ABC: Why are there No Large Scale Geo-engineering Experiments?

Guest essay by Eric Worrall

Climate scientists are frustrated that nobody is attempting large scale geo-engineering experiments, despite admitting that a successful attempt to geo-engineer the global climate could trigger a nuclear war.

Saviour or scientific hubris? Geoengineering the planet to counter climate change

ABC Radio National / 
By Antony Funnell for Future Tense

The eruption of Mt Pinatubo changed everything.

As the top of the mountain disintegrated, a dense plume of ash and gas surged 35 kilometres into the air.

The resulting cloud of sulphur-dioxide and muck covered the Philippines and soon began spreading.

It was 1991, and by some estimates more than five cubic kilometres of volcanic material was pumped into the stratosphere, including around 10 billion tonnes of sulphur.

Local weather patterns were temporarily altered, and the temperature of the planet dipped by 0.5 degrees Celsius over the next two years.

…

By 2010 a large number of “geoengineering” experiments were under consideration — but now major experimentation appears to have stalled.

…

Climatologist Alan Robock of Rutgers University says people started asking ‘What’s the worst thing that could happen?‘

“The answer was global nuclear war,” he tells ABC RN’s Future Tense.

“Because if one country did something that they thought would help them and it was harmful to another country, they might be quite upset.”

…

Read more: https://www.abc.net.au/news/2020-08-27/geoengineering-controversial-science-to-combat-climate-change/12588828

While climate scientists were busy getting excited by the impact Mount Pinatubo had on global temperature, other scientists noticed another, far more sinister impact of the eruption.

Estimating global agricultural effects of geoengineering using volcanic eruptions

Published: 08 August 2018

Jonathan Proctor, Solomon Hsiang, Jennifer Burney, Marshall Burke & Wolfram Schlenker

Nature (2018)

Solar radiation management is increasingly considered to be an option for managing global temperatures, yet the economic effects of ameliorating climatic changes by scattering sunlight back to space remain largely unknown. Although solar radiation management may increase crop yields by reducing heat stress, the effects of concomitant changes in available sunlight have never been empirically estimated. Here we use the volcanic eruptions that inspired modern solar radiation management proposals as natural experiments to provide the first estimates, to our knowledge, of how the stratospheric sulfate aerosols created by the eruptions of El Chichón and Mount Pinatubo altered the quantity and quality of global sunlight, and how these changes in sunlight affected global crop yields. We find that the sunlight-mediated effect of stratospheric sulfate aerosols on yields is negative for both C4 (maize) and C3 (soy, rice and wheat) crops. Applying our yield model to a solar radiation management scenario based on stratospheric sulfate aerosols, we find that projected mid-twenty-first century damages due to scattering sunlight caused by solar radiation management are roughly equal in magnitude to benefits from cooling. This suggests that solar radiation management—if deployed using stratospheric sulfate aerosols similar to those emitted by the volcanic eruptions it seeks to mimic—would, on net, attenuate little of the global agricultural damage from climate change. Our approach could be extended to study the effects of solar radiation management on other global systems, such as human health or ecosystem function.

Read more: https://www.nature.com/articles/s41586-018-0417-3

Turns out plants need sunlight. Reflecting sunlight back into space instead of letting it reach the leaves of plants is bad for plant growth.