3+ landfall hurricanes to hit (i.e., with the hurricane eye) the continental US were in 2005

    http://suyts.wordpress.com/2012/08/27/the-inevitable-blathering-about-climate-change-and-hurricanes/

    New paper and ace through 2012, very low.

    CAGW is not happening with hurricanes, droughts, tornados or SL rise. However, every food crop in the world is growing 10% to 15% more food due to increased CO2, whatever the cause.

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