Yes, Hurricanes are Getting Stronger

November 11, 2019

Hurricanes are relatively rare events, in that you only get about 90 of them globally each year, and only a dozen or so of those will be in the Atlantic. Thus there has been some fuzziness about whether we have a long enough data set to talk about increasing strength of storms.
New study from Aslak Grinsted, who I’ve interviewed several times in Greenland, uses a novel approach. Yes, hurricanes are getting more destructive.

I had brought this topic up with Jim Kossin of NOAA (who was not involved in the current study) when I interviewed him a few months ago. I asked him if we had a long enough data set for a signal to rise above the tropical storm noise.
In a word, yes. See above.

Proceedings of the National Academy of Science:

We present an approach to normalize hurricane damage, where damage is framed in terms of an equivalent area of total destruction. This has some advantages over customary normalization schemes, and we demonstrate that our record has reduced variance and correlates marginally better with wind speeds and pressure. That is, it allows us to better address climatic trends. We find that hurricanes are indeed becoming more damaging. The frequency of the very most damaging hurricanes has increased at a rate of 330% per century.

Phys.org:

A new study by researchers at the Niels Bohr Institute, University of Copenhagen, Aslak Grinsted, Peter Ditlevsen and Jens Hesselbjerg shows that hurricanes have become more destructive since 1900, and the worst of them are more than three times as frequent now than 100 years ago. A new way of calculating the destruction, compensating for the societal change in wealth, unequivocally shows a climatic increase in the frequency of the most destructive hurricanes that routinely raise havoc on the North American southern and east coasts. The study is now published in PNAS.

In order to compare hurricanes and follow their development over time, the traditional way of calculating hurricane damage was to survey the subsequent cost of the damage done by each storm. In other words, what would a hurricane from the 1950s cost if it made landfall today? Using this method, a typical finding is that the majority of the rising tendency in damage can be attributed to the fact that there are more of people with greater wealth, and there is quite simply more costly infrastructure to suffer damage. But evidence of a climatic change in destructive force by hurricanes has been obscured by statistical uncertainty.

Aslak Grinsted has calculated the historical figures in a new way. Instead of comparing single hurricanes and the damage they would cause today, he and his colleagues have assessed how big an area could be viewed as an “area of total destruction,” meaning how large an area a storm would have to destroy completely in order to account for the financial loss. Simultaneously, this makes comparison between rural areas and more densely populated areas like cities easier, as the unit of calculation is now the same: the size of the “area of total destruction.”In previous studies, it proved difficult to isolate the climate signal. The climate signal should be understood as the effect climate change has on hurricane size, strength and destructive force. It was hidden behind variations due to the uneven concentration of wealth, and it was statistically uncertain whether there was any tendency in the destruction. But with the new method, this doubt has been cleared. The weather has, indeed, become more dangerous on the south and east coasts of the U.S. Furthermore, the result obtained by the research team is more congruent with the climate models used to predict and understand the development in extreme weather. It fits with the physics, quite simply, that global warming has the effect that there is an increase in the force released in the most extreme hurricanes.

AP:

Looking at 247 hurricanes that hit the U.S. since 1900, the researchers found the top 10 percent of hurricanes, those with an area of total devastation of more than 467 square miles (1,209 square kilometers), are happening 3.3 times more frequently, according to a study in Monday’s Proceedings of the National Academy of Sciences.

Eight of the 20 storms with the highest area of total destruction since 1900 have happened in the last 16 years, a much larger chunk than would randomly occur, Grinsted said.

Two storms stood out from the rest: 2017′s Hurricane Harvey, with an area of total destruction of 4,570 square miles (11,835 square kilometers), and 2005′s Katrina, at 2,942 square miles (7,621 square kilometers). The average was 159 square miles (411 square kilometers) — which means Harvey’s destructive footprint was 30 times larger than average.

Climate scientists have predicted and shown that higher temperatures in the oceans and the atmosphere, a result of burning coal, oil and other fuels, is creating more extreme weather and storms.

“Their result is consistent with expected changes in the proportion of the strongest hurricanes and is also consistent with the increased frequency of very slow-moving storms that make landfall in the U.S.,” said National Oceanic and Atmospheric Administration hurricane scientist Jim Kossin, who was not part of the research.

Other experts weren’t so convinced, however. Colorado State University hurricane scientist Phil Klotzbach says his review of the most powerful storms to hit the U.S., using barometric pressure, shows no increase.

9 Responses to “Yes, Hurricanes are Getting Stronger”

  1. rhymeswithgoalie Says:

    Tangential from 2014 (xkcd #1407):

    Not shown: Harvey in Texas, Michael in FL panhandle, Irma FL’s SW peninsula, Florence in NC.

    Note that 2019’s “mere” Tropical Storm Imelda probably ate some of Rita’s memory in Texas.

  2. redskylite Says:

    Yet more reinforcement to the known physics of a warming atmosphere, none other than Judith Curry co-authored a strong paper emphasizing this way back in 2005.

    Still some are transfixed by all the scientific learning and research on this. There is no reason to stay in the fossil fueled past, no reason at all.

    =========================================

    “We conclude that global data indicate a 30-year trend toward more frequent and intense hurricanes, corroborated by the results of the recent regional assessment. This trend is not inconsistent with recent climate model simulations that a doubling of CO2 may increase the frequency of the most intense cyclones
    Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment

    P. J. Webster, G. J. Holland, J. A. Curry, H.-R. Chang
    See all authors and affiliations

    Science 16 Sep 2005:
    Vol. 309, Issue 5742, pp. 1844-1846
    DOI: 10.1126/science.1116448

    • redskylite Says:

      Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment

      P. J. Webster1, G. J. Holland2, J. A. Curry1, H.-R. Chang1
      See all authors and affiliations

      Science 16 Sep 2005:
      Vol. 309, Issue 5742, pp. 1844-1846
      DOI: 10.1126/science.1116448

      We examined the number of tropical cyclones and cyclone days as well as tropical cyclone intensity over the past 35 years, in an environment of increasing sea surface temperature. A large increase was seen in the number and proportion of hurricanes reaching categories 4 and 5. The largest increase occurred in the North Pacific, Indian, and Southwest Pacific Oceans, and the smallest percentage increase occurred in the North Atlantic Ocean.

      https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-18-0189.1

    • rhymeswithgoalie Says:

      A nit: The “warming atmosphere” is largely a side effect of the warming oceans, and hurricanes are embiggened by high SST’s (minus any increase in wind shear).

  3. dumboldguy Says:

    So what else is new? Just another one of the climate change predictions that is coming true, and most of them are turning out to be worse than first predicted. We operate on a human time scale that doesn’t look very far into the future—-too bad we can’t convert to geologic time, in which so many bad things are happening in the blink of an eye—-might produce some action.

  4. Kiwiiano Says:

    I just wandered in from Quora, where yet another storm is raging over whether ‘Hurricanes are stronger’. There seems to be a need to stop referring to them as ‘hurricanes’ because that term only represents about 13% of the damaging tropical storms.

    Better to use the term ‘cyclones’ which may force more people to recognise that the USofA is not the entire planet. Even if some Nth Atlantic cyclones are weakened by local jet stream changes, count your lucky stars, it doesn’t apply everywhere.

    • rhymeswithgoalie Says:

      Aye, but even “cyclones” are thought of by too many people as largely wind events, even though strong, “wind-proof” structures can be readily damaged or taken out by storm surge or rain-based flooding.


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