A geoengineering technique aimed at reducing high temperatures in California could intensify heatwaves in Europe, according to a study assessing the unintended consequences of human intervention on the climate. Researchers are concerned that nothing is currently preventing this intervention.
The study shows that targeted interventions to lower temperatures in one area for one season could have temporary benefits for some populations but could trigger side effects in other parts of the world, as reported by The Guardian.
The technique for cooling temperatures in an area, called marine cloud brightening, involves spraying reflective aerosols (usually in the form of sea salt or seawater) into stratocumulus clouds above the ocean to reflect more solar rays back into space.
The increase in global temperatures in recent years has led some research institutions and private organizations to engage in geoengineering research that was previously practically taboo.
In Australia, scientists have been attempting marine cloud brightening strategies for at least four years to try to cool the Great Barrier Reef and slow down its bleaching process.
Earlier this year, scientists from the University of Washington sprayed sea salt particles on the flight deck of a decommissioned aircraft carrier, the USS Hornet, anchored in Alameda, in the San Francisco Bay. The experiment was halted by local authorities to verify if the spray contained chemicals that could pose a risk to the health of people or animals in the bay area, according to The New York Times.
What Scientists Observed
The consequences of climate intervention could be much more extensive and harder to predict, as shown by the new study published on Friday in Nature Climate Change, the first to demonstrate that the effects of cloud brightening can diminish or reverse as climate conditions change due to the human impact of burning fossil fuels and forests.
Using computer models of the Earth's climate system in 2010 and 2050, researchers simulated the impact of two cloud brightening operations carried out in different regions of the northeastern Pacific Ocean, one in subtropical areas near California and one at mid-latitudes near Alaska. Both were designed to reduce the risk of extreme heat in the target region - the U.S. West Coast.
The simulation in 2010 indicated that the operation near Alaska would reduce the risk of exposure to dangerous heat in the target region by 55%, while the closer subtropical test would result in smaller but still significant gains of 16%.
In the more disrupted climate simulations of 2050, the same two operations produced very different results, as there were fewer clouds, higher baseline temperatures, and a slowing down of the Atlantic Meridional Overturning Circulation (Amoc), the main ocean current system in the South and North Atlantic Ocean.
Under these mid-century conditions, the operation near Alaska would have a drastically reduced effect on alleviating heat stress in the U.S. West, while the subtropical operation would raise temperatures more - the opposite of the desired outcome.
Therefore, the climate is a complex system with closely interconnected elements, and human intervention negatively alters its normal functioning. In other words, you throw water in one part of the world, but it burns in another.
Frightening Discoveries
The study authors say their findings are "frightening" because there are not enough regulations in place to prevent the regional application of this technique. Therefore, there are no means to prevent or hold accountable countries, cities, companies, or even wealthy individuals who might attempt to modify their local climate, if it is to the detriment of people living elsewhere, potentially leading to harmful competition and conflicts.
"Our study is very specific. It shows that marine cloud brightening could be very effective for the U.S. West Coast if done now, but it could be inefficient there in the future and could cause heatwaves in Europe," said Jessica Wan, a member of the research team led by the Scripps Institution of Oceanography at UC San Diego.
"There are no regulations in solar geoengineering at this moment. That is scary. Science and policy need to develop together. We do not want to reach a point where one region is forced to engage in geoengineering to counter what another part of the world has done in response to droughts and heatwaves," she emphasized.
T.D.