Trying to cool the Earth by dimming sunlight could be worse than global warming

Geoengineering aims to intervene in the Earth’s climate to combat global warming.

A group of 60 scientists called on Fr. moratorium on solar geoengineering last month, including technologies such as stratospheric aerosol injection (SAI). This includes a fleet of aircraft that emit aerosol particles – which reflect sunlight back into space – into the atmosphere, cooling the Earth.

SAI can make the sky a little whiter. But it worries us the least. SAI can pose a serious threat, potentially worse than the warming it is trying to eliminate. To understand the risks, we embarked on risk assessment of this controversial technology.

Colder Earth means less water will evaporate from its surfaces into the atmosphere, changing precipitation models. This can have dramatic effects in all of the world’s ecosystems – but their exact nature effects depends on how the SAI is used. Poor coordination of aerosol emissions can lead to extreme rainfall in some places and severe drought in others, further contributing to the spread of disease.

SAI can also make natural disasters worse than they are now. Volcanic eruption, as in Iceland Eyjafjallajokull volcano in 2010, can naturally cool the Earth in the form of plumes of ash block sunlight from reaching the surface of the planet. If this had happened during the deployment of the WIPO, it would have been urgent adjusted (a difficult feat) to avoid overcooling one hemisphere and resulting in extreme weather conditions.

Looks like though nuclear war it may seem unlikely, global nuclear capabilities continue to grow, and poor policy decisions are not lacking. A “nuclear winter,”, During which global temperatures have been declining for years due to soot clouds from fires caused by nuclear nuclei, may be deepened by SAI.

Drought global warming

The effects of SAI can be much worse than a whitewashed sky.

Stopping shock

SAI is likely to expect that aerosols are constantly sprayed into the atmosphere by aircraft fleets, as particles have a half-life of approximately eight months. Satellites will be needed to coordinate these efforts and assist in monitoring any atmospheric changes.

Any disaster serious enough to shut down these systems forever could cause “cessation of shock“. If the SAI system, which effectively “hides” global warming, were suddenly removed for an extended period, the Earth could heat up by a few degrees in a matter of decades. When we already see fires, heat and sudden floods around the world from around 1.1 ° C warming since 1850, imagine what a 3-4 ° C warming will lead to.

There are many ways in which the SAI system can be disrupted. An unprecedented explosion of solar matter associated with Fr. solar flarecan knock out the world electrical systems crashing into the Earth’s magnetic field. It could damage aviation and satellite systems required for SAI.

Hoping that disasters just won’t happen in the next century would also be a mistake. One model that assesses the likelihood of a nuclear war between Russia and the United States assesses that 0.9% per year. Estimates buoy space weather events range from 0.46% to 20.3% per year.

In October 2021, a solar flare of class X

Unexpected solar activity can disable the SAI system.

SAI can also become an attractive target for cyber attacks. In 2019, a group of hackers named DarkSide seized the American oil company Colonial Pipeline hostage by launching ransomware attacks on their computer systems. Fearing widespread fuel shortages in the U.S., operators were forced to pay £ 3.7 million to DarkSide in exchange for reactivating their systems.

And in 2000, an automated sewer system in Australia’s small coastal region of Maruchi released hundreds of thousands of gallons of sewage into the sea. These “leaks” were actually caused by one dissatisfied former employee the company that installed the system. An international infrastructure system that masks global warming will attract more cause for controversy, will have a larger workforce than a local sewer system, and is likely to bring in even greater payouts.

A political mess?

Of course, it is possible that SAI will end up being used responsibly. But if one thing goes wrong enough – like one unpredictable solar storm – the hidden risks of SAI can be released. Predictions of average or “most likely” SAI outcomes are generally good. But, although much less likely, the SAI’s worst-case scenario could be catastrophic.

If SAI is used sparingly to compensate for a smaller number warming any negative effects will be minimized. Most SAI models assume ideal conditionswhere a cooperative group of countries rationally and diligently deploys SAI. Unfortunately, international politics is there chaotic.

A small group of countries that prefer a colder Earth could start using SAI without an international agreement. However, there is little research on what the possible consequences of this more disorganized use of SAI may be.

Ideally, those who run an SAI would ensure that its infrastructure is disaster-resistant, managed jointly between countries, has extensive backups, and is closely monitored throughout the time the SAI is deployed (probably decades and possibly more than a century). And to ensure that we do not fall into the trap of relying on VAI indefinitely, we will still have to reduce greenhouse gas emissions to pure zeroalso as removal of excess emissions from the atmosphere.

COVID angry woman mask

Poor governance during a pandemic may leave little hope for WIPO governance in the future.

But to assume that such management would be naive. Just consider the pandemic. From insufficient investment in testing on COVID and developing vaccines to give false confidence herd immunity, politicians have not established themselves as reliable decision-makers. Imagine the conflict around the location of a chemical mask above the Earth.

WIPO can become a very politicized problem if changes in the use of WIPO are driven by political fluctuations rather than sound science. And the fossil fuel industry and her fans may well be interested in using WIPO to delay the use of renewable energy sources.

Is SAI worse than climate change? We are still uncertain. What we can say: in a world where things are not going well, the SAI is a sensible response to the climate crisis. But we live in a world of complexity and chaos, where relying on SAI would be very unwise. Tightly linking the climate system with the world economic and political system, the use of AIS would raise the planet Damocles sword.


  • Luke Kemp – Postdoctoral Research Fellow in Existential Risk, Cambridge University
  • Aaron Tan – PhD in Climate Management[{” attribute=””>Australian National University

This article was first published in The Conversation.The Conversation Trying to cool the Earth by dimming sunlight could be worse than global warming

Back to top button