It sounds like a mixture of science fiction fantasy and children’s logic: if the sun is too dazzling, you just have to create shadows. The idea sounds as logical as it is impossible, but the US government is apparently seriously considering the idea. The White House recently released a research paper related to changing solar irradiance — also called geoengineering.
The 44-page report examines what is known as “Solar Radiation Management” (SRM). The researchers discuss various options for sun protection, which should cool down the earth’s climate. These approaches range between “sounds logical” and “science fiction”: The research team sees the most feasible option in injecting a large quantity of aerosols, i.e. particles of sulfur oxide, into the stratosphere and thus reflecting the sun’s rays.
A second more or less realistic option would be to link the geoengineering directly to the given weather conditions. More specifically, sea clouds could be brightened by injecting sea salt, increasing their reflectivity. This would theoretically make it possible to slow down ocean warming.
But in addition to these halfway comprehensible ideas, the scientists also dealt with approaches that sound more like “Star Wars” than serious science. For example, giant solar shields could be thrown into space between the sun and the earth, blocking sunlight from reaching the earth’s surface. Another rather far-fetched approach would be to brighten the surface of the earth in general.
In order to achieve this, forest areas in snow-covered areas can be cleared, desert and ice areas can be completely covered with light-colored materials, or mountains and the roofs of houses can be painted white. In addition, one approach deals with reducing so-called “cirrus clouds”. The idea: By dissolving these pure ice clouds, which occur at high altitudes, heat could escape into space.
But how realistic are these approaches anyway? Many scientists have criticized geoengineering approaches for years. The consequences are too unpredictable when humans intervene in natural processes. The climate researcher Mojib Latif from the Hemholtz Institute for Ocean Research in Kiel told “Bild” that he would describe the theories presented as “entry into a catastrophe”. The earth system is too complex to experiment with.
There are a number of side effects that cannot be assessed. For example, the ozone layer could be damaged. In addition, such a project cannot be ended so easily, according to Latif. “You would have to keep it running for centuries to avoid spontaneous reheating of the Earth because the CO2 stays in the atmosphere for so long.”
Latif also emphasized that the whole thing also had a political dimension: “It’s about using fossil fuels longer. That’s why certain circles are targeting it.” Scientists also repeatedly point out that geoengineering could also be used as a weapon. So does Latif: “The country that holds this technology in its hands may be able to use it as a weapon. For example, it could black out other countries.”
It is unclear whether and when such a project will actually become a reality. The White House said the report was released “in response to a mandate from Congress.” He identified “critical gaps in knowledge” and “points out potential research areas that could improve understanding of the risks and benefits of solar radiative modification.” However, the report does not have a direct impact on current policies, the government said: “It is important that this report does not represent any change in the policies or activities of the Biden-Harris administration, which continues to focus on reducing emissions that increasing resilience, promoting environmental justice and achieving true energy security.”
There are currently no plans for a comprehensive research program, according to the White House. Should this attitude change, the first drafts would already be in the drawer.
Sources: White House research report, image
