Guest post by Chip Knappenberger (above graphic by Anthony)
The press has been quick to jump on the idea that post-tropical cyclone Sandy (it was not a hurricane at landfall) was worsened by anthropogenic global warming and that “superstorms” are here to stay.
But I must ask the impertinent question: could anthropogenic global warming actually have lessened the impacts of Sandy?
There are basically three pro-global warming talking points involving Sandy: 1) global warming has caused sea levels to rise, thus making the storm surge larger, 2) global warming has led to higher sea surface temperatures and thus stronger hurricanes, and 3) global warming is making extratropical circulation features more conducive to intense and slower moving storm systems.
There is precious little evidence to definitively support any of these points when applied to Sandy, and, in fact, there exists a body of evidence pointing to the opposite conclusion—that anthropogenic global warming may have actually acted to mitigate the intensity of Sandy. Perhaps what lies closest to our current best understanding is that anthropogenic global warming made little contribution one way or the other.
Let’s start with sea level rise. Water levels at New York City’s Battery Park location have been measured and recorded since 1856. The full record shows an overall (relatively steady) rise of about 0.11 inches per year, for a total rise between 1856 and now of just a bit more than 17 inches. How much of this has to do with anthropogenic global warming? Maybe a third, or about 6 inches. Of the rest, about half was caused by a subsidence of the land (geological processes related to the end of the last ice age, see Engelhart et al., 2009 for example), and the remainder to a warming up from the naturally occurring cold period which ended in the mid-19th century. So of the total 17.34 feet of water (above the station datum) recorded at The Battery tide gauge during the height of Sandy, about 0.5 feet of that could probably be linked to anthropogenic global warming. This is not nothing, but the overwhelming majority of the damage done by the storm surge would have happened anyway. For comparison, the influence of the full moon that night was about as large as the influence of anthropogenic global warming.
As to anthropogenic global warming’s impact on the path, frequency, and intensity of hurricanes, there is a mixed bag of potential outcomes which may be detectable far in the future (towards the end of the century) if anthropogenic greenhouse gas emissions continue to rise. The current science suggests that the frequency of hurricanes could decrease, the intensity may increase slightly, and the preferred path may be displaced out to sea (Wang et al., 2010). The net effect on the U.S. is anyone’s guess at this point (but 2 of the 3 argue for fewer hurricane impacts in the U.S.). But what virtually everyone does agree upon is that any influence of anthropogenic global warming on hurricane characteristics is not detectable in today’s climate (see for example, Knutson et al., 2010). So that talking point is basically off the table.
Which brings us to the third global-warming-made-Sandy-worse talking point—the influence of anthropogenic global warming on the extratropical circulation characteristics.
This is where the rubber really meets the road when it comes to Sandy’s behavior. Without the northward, and ultimately westward pull from the upper atmospheric jet stream, Sandy would have progressed harmlessly eastward, away from the Northeast coast, and out to sea. But that is not what happened. Instead, a fairly deep trough (southward excursion) of the jet stream was coincidentally passing through the eastern U.S. just as hurricane Sandy was progressing up (but offshore) the U.S. Eastern Seaboard. This trough had the effect of attracting Sandy, and drawing it northwestward, pumping energy into it, and changing its character from a hurricane to an extra/post tropical storm system (also known as a Nor’easter in this part of the country). In October, this type of behavior is not particularly unusual. The preferred tropical cyclone track maps provided by the National Hurricane Center (Figure 1) indicate a general tendency for tropical cyclones in October to curve back into the northeastern U.S.—just like Sandy did.
In fact, since the beginning of the 20th century, there have been about a dozen or so tropical cyclones that have made landfall in the U.S. north of Cape Hatteras which had a westerly component to their trajectory either immediately before or just after they came ashore. This includes historically damaging storms such as the 1903 New Jersey hurricane, the 1938 Long Island Express hurricane, and 1972’s Hurricane Agnes which is still the flood of record in many parts of the Northeast.
The last one was tropical storm Danielle, over twenty years ago. This is the longest interval in the record (since 1900) between westward-component storms north of Hatteras. So much for the influence of global warming!
So, given this fairly typical behavior—why would anyone even consider that anthropogenic global warming played a role in Sandy?
