Are Tropical Cyclones Getting Worse?

     Harvey has rekindled the debate between climate change advocates and deniers over whether tropical cyclones are becoming more frequent and intense.  Both sides tend to overstate their respective cases.
     Trying to get a handle on whether these storms are getting worse is not as easy as it might seem.  First, exactly how you measure the intensity of a storm is somewhat problematic.  Hurricane Sandy, which caused extensive damage to the East Coast and was frequently referred to in the media as a “superstorm,” was only a Category 1 storm on the Saffir-Simpson scale.
     The Saffir-Simpson scale is exclusively determined by wind speed.  [Click here for discussion of the scale.]  But we have learned that wind speed is just one factor in determining the severity of a storm and the resulting damage.  For example, the physical size of the storm is another important indicator of its tidal surge.  And, of course, the resulting damage from any storm is largely determined by where it makes landfall and the population and property in its path.  Had Sandy made landfall along a coastline with far less population, no one would have referred to it as a “superstorm.”
     Another problem is that the farther we go back into historical records, the less accurate the information is about the incidence and the severity of the storms.  Since the 1960s we have had reliable data from satellites.  But that is the blink of the eye on the scale of climate history.  Before that, the data is much less accurate, relying frequently on incomplete narrative accounts and spotty meteorological observations.
     Nonetheless, the National Weather Service has compiled a list of tropical cyclones that have occurred in the Atlantic basin since 1850, based on the best information they have.  They have categorized the storms into three categories: tropical storms, hurricanes and major hurricanes.  Click here to see the table.
When you graph this table, it looks like this:
    The upward trend is pretty clear, at least, on this most global level of the data.  And the 2017 data will tilt the trend lines a bit higher since this has been such an active season.

If we look only at all the storms that reached tropical storm status since 1970, the trend line flattens out significantly, supporting the notion that there is an observational bias before 1970 that under counted storms.  The trend is still up but it is considerably less dramatic than the hyperbole we frequently hear from climate change advocates.

     Of course, history is not necessarily a predictor of the future.  But these trend lines significantly undermine those who argue that the current spike in storms is nothing more than a naturally recurring weather cycle.

Weather events, by their nature, are episodic and tend to be cyclical.  There are lots of highs and lows.  Climate change advocates cherry pick the highs to bolster their case and climate change deniers do the same with the lows.

I think there are two conclusions we can draw from the data.

First, tropical cyclones do appear to be getting somewhat worse.  You can attribute that to climate change or not, but the best bet going forward is that we need to prepare for more frequent and intense storms.  However, there is little in the historical record to support a prediction that the increase will be dramatic.[1]

     Second, storms of relatively similar strengths are causing much more damage now than in the past because there are so many more people and so much more property in their paths.
Both of these conclusions support policies that would better prepare our coastlines to withstand storms and to mitigate their impact.  That means building structural protections, improving flood control, adopting better building codes, being more careful where we build things and restoring natural features that dampen the impact of the storms, e.g., wetlands and oyster reefs.
     While pursuing policies which will reduce carbon emissions is a laudable goal, there is no evidence that policies to that end will have any short or medium term effect on reducing the frequency or severity of tropical cyclones.
     Of course, it is not an “either-or” choice.  We can work to make our coast lines more resilient and to reduce carbon emissions at the same time.  But if the goal is to reduce the impact of tropical storms in the short or medium term, we need policies primarily aimed at strengthening our coastal defenses.

[1] The issue of whether tropical cyclones are getting worse and the effect of climate change on tropical storms is a topic that is hotly debated within the meteorological community.  Ryan Maue, a well-known climate change denier, has made the case that frequency and intensity of tropical cyclones has actually declined in recent years. [Click   here to see his data and argument.]  However, the conclusion that storms are gradually getting more frequent and intense represents the consensus opinion of the meteorological community.  [Click here.]
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4 thoughts on “Are Tropical Cyclones Getting Worse?”

  1. Bill, Climate Change is not only a complicated area, it is backed by dollars and corruption, such as Climate Gate showed recently. For example the 97% consensus by scientists is simply a lie and has been debunked a number of times.

