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MIT study explores how solar geoengineering would alter the climate

MIT study explores how solar g...
MIT scientists have conducted a climate study, finding that extratropical storm tracks seen in blue would change significantly through solar geoengineering
MIT scientists have conducted a climate study, finding that extratropical storm tracks seen in blue would change significantly through solar geoengineering
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MIT scientists have conducted a climate study, finding that extratropical storm tracks seen in blue would change significantly through solar geoengineering
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MIT scientists have conducted a climate study, finding that extratropical storm tracks seen in blue would change significantly through solar geoengineering

One of the proposed ways to counter the effects of global warming is by using atmospheric aerosols to reflect heat away from the Earth, and a great deal of research is going into not just how this might work, but whether or not it is a good idea. A new study from MIT has explored some of the potential flow-on effects of such a move and found it would likely trade one set of problems for another, by weakening storms, destabilizing ice sheets and leading to more polluted urban areas.

The research was carried out by MIT’s Department of Earth, Atmospheric and Planetary Sciences, with the team setting out to explore some of the long-lasting effects of solar geoengineering on the climate. These types of schemes vary in their proposed approaches, but generally take inspiration from volcanic eruptions that spew reflective particles into the stratosphere that temporarily bounce the Sun’s energy back into space and temporarily cooling the planet.

For their investigations, the team used a solar geoengineering model in which enough solar radiation is blocked to balance out the warming effects if carbon dioxide concentrations in the atmosphere, which is already at record levels, were to quadruple. Known as the G1 experiment, this model enabled the team to explore the various repercussions of injecting vast amounts of aerosols into the stratosphere, with a strong alteration of extratropical storm tracks the leading consequence.

This refers to the zones in the middle and high latitudes where storms form to create extratropical cyclones, with the strength of the storm tracks directly linked to the severity and frequency of the storms. The team found that under its G1 scenario, storm tracks in both hemispheres would be greatly weakened, which would mean less ferocious winter storms but would bring a host of other climate consequences.

Weaker storms, the scientists note, would also mean more stagnant summertime conditions. This echoes the findings of a similar study at the University of Exeter in 2017, which found that solar geoengineering could reduce the frequency of some cyclones and cause drought in parts of Africa, though the MIT paper goes a little bit further.

“A weakened storm track, in both hemispheres, would mean weaker winter storms but also lead to more stagnant weather, which could affect heat waves,” says Charles Gertler, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences and study author. “Across all seasons, this could affect ventilation of air pollution. It also may contribute to a weakening of the hydrological cycle, with regional reductions in rainfall. These are not good changes, compared to a baseline climate that we are used to.”

Reduced winds to clear away pollution and maintain healthy air quality is just one of the possible outcomes of solar geoeingeering, with the scientists warning it could also alter the circulation of ocean currents, which would have an impact on the stability of ice sheets. This could prove particularly influential down south.

“In the Southern Hemisphere, winds drive ocean circulation, which in turn could affect uptake of carbon dioxide, and the stability of the Antarctic ice sheet,” says co-author Paul O’Gorman. “So how storm tracks change over the Southern Hemisphere is quite important.”

Further, the team found that these weaker storm tracks were closely correlated to changes in temperature and humidity, with the modeling indicating that solar geoengineering could cause the equator to cool while the poles continue warming. This reduced difference in temperature between the poles and equator is what could lead to the weaker storm tracks, according to the team, and kick off a chain reaction of climate consequences that we may not be prepared to grapple with.

“Reflecting sunlight isn’t a perfect counterbalance to the greenhouse effect,” says O’Gorman. “There are multiple reasons to avoid doing this, and instead to favor reducing emissions of CO2 and other greenhouse gases.”

The research was published in the journal Geophysical Research Letters.

Source: MIT

6 comments
Nobody
Years ago to offset global warming, I suggested using additives to jet fuel to make the contrails more reflective during the day and to not use the additives for night flights. The only real evidence at the time was the no fly order after 9/11 that stopped most air traffic over the U.S. for several days. One report was that the average temperature was affected by the lack of contrails. I could find no takers for my idea. I was not surprised since such a deliberate attempt could have had many unforeseen effects. It will be interesting to see what claims come out from the current reduction in air traffic.
mark00
You might be tempted to conclude that geoengineering is not worth trying, but if carbon dioxide quadruples, it is likely that desperation will force us into geoengineering to prevent devastating agricultural/environmental collapse. Like any other no-win scenario, the wisest approach is to avoid it, but many of the powers-that-be want us to continue the way we have been because it is profitable for them.
Trylon
“Reflecting sunlight isn’t a perfect counterbalance to the greenhouse effect,” says O’Gorman. But remember that perfect is the enemy of good. We must use all the tools at our disposal. Unfortunate, but necessary.
Nelson Hyde Chick
Basically we have screwed the planet, and any fix will come with unwanted side effects. And the world is going to go to shit because humanity is too selfish and stupid to breed responsibly.
Karmudjun
There are many avenues of scientific research in the works - while we know plants pull CO2 effectively from the atmosphere at the previously lower levels of the lower 300ppm levels (we are now in the 400ppm atmospheric range) and the oceans have acidified slightly working as a huge CO2 sink to the detriment of corals and other sea life, we don't know what other mitigation processes will become feasible in the future. Yes, making an effort by changing the atmospheric make-up could have foreseen and unforeseen repercussions on our planet & life as we used to know it. But to paraphrase Bill Faulkner "Humans shall not only survive, but we shall prevail". It doesn't have to be pretty, or cheap, or without consequences - but somewhere, somehow humanity will prevail.
jgb
Manufacturing these power sources uses more CO2 than a coal power plant would ever use. This does not include the pollution of dumping them after their useful lives are over.