For two reasons: 1) any bad weather these days is immediately linked to global warming by someone with an agenda, and 2) there was a paper published last spring (Francis and Vavrus, 2012) in which the authors concluded that the decline of Arctic sea ice (tied to anthropogenic global warming) was causing the Arctic to warm up faster than the lower latitudes, reducing the natural north-south temperature gradient which is where the jet stream (and extratropical storms) gain energy. According to Francis and Vavrus, a less energetic jet stream contracts and becomes more meandering, with relatively deeper troughs and higher ridges which produce slower moving storm systems and more extreme weather.
Since Sandy was strengthened and pulled ashore by a deep trough/ridge system in the jet stream, folks are quick to assume that the Francis and Vavrus mechanism tying in anthropogenic global warming must be involved.
Not so fast!
This is like claiming to have made a new discovery that, when flipping a coin, heads are now more likely to occur than tails. And wouldn’t you know, the next time the coin is flipped, it came up heads—to which you proclaim, “See, I told you so.” And since heads are associated with a bad outcome, the press flock to your explanation. But what is completely overlooked, is that other researchers have examined every coin flip for the past 60 years and found that heads and tails occur with equal likelihood. So the current heads outcome is simply part of the natural 50-50 occurrence of heads or tails.
In this case, the other researchers are a pair of atmospheric scientists from Cornell University which have examined the forward speed of all nor’easters along the East Coast from 1951 through 2006 (Bernhardt and DeGaetano, 2012). And what they found, in their own words, was “There was no clear trend in [nor’easter forward] speed during the time period, although considerable season-to-season variability was present.” In other words, while there is a lot of storm-to-storm and season-to-season variability, there is no overall trend towards slower moving nor’easters (Figure 2)—so much for the Francis and Vavrus hypothesis.
And, there has been a lot of other research on changes in the patterns and characteristics of the Northern Hemisphere jet stream during the period of anthropogenic global warming which did not find that same thing that Francis and Vavrus found (we detailed many of these findings in our March 8, 2012 Current Wisdom). At least one of those papers suggested that the methodology employed by Francis and Vavrus “can generate false, or mask actual, variability patterns including trends” (Strong and Davis, 2007). Others concluded that global warming contracted, the jet stream, flattened it over the eastern U.S., and sped it up a bit—characteristics, which, along with a decreased temperature gradient, if applied to Sandy, would have combined to produce a less intense post tropical storm system than if global warming had not been occurring.
So rather than anthropogenic global warming making Sandy worse, it could have actually lessened its intensity and impacts.
The truth is, is that it is impossible to know how, or even if, global warming played any role at all in the lifecycle of Sandy. The science is all over the map, and the signal-to-noise ratio is so low that no matter what is occurring its impact in any direction is undetectable.
But it is sexier and has much more press appeal to proclaim that the destruction wrought by “superstorm” Sandy is the product of our unrestrained fossil fuel consumption, rather than the equally plausible opposite—that anthropogenic climate changes may have combined to lessen Sandy’s intensity.
References:
Bernhardt, J.E., and A.T. DeGaetano, 2012. Meteorological factors affecting the speed of movement and related impacts of extratropical cyclones along the U.S. east coast. Natural Hazards, 61, 1463-1472, doi:10.1007/s11069-011-0078-0
Engelhart, S.E., et al., 2009. Spatial variability of late Holocene and 20th century sea-level rise along the Atlantic coast of the Unites States. Geology, 37, 1115-1118.
Francis, J., and S. Vavrus, 2012. Evidence linking arctic amplification to extreme weather in mid-latitudes. Geophysical Research Letters, 39, L06801, doi:10.1029/2012GL051000.
Knutson, T. R., et al., 2010. Tropical cyclones and climate change. Nature Geoscience, 3, 157-163, doi: 10.1038/ngeo779
Strong, C., and R. Davis, 2007. Winter jet stream trends over the Northern Hemisphere. Quarterly Journal of the Royal Meteorological Society, 133, 2109-2115, doi:10.1002/qj.171
Wang, C., et al., 2011: Impact of the Atlantic warm pool on United States landfalling hurricanes. Geophysical Research Letters, 38, L19702, doi:10.1029/2011GL049265.
