Aluminum Oxide and Calcium Carbonate: Potential Alternative Particles for Applications in Solar Geoengineering - Preprint

[Geoengineering News]

https://static1.squarespace.com/static/671edd03eb405e5d480d2c13/t/672570df19170c17fe4b5007/1730506975574/Solar+Geoengineering+Paper.pdf

Authors: Eliana Linder and Sophia Zouak

Abstract

The detrimental causes and effects of global warming make it a pressing issue to address while offering limited resolutions for remediation. Solar geoengineering offers a potential mitigation via the insertion of aerosols into the lower stratosphere with the aim of reflecting incoming solar radiation. Sulfates are primarily investigated, however, it was determined that sulfates exacerbate ozone depletion, prompting new particles to be investigated. This experiment aimed to determine if particles like calcium carbonate (CaCO3) and aluminum oxide (Al2O3) can reduce solar radiation. Particles were injected into an air chamber, stimulating lower stratospheric conditions, with three phases: 0.3 g particle injection, 0.1 g particle suspension, and 0.1 g particle suspension with humidity. A heat lamp was placed on top and a solar cell at the bottom of the chamber to assess the particles’ ability to reflect light. During 0.3 g injection, Al2O3 was significantly more effective compared to CaCO3 and control, by scattering the light and decreasing solar cell potential by 59.06%(p< 0.001). During 0.1 g suspension, 0.1 g of particles showed CaCO3 with a greater decrease in solar panel output of 2.3%, because Al2O3 particles were smaller (< 50 nm) and more susceptible to being sucked out of the chamber from the vortex created during suspension trials. During humidity trials, the potential output for both CaCO3 and Al2O3 dropped at similar rates from 2.32 to 2.27 volts. CaCO3 and Al2O3 both demonstrate promising applications in solar geoengineering, being able to reflect a substantial amount of light.