Scientists to Spray the Skies With Reflective Particles to Cool Down Planet Earth

To "mitigate" climate change.

Scientists are considering spraying a fine mixture of materials such as sulfur dioxide, alumina, or calcium carbonate into Earth’s stratosphere to help cool the planet. Researchers would use sensors to measure the particles’ reflectivity, dispersion, and interactions with other compounds in the atmosphere to gauge the effectiveness of their plan. This approach represents a new level of geoengineering, which involves using technology to modify the planet’s atmosphere.

Geoengineering can involve removing carbon dioxide from the atmosphere or using more controversial technologies that temporarily modify the skies to cool the world. Scientists from Harvard University are planning to launch aerosol injections into the stratosphere at an altitude of around 20 kilometers to study the pros and cons of deliberately altering Earth’s climate to combat global warming. The project, dubbed the largest geoengineering program in history, is funded by Bill Gates and other foundations and is expected to cost around $20 million.

Releasing particles into the atmosphere

The mission aims to release clouds of miniature particles into the atmosphere, which would create a barrier reflecting sunlight back into space and preventing heat from being absorbed by Earth. Currently, researchers are conducting lab experiments on chemicals to understand how they may behave in Earth’s atmosphere and running computer simulations to predict the cooling effect of chemical clouds.

Scientists plan to launch a balloon into the atmosphere and observe how particle clouds behave in real-world conditions. According to Lizzie Burns, program director of Harvard’s Solar Geoengineering Research Program, the physical and ecosystem risks of this small-scale experiment are minimal. However, not all experts agree.

Some warn that geoengineering could trigger more intense hurricanes, posing a threat to coastal cities worldwide, or cause droughts that devastate Africa’s Sahel region. The most concerning risk is the potential weaponization of solar geoengineering, which some experts believe could lead to global conflict.