It isn’t. Well, it is a little, but not totally. OK, it is, but actually, it is complicated.

First, you are probably asking about the Atlantic hurricane season, not the global issue of hurricanes and typhoons and such. If you are asking world-wide, recent prior years were worse if counted by how many humans killed and how much damage done.

With respect to the Atlantic, this was a bad year and there are special features of this year that were bad in a way that is best accounted for by global warming. But looking at the Atlantic hurricanes from a somewhat different but valid perspective, last year was worse (so far) and this year is ordinary, within the context of global warming. So, let’s talk about the global warming question first.

How Global Warming Makes Hurricane Seasons Worse

The effects of global warming on hurricanes in the Atlantic have two interesting features that must be understood to place this discussion in proper context.

First, we are having a bunch of bad decades in a row probably because of global warming. If we compare pre-1980, for a decade, with post 1980, or pre vs. post 1990, or anything similar, the more recent years have had more hurricanes than the earlier years. Comparing to even earlier time periods is tricky because of differences in available data (Satellites make a difference, probably, even with giant weather features like hurricanes). This is mainly due to increasing sea surface temperatures, but there are other factors as well.

Hurricanes are more likely to form when sea surface temperatures are higher. Higher sea surface temperatures can make a hurricane larger or stronger. Hurricanes will last longer if there is more, higher, hurricane-hot sea to travel over. If sea surface temperatures are high enough to cause hurricanes earlier in the year or later in the year, the hurricane season can be longer. Possibly, storms that in a non-warmed world would not have made it to “named storm” status are moved to that level of strength and organization because of the elevated sea surface temperature.

Sea surface temperature increases of small amounts cause large changes in hurricanes, and large changes in hurricanes cause larger changes in potential damage level. The increase in Atlantic sea surface temperatures over recent decades have probably been sufficient, according to my thumb-suck estimate that I strongly suspect is close to correct, to make about half the hurricanes that would have existed anyway jump up one category. Then, when hurricanes get stronger, the amount of damage they can do goes up exponentially. So the sea surface temperature increases we’ve see with global warming easily explain the fact that we’ve had more hurricanes overall, and stronger ones, over the last twenty or thirty years than during the previous years back to when the data are still pretty good.

Second, the science says this will get worse. There is one 2007 study (by Vecci and Soden, in Geophysical Research Letters) that suggests that maybe in the Atlantic, smaller size hurricanes will be less likely to form because of increased vertical wind shear, but that study does not mean much for larger or stronger hurricanes. This decade old study is constantly cited as evidence that global warming will not increase hurricanes in the Atlantic. Other studies show that the overall amount of hurricane activity, and the potential higher end of hurricane strength, and the size, and the speed at which they form, and the amount of water they can contain, and possibly the likelihood of a hurricane stalling right after landfall, go up. Up. Up. Up. One study says down and that word, “down” it resonates across the land like a sonic boom. The other studies say we can expect, and to varying degrees already see, up, up, up, up, up, and denial makes words like “up” and “more” and “worse” and “exasperated” dangerously quiet. Please don’t fall into that trap. Oh, by the way,the one study that says “down” has not been replicated and though experts feel it has some merit, it is far from proven and there are reasons to suggest it my be problematic.

Comparing the 2017 Atlantic Hurricane Season to Other Years

Funny thing about hurricanes: They exist whether or not they menace you. Every year a certain number of hurricanes (usually) form and wander about in the Atlantic ocean for a while, maybe hitting some boats, but otherwise doing little more than causing some big waves to eventually reach beaches in the Caribbean or the eastern US.

This year, we’ve had four major hurricanes so far. Harvey, which maxed out as a Cat 4, ravaged and flooded Texas and Louisiana. Irma, maxing at Cat 5, ravaged Florida after wiping out islands in the Leewards and doing great damage to Cuba and elsewhere in the Caribbean. Maria, maxing out as a Cat 5, did major damage in the Leewards and notably wiped out Puerto Rico. So, four Major Hurricanes formed in the Atlantic and hit something major.

Meanwhile, Jose, another Major hurricane at Cat 4 status, still spinning about in the North Atlantic, is one of those that hit nothing. And that’s all so far this year.

Last year, there were almost exactly the same number of named storms in total (so far) and just like 2017, 2016 had four major hurricanes.

