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Asiaís air pollution may be keeping tropical storm activity down
Watts up With That? ^ | June 25, 2013 | Anthony Watts

Posted on 06/26/2013 6:53:44 PM PDT by Ernest_at_the_Beach

Aerosol_optical_depth

Above, May 2013 Aerosol Optical Depth. Uou can see the United States and Europe is relatively clear, while Asia has high amounts of aerosols. Image: NASA Earth Observatory

From the Law of Unintended Consequences and The Clean Air Act, comes this bit of news. Since the 1970′s The Clean Air Act has benefited breathing in many American cities with tangible results (just look at Los Angeles), but it may have had a role in increasing tropical storm activity.

This new paper suggests that due to the reduction of aerosols and particulates in the atmosphere might have been the main cause of a recent increase in tropical storm frequency in the North Atlantic.

Aerosol levels have increased since the start of industrial revolution, but as we know there have been periods when aerosol emissions declined; the Great Depression, World War II and after clean air legislation was enacted in Europe and the United States in the 1970s and 1980s.

The paper suggests that these periods of reduced emissions eventually increased tropical storm frequency.

Anthropogenic aerosol forcing of Atlantic tropical storms

N. J. Dunstone, et al. Nature Geoscience (2013) doi:10.1038/ngeo1854

Received 04 December 2012 Accepted 15 May 2013 Published online 23 June 2013

The frequency of tropical storms in the North Atlantic region varies markedly on decadal timescales1, 2, 3, 4, with profound socio-economic impacts5, 6. Climate models largely reproduce the observed variability when forced by observed sea surface temperatures1, 8, 10. However, the relative importance of natural variability and external influences such as greenhouse gases, dust, sulphate and volcanic aerosols on sea surface temperatures, and hence tropical storms, is highly uncertain11, 12, 13, 14, 15, 16. Here, we assess the effect of individual climate drivers on the frequency of North Atlantic tropical storms between 1860 and 2050, using simulations from a collection of climate models17. We show that anthropogenic aerosols lowered the frequency of tropical storms over the twentieth century. However, sharp declines in anthropogenic aerosol levels over the North Atlantic at the end of the twentieth century allowed the frequency of tropical storms to increase. In simulations with a model that comprehensively incorporates aerosol effects (HadGEM2-ES; ref. 18), decadal variability in tropical storm frequency is well reproduced through aerosol-induced north–south shifts in the Hadley circulation. However, this mechanism changes in future projections. Our results raise the possibility that external factors, particularly anthropogenic aerosols, could be the dominant cause of historical tropical storm variability, and highlight the potential importance of future changes in aerosol emissions.

h/t to Marc Hendrickx


TOPICS: Conspiracy; Science; Weather
KEYWORDS: climatechange; globalwarminghoax

1 posted on 06/26/2013 6:53:44 PM PDT by Ernest_at_the_Beach
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To: Ernest_at_the_Beach

A guy on the Climate Change Channel was selling the theory that melting polar ice caps were suppressing tornado activity in the US.

That was the week before the Moore, OK F-5.


2 posted on 06/26/2013 6:55:17 PM PDT by nascarnation (Baraq's economic policy: trickle up poverty)
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To: Ernest_at_the_Beach

I thought man-made global warming (pollution) was the reason for all the bad storms on the planet. Al Gore told me so. It causes good weather, bad weather, hot weather, cold weather, and extreme weather. And Al Gore can charge you carbon credits for all of them.

It’s a scam, repeat, it’s a scam.


3 posted on 06/26/2013 7:03:16 PM PDT by Lets Roll NOW (A baby isn't a punishment, Obama is)
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To: Ernest_at_the_Beach

Aerosols are another form of condensation nuclei. The more you have in the atmosphere the more clouds and storms are produced. What a bunch of morons.


4 posted on 06/26/2013 7:21:56 PM PDT by Jack Hydrazine (I’m not a Republican, I'm a Conservative! Pubbies haven't been conservative since before T.R.)
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To: Ernest_at_the_Beach

High emissions also appear in Central America, West Africa, the Middle East and the Congo.


5 posted on 06/26/2013 9:12:12 PM PDT by justa-hairyape
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