Climate Engineering: Potential Perils and Unintended Consequences
A recent study has raised alarms about the risks of geoengineering techniques intended to cool specific regions. The research, published in Nature Climate Change, highlights that efforts to reduce temperatures in California through marine cloud brightening could inadvertently lead to severe heatwaves in Europe.
Marine cloud brightening involves spraying sea salt particles into clouds to reflect more sunlight away from the Earth. While this could potentially lower temperatures locally, the study reveals that such interventions might have unintended, far-reaching effects. For instance, a model simulating the climate of 2010 and 2050 showed that an operation near Alaska, initially effective in reducing heat exposure in the US, could fail in the future and instead exacerbate heat stress in Europe due to altered climate conditions and the slowing of the Atlantic meridional overturning circulation (Amoc).
Jessica Wan, from UC San Diego's Scripps Institution of Oceanography, emphasized the urgency for policymakers to establish governance and transparency guidelines for geoengineering. The lack of regulation means that regions could independently attempt geoengineering, potentially leading to global conflicts and environmental damage.
The study serves as a stark reminder of the complex and interconnected nature of our climate system. As global temperatures continue to rise, the temptation to engage in geoengineering grows, but so do the risks of unintended consequences.
Environmental advocates and concerned citizens must push for comprehensive regulations to ensure that any climate intervention considers the global impact, not just local benefits.
A geoengineering technique designed to reduce high temperatures in California could inadvertently intensify heatwaves in Europe, according to a study that models the unintended consequences of regional tinkering with a changing climate.
The paper shows that targeted interventions to lower temperature in one area for one season might bring temporary benefits to some populations, but this has to be set against potentially negative side-effects in other parts of the world and shifting degrees of effectiveness over time.
The authors of the study said the findings were “scary” because the world has few 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 over the ocean to reflect more solar radiation back into space.
Experts have said the paucity of controls means there is little to prevent individual countries, cities, companies or even wealthy individuals from trying to modify their local climates, even if it is to the detriment of people living elsewhere, potentially leading to competition and conflict over interventions.
The recent sharp rise in global temperatures has prompted some research institutions and private organisations to engage in geoengineering research that used to be virtually taboo.
In Australia, scientists have been trialling marine cloud brightening 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 sprayed sea-salt particles across the flight deck of a decommissioned aircraft carrier, the USS Hornet, docked in Alameda in San Francisco Bay. This experiment was halted by the local government to allow it to evaluate whether the spray contains chemicals that might pose a health risk to people or animals in the Bay area.
The new paper suggests the consequences could be much further reaching and harder to predict. Published on Friday in Nature Climate Change, the authors claim to be the first to demonstrate that cloud brightening effects can diminish or reverse as climate conditions change due to the already dramatic human impacts of burning fossil fuels and forests.
Using Earth system computer models of the climate in 2010 and 2050, they simulated the impacts of two cloud brightening operations carried out over different regions of the north-eastern Pacific Ocean, one in the subtropics near California and one in the mid-latitudes near Alaska. Both were designed to reduce the risk of extreme heat on the target region, the US west coast.
Counterintuitively, the more distant operation had the greater impact because it tapped into “teleconnections”, links in the climate system between geographically remote parts of the world.
The 2010 simulation suggested the operation near Alaska would lower the risk of dangerous heat exposure in the target region by 55% – equivalent to 22 million people-days per summer – while the closer subtropical test would cause smaller but still significant gains of 16%.
In simulations of the more disrupted climate of 2050, however, the same two operations produced very different results because there were fewer clouds, higher base temperatures and 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 relieving heat stress in the western US, while the subtropical operation would push temperatures higher – the opposite of the desired result.
The consequences outside the target regions were also markedly different between 2010 and 2050. At the earlier date, the simulations suggested Europe would also be cooled by the marine cloud brightening in the north Pacific. However, by 2050, the local cooling operation would increase heat stress around the world, particularly over Europe, as a result of the slowing of Amoc.
“Our study is very specific,” said Jessica Wan, who is part of the research team led by UC San Diego’s Scripps Institution of Oceanography. “It shows that marine cloud brightening can be very effective for the US west coast if done now, but it may be ineffective there in the future and could cause heatwaves in Europe.”
She said the results should concern policymakers, and prompt them to establish governance structures and transparency guidelines, not just on a global level but regionally.
“There is really no solar geoengineering governance right now. That is scary. Science and policy need to be developed together,” she said. “We don’t want to be in a situation where one region is forced to do geoengineering to combat what another part of the world has done to respond to droughts and heatwaves.”
Frequently Asked Questions (FAQs)
1. What is geoengineering? Geoengineering refers to large-scale interventions in the Earth’s climate system to counteract climate change. Techniques include solar radiation management and carbon dioxide removal.
2. What is marine cloud brightening? Marine cloud brightening involves spraying reflective aerosols, such as sea salt, into clouds over the ocean to make them reflect more sunlight away from the Earth, potentially cooling the planet.
3. What are the potential risks of geoengineering? Geoengineering can have unintended side effects, such as changing weather patterns, causing droughts or heatwaves in regions far from where the intervention takes place.
4. Why is there a concern about the lack of regulation? Without regulation, individual countries, cities, or even private entities could conduct geoengineering projects that benefit them but harm others, leading to conflicts and adverse global impacts.
5. What did the study find about future effects? The study found that while marine cloud brightening might help cool certain areas now, its effectiveness could decrease in the future due to changing climate conditions, and it might even worsen heatwaves in other regions like Europe.
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