You remember Matthew, which scraped the Atlantic coast and was rather damaging. But do you remember Gaston (Cat 3)? Nicole (Cat 4)? Otto (Cat 3)?

Gaston and Nicole wandered about in the Atlantic and hit nothing. Otto was for real, it hit Central America, but not the US, so from the US perspective, it counts as a non-hitting hurricane. Also, it was only barely cat 3 and weakened quickly.

From 2000 to 2016, inclusively, we have had an average of 15 named storms per year, with a minimum of 8 and a maximum of 28, with most years being between 10 and 16. So far 2017 has had 13 named storms. We may have a couple more. So, likely, we will be right in the middle.

For the same period, the number of hurricanes has ranged from 2 to 15 with an average of about 7. This year, we have had … wait for it … 7. We may or ma not get another one, not very likely two more. In other words, this is an average year for the number of hurricanes.

For the same period, the number of major hurricanes ranges from 0 (though only one year ad zero, it is more typical to have 2 in a low year) to 7, but again, 7 is extreme. It is usually from 2-5. The average is just over 3. This year, we have four. That’s pretty typical.

So, within the context that the last couple of decades has had a somewhat higher than average frequency of hurricanes, and probably more strong ones than previous decades, this we had a typical year this year.

Why does it feel different? Why is it in fact difference, with respect to the horror of it all? Because we had more landfalls, and more serious landfalls.

Keep in mind that Harvey could have hit Houston differently and done more damage. Keep in mind that Cuba beat up Irma, then Irma failed to strike Florida in just the right way to do maximum damage. Keep in mind that after wiping out Puerto Rico, Maria swerved quickly out to sea. In other words, keep in mind that this year could have been much worse than it was.

This is the point that you must understand: Any year can be like this year, or worse. And, with increasing sea surface temperatures and other global warming related factors, worse still.

Comments

  1. #1 MikeN
    September 25, 2017

    >So, four Major Hurricanes formed in the Atlantic and hit something major.

    You only listed three.

    You say a decade before 1980, and then start in 1972.

  2. #2 Jeff Harvey
    September 26, 2017

    Maria was a category 5, not a 4. And there is no doubt that these hurricanes were turbo-charged by climate change.

  3. #3 Lionel A
    September 26, 2017

    The Quibbler quibbles at #1 whilst their present could be his future.

    Meanwhile; the world’s most powerful toddler … er um …. toddles having taken on sports people ignoring his other responsibilities.

  4. #4 RickA
    September 26, 2017

    Jeff Harvey #2:

    You are correct that Maria was a category 5 storm.

    However, when it hit Puerto Rico, it was a category 4 storm.

    I am sure that is what Greg meant.

  5. #5 gilbert
    September 26, 2017

    Maria, maxing out as a Cat 4

    Maria was a Cat 5 storm when it hit Dominica. It maintaned its strength until it underwent ‘eyewall replacement cycle and weakened just off the coast of Puerto Rico.

    There has been a CAT 5 which hit Puerto Rico; That was in 1928.

  6. #6 Greg Laden
    September 26, 2017

    Maria was indeed a Cat 5, I misspoke or misnumbered or something.

  7. #7 MikeN
    September 26, 2017

    > the world’s most powerful toddler … er um …. toddles having taken on sports people ignoring his other responsibilities.

    He is a dictator obsessed with power and ego. Now he has made his opponents kneel before him.

  8. #8 Jeff Harvey
    September 27, 2017

    Rick, when it obliterated Dominica it was Category 5. I don’t want to quibble, but indeed this is by far the worst hurricane season on record and its just over half way through. The oceans are very warm. I don’t see the luke-warmers saying much these days. All of those alleged benefits of AGW they keep bleating on about. Utter tosh. Non-linear responses in natural systems are never factored in.

  9. #9 RickA
    September 27, 2017

    Jeff #8:

    The luke-warmers aren’t saying much because there is nothing surprising about another category 5 hurricane.

    Cat 5 have happened before and they will happen again.

    Meanwhile, the world has been warming for 20,000 years and the oceans have risen 120 meters over that time.

    All but the last 8 inches (or so) of sea level rise supposedly completely natural and some fraction of the 8 inches due to humans.

    I am pretty sure that humans should be able to move to higher ground over the next century or two – so I am not that concerned.