Global Science Report is a weekly feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”
Related articles
- IPCC – “Sandy Was Not Caused By Anthropogenic Global Warming” (toryaardvark.com)
- NOAA Climate Investigator – No link between Sandy and Global Warming (iceagenow.info)
- Tisdale: Where’s The Anthropogenic Global Warming Signal in the NODC Ocean Heat Content Data (0-700Meters)? (wattsupwiththat.com)
- There will probably be fewer Sandy-like storms in the future (chron.com)
- Climatologist says Sandy not caused by global warming. (wsfa.com)
- Gore blames ‘global warming’… (washingtontimes.com)
from the article:
” there exists a body of evidence pointing to the opposite conclusion—that anthropogenic global warming may have actually acted to mitigate the intensity of Sandy”
so far as i can tell, nobody has substantiated the belief in anthropogenic global warming in the first place.
you’ve heard of a ‘loaded question’? meet the ‘loaded answer’.
the technique of smuggling a hidden premise is a well known tool of the propagandist.
the effects of the belief in something unwarranted are well known.
I contend that reduced anthropogenic aerosols over the east coast USA urban conurbations likely had a greater impact on Sandy than GHG warming, by decreasing precipitation and increasing central pressure and hence wind speed, with a secondary effect from increased SSTs due to reduced aerosol seeded clouds.
Aerosol Effects on Intensity of Landfalling Hurricanes as Seen from Simulations with the WRF Model with Spectral Bin Microphysics
http://journals.ametsoc.org/doi/abs/10.1175/2009JAS3210.1?journalCode=atsc
This has been known for at least 50 years and shown experimentally by seeding the outer bands of hurricanes.
@Chip
Well written and easily understood.
@rgb
Also very well argued and complete. A nice piece of writing.
Of all the hollow things claimed as proof of AGW the “super-storm” Sandy has to gong the loudest. What a boatload of crap.
I am sorry for all those who continue to suffer from the after-effects of the storm. For such an unprepared city as NYC it could easily have been far worse if the storm was more compact and had a well-developed eye.
Even Karl has his say on the subject. I think it fair to say that the same old, tired, nodding heads have been trying to “connect the dots” and force poor old Sandy to join their team.
http://market-ticker.org/akcs-www?post=213526
regards
Jimbo says:
November 5, 2012 at 1:22 pm
That’s only temporary. That other science journalist who became temporarily famous by pieing Lomborg also uttered something like that at one point. Don’t know his name anymore, too many of them throw stuff at people with a different opinion. Appell is still convinced we’re about to kill the Polar Bear.
Joachim Seifert says:
November 5, 2012 at 10:28 am
“Why should the central government chip in for stupidness of individuals, who do not
pay their insurance……?? JS”
But the US government chips in for everybody who pays his insurance as well as they have artificially cheap federal insurance. They wouldn’t get a private company that insures them in that spot. Why? Buying votes.
Jimbo
try this link
http://en.wikipedia.org/wiki/1620-1639_Atlantic_hurricane_seasons
the 1635 hurricane was of particulat note as it caused a 22 foot storm surge. many ships logs are being digitised and may add to the list but the population was so small at the time that many hurricanes would have gone unrecorded and unseen.
tonyb
Code tech
[If AGW believers truly believed that Sandy represents “the new normal”, they would be vocal proponents of better preparedness and more intelligent design and construction of buildings and neighborhoods. Since their sole urging seems to be more about profit making and increased taxation to force others to use less petroleum, I have to assume that most don’t actually believe what they are so loudly claiming.]
Every rational person should be such a vocal proponent, IMHO.
IMHO, the only way in which Sandy may represents evidence of global warming is if (a) its uniqueness is representative of a ‘new normal’, which we don’t know and (b) if changes to Arctic and sub-Arctic circulation patterns contributed to Sandy’s unique nature and this is a harbinger of a ‘new normal’ in Atlantic storm dynamics, which we also don’t know. What we do know is that climate change is slow, so we will have plenty of time to find out.
