Tropical cyclones on track to grow more intense as temperatures rise

Tropical cyclones on track to grow more intense as temperatures rise
NASA's Terra satellite captured this image of Super Typhoon Nepartak approaching Taiwan on July 7. Credit: NASA Goddard MODIS Rapid Response/Jeff Schmaltz

Powerful tropical cyclones like the super typhoon that lashed Taiwan with 150-mile-per-hour winds last week and then flooded parts of China are expected to become even stronger as the planet warms. That trend hasn't become evident yet, but it will, scientists say.

So far, the warming effects of greenhouse gases on have been masked, in part by air pollution.

Over the past century, tiny airborne particles called aerosols, which cool the climate by absorbing and reflecting sunlight, largely cancelled out the effects of planet-warming greenhouse gas emissions when it came to tropical storm intensity, according to a new scientific review paper published this week in the journal Science. That might sound like a good thing, but many of those particles came from the burning of fossil fuels and wood, and contributed to acid rain, smog and lung damage. As vehicles and power plants added filters and scrubbers to reduce their impact on human health, levels of man-made aerosols in the atmosphere began to decline. At the same time, greenhouse gas concentrations continued to rise.

That compensating effect won't continue if greenhouse gas warming keeps increasing, the scientists write. Using model simulations, they provide new calculations of the cancelling effects of aerosols and greenhouse gases on tropical cyclones worldwide. They also take a closer look at the still-developing understanding of how climate change will affect tropical cyclones, also known regionally as typhoons or hurricanes.

"The fact that global warming's fingerprints don't yet jump out at us when we look at hurricanes isn't surprising - it's what current science tells us we should expect," said lead author Adam Sobel, a professor at Columbia University's Lamont-Doherty Earth Observatory and School of Engineering. "The same science tells us that those fingerprints will show up eventually in more ultra-powerful storms."

Increasing potential intensity

The scientists examined a wide range of published analyses of tropical cyclone data and computer modeling, looking specifically at potential intensity, which predicts the maximum intensity that tropical cyclones could reach in a given environment. Their new global calculations of the cancelling effect follow a 2015 study led by Lamont's Mingfang Ting, with Suzana Camargo, also a coauthor on the new paper, that showed similar effects over the North Atlantic, where hurricanes that make landfall in the United States form.

Tropical cyclones on track to grow more intense as temperatures rise
Changes in potential intensity in the Northern and Southern Hemispheres as reflected in the CMIP5 computer model. Black is historical data, blue is the influence of aerosols only, red is the influence of greenhouse gases only, and green shows the difference between the historical data and the influence of aerosols Credit: Sobel et al., Science 2016

Many factors contribute to a tropical cyclone's intensity. At the most basic, the storm's convective strength - the boiling motion of air rising from the ocean surface to the atmosphere - depends on the temperature difference between the surface ocean and the upper atmosphere. Computer models that simulate the physics of tropical cyclones suggest that this difference should increase as the climate and sea surface temperatures warm, and that tropical storm strength should increase with it.

Less well understood is how climate change should influence the number of tropical cyclones that form each year. Computer models indicate that while the total number of cyclones should decline in a warming climate, more intense, highly destructive storms like Super Typhoon Nepartak are likely to become more common.

We have seen harbingers of that change in recent years: Typhoon Haiyan, also known as Yolanda, killed more than 6,300 people as it devastated parts of the Philippines as a Category 5 storm in 2013. Last year, Hurricane Patricia became the second most-intense tropical cyclone on record when its sustained winds reached 215 mph before weakening to hit Mexico with winds still powerful at 150 mph.

The scientists' review finds that the largest increases in tropical cyclone potential intensity are expected to be at the margins of the tropics, particularly in the Atlantic and Pacific. The amount of rain that tropical storms bring is also expected to increase as the planet warms, due to increasing water vapor; and coastal flooding from storm surges that accompany tropical storms are expected to become more of a problem as sea levels rise. The scientists also describe a shift in tropical cyclone tracks toward the margins of the tropics, noting that it is unclear if the shift is a response to warming. Simulations for the western North Pacific suggest that it is, at least in part.

Detecting the influence of climate change

Two factors make it difficult to detect greenhouse gas-related trends in tropical cyclone intensity, as the authors explain.

One is the influence of aerosols. Model calculations indicate that aerosols have about twice the effect of greenhouse gases on a tropical cyclone's potential intensity. So while levels have been greater than aerosol levels for many decades in terms of absolute magnitude - which is why the planet has warmed by about 1.5?F since the Industrial Revolution - they have only recently surpassed the cooling effect of aerosols in terms of their influence on tropical cyclone intensity.

The other challenge is natural variability. Tropical cyclones are relatively rare - the world averages around 90 per year - and that number fluctuates from year to year and decade to decade, due in large part to natural causes. It is statistically difficult to detect long-term trends within that large natural variability, Sobel said. Satellite records that can monitor worldwide also only go back to the 1970s.

Scientists at Lamont, including Sobel, Camargo and coauthors Allison Wing and Chia-Ying Lee, are using both observations and computer models to expand understanding of how tropical cyclone behavior has changed and the physical mechanisms by which climate affects extreme weather. Among other projects, they are developing a tropical cyclone risk model that can be used in urban planning that incorporates climate factors in determining the probability of a tropical cyclone making landfall at a given location.