    As regards hurricanes, “the hurricane-global warming link is clearly more complicated than a simple “warming in—bigger hurricanes out” stories that abound today. It’s not at all clear that warmer world will have more storms, and many studies indicate that increases in hurricane strength will be hard to detect because of the tremendous year-to-year natural variability. We don’t even have decent hurricane histories because satellite coverage — the only way to truly measure global activity — has only been maintained for 35 years. Aircraft have investigated storms in the Atlantic and Western Pacific since World War II, but coverage was certainly not complete, and may not be reliable before 1960. Long-term geological records for individual sites can be used to find evidence for storms as far back as 5000 years ago, and those histories indicated there is nothing really unusual about the current hurricane regime.” (The above summary is quoted from a book by Patrick J. Michaels and Robert C. Balling’s “Climate of Extremes”)

    Better yet is the validity of whether or not global warming is a occurring or not, the basis for which the argument begins. For global warming validity, you need to look at no consensus, why scientists disagree, scientific method vs. political science, flawed projections (models), false postulates, unreliable circumstantial evidence, and policy implications. Lastly, the subject expertise for global warming requires input from astronomy, biology, botany, cosmology, economics, geochemistry, geology, history, oceanography, paleontology, physics, and scientific forecasting and statistics, among other disciplines. Read the latest book on the fallacy of global warming as a fact: “Why Scientists Disagree About Global Warming” by Craig D. Idso, Robert M. Carter and Fred Singer (2015). My credentials: Sr. Staff Environmental Engineer over 25 years. I have studied this subject since it started and find it far, far, from being a theory, but simply a hypothesis. It’s all about dollars and globalism. It does not qualify as a “scientific method”.

    You are right about population planning in areas along the coast. This is the main problem that needs solving. Forget global warming solutions.

  2. Regarding the scientific method, a scientist friend of mine (I am an engineer) states that the first step is to make observations is what do I see in nature? The next step is to ask questions about the observation. Then, the scientist then formulates a hypothesis that might explain the causes. Then he develops testable ways to predict the outcome. This allows him or her to verify or falsify the hypothesis. If it is false, I can refine the hypothesis and do further testing. If it is true, I can move forward to develop general theories that are consistent with what I have learned. That is the way real science is done.

    Take global warming; this topic has a testable hypothesis: the world’s average temperature is increasing. The data gathered to support this hypothesis show that the earth is not necessarily getting warmer (last 18 years show this). As a result, the hypothesis has been renamed “climate change”. But the hypothesis that the weather will change from day to day is not scientific, as it is neither important nor interesting. Of course the weather changes from day to day.

    What is actually meant by climate change is that man-made pollutants have caused significant and substantial changes to the world’s climate. But as far as we know, no studies have been proposed that would determine: a) how much of any particular weather change can be attributed to man, or b) whether any specific changes in human activity would have a mitigating effect on such climate change.

    Instead, the approach employed to study the question involves the use of computer models. If one has great confidence in the accuracy of climate-change models, he may well believe that man-made pollutants much be minimized to avoid future weather-related catastrophes. If he lacks confidence in the models, he’ll more likely believe that the predictions of disaster are overblown. This is the heart of the climate-change debate, and much name-calling has gone back and forth between those who believe in the accuracy of the models and those who don’t. The models are not validated.

    This is actually rather odd, because we know of no other topic on which people’s opinions are based on their belief in the accuracy on inaccuracy of computer models. The question boils down to “Do you believe in the predictive capacity of these models?

    I am sympathetic somewhat to models, but that does not mean I trust these models. Thus, there is very little science in climate science. No one can show that the models are validated. Moreover, even when a scientist expresses an opinion, it does not mean he did a scientific study to verify it. All scientists have opinions, but not all do good science to prove their theories. Having an opinion is not the same as doing good science.

    Real science should be based on hypothesis-testing, not a priori dogma. The IPCC already assumes that climate-change is occurring, not if climate-change can occur. The cart is before the horse and the hypothesis is much corrupted. In this case, the scientific method is not being utilized to develop this hypothesis. My friend, this is all about making dollars and moving our great Country to globalism. Global warming or climate-change caused by humans is not even close to a fact. The predictions are flawed.

    My friend the scientist wrote most of this comment, I just used his words since I am a retired engineer. His PhD is in engineering and masters in medical science. My degree is in chemical engineering. We are also Christians whereby Truth is the answer we look for through the scientific method. The biggest problem is most of the public do not even know what the scientific method means.

  3. On Bill Freeman’s first note above, the time for satellite coverage is not 35 years, but 44 years. The Christian friend I discuss in the second note above is Dr. Thomas S. Buchanan at the University of Delaware. The article I quote is titled “Discipled Science” published in the Christian magazine “Touchstone”, September/October 2017 issue. This should help if anyone wants to check out my message. Having worked on environmental issues for years, this type discussion needs to be addressed today.

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