Reflecting sunlight: Geoengineering to reflect the Sun’s rays to cool the Earth

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  Quantumrun Foresight
• February 21, 2022

Insight summary

Researchers are exploring a plan to cool Earth by spraying dust particles into the stratosphere, a method inspired by natural processes observed in volcanic eruptions. This approach, known as geoengineering, has sparked debate due to its potential to alter global climates, affect agriculture and biodiversity, and shift operational strategies for businesses. While some see it as a necessary response to climate change, others warn it could distract from efforts to reduce greenhouse gas emissions and promote sustainable practices.

Reflecting sunlight context

Researchers at Harvard University are working on a radical plan to cool the Earth. They propose spraying calcium carbonate dust particles into the stratosphere to cool the planet by reflecting some of the sun’s rays into space. The idea came from the 1991 eruption of Mount Pinatubo in the Philippines, which injected an estimated 20 million tons of sulfur dioxide into the stratosphere, cooling the Earth to pre-industrial temperatures for 18 months.

Scientists believe a similar process can be used to cool the Earth artificially. This deliberate and large-scale attempt to influence the Earth’s climate is referred to as geoengineering. Many in the scientific community have warned against the practice of geoengineering, but as global warming continues, some scientists, policymakers, and even environmentalists are reconsidering its use due to current attempts to curb global warming being inadequate. 

The project entails using a high-altitude balloon to take scientific equipment 12 miles into the atmosphere, where about 4.5 pounds of calcium carbonate will be released. Once released, the equipment in the balloon would then measure what happens to the surrounding air. Based on the results and further iterative experiments, the initiative can be scaled for planetary impact.

Disruptive impact 

For individuals, reflecting sunlight through geoengineering could mean changes in local climates, affecting agriculture and biodiversity. For businesses, especially those in agriculture and real estate, these changes could lead to shifts in operational strategies and investment decisions. The potential large-scale influence of such a project on Earth's climate has led some to argue that it crosses the ethical boundaries of scientific experimentation.

However, others counter that humans have already been engaging in geoengineering, specifically through the significant amounts of carbon emissions released into the atmosphere since the onset of industrialization. This perspective suggests that we are merely shifting from unintentional to intentional manipulation of our environment. Governments, therefore, may need to consider regulations and policies to manage these interventions and mitigate potential risks.

The scientific community and environmental organizations are closely monitoring these developments, expressing concerns that such endeavors could divert global focus from reducing greenhouse gas emissions using existing technologies and strategies. This is a valid concern as the promise of a "quick fix" could undermine efforts to transition towards sustainable practices. It is crucial to understand that while geoengineering might offer a part of the solution, it should not replace efforts to reduce emissions and promote sustainability.

Implications of reflecting sunlight 

Wider implications of reflecting sunlight may include:

• Severe and unpredictable effects on the Earth’s climate, causing unforeseen complications for life on the planet, such as affecting wind patterns, storm formations and causing novel climate changes.


• Protests by environmentalists and the public at large once the dangers of geoengineering become known.


• Geoengineering lulling governments, large companies, and businesses into a sense of complacency regarding climate change.


• Shifts in population distribution as people move away from areas with unfavorable climate changes, leading to significant demographic changes and challenges in urban planning and resource allocation.


• Fluctuations in food prices and availability, which could have profound economic implications, affecting both local economies and global trade.


• New industries focused on the development, deployment, and maintenance of these technologies, generating new job opportunities but also requiring workforce retraining and adaptation.


• Political tension as global consensus would be required, leading to conflicts over governance, equity, and decision-making power among nations.


• Impacts on biodiversity as ecosystems adjust to changes in sunlight and temperature, leading to shifts in species distribution and possibly even species extinction.

Questions to consider

• Does geoengineering hold any positive promise, or is it a risky initiative with too many variables to control?


• If geoengineering succeeds in cooling the Earth, how might it impact the environmental initiatives of large greenhouse emitters, such as countries and large companies?