  10. #10 Lionel A
    September 28, 2017

    The ever obtuse RickA plays the classic same ol’ same ol’ nothing to see here move on shtick whilst mother nature is become decidedly irate about continued warming, more rapid than for millennia, mostly in the oceans and melting of the cryosphere.

    On hurricanes with a snippet on SLR:

    One study indicates that hurricanes are intensifying more quickly than 30 years ago. Of course, there are other factors that can limit how powerful a hurricane becomes, such as how the wind changes directions and speed upward through the atmosphere.

    Warming oceans and melting land ice have also caused about seven inches of global sea level rise over the past century. This gives storm surge —the coastal flooding that hits suddenly before landfall — a springboard to send floodwaters higher and push further inland than they used to. That in turn can cause more damage to infrastructure and puts additional lives at risk.

    There has already been an increase in frequency and intensity of the strongest hurricanes in the Atlantic since the satellite era began. Looking forward, hurricanes are projected to produce more rain.

    Source.

    And that is just for starters!

  11. #11 Bernard J.
    September 28, 2017

    Meanwhile, the world has been warming for 20,000 years…

    You may want to assert that, but you are wrong. The Holocene maximum occurred about 7,000 years ago, and the planet has been steadily cooling ever since – up to the advent of the Industrial Revolution, that is…

    Marcott’s et al 2013 RegEM reconstruction puts the mean global temperature at the time at a little less than 0.3 K over the HadCRU 1961-1990 global mean. At the start of the Industrail Revolution that had dropped 0.7 K, to around 0.4 K below the 1961-1990 global mean.

    There’s a straightforward explanation for the consistently decreasing global temperature over the last 7 millenia, and that’s the decrease in the Milanković forcing, which was approximately 470 Wm2 at the time of the Holocene maximum, and which has dropped by about 40 Wm2 to 430 Wm2 today.

    Oh, and the development of agriculture and the advent of large scale land clearing, both of which started approximately contemporaneously with the Holocene maximum, have put a brake on cooling, due to a reduction in orbital forcing. Salinger (2006) puts the value at about 0.8 K. Ruddiman (2014) puts it at 0.9 to 1.2 K. He also asserts an albedo change from clearing that results in 0.2-0.3 K cooling.

    Take all that into account and you’ll understand (assuming that you possess the intellectual faculty) that we should probably now be at least 1.0-1.2 K below the HadCRU 1961-1990 baseline, which makes a mockery of your “warming for 20,000 years.”

    Instead, last year’s global mean temperature was about 1 K above the 1961-1990 baseline, and this is the result of a combination of agriculture/clearing, fossil CO₂ emission, and aerosol negative forcing.

    The climate should be cooling but instead it’s warming, rapidly, and humans are the cause. And humans have manifested about 2 K of warming to date.

    …and the oceans have risen 120 meters over that time.

    As with temperature, the oceans should be starting to fall, but given the enormous heat capacity of water we’d probably not expect to yet see much in the way of dropping sea level compared to the Holocen maximum. That said, the preindustrial human-caused warming is probably going to be responsible for about the same amount of sea level rise that we’ve caused since the Industrial Revolution… We’ve realised about 22 cm of rise since 1880, so we may already have manifested what is effectively around half a metre of sea level rise.

    And that high heat capacity of water that I mentioned earlier is masking much more sea level rise that’s already fixed into the system. Further, given that atmospheric CO₂ concentration is increasing at an accelerating rate, we’re baking in many metres of sea level rise, even if no one alive today will be around to see it. Levermann et al suggest 2.3 metres of sea level rise per 1.0 K, and Foster and Rohling (2013) calculate that a rise in temperature of 2.0 K over the 20th century baseline will see sea level rise more than nine metres over the Holocene plateau.

    You may be cavalier about misrepresenting the numbers, and cavalierly dimissing the artificially-low figures that you manufacture, but anyone with a conscience and an ethical code should be far more concnered about what we’re doing to the planet than the apathy that you display.

  12. #12 MikeN
    September 28, 2017

    >up to the advent of the Industrial Revolution, that is…

    Also the start of big improvement in standard of living. A reasonable tradeoff.

  13. #13 RickA
    September 28, 2017

    Bernard J #11 says “Instead, last year’s global mean temperature was about 1 K above the 1961-1990 baseline . . .”