Regardless of whether Sandy representst the ‘new normal’ your point is well-made. Residents who accept risks by building in high risk areas in dwellings unsuitable to cope with the risks should carry the risk, not the rest of us premium payers and taxpayers. I would include the following as relevant risks:
(1) storms
(2) floods
(3) hail
(4) wildfire
(5) heat
(6) earthquake
(7) tsnuami
(8) drought
(9) coastal processes (deposition, erosion)
(10) avalanches
(11) preciptitation events
(12) tornadoes
(13) volcanoes
(14) sea level change
They should manage the risks by:
(1) not building in high risk areas
(2) erecting buildings that can cope with the risks
(3) paying extra for infrastructure because infrastructure in high risk areas is usually more expensive.
(4) paying a regular levy for the maintenance of rescue crews and equipment as well as for standing amounts of supplies of emergency shelters, health products, emergency sanitation and emergency water supplies.
There has been some discussion about whether Sandy is ‘unprecendented’. This misses the point, IMHO. The insurance premium increases as a result of Sandy will definitely be unprecedented in the sense that they will not have happened before. These increases represent an unfair transfer of risk from the risk takers to the rest of us.
Meanwhile, the fossil fuel burning advocates are telling us that their ‘risks’ are not as ‘real’ as the changes in risks to all of the above to all of the rest of us. OTOH, those who want toaddress the fossil burning risks want us to transfer risks from future generations to the current generation.
One thing is for certain: there are no certainties in risk management.
This morning’s American Society of Civil Engineers SmartBrief carried top story items:
ASCE warned years ago NYC faced huge storm-surge threat
ASCE warned of a major storm-surge threat to New York City during a 2009 seminar where it proposed measures designed to reduce risks. “Scientists and engineers were saying years before Katrina happened, ‘Hey, it’s going to happen, folks. Stop putting your head in the sand,'” said Malcolm Bowman of the State University of New York. The “most workable plan” would be the construction of a nearly five-mile barrier from Sandy Hook, N.J., to the Rockaway Peninsula, and another barrier across the East River, according to Bowman. The New York Times (tiered subscription model) (11/4)
Link to full NY Times article is:
http://www.nytimes.com/2012/11/05/nyregion/in-2009-engineers-detailed-storm-surge-threat-to-new-york-city.html?_r=0
The second article covers protecting the city before the next storm:
http://www.nytimes.com/2012/11/04/nyregion/protecting-new-york-city-before-next-time.html
This sort of article is misguided. How in the world can skeptics scoff at the alarmists who shout “AGW makes weather events worse” and then concede that AGW makes weather events less worse? Haven’t we just admitted AGW has a major effect on isolated weather events, which is what the alarmists are trying to get everyone to believe? We go from arguing that AGW cannot influence weather generally and step three paces back to saying that of course it can, but only in good ways. wtf? Try making THAT case to the public after each devastating weather event.
Stop helping Chip.
Using simplistic Boolean logic, [A] the large cold-front was certainly Not caused by Global Warming and appears to be the result of the onset of an early winter being experienced across the Northern Hemisphere.
[A] :=False.
[B] the tropical cyclone ‘Sandy’ with hurricane force winds recorded offshore (it was not a hurricane at landfall) and it appeared during a normal hurricane season during a mild El Nino at the height of solar activity, It also had the component of a high tide. By it’s self, would ‘Sandy’ be considered unusual? certainly Not.
[B]:=False
[C] Is there a component to this ‘post-tropical cyclone’ caused by global warming? A+B=C
[C] = False.
This storm was simply two natural and separate systems forming under different circumstances and (opposites attract) they began interacting to form a larger cyclone formation which grew weaker and dissipated after land fall.
IMHO at the time, as I was watching the formation of these two systems I did wonder if the cold front would attract sandy westward.
Mr Black says:
November 5, 2012 at 2:58 pm
This sort of article is misguided. How in the world can skeptics scoff at the alarmists who shout “AGW makes weather events worse” and then concede that AGW makes weather events less worse?
——————————————————————-
Above conclusions are not referring to the single weather event but the likelyhood of such events.
And keep in mind that historic MEASURED data suggests, that there have been more severe storms during the little ice age. SOME climate alarmists suggest that SOME MODELS suggest, there MAY be more severe storms IF temperatures rise.
This is historical evidence versus MODELS with IFs and MAYBEs.
