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Scientists Suggest ‘Cloud Brightening’ To Halt Hurricanes

As Tropical Storm Isaac batters southeastern Louisiana and nearby coastal areas with surging seas, howling winds, and torrential rainfall, it’s nearly impossible to imagine that humans could have done anything to stop such powerful force of nature.

Nearly impossible, but not quite.

A team of atmospheric scientists, writing in the journal Atmospheric Science Letters, has imagined precisely that. They suggest that brightening the clouds that float above hurricane-forming regions could effectively cool the sea surface below, thus depriving tropical storms of the heat on which they depend to sustain their destructive power.

Credit: egoyodax/flickr

“We’re probably a couple of years away from being able to conduct field tests,” said lead author John Latham, of the University of Manchester, England. “But as these things go, it probably wouldn’t be very expensive.”

The hurricane-stopping technique is a smaller-scale version of an idea Latham and others have proposed to slow global warming all over the planet. Known as marine cloud brightening, or MCB, it’s one of many versions of geoengineering — the idea of counteracting global warming with some sort of technological counter-measure to cool the planet, prevent heat-trapping CO2 from entering the atmosphere, or sucking it out once it’s there

With MCB, scientists propose to spray microscopic droplets of sea water into clouds that typically cover a quarter or so of the ocean’s surface at any given time, perhaps using unmanned Flettner rotor ships guided by satellites. In theory, at least, the effect would be to make the clouds more reflective, so that more of the sunlight that hit them would bounce back into space without warming the Earth.

Latham and his colleagues published a major study on MCB in the journal Philosophical Transactions of the Royal Society last month; the new study on hurricane suppression, Latham said, “is kind of a reduced-area version,” targeted at patches of ocean off the coasts of Africa, South America and North America where hurricanes and Pacific typhoons are often born. “As soon as oceanic waters start to receive less sunlight,” Latham said, “the cooling will start.”

It will, that is, if the technology behind cloud brightening moves forward. “There will be opposition to any kind of geoengineering,” Latham said, largely because of the fear that something could go very wrong.

“We don’t claim to have dotted every ‘i’ and crossed every ‘t’ on this issue,” Latham said. “We need to look very closely at the issue of adverse consequences.”

That’s the case, not just with this project, but with every form of geoengineering, where the specter of unintended consequences haunts even the best-intentioned of projects. One possible side effect of reducing the sunlight reaching Earth, for example, could be reduced rainfall in Europe and North America.

The danger is less for hurricane suppression simply because it could conceivable be done in over a very small area — as little as 5 percent of the ocean surface, according to the new study.

“The way it stands at the moment,” Latham said, “is that if we can get this to work, it should be possible to choose where to seed, both on basis of cooling the surface water, but also on not cooling over land in regions that won’t tolerate it.”

Nevertheless, says the paper, the climate models that develop these reassuring conclusions aren’t reliable enough yet to be trusted. “We conclude therefore,” write the authors, “that it is possible that unacceptable rainfall changes may result from MCB seeding, and if these cannot be corrected MCB should never be deployed.”

The conclusion, Latham said, is that, “we’re not ready to do even small-scale experiments yet. We need to carry this work a bit further theoretically.”

Comments

By Bob Fishell (Naperville IL)
on August 29th, 2012

I would offer a profoundly unscientific conjecture: nature is smarter than we are. I don’t have much to offer in evidence of this except for a few anecdotes in the annals of trying to mitigate nature by messing with it:

Cane toads
Melaleuca trees
Kudzu

Perhaps we can accelerate the process of not burning stuff instead.

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By Margaret Weiner
on August 29th, 2012

I wholeheartedly agree with Bob’s comment, having read a whole book (now outdated) on unintended consequences, WHY THINGS BITE BACK, as well as having lived with Kudzu, anti-biotic resistent bacteria,  dying honeybee populations, etc.

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By Mary R
on August 30th, 2012

Reducing storm strength may reduce rainfall to the corn belt of the United States in later summer when the soils have usually dried under the intense heat. Saving the coasts but reducing the food supply is a tough trade-off.