    I don’t think that is correct.

    Using your own numbers (and Marcott 2013) we are 0.6C above the 1961-1990 baseline. The Marcott 2013 chart shows we started from -0.4C at the little ice age and rose 1C to 0.6C above zero (the baseline).

    So as you said, according to Marcott 2013, we are now 0.3C above the mean global temperature of about 7000 years ago.

    So I see that we are 0.6C above the 1961-1990 baseline.

    We are 1C above the low temperature of the little ice age, and perhaps that is what you meant to say.

    That 0.3C we are above the peak temperature of 7000 years ago is very tiny – just a little more than the .2C warming caused by the 2015-2016 el nino (which we are now cooling off from).

    My point is that the sky is not falling.

    I am more worried about what turning off fossil fuels will do to the population of the world than I am about the warming we are causing.

    Many pretend we can generate 100% of our power with renewable – but they are not correct.

    We could and should go nuclear – that is the best baseload power which doesn’t produce carbon emissions. That is what I advocate.

    Until the world catches up to the nuclear reality (that we have to go nuclear in a big way), we will continue to burn fossil fuels – and I am ok with that. That is what the world has chosen to do, given the choice between technologically available nuclear and pie in the sky 100% renewable. Eventually, the majority will get it, and we will build lots and lots of nuclear power plants – but we are not there yet.

    In the meantime don’t panic.

  14. #14 Lionel A
    September 28, 2017

    #12

    Sheesh! Go talk to people across the world affected by extreme weather events about that and see how long you live.

    It isn’t a reasonable trade of for a numpty like MikeN to live the life of Riley whilst others get swallowed up in mud slides, have their homes flooded for the second, third or whatever time, or blown out into the ocean, etc., etc., etc.

    One thing you do do well MikeN is crass.

  15. #15 Lionel A
    September 28, 2017

    #13 Unbelievable, round the houses we go again.

    BTW the sky is falling but the nature of that and the mechanism is too complex for you to grasp.

  16. #16 RickA
    September 28, 2017

    Lionel A #14:

    Do a poll and ask everybody in the world if they want to live like those poor people in Puerto Rico (no power).

    I can assure you that everybody who has power wants to keep it, and those without power want it.

    Sure – it would be great if we could generate all our power requirements without using fossil fuels – but that is not possible today (without a giant expansion of nuclear that is).

    Maybe we will invent a non-nuclear form of baseload power generation which doesn’t generate carbon emissions. That is one advantage of having 8 billion minds available to work on this problem. We might invent our way out of the current minor issue we have.

  17. #17 dean
    September 28, 2017

    “You may want to assert that, but you are wrong.”

    That is rickA’s stock in trade, but he isn’t wrong due to accident: he’s wrong intentionally.

    “You may be cavalier about misrepresenting the numbers, and cavalierly dimissing the artificially-low figures that you manufacture”
    Again, stock in trade.

    “, but anyone with a conscience and an ethical code ”

    Bingo — the two biggest thing he’s not only demonstrated he lacks but views as weaknesses in people.

  18. #18 MikeN
    September 28, 2017

    Similar results for GDP per capita and other measures.

    http://www.drmichaeljoyner.com/wp-content/uploads/2013/05/global-life-exp.jpg

  19. #19 RickA
    United States
    September 28, 2017

    dean #17:

    I am right.

    It is warmer than it was 20000 years ago.

    The ocean has risen 120 meters over the last 20,000 years.

    About 98% of that is totally natural (all but at most 22 cm per Bernard).

    Relax – don’t worry.

  20. #20 Bernard J.
    September 28, 2017

    Bernard J #11 says “Instead, last year’s global mean temperature was about 1 K above the 1961-1990 baseline . . .”

    I don’t think that is correct.

    Using your own numbers (and Marcott 2013) we are 0.6C above the 1961-1990 baseline. The Marcott 2013 chart shows we started from -0.4C at the little ice age and rose 1C to 0.6C above zero (the baseline).

    So as you said, according to Marcott 2013, we are now 0.3C above the mean global temperature of about 7000 years ago.

    We’re both not correct, actually, but you more so than me. And in my defense I was typing at 2:00 am after already losing text once to a Firefox crash*, so I didn’t make clear in my second attempt my comment about warming over the last half century.