Beyond that, Pierce Corbyn (and others) see a direct connection between the “unusual” location of the waether pattern controlling Jet Stream,and solar activity. Again, historic evidence and correlations, not a computer model.
Here is a hurricane that finally petered out in Newfoundland – it supported the American Revolution by destroying British ships – it was an October one too.:
http://en.wikipedia.org/wiki/List_of_deadliest_Atlantic_hurricanes
“The Great Hurricane of 1780, also known as the Hurricane San Calixto II, is the deadliest Atlantic hurricane on record. Well over 25,000 people died when the storm passed through the Lesser Antilles in the Caribbean between October 10 and October 16. The hurricane struck Barbados with wind gusts possibly exceeding 320 km/h (200 mph), before moving past Martinique, Saint Lucia, and Sint Eustatius; thousands of deaths were reported on each island. Coming in the midst of the American Revolution, the storm caused heavy losses to British and French fleets contesting for control of the area. The hurricane later passed near Puerto Rico and over the eastern portion of the Dominican Republic, causing heavy damage near the coastlines, and ultimately turned to the northeast before being last observed on October 20 southeast of Cape Race, Newfoundland.”
Sandy was a wuss in comparison and the CO2 was what? 300 ppm?
Guest Blogger Said
“‘Instead, a fairly deep trough (southward excursion) of the jet stream was coincidentally passing through the eastern U.S. just as hurricane Sandy was progressing up (but offshore) the U.S. Eastern Seaboard. This trough had the effect of attracting Sandy, and drawing it northwestward, pumping energy into it, and changing its character from a hurricane to an extra/post tropical storm system (also known as a Nor’easter in this part of the country)”
No, that is incorrect. Storms occur when warm, moist air masses collide with cold, dry air masses. The energy that is released during the storm originates in the water in the warm, moist air mass, not the cold ,dry air mass.The coldness and dryness of the cold, dry air mass only causes more of the energy in the warm, moist air mass to be released. The cold, dry air mass does not “pump energy” into a storm.
Stop misinforming people. There is enough of that already.
Even Trenberth seems to have become remarkably constrained (perhaps recognizing that the average person can very easily read up on historical records):
http://www.livescience.com/24377-weather-climate-hurricane-sandy.html :
There currently is no “global warming”
http://www.woodfortrees.org/plot/hadcrut4gl/from:2002/to:2012/plot/hadcrut4gl/from:2002/to:2012/trend/plot/hadcrut3vgl/from:2002/to:2012/plot/hadcrut3vgl/from:2002/to:2012/trend
but there is a strong cooling trend of ca. -0.04 degree C per year on maxima
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
which is likely to be added to the normal polar/equator differential and the autumn differential thereby causing more clouds and potentially bigger weather systems in the NH.
I am a bit worried we are not out of the woods yet. There could be a few more of these storms in this decade.
When Trenberth refers to climate change, he doesn’t say by what cause. He could be referring to climate change caused by GHGs, aerosols, solar variation, ocean cycles, land use changes, etc.
This is quite deliberate. Trying to equate all causes of climate change with CO2/GHG caused climate change.
Hoe can you claim that AGW caused a 6in rise in sea levels since 1858? The AGW theory has yet to find definitive proof that it happens. Dr. Richard Lindzen has been looking for over 40 years and has yet to find any. Your claim is a leap of faith.
“So of the total 17.34 feet of water (above the station datum) recorded at The Battery tide gauge during the height of Sandy …. ”
===========
17.34 ?
****
Howskepticalment says:
November 5, 2012 at 2:36 pm
Meanwhile, the fossil fuel burning advocates are telling us that their ‘risks’ are not as ‘real’ as the changes in risks to all of the above to all of the rest of us.
****
Unless you walk wherever you go, don’t use electricity, don’t live in a heated house, don’t use manufactured goods, don’t eat anything other than purely “organic” food, etc, etc, etc, then you must be a “fossil fuel burning advocate” because nobody is forcing you to do these things — you do them voluntarily.
Jeff says:
“Okay, agreed then: anthropogenic global warming is a reality.”
Thanks, ‘Captain Obvious’. If you’ve been following this debate for more than three hours, you already know that skeptics and climastrologists agree on three main issues:
1. Climate change is occurring. – Yes, it’s been occurring for 3.8 billion years and will continue to occur until the sun burns out.
