In response to the negative effects of global warming, some scientists have suggested ways to reflect heat from the Earth through atmospheric aerosols. But a new study by the Massachusetts Institute of Technology (MIT) suggests that the move also has a long-term side effect, such as weakening the temperate storm trajectory of both hemispheres, destabilising the ice sheet, and causing pollution in some urban areas to become more serious.
The blue image above is a simulated temperate storm trajectory (from: MIT)
The study, conducted by mIT’s Department of Earth, Atmospheric and Planetary Sciences, focused on exploring the long-term climate impacts of Earth cooling engineering.
Although the proposed modalities vary, their purposes are quite consistent. For example, volcanic eruptions are inspired to send ash particles into the stratosphere, reflecting the sun’s energy back into space to temporarily lower the Earth’s temperature.
The team used a solar geoengineering model that could block solar radiation and balance the effects of warming if the concentration of carbon dioxide in the atmosphere reached a record four times.
The model, called the G1 experiment, allowed the team to explore the effects of injecting large amounts of aerosols into the stratosphere, and found strong changes in temperate storm trajectories.
It refers to temperate cyclones formed in mid- and high-latitudes, and the intensity of storm paths is directly related to intensity and frequency. But in the G1 scenario, the storm trajectory of both hemispheres has been significantly weakened, meaning that winter storms are less ferocious and have other consequences.
The scientists point out that weaker storms also mean longer summer weather, echoing a similar study published by the University of Exeter in 2017. If earth cooling is enforced, the reduction of temperate storms will lead to drought in parts of Africa.
Charles Gertler, a graduate student in the Department of Earth, Atmospheric and Planetary Sciences at MIT, said the weakening of the storm’s trajectory in the northern and southern hemispheres meant that winter storms were less intense, but could also delay heat waves.
In all seasons, this may affect the wind-blown air, as well as the weakening of the hydrological cycle and the reduction of regional rainfall. This change is worrying compared to the climate benchmarks we’ve long used to.
Scientists warn that a weakening storm could also alter currents, which in turn could affect the stability of the polar ice sheets, particularly antarctica. Study co-author Paul O’Gorman said:
In the southern hemisphere, where wind drives ocean currents, the opposite has the potential to affect the absorption of carbon dioxide and the stability of the Antarctic ice sheet, so storm trajectories have a very important impact on climate change in the southern hemisphere.
In addition, the team found that these weaker storm trajectories were closely related to changes in temperature and humidity.
The model suggests that earth cooling engineering may lead to cooler equators while the poles continue to warm. A decrease in the temperature difference between the poles and the equator could lead to a weakening of the storm path, raising concerns about the unpredictable ripple effect of the climate.
With this in mind, O’Gorman believes that reflective sunlight does not completely offset the greenhouse effect, and there are many reasons why we should avoid doing so and instead seek to reduce carbon dioxide and other greenhouse gas emissions.
Details of the study have been published in the recent lying geophysical Research Letters.
Originally published as “Weakening of extratropical Storm Tracks in Solar Geoengineering Scenarios.”