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By Judy Bell (Saint Petersburg, Florida 33712)
on August 30th, 2012

If man should EVER be able to control the weather, it will be the end of all of us. Goodness I hope I never live to see this.

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By Lewis Cleverdon
on August 30th, 2012

Bob - with respect I would differ with you on this for several reasons.

First, the goal of cloud brightening is not to mitigate nature as you put it, it is to control the warming causing the destabilization of natural systems and carbon stocks (whose release would cause extreme warming impacting all species, not just human societies) while the problematic anthro-GHG emissions are being ended and the airborne anthro-GHG stocks are gradually cleansed. IMHO no albedo restoration technology has a rational justification unless it is seen as operating in concert with both emissions control and airborne carbon recovery.

Second, we are long past the point where the use of albedo restoration was optional; with six out of seven interactive mega-feedbacks of warming now accelerating, and several having the potential to dwarf anthro-emissions, we face a stark choice. If as you suggest we speed up emissions control, say raising the goal to near-zero global GHG output by 2050, then we’ll still have another 20 to 40 years of timelagged warming to endure - until say 2080 - due to the oceans’ thermal inertia. An unintended consequence of ending emissions is that we also end our output of fossil sulphate, and thus stop maintaining the cooling ‘sulphate parasol’, which Hansen et al report will raise received warming by 80% to 140%. Thus the greatly raised warming by 2080 is likely to be at least doubled by this effect, with ruinous climate destabilization as its direct consequence.

In this light the failure to control global temperature by albedo restoration would be to invite near-certain catastrophic open-ended warming as the mega-feedbacks begin to interact and multiply the warming regardless of our best efforts at emissions cuts.

Third, the reason that cloud-brightening research is proposed by Latham, Salter and others as the means of achieving albedo restoration is that it apparently offers the best prospect of effectiveness, affordability and manageability. No developer of a technology can know all of its consequences and it would be irrational to adopt a ‘fear of the unknown’ block on all and any development. For example, society’s deep dependence on antibiotics - that are now being made useless by the evolution of resistant microbes - was inconceivable at the outset, but few would wish we’d not used antibiotics to avoid suffering and deaths.  Stringent management of new technologies is the necessary qualifier - there is good evidence to show that the routine application of antibiotics to factory-farmed livestock has been the major cause of resistant microbes - had this been banned by global legislation when first spotted in the ‘70s, we’d likely not face the present growing problem.

Cloud brightening is uniquely amenable to management compared to other albedo restoration options. One option: releasing vast numbers of little mirrors in space - would leave us with an irretrievable sun shade. Another: spraying sulphate aerosols continuously at very high altitude - would mean at least two years of worldwide effects (including sulphate pollution) before they rained out. Cloud brightening by contrast would rain out within seven to nine days on average, and can be directly targeted on clouds within a particular area or region of the greatest concern - such as the Arctic Ocean - meaning that in the event of seriously adverse effects the operation can be closed down very swiftly. It also uses rather insignificant quantities of the natural sea salt in seawater as its active ingredient.

In short, the stark choice we face is between relying solely on emissions control - which patently cannot resolve or even limit the scale of the warming we have engendered - or adding novel albedo restoration and carbon recovery programs to that emissions control treaty, and developing the safest effective technologies that a global scientific effort can provide. On this aspect I guess we may perhaps agree - the development and operation of any such programs must be under the stringent supervision of a scientific commission that is answerable to all nations - i.e. to the General Assembly of the UN.

Regards,

Lewis

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By Phil Kithil (Santa Fe, NM 87501)
on September 4th, 2012

As inventor of the Atmocean, Inc. wave-driven upwelling technology to cool the upper ocean and reduce hurricane intensity, I can tell you our models showed that you need to cool the ocean very near to landfall, not in the hurricane origination region referenced by Latham et al. Only by lowering the upper ocean heat content close to landfall, do you gain any hope of reducing the intensity. If you are much farther out, the storm will regain intensity as it passes over nearshore warm water.

Also, with a targeted rather than shotgun approach, the unintended consequences probably are much reduced.

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