Should we change the clouds?

In 1991 in the Philippines, a volcano named Mount Pinatubo blew its top. The second-largest volcanic event of the 20th century, the Pinatubo eruption left over 200,000 people without homes, caused more than a half-billion USD in damages, and killed hundreds. 

While the event caused enormous devastation, another consequence caught the attention of climate scientists. The volcano sent up an ash cloud hundreds of kilometers across, and all that material in the air lowered temperatures on the planet by around 0.5° C for two years. 

As global temperatures continue to climb and we experience more severe weather events as a result, some researchers are advocating for methods that artificially recreate the temperature-reducing effects of the Pinatubo ash cloud. Additionally, various groups and start-ups are working on technologies to either help cool the Earth or remove carbon from the atmosphere. 

This all raises an interesting question: Is climate change an issue we can engineer away? 

How geoengineering can fight climate change 

The main reason for climate change is the huge increase in carbon emissions from burning fossil fuels like coal, gas, and oil that started with the industrial revolution. Increased carbon is a problem because carbon absorbs and radiates heat. As more of it builds up in Earth’s atmosphere, one result is that more of the sun’s heat stays on Earth instead of dissipating in space, which leads to higher average global temperatures that in turn generate unpredictable weather patterns. 

The two main fields in geoengineering focus on different areas of this climate change conundrum. One, carbon removal, seeks to keep or take carbon out of the atmosphere to avoid the consequences explained above. Some technologies capture carbon at a source, like a factory smokestack, while others can take carbon out of the air in any location. 

The other field is solar geoengineering and its aim is to reduce global temperatures by limiting the amount of the sun’s energy that reaches or stays on Earth. Some of the methods being considered in this area include making clouds more reflective so that they send more of the sun’s energy back into space, thinning out the highest layer of clouds so that more heat can escape from earth, and sending physical sun shields into space. 

Is geoengineering the best answer? 

Of the two fields, carbon removal is more advanced and widely accepted. Many companies are already using carbon removal or carbon capture technology to limit their emissions. It’s commonly believed that some amount of carbon removal technology will be needed to halt the rapid advance of climate change in the near future. 

Solar geoengineering is less far along for many reasons. One of the biggest is that it involves manipulating forces humans don’t fully understand. For example, if we chemically change clouds to make them more reflective or thin them out near the top of Earth’s atmosphere, we’re not sure how those changes could affect the world’s climate beyond just reducing temperatures. Additionally, it would require international agreements and trust as it would be impossible to control where altered clouds traveled. 

And there’s a bigger concern that makes some climate activists skeptical of all geoengineering: Why devote time and resources to tech and methods that won’t be an eternal solution?  

Even if we could capture all the carbon produced by burning fossil fuels, they will eventually run out. Additionally, how do we safely store all the carbon we capture? 

Even if changing clouds or blocking sunlight led to no negative side-effects, neither solution addresses how carbon build-up is causing things like ocean acidification. We could also become dependent on solar geoengineering because once we started doing it, it would be hard to stop without having global temperatures make a terrifying sudden rise. 

Skeptics of geoengineering say that we should instead be investing in more permanent fixes, namely advancing renewable energy and figuring out other ways to drastically cut – not capture or remove – carbon emissions. 

Of course, that strategy has its drawbacks, too. The biggest one is getting people, businesses, and governments on board to make the sort of investments and societal changes required to stop climate change before its results become ever more catastrophic.