A study was conducted to see if artificial dimming of the sun could stop the melting of glaciers

A study was conducted to see if artificial dimming of the sun could stop the melting of glaciers

With so-called geoengineering methods, the climate could theoretically be artificially influenced and cooled.

Researchers from Bern have now investigated whether artificial “sun-darkening” could prevent the melting of the West Antarctic ice sheet.

The results show that the artificial effect cannot do without decarbonisation and entails high risks.

Is there a stopgap solution that can stop climate change? The term geoengineering has been used for some time to discuss technical methods that artificially affect the climate.

However, the majority of climate researchers have so far criticized them: high risks, unthinkable consequences for future generations.

In a recent publication in the journal Nature Climate Change, researchers led by Johannes Sutter of the Institute of Physics, Department of Climate and Environmental Physics (KUP) and Johannes Sutter of the Oeschger Climate Change Research Center at the University of Bern, found that melting ice in West Antarctica can artificially reduce solar radiation.

They explore the question of whether it can be prevented by influencing Additionally, researchers warn of the unforeseen side effects of geoengineering.

Avoiding a central climate tipping point

“The window of opportunity for global temperature rise to fall below 2 degrees is fast closing,” says ice modeling expert Johannes Sutter. Therefore, the effects and risks of “solar radiation management” need to be investigated in theoretical models.

The term Solar Radiation Management (SRM) summarizes various methods aimed at blocking solar radiation and thus making it cooler on Earth.

A major reason for the increased interest in geoengineering is the avoidance of tipping points where the climate can change suddenly and irreversibly.

These include, among other things, the melting of the West Antarctic and Greenland ice sheets and the corresponding meter-high rise in sea level.

“Observations of ice rivers in West Antarctica show that we are very close to or have already passed the so-called tipping point,” explains Johannes Sutter, “so we wanted to use our work to find out whether ice sheet collapse could theoretically be prevented by Solar Radiation Management.”

Artificially dimming the sun

Specifically, Sutter and colleagues investigated what would happen if it were possible to block solar radiation from Earth to some extent with aerosols (particles suspended in a gas) introduced into the stratosphere to darken the sun.

So far, the global effects of Solar Radiation Management (SRM) have been explored. The Bernese study is the first to use ice model simulations to show what impact such a measure would have on the Antarctic Ice Sheet.

The study examines the possible evolution of the ice sheet under various future greenhouse gas scenarios and comes to differentiated conclusions: If emissions continue unabated and SRM occurs by the middle of this century, the collapse of the West Antarctic Ice Sheet may be somewhat delayed, but not prevented.

In the medium emissions scenario, the SRM, deployed in the middle of the century, could prove to be an “effective tool” for slowing or even preventing ice sheet collapse.

According to model calculations, SRM works best when implemented as early as possible and combined with ambitious climate protection measures.

However, as the study authors emphasize, “our simulations show that rapid decarbonization is the most effective way to prevent long-term collapse of the West Antarctic Ice Sheet.”

The chances of a long-term stable ice sheet are greatest if greenhouse gas emissions are reduced “without delay” to net zero.

Possible side effects have hardly been investigated

But how should you imagine the darkening of the sun in practice? According to Johannes Sutter, an entire fleet of extremely high-flying aircraft would have to spew millions of tons of aerosols into the stratosphere.

However, this technical intervention to the climate will need to be sustained uninterrupted and for centuries. If the intervention were to be stopped as long as the concentration of greenhouse gases in the atmosphere remained high, the temperature on Earth would rise sharply by several degrees.

Johannes Sutter points out that the consequences of such a shock shock are just one of the possible dangers posed by SRM.

Potential adverse effects are still poorly understood, but range from a change in monsoon regime to a change in ocean and atmospheric circulation.

The acidification of the oceans would also continue. Critical voices also warn of political and social implications: Using techniques such as dimming the sun can slow or even prevent climate protection measures. Thomas Stocker, Professor of Climate and Environmental Physics at the University of Bern and co-author of the study, said: “Geoengineering is another global experiment that must be avoided at all costs, according to Article 2 of the UN Framework Convention on Climate Change, and a potentially dangerous human intervention in the climate system. will,” he says.

doi: https://doi.org/10.1038/s41558-023-01738-w

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