July 22, 2024

A geoengineering technique designed to reduce high temperatures in California may inadvertently cause heat waves Europeaccording to a study modeling the unintended consequences of local tinkering with a changing climate.

The paper shows that targeted interventions to reduce temperature in one area for one season may have temporary benefits for some populations, but this must be set against potential negative side effects in other parts of the world and shifting degrees of effectiveness over time.

The authors of the study room said the findings were “frightening” because the world has little or no regulations in place to prevent regional applications of the technique, marine cloud brightening, which involves spraying reflective aerosols (usually in the form of sea salt or sea spray) into stratocumulus clouds clouds over the ocean to reflect more solar radiation back into space.

Experts said the lack of controls meant there was little to prevent individual countries, cities, companies or even wealthy individuals from trying to change their local climate, even if it was to the detriment of people living elsewhere, potentially leading to competition and conflict. lead on interventions.

The recent sharp rise in global temperatures has prompted some research institutions and private organizations to engage in geoengineering research that was previously virtually taboo.

In Australia were scientists ordeal marine cloud clearing strategies for at least four years to try to cool the Great Barrier Reef and slow its bleaching.

Earlier this year, scientists at the University of Washington sea ​​salt particles sprayed over the flight deck of a decommissioned aircraft carrier, the USS Hornet, docked in Alameda in San Francisco Bay. That experiment was stopped by the local government to enable it to evaluate whether the spray contained chemicals that could pose a health risk to people or animals in the Bay area.

The new paper suggests that the consequences could be much more far-reaching and harder to predict. Published on Friday in Nature Climate Change, the authors claim to be the first to demonstrate that cloud-clearing effects could be reduced or reversed as climate conditions change due to the already dramatic human impacts of burning fossil fuels and forests.

Using computer models of the Earth System’s climate in 2010 and 2050, they simulated the impact of two cloud clearing operations conducted over different regions of the northeast Pacific, one in the subtropics near California and one in the midlatitudes near Alaska . Both are designed to reduce the risk of extreme heat in the target area, the US West Coast.

Counterintuitively, the more remote operation had the greater impact because it exploited “teleconnections,” links in the climate system between geographically distant parts of the world.

The 2010 simulation suggested that the operation near Alaska would reduce the risk of dangerous heat exposure in the target area by 55% – equivalent to 22 million person-days per summer – while the closer subtropical test would produce smaller but still significant gains of 16% cause. .

However, in simulations of the more disrupted climate of 2050, the same two operations produced very different results because there were fewer clouds, higher base temperatures and different ocean current patterns, notably a slowing of the Atlantic meridional overturning circulation (Amoc). Under these mid-century conditions, the operation near Alaska would have a drastically reduced effect on alleviating heat stress in the western US, while the subtropical operation would push temperatures higher—the opposite of the desired result.

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The effects outside the target regions were also markedly different between 2010 and 2050. At the earlier date, the simulations suggested that Europe would also be cooled by the marine cloud brightening in the northern Pacific. However, by 2050, the local cooling will increase heat stress around the world, especially over Europe, due to the slowing of Amoc.

“Our study is very specific,” says Jessica Wan who is part of the research team led by UC San Diego’s Scripps Institution of Oceanography. “This shows that marine cloud clearing can be very effective for the US West Coast if done now, but will be ineffective there in the future and cause heat waves in Europe.”

She said the results should concern policy makers, prompting them to establish governance structures and transparency guidelines, not only at a global level, but regionally.

“There’s really no solar geoengineering management right now. It’s scary. Science and policy have to be developed together or we’ll be stifled,” she said. “We don’t want to be in a situation where one region forced to do geoengineering to combat what another part of the world has done to respond to droughts and heat waves.”

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