Are Powerful Hurricanes Becoming More Frequent?

According to Kerry Emanuel :

“Most of the models suggest that the more powerful storms become more numerous.”

” While hurricanes might become more powerful, Emanuel said, there will likely be fewer hurricanes overall this century, and hurricane trends would vary widely around the globe.

The graph above plots the ten year running mean of the number of category five hurricanes making landfall. As you can see, the peak occurred during the 1930s and it has been relatively level since. There were four category five hurricanes which made landfall between 1924 and 1935, but only two during the past decade. It has been 18 years since a category five hurricane struck the US.

At some point, people need to check and see if their models actually work!

About Tony Heller

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16 Responses to Are Powerful Hurricanes Becoming More Frequent?

  1. Matt says:

    Your plot above doesnt make any sense… If I’m reading it right, there were 0.1 hurricanes in 2000? Or is it 0.1 hurricanes per year per decade? And why a running average?

    Furthermore, including just hurricanes that make landfall as cat 5 doesn’t lead to the conclusion that there are fewer cat 5 hurricanes. The only conclusion you can logically reach form this is that there are fewer cat 5 hurricanes making landfall, not that the number of strong storms has decreased. Indeed, just looking at the number of storms since satellite records have begun, the last decade had by far the largest amount of cat 5 storms compared with any other.

    • It is a ten year running mean.

      The only accurate historical records we have are for hurricanes making landfall. Prior to satellites and sophisticated radar, people had no way of knowing if a hurricane hit 5 status for a few hours. I’m assuming that you read my other articles on this subject.

      • Matt says:

        Steve,

        Yes, I’ve read your other articles, and agree that historical records are not complete prior to satellite and radar coverage of the whole Atlantic. But that does not mean you can draw the conclusion that you have. Lets see what the available data tells us (i.e. dates after satellite coverage was established in 1966):

        5 Year Period beginning: # cat 5 storms:
        1965 2
        1970 1
        1975 2
        1980 1
        1985 2
        1990 1
        1995 1
        2000 2
        2005 6

        So prior to 2000, there were a maximum of 3 cat 5 storms per decade. Then in the ’00s we had 8. Seems to me to be an increase…

      • There were a lot of storms in 2005. satellite coverage in 1966 was very primitive.

      • Matt says:

        So that doesn’t meet the definition of ‘more frequent’?

      • Our ability to measure hurricanes in the ocean is much greater now than in the past. The only apples-for-apples comparison is hurricanes making landfall.

      • Matt says:

        Why are we going in circles?

        – Yes, we can detect more seaborne hurricanes now.

        – Yes, hurricanes making landfall is a consistent measurement through time.

        -No, you cannot draw any conclusions about the total number of hurricanes from the number making landfall.

  2. bjedwards says:

    There is nothing in Emanuel’s interview suggesting “category 5 hurricanes making landfall” would increase.

    What is the point of your post?

  3. PJB says:

    The null hypothesis must be that [CO2] makes no difference to phenomenon “X”.

    Therefore the experiment (ie real, actual measured data and NOT simulations based on theory) need clearly present the interaction of variables studied and if a statistically significant (typically at the 95% confidence limit) relationship is developed , then there is reason to associate [CO2] to “X”.

    Anything else is not science, it is belief, or worse, agenda.

  4. sod says:

    The null hypothesis must be that [CO2] makes no difference to phenomenon “X”.
    .
    you are wrong. there also is physics. physics tells us, that there might be a connection between car accidents and broken bones. a study not supporting the connection, doesn t change that fact. (plenty of car accidents without broken bones, plenty of other opportunities to break a bone)

    • PJB says:

      Correlation is not causation. That is the purpose of the exercise, to determine the inter-relationships and define how they interact and the resultant causes and effects.

      To date, [CO2] fails miserably as a predictor of anything significant other than how it follows ocean temperatures.

      p.s. a null hypothesis cannot be “wrong”. It is a way of framing an investigation to allow conclusions to be drawn.

  5. Neven says:

    Category 5 hurricanes are rather rare, yes? What about category 3 and 4 hurricanes? They do significant damage too, don’t they?

    When can we expect an updated image from this site?

    • I discussed Igor and Julia yesterday. You must have missed that article.

      • Neven says:

        I did miss it, like I did the article after this one which has some stats on Cat. 3 and 4 hurricanes. Perhaps you should collect these ultra-small articles (with 100 words and 1 or 2 graphs) and combine them in one big article discussing one subject ore other. Your machinegun style makes it hard for me to keep track. Besides, quantity is not quality.

  6. Rich Miller says:

    The question is not whether this individual “frankenstorm” is direct evidence of the negative impact of climate change, but how has climate change produced the condions that allowed this kind of freakish storm to form, and are we prone to more such unusual events. The North Atlantic Oscillation is an important variable in this, and what was unusual in this case is the unprecedented intensity of its variation. This produced a very strong high pressure just west of Greenland that drove Sandy to the west. What made this kind of variation possible? Don’t focus on this storm only and lose sight of the big picture. See, for example:
    http://blogs.scientificamerican.com/guest-blog/2012/10/31/frankenstorm-sandy-stitched-together-from-elements-both-natural-and-unnatural/

    Rich Miller, Registered Professional Geologist (retired), Virginia

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