I have written a LOT on hurricanes and climate change, lots of summary info here:
Trenberth, K. E., L. Cheng, P. Jacobs, Y. Zhang, and J. Fasullo, 2018: Hurricane Harvey links to ocean heat content. Earth's Future, 6, 730-744, Doi: 10.1029/2018EF000825 [PDF]
available at my web site.
Basically there is more energy available and more activity is expected. This can occur in several ways:
more intensity
Bigger
longer lasting
heavier rainfalls.
The first 3 are not independent of the last one. There is good evidence for all of these but not strong observations on duration and size. Eyewall replacements lead to bigger storms. In general for hurricanes a 30% increase in precip occurs but whether manifested at one place depends on speed of storm.
Please check out the paper which is not behind a paywall
“…we also need to better adapt to the types of extremes we have already experienced in the past.”
Such a key point. A lot of vulnerability could be reduced just by designing for past events.
It was Hurricane Hazel in 1954 that prompted a great deal of storm preparedness in Ontario probably preventing a lot of loss that otherwise would’ve occurred in following years
Sure but adaptation to current conditions is a good first step that has the advantage of not getting caught up in negative polarization. We don’t need to risk adaptation following in the footsteps of vaccines (yet).
The hydrological cycle is earth's AC: ice-->water-->water vapor--> outer space, as it works to reduce the heat energy imbalance that we are building primarily from burning fossil fuels, 8 billion tons of coal/yr., and 100M barrels of oil/day, thus releasing heat energy, and the GHGs sequestering solar radiation as IR heat. The massive amounts of melting global ice, 1.2 trillion tons/yr., and heating 321 million cubic miles of oceans already at 70degF at midlatitudes, is driving 1-1.4 trillion tons of water vapor into the atmosphere. So, it's like my ole Ma used to say: what goes up must come down, and there are 10-14 trillion tons of water vapor in the atmosphere at any one time, as it only remains there for 10-14 days before falling back down to the surface as snow, ice (hail), or rain, and all the while providing increasing heat energy to drive ever bigger moisture laden storms, like Helene. Data from C3S indicates a 0.2 degC ANNUAL ave global temp increase, so 1 degC increase every 5 yrs., which NONE of the academic "expert" models have reported. Do some of your won research on the net, I did. Good luck and may God help us if we don't dramatically reduce our own individual carbon footprints.
Polymath, Eliot Jacobson, has calculated that our current heat energy imbalance is the equivalent of at least 20+ Hiroshima nuclear bomb blasts PER SECOND, and each one releases 63 trillion BTUs. Our mindless continued burning of fossil fuels and the resultant solar IR radiation from the GHGs are the reasons. Answer your question?
When a community experiences a 1000 flood and 2 100uear goods in 2 years, one can say we have reached a tipping point. Cannot remember the community but read it this week
JAM: "I can practically guarantee most catchments are far less resilient to precipitation than ever before, resulting in faster more damaging discharges."
JAM: "Somehow watershed planning and awareness has dropped several notches since the fashionable CO2 problem took over."
Uh. That might be true, but how do you know? Bearing in mind that every flood has multiple contributing physical causes, many of them with trends that track human cultural fashions. Examples on display now are the extirpation of beavers for hats before about 1840, and later cut'n'run logging followed by overgrazing. Watershed restoration is said to have originated in Asheville in the 1890s. It would be interesting to correlate metrics of restoration and management effort since then with historical flooding trends for individual watersheds. Has that been done, to your knowledge?
As for CO2 being "fashionable": snort! Global warming isn't the sole cause of Hurricane Helene's destruction, but anthropogenic GHGs are the sole cause of global warming, fashionable or not. If you just want to promote watershed restoration, you don't need to deny that CO2 contributed to the magnitude of Asheville's tragedy!
We adapt neither for today’s climate nor for that of tomorrow. We also do not take enough preventive action to mitigate climate change and avoid its impacts. A failure of homo sapiens, unfortunately.
i.e. "Early modeling results suggest" is not "Climate change made". I amy suspect that the modelling is valid, but why mislead like a sensationalist newspaper. I send climate sceptics to your site because your discussions tend to be balanced - but your headlines certainly aren't and it gives them the impression of just another sensationalist blog. The first line always matters, as when giving a talk....you grab people then or you don't. They are the ones who need convincing, not your regular "believers".