    I’d originally made reference to the fact that Marcott et al use HadCRU as a reference baseline for their work, but that Berkeley Earth is probably the best construction of temperature change over the modern period. Berkeley Earth put warming from the 1951-1980 baseline through to 2016 at 0.94 K, which is the basis for my original comment that last year’s global mean temperature was about 1 K above the baseline. I definitely screwed up with not retyping my original comparison of HadCRU and BE (mea culpa), which orphaned to the HadCRU baseline, but that doesn’t substantively change the actual numbers.

    Which are:

    1) Prior to the Industrial Revolution, mean global temperature had dropped by about 0.7 K

    2) From 1000 Ad to 1750 AD global temperature was dropping at a rate of approximately 0.8 K per millennium. On that trajectory the planet would be expected to have cooled ~ 0.2 K since the beginning of the Industrial Revolution, although it’s entirely plausible that forcing would have diminished to that of the background rate for the the last 7 millennia, which would still result in cooling since the commencement of the Industrial Revolution. Analysis of all forcings gives no indication that significant ‘natural’ net warming would be expected over the last two and a half centuries.

    3) Pre-IR human carbon emissions caused about 1.0 K of net warming, at central estimate.

    4) Berkeley Earth indicates that last year’s global temperature was about 1 K (0.94 to two significant figures) over the BE 1951-1980 baseline, and 1.29 K higher compared to the 1850-1900 baseline (which will still be higher than the expected global temperature sans Industrial Revolution.

    5) Human-caused planetary warming amounts to a little over 2.0 K according to Ruddiman et al* in 2014 (see especially the box in figure 3), and given the two record warm years since then, this is a conservative and now outdated estimate. Temperature analyses separate to Ruddiman’s give a similar estimate.

    These are the numbers that matter, RickA, and not your mendacious smoke and mirrors tripe intended to gull an unsuspecting audience into thinking that the human impact is somehow just a fraction of a degree of warming.

    Given that you seem to be refractory to understanding the literature, you should start here:

    *Does pre-industrial warming double the anthropogenic total?

    According to the early anthropogenic hypothesis, land clearing and agriculture caused emissions of greenhouse gases to begin to alter climate as early as 7000 years ago (Ruddiman, 2003). Climate-model simulations based on the CO2 and CH4 concentrations proposed in the hypothesis suggest that humans caused a global mean warming of 0.9 to 1.5°C before the start of the industrial era. Additional pre-industrial effects on land surface reflectance (changes in albedo resulting from forest clearance) may have cooled climate enough to cancel 0.2 to 0.3°C of this warming effect, leaving a net early anthropogenic warming contribution of between 0.7°C and 1.2°C. This proposed early anthropogenic warming is comparable with, and likely larger than, the measured 0.85°C warming during the last 150 years. If the simulations based on the early anthropogenic hypothesis are correct, total anthropogenic warming has been twice or more the industrial amount registered to date.

  21. #21 Bernard J.
    September 28, 2017

    About 98% of that is totally natural (all but at most 22 cm per Bernard).

    Show your calculations.

    You’re excluding the impact of pre-Industrial Revolution, human-caused warming, and you’re ignoring the sea level rise already that is committed to as a result of the significant thermal inertia resulting from the high heat capacity of water, but that has yet to manifest.

    I stand by my assertion. The net amount of sea level rise resulting from human carbon emissions since the Holocene maximum is probably around 45 cm, or 0.5 metre to the nearest significant figure, and given the inescapable commitment to further sea level rise even with today’s atmospheric carbon dioxide concentration, that 0.5 m SRL is a conservative estimate.

    If you disagree, use actual data to refute me.

  22. #22 Bernard J.
    September 29, 2017

    About 98% of that is totally natural…

    There’s also the issue of your straw man.

    The amount of sea level rise following the last glacial maximum through to the Holocene maximum is largely irrelevant to modern human society. Our civilisation’s development has almost entirely occurred within the last 7 millennia, during which time the global mean sea levels has been effectively at plateau. Much of our infrastructure is perched at the ocean’s edge for this reason, and it is this disproportionate present of human infrastructure along coastlines that makes sea level rise such an issue.

    So it doesn’t matter how many dozens of metres the seas rose several millennia ago – what’s important is that much of our developed infrastructure is within metres of the current sea level, and we’ve put enough CO₂ into the atmosphere to cause warming that will raise that sea level by metres over the next few centuries.