2. The Earth is getting warmer. – Thankfully, since the end of the last ice age (approximately 15,000 years ago), the Earth has been getting progressively warmer. When climate change shifts in the other direction, things are going to get ugly for a really long time.
3. Humans are contributing to the warming trend. – No doubt. The only issues still being debated are how much, and how do we know?
Climastrologists believe the release of anthropogenic CO2 will have a catastrophic impact on our climate. Their belief is based primarily on computer generated climate model projections and double-secret statistics. Skeptics aren’t convinced. We want to see reproducible, empirical data that clearly demonstrates how much impact humans are having, and what the effects will be.
You apparently believe humans are having a greater impact on the climate than most of us here. As skeptics, we welcome any and all empirical data that supports your beliefs. If you have some, please present it; if not, vaya con Dios.
There have been a few here that suggest that anthropogenic climate change or man-made global warming is not happening. Do they really mean that it is definitely not happening, or that there is no evidence of it?
The science is pretty clear that adding CO2 to the atmosphere, like we humans do, and all else being equal, the CO2 will cause some warming. For a doubling of CO2, that warming is near 1 degree C. (+/- about three tenths of a degree). Beyond that, the science is very unclear. First of all, nothing is equal. Everything is in flux. So there is a great deal of uncertainty, even before we get to the arguments about positive and negative feedbacks.
I tend to believe that natural climate variability is far greater than 1 degree C, and that feedbacks for increasing CO2 are negative, meaning that the human influence on global temperature will always be less than one degree, even if CO2 is doubled from pre-industrial levels. In other words, anthropogenic climate change is not a crisis (and might even be largely beneficial). Spending any money combating it is a waste and counterproductive.
Yet, I believe that humans are having a warming influence, even though it is a small one. If global temperatures cool over the next few decades, as I believe they will, I will still believe that humans are having a warming effect. It will be swamped by natural variability and, again, (the human effect is) largely beneficial.
So I ask for a clarification from those of you who say it (man-made global warming) isn’t happening. Do you mean that increasing CO2 in the Earth’s atmosphere is not having any impact, that humans are not responsible for the increasing CO2, or that the increase in CO2 may be having an impact, but it is too small to differentiate from natural climate fluctuations?
“How much of this has to do with anthropogenic global warming? Maybe a third, or about 6 inches.”
This makes no sense. To claim that we are responsible for a third of the rise means that we are responsible for a third of the warming.
When we contribute only 3-5% of the CO2, which is only 3-5% of the greenhouse gases, the 33 deg C that we are supposed to have from greenhouse effect in the atmosphere overall becomes a mere 0.05 deg C contribution by man (ONLY if a greenhouse gas can warm the climate, which it cannot based on solid thermodynamic principles), only one 12th of the 0.6 deg of warming in the last 100 years. Cut this in half due to our 1950-to-now contribution and we have one 24th of the effect. One 24th of 17 inches is 7/10ths of an inch. This is negligible and can be ignored.
As the Arctic Rim temperature stations show no warming at all in the Arctic in over 50 years and it is clear that there has been no global warming in 16 years, it is patently impossible for ANYTHING to be due to anthropogenic global warming, the scam/junk science foundation of a political agenda.
Jim Clarke says:
November 6, 2012 at 8:42 am
“The science is pretty clear that adding CO2 to the atmosphere, like we humans do, and all else being equal, the CO2 will cause some warming.”
CO2 does not cause warming, What CO2 does, is efficiently transport radiation at a certain wavelength in the infrared part of the spectrum, the more CO2 there is in the mix of a given volume of an atmosphere the more efficiently CO2 transports this radiation, meaning that its thermal properties will warm faster but also cool faster than the same given volume of an oxygen and nitrogen atmosphere, CO2 does not trap heat. clouds of water vapor can trap heat and block heat, CO2 does not. The thermal properties CO2 will not above a certain threshold where the more radiation to expose CO2 to after it reaches saturation it’s temperature will not rise further.
So therefore adding CO2 to an atmosphere like earths, where CO2 is already present will not raise temperatures above the typical thermal threshold that it’s known physical properties allow.
As far as agw goes, it’s a dud!