Comments like "In 1916 the remnants of a hurricane caused the Swannanoa River at Biltmore NC, near Asheville, to rise to 20.7 feet, a record that was only surpassed last week when the river reached 26.1 feet in the aftermath of hurricane Helene" are near meaningless. Are you suggesting that land change over 108 years does not affect runoff and river levels? Things like this, numbers of people or homes affected, area affected, value of damage done have no place in serious discussion. Same with fires (eg the area affected by western USA fires had been steadily decreasing until the last couple of decades but the human impact increasing (because the population in the forested mountains had increased by 800%). Things like rainfall and leaf moisture are absolutes and are available data nowadays, not this other "evidence".
Nobody cares. Recognizing changes in catchment characteristics would require individuals and communities to take real responsibility and action. Instead, we’re told that simply voting for the right national candidate will prevent catastrophic floods. It's nutty but here we are. A river stage rising from 20 to 26 feet over 100 years is solely blamed on CO2—an oversimplification that suits investment portfolios more than anything else.
I don't think anybody is saying both things can't be true. Of course land use changes are impactful, but such can also be exasperated by the impacts of climate change.
Once more time: climate change was a contributing cause, not the sole cause, of Helene's historic rainfall amount. Global warming only made it between 20% and 50% heavier than it would have been otherwise (nytimes.com/2024/10/02/opinion/hurricane-helene-climate-change.html and links therein). Mr. Hughes is asking for more evidence than climate specialists require to make the connection.
And no, you don't need to see pigs fly to imply they smell bad in the air, because there's already a consensus of mammalogists that they smell bad on the ground ("If I have seen further, it is by standing on the shoulders of giants" -I. Newton), and good old Occam's Razor implies they smell bad in the air too. MJH's view of scientific culture and practice is naive. Scientists don't waste time arguing about truth that's already established, or else there'd be no scientific progress.
With respect to climate change and extreme weather, physical climatic factors, e.g. the historically high surface water temperature in the Gulf of Mexico, both accelerated Helene's winds and enhanced the total amount of water it transported inland. Dr. Ricky Rood says,
“The climate is so warm that every storm or weather event is influenced by a warming climate. It’s impossible to have an event, especially an extreme event, that doesn’t have some relation to climate change.”
IOW, the anthropogenic contribution to the average intensity (wind speed, rainfall amount, latitudinal excursion) of hurricanes is "confirmed to such a degree that it would be perverse to withhold provisional assent" (SJ Gould). "Provisional" means it's up to you to provide evidence to the contrary, not the other way around. BTW, the word both Bernt and MJH are thinking of is "exacerbated".
It is clearly implied that the river rise of that amount is caused by climate change with no evidence to support that. Pigs might fly but you need to see one with wings before you can imply that they cause a bad smell in the air. Science is not about "things that cant be true" it is about evidence for things that support truth and which lack evidence to the contrary. And yes it is exasperating.....it has become the norm in climate articles to present supposition as fact. It will never convert "deniers" as it is too transparently just "propaganda" and does not deserve to be here.
Your headlines are commonly unreasonable even though your articles themselves are mostly accurate and qualified. I don't question that Helene may have been stronger because of climate change but I do find weaknesses in many studies (eg hurricanes appear to have been worse in the 18th C than the 20th but because we don't have accurate measurements this is not included in models (understandably) and not mentioned (less understandably). Written records suggest far worse for some (despite the presence of less people and property to be impacted.
I am a bit confused by your figure tit;ed:"Percent change in heavy precipitation per degree warming, defined as the heaviest daily precipitation event of the year for each location".
Doesn't that only show a maximum 14% increase for a full degree of warming?
It does, though the event we are seeing today is a less than once in a year event, as as the piece notes there is reason to expect some superscaling of the CC relationship from tropical cyclones.
To the extent that the flooding can be attributed to the accumulation of CO2 in the atmosphere, does that no also imply that additional investments in hardening infrastructure, slowing run-off, making residential and commercial assets let vulnerable? Were adaption investments have higher NPV with the CO2 accumulation than without it?
I have written a LOT on hurricanes and climate change, lots of summary info here:
Trenberth, K. E., L. Cheng, P. Jacobs, Y. Zhang, and J. Fasullo, 2018: Hurricane Harvey links to ocean heat content. Earth's Future, 6, 730-744, Doi: 10.1029/2018EF000825 [PDF]
available at my web site.
Basically there is more energy available and more activity is expected. This can occur in several ways:
more intensity
Bigger
longer lasting
heavier rainfalls.
The first 3 are not independent of the last one. There is good evidence for all of these but not strong observations on duration and size. Eyewall replacements lead to bigger storms. In general for hurricanes a 30% increase in precip occurs but whether manifested at one place depends on speed of storm.
Please check out the paper which is not behind a paywall
Keviun Trenberth
Kevin: we would welcome a guest post about your work on this ;)
“…we also need to better adapt to the types of extremes we have already experienced in the past.”