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More information: "Human influence on tropical cyclone intensity," Science, science.sciencemag.org/cgi/doi … 1126/science.aaf6574
Journal information: Science

Citation: Tropical cyclones on track to grow more intense as temperatures rise (2016, July 14) retrieved 20 May 2019 from https://phys.org/news/2016-07-tropical-cyclones-track-intense-temperatures.html
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Jul 14, 2016
Seeing as we have had a dearth of hurricane storms are you admitting there has been no global warming and lied about the "warmest year on record " comments? We know, and always have known, hurricanes are the result of oceanic heat cycles. We also have also known the SUN is the major climate engine for our planet. Too many articles about how warming will destroy us reveal the fabric of the current political machinations. Too many factscan reveal the lies....just saying.

Jul 14, 2016
It may be that the recent "super-cyclones" from the last couple of years are already showing the increase in intensity they are discussing in this article. Aerosols in the Pacific have been falling as a result of actions by the Chinese to get their pollution under control. The last couple of Pacific cyclone years have seen a way higher number than average, as has been predicted due to global warming, and even taking into account the lower number of Atlantic hurricanes, the overall number is still higher than average.


Jul 14, 2016
Seeing as we have had a dearth of hurricane storms are you admitting there has been no global warming and lied about the "warmest year on record " comments? We know, and always have known, hurricanes are the result of oceanic heat cycles. We also have also known the SUN is the major climate engine for our planet. Too many articles about how warming will destroy us reveal the fabric of the current political machinations. Too many factscan reveal the lies....just saying.


Alternatively, you could just learn to read. This article is about hurricane intensity. And as we have said a thousand times, the predictions for the impact of warming on hurricanes, cyclones and typhoons - with some regional exceptions - is for LESS of higher INTENSITY. Which is what this article is about.

Jul 14, 2016
What nonsense. We heard all this 20 years ago about Atlantic seaboard hurricanes and it didn't happen. Blanket media coverage, much higher and more extensive insurance payouts have contributed to the wrong idea that storm systems are "worse" today than decades ago. Nothing could be further from the truth. Frequency and severity have decreased and not intensified, respectively.

Jul 15, 2016
Meanwhile, gloBull warming has taken a vacation from the Atlantic. More fodder for the hungry, ignorant Chicken Littles...eat up.

Jul 15, 2016
Meanwhile, gloBull warming has taken a vacation from the Atlantic. More fodder for the hungry, ignorant Chicken Littles...eat up.

Meanwhile monkey goracle cooked his last braincell into popcorn, more bannanas for you ?

Bart with another fart brained comment moment which is a goracle sock monkey.

Jul 15, 2016
LOL another cracker well said Helo


Jul 15, 2016
What nonsense. We heard all this 20 years ago about Atlantic seaboard hurricanes and it didn't happen. Blanket media coverage, much higher and more extensive insurance payouts have contributed to the wrong idea that storm systems are "worse" today than decades ago. Nothing could be further from the truth. Frequency and severity have decreased and not intensified, respectively.

Well, actually, no we didn't hear that. One of the original predictions of rising atmospheric temperatures is that, in the absence of other factors, there could be more of them and they would be. on average, more intense. Overall, and especially in the Pacific, this has held true.

Since then, as more information has become available, the models have been refined and they have adjusted their predictions to advise that they will likely be less Antarctic hurricanes due to a specific combinations of factors, but those that due form and hold together will be more severe. Again, so far, they are right.

Jul 15, 2016
Again, so far, they are right.

LOL.
Remember when the prophesy was that our children will never know what snow is, and then we were blanketed with snow and so the prophesy became globull warming will cause more snow.
So what are the prophesies for globull warming so far --
-- No rain, unless it is raining.
-- More rain, unless it is not raining.
-- No snow, unless it is snowing.
-- More snow, unless it is not snowing.
-- More lies, unless....well... being a cult... lying is the only way they can keep their flock of ignorant Chicken Littles hunger for doom and gloom, satiated.

Jul 15, 2016
Remember when the prophesy was that our children will never know what snow is
never happened
and then we were blanketed with snow and so the prophesy became globull warming will cause more snow.
never happened
So what are the prophesies for globull warming so far --
-- No rain, unless it is raining.
-- More rain, unless it is not raining.
-- No snow, unless it is snowing.
-- More snow, unless it is not snowing.
-- More lies, unless....well... being a cult... lying is the only way they can keep their flock of ignorant Chicken Littles hunger for doom and gloom, satiated.
Typical denial by a childish, petulant, LYING, goof.

Jul 16, 2016
So what are the prophesies for globull warming so far
That if we keep adding ghg to the atmosphere - the system will keep warming. http://data.giss....aphs_v3/
In other news, when the Sun comes up it's morning.

Jul 16, 2016
The AGW Cult's peer reviewed "science".
http://www.nature...-1.14525

Jul 16, 2016
The AGW Cult's peer reviewed "science".[sic]


Yes, precisely: real science says what it does not know because that's where the Interesting Stuff is. Real cultists whine that "scientists can't make up their minds." Religionist denier tactic number 1356.

Do you not understand that your very choice of methods of argument shows what you are? When you lie, everyone can see it.

Jul 17, 2016
This is hilarious, A1 G.O.

Monkey Goracle stumbling over the words he reads...... yet again.... :D

Jul 17, 2016
When you lie, everyone can see it.

LOL.
Of course, being the consummate mouth-breather, when you lie, YOU can't see it.
Now tell us more about the zooplankton from 10000 years ago that fed on melting glacier debris and released CO2 which lagged temperature by 800 years.

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