    Your penchant for using fallacious lawyer logic to paint over the facts won’t change the implacable unfolding import of what we’re doing to the planet.

  23. #23 Lionel A
    September 29, 2017

    Relax – don’t worry.

    Another gauche declaration from the master of such.

    Oh but there is an element of truth because the fifth major Atlantic hurricane this year is expending itself out at sea so no worries ………….. except for those already lashed by Harvey, Irma, Jose and Maria.

    After nudging ever closer to Category 3 strength for almost a day, Hurricane Lee finally made the cut on Wednesday morning. Lee’s top sustained winds were 115 mph at 11 am EDT, making it a low-end Cat 3 storm. Lee is this year’s fifth major hurricane in the Atlantic, after Harvey, Irma, Jose, and Maria. Those four predecessors all hit Category 4 or 5 strength, and all of them but Jose proved to be devastating, multi-billion-dollar storms. Fortunately, Lee is flexing its muscle far from land in the central North Atlantic, close to 500 miles east-southeast of Bermuda.

    https://www.wunderground.com/cat6/maria-pulling-away-north-carolina-lee-major-hurricane“>Source.

    And it looks like we could have our collars felt here in the UK this weekend as the remnants of Lee, then Maria and maybe a third storm brewing up off the coast of Canada roll in. Should we brace ourselves for a repeat of the 2013-2014 season?

    Give up your myopia Rick it makes you look bad. Get a global perspective of the effects that are in train due to human activities and the deleterious effects upon millions this is already having and which will get worse.

    Study Tony Juniper’s book What’s Really Happening To Our Planet? which is sort of an update on the earlier excellent book by James Bruges ‘The Little Earth Book’ which is still worth a read.

    Your insouciance about the suffering and fate of millions makes you look sociopathic and studying those two books may work a cure.

  24. #24 Lionel A
    September 29, 2017

    Oops. Darned html and no preview!

    Relax – don’t worry.

    Another gauche declaration from the master of such.

    Oh but there is an element of truth because the fifth major Atlantic hurricane this year is expending itself out at sea so no worries ………….. except for those already lashed by Harvey, Irma, Jose and Maria.

    After nudging ever closer to Category 3 strength for almost a day, Hurricane Lee finally made the cut on Wednesday morning. Lee’s top sustained winds were 115 mph at 11 am EDT, making it a low-end Cat 3 storm. Lee is this year’s fifth major hurricane in the Atlantic, after Harvey, Irma, Jose, and Maria. Those four predecessors all hit Category 4 or 5 strength, and all of them but Jose proved to be devastating, multi-billion-dollar storms. Fortunately, Lee is flexing its muscle far from land in the central North Atlantic, close to 500 miles east-southeast of Bermuda.

    Source.

    And it looks like we could have our collars felt here in the UK this weekend as the remnants of Lee, then Maria and maybe a third storm brewing up off the coast of Canada roll in. Should we brace ourselves for a repeat of the 2013-2014 season?

    Give up your myopia Rick it makes you look bad. Get a global perspective of the effects that are in train due to human activities and the deleterious effects upon millions this is already having and which will get worse.

    Study Tony Juniper’s book What’s Really Happening To Our Planet? which is sort of an update on the earlier excellent book by James Bruges ‘The Little Earth Book’ which is still worth a read.

    Your insouciance about the suffering and fate of millions makes you look sociopathic and studying those two books may work a cure.

  25. #25 RickA
    September 29, 2017

    Lionel #24:

    Thank you for worrying about how others perceive me.

    Although it is unnecessary, as I do not care if you (or others) think I am sociopathic.

    If you choose to worry about the weather, that is your choice.

    I say – enjoy worrying (since it seems to make you happy)!

  26. #26 Bernard J.
    September 30, 2017

    You’re avoiding the numbers RickA.

    You’ve made statements above and elsewhere that are divergent from those that science presents, and on the basis of your stated divergences you make assumptions that there is little risk from humans warming the planet.

    Can you please detail the basis for your own particular framing of the human impact on the Earth’s climate, with reference to all of the relevant empirical data? Unsubstantiated assertion might work for lawyers who hope that the opposing counsel will miss the errors of logic and fact, but here we expect a basic level of explained analysis and due diligence in addressing all germane variables.