Such a key point. A lot of vulnerability could be reduced just by designing for past events.
It was Hurricane Hazel in 1954 that prompted a great deal of storm preparedness in Ontario probably preventing a lot of loss that otherwise would’ve occurred in following years
https://www.heritagetrust.on.ca/pages/programs/provincial-plaque-program/provincial-plaque-background-papers/hurricane-hazel
But can't adaptation be _even better_ based on climate model-informed expectations, better that is than relying on past events alone.?
Sure but adaptation to current conditions is a good first step that has the advantage of not getting caught up in negative polarization. We don’t need to risk adaptation following in the footsteps of vaccines (yet).
Thanks for all your work keeping us educated and informed. I’m so glad I found your posts!
The hydrological cycle is earth's AC: ice-->water-->water vapor--> outer space, as it works to reduce the heat energy imbalance that we are building primarily from burning fossil fuels, 8 billion tons of coal/yr., and 100M barrels of oil/day, thus releasing heat energy, and the GHGs sequestering solar radiation as IR heat. The massive amounts of melting global ice, 1.2 trillion tons/yr., and heating 321 million cubic miles of oceans already at 70degF at midlatitudes, is driving 1-1.4 trillion tons of water vapor into the atmosphere. So, it's like my ole Ma used to say: what goes up must come down, and there are 10-14 trillion tons of water vapor in the atmosphere at any one time, as it only remains there for 10-14 days before falling back down to the surface as snow, ice (hail), or rain, and all the while providing increasing heat energy to drive ever bigger moisture laden storms, like Helene. Data from C3S indicates a 0.2 degC ANNUAL ave global temp increase, so 1 degC increase every 5 yrs., which NONE of the academic "expert" models have reported. Do some of your won research on the net, I did. Good luck and may God help us if we don't dramatically reduce our own individual carbon footprints.
— W H A T I S THE R E A L REASON FOR THE INCREASED HEAT LEVELS —- ⁉️⁉️⁉️⁉️⁉️⁉️⁉️⁉️⁉️⁉️⁉️
Human emissions of CO2 and other greenhouse gases, mediated by human emissions of aerosols.
Polymath, Eliot Jacobson, has calculated that our current heat energy imbalance is the equivalent of at least 20+ Hiroshima nuclear bomb blasts PER SECOND, and each one releases 63 trillion BTUs. Our mindless continued burning of fossil fuels and the resultant solar IR radiation from the GHGs are the reasons. Answer your question?
When a community experiences a 1000 flood and 2 100uear goods in 2 years, one can say we have reached a tipping point. Cannot remember the community but read it this week
or there's something wrong with how statistical methods are applied and communicated.
Maybe, but how do you know that? Have you taken any statistics courses?
yes, somehow watershed planning and awareness has dropped several notches since the fashionable CO2 problem took over.
In some ways this might be net damaging, hard to say for sure. There is no glory in conserving river catchments.
I can practically guarantee most catchments are far less resilient to precipitation than ever before, resulting in faster more damaging discharges.
JAM: "I can practically guarantee most catchments are far less resilient to precipitation than ever before, resulting in faster more damaging discharges."
Yes, that's a trend that began with the spread of intensive agriculture (link.springer.com/article/10.1007/s11069-020-03898-w). When tree cover declines and more ground is disturbed, runoff is more rapid and flood crests are higher. Fortunately for investigators, precipitation runoff is closely monitored all over N. America, including Asheville (water.noaa.gov/gauges/bltn7). Changes in watershed vegetation cover are also tracked (link.springer.com/article/10.1007/s100219900052).
JAM: "Somehow watershed planning and awareness has dropped several notches since the fashionable CO2 problem took over."
Uh. That might be true, but how do you know? Bearing in mind that every flood has multiple contributing physical causes, many of them with trends that track human cultural fashions. Examples on display now are the extirpation of beavers for hats before about 1840, and later cut'n'run logging followed by overgrazing. Watershed restoration is said to have originated in Asheville in the 1890s. It would be interesting to correlate metrics of restoration and management effort since then with historical flooding trends for individual watersheds. Has that been done, to your knowledge?
As for CO2 being "fashionable": snort! Global warming isn't the sole cause of Hurricane Helene's destruction, but anthropogenic GHGs are the sole cause of global warming, fashionable or not. If you just want to promote watershed restoration, you don't need to deny that CO2 contributed to the magnitude of Asheville's tragedy!
We adapt neither for today’s climate nor for that of tomorrow. We also do not take enough preventive action to mitigate climate change and avoid its impacts. A failure of homo sapiens, unfortunately.
Zeke, thanks for this early, preliminary summary. zf
i.e. "Early modeling results suggest" is not "Climate change made". I amy suspect that the modelling is valid, but why mislead like a sensationalist newspaper. I send climate sceptics to your site because your discussions tend to be balanced - but your headlines certainly aren't and it gives them the impression of just another sensationalist blog. The first line always matters, as when giving a talk....you grab people then or you don't. They are the ones who need convincing, not your regular "believers".
Comments like "In 1916 the remnants of a hurricane caused the Swannanoa River at Biltmore NC, near Asheville, to rise to 20.7 feet, a record that was only surpassed last week when the river reached 26.1 feet in the aftermath of hurricane Helene" are near meaningless. Are you suggesting that land change over 108 years does not affect runoff and river levels? Things like this, numbers of people or homes affected, area affected, value of damage done have no place in serious discussion. Same with fires (eg the area affected by western USA fires had been steadily decreasing until the last couple of decades but the human impact increasing (because the population in the forested mountains had increased by 800%). Things like rainfall and leaf moisture are absolutes and are available data nowadays, not this other "evidence".
Nobody cares. Recognizing changes in catchment characteristics would require individuals and communities to take real responsibility and action. Instead, we’re told that simply voting for the right national candidate will prevent catastrophic floods. It's nutty but here we are. A river stage rising from 20 to 26 feet over 100 years is solely blamed on CO2—an oversimplification that suits investment portfolios more than anything else.
I don't think anybody is saying both things can't be true. Of course land use changes are impactful, but such can also be exasperated by the impacts of climate change.
Once more time: climate change was a contributing cause, not the sole cause, of Helene's historic rainfall amount. Global warming only made it between 20% and 50% heavier than it would have been otherwise (nytimes.com/2024/10/02/opinion/hurricane-helene-climate-change.html and links therein). Mr. Hughes is asking for more evidence than climate specialists require to make the connection.
And no, you don't need to see pigs fly to imply they smell bad in the air, because there's already a consensus of mammalogists that they smell bad on the ground ("If I have seen further, it is by standing on the shoulders of giants" -I. Newton), and good old Occam's Razor implies they smell bad in the air too. MJH's view of scientific culture and practice is naive. Scientists don't waste time arguing about truth that's already established, or else there'd be no scientific progress.
With respect to climate change and extreme weather, physical climatic factors, e.g. the historically high surface water temperature in the Gulf of Mexico, both accelerated Helene's winds and enhanced the total amount of water it transported inland. Dr. Ricky Rood says,
“The climate is so warm that every storm or weather event is influenced by a warming climate. It’s impossible to have an event, especially an extreme event, that doesn’t have some relation to climate change.”
IOW, the anthropogenic contribution to the average intensity (wind speed, rainfall amount, latitudinal excursion) of hurricanes is "confirmed to such a degree that it would be perverse to withhold provisional assent" (SJ Gould). "Provisional" means it's up to you to provide evidence to the contrary, not the other way around. BTW, the word both Bernt and MJH are thinking of is "exacerbated".
It is clearly implied that the river rise of that amount is caused by climate change with no evidence to support that. Pigs might fly but you need to see one with wings before you can imply that they cause a bad smell in the air. Science is not about "things that cant be true" it is about evidence for things that support truth and which lack evidence to the contrary. And yes it is exasperating.....it has become the norm in climate articles to present supposition as fact. It will never convert "deniers" as it is too transparently just "propaganda" and does not deserve to be here.
Why no security on your website - every time I sign up or log in it asks again for my "handle" yet never uses it and always prints my full name!
I’ve been telling Zeke to fix this. Thanks for bringing it up — hopefully he’ll get around to it.
Your headlines are commonly unreasonable even though your articles themselves are mostly accurate and qualified. I don't question that Helene may have been stronger because of climate change but I do find weaknesses in many studies (eg hurricanes appear to have been worse in the 18th C than the 20th but because we don't have accurate measurements this is not included in models (understandably) and not mentioned (less understandably). Written records suggest far worse for some (despite the presence of less people and property to be impacted.
I am a bit confused by your figure tit;ed:"Percent change in heavy precipitation per degree warming, defined as the heaviest daily precipitation event of the year for each location".
Doesn't that only show a maximum 14% increase for a full degree of warming?
It does, though the event we are seeing today is a less than once in a year event, as as the piece notes there is reason to expect some superscaling of the CC relationship from tropical cyclones.
To the extent that the flooding can be attributed to the accumulation of CO2 in the atmosphere, does that no also imply that additional investments in hardening infrastructure, slowing run-off, making residential and commercial assets let vulnerable? Were adaption investments have higher NPV with the CO2 accumulation than without it?