Guest essay by Eric Worrall

More bad news for geogengineering.

Solar geoengineering could cause unwanted changes in climate, new modelling suggests

20 Jun 2020

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“Novel changes in climate”

“Our results show that solar geoengineering will not simply reverse climate change,” Gertler explains. “Instead, it has the potential itself to induce novel changes in climate.”

In the Northern hemisphere storm tracks are also predicted to weaken with climate change. The latest work suggests that this would occur at a similar magnitude as with solar geoengineering. In the southern hemisphere, however, global warming is expected to increase the intensity of the storm tracks and shift them south. With solar geoengineering these storm track would weaken, with some of the models indicating that there may also be a poleward shift in these systems.

“A weakened storm track, in both hemispheres, would mean weaker winter storms but also lead to more stagnant weather, which could affect heat waves,” Gertler says. “Across all seasons, this could affect ventilation of air pollution. It also may contribute to a weakening of the hydrological cycle, with regional reductions in rainfall. These are not good changes, compared to a baseline climate that we are used to.” In the southern hemisphere changes in storm track intensity could impact wind‐driven ocean circulations and affect the stability of Antarctic ice sheets, the researchers warn.

“This work highlights that solar geoengineering is not reversing climate change, but is substituting one unprecedented climate state for another,” Gertler says.

Read more: https://physicsworld.com/a/solar-geoengineering-could-cause-unwanted-changes-in-climate-new-modelling-suggests/

The abstract of the study;

Weakening of the Extratropical Storm Tracks in Solar Geoengineering Scenarios

Charles G. GertlerPaul A. O’GormanBen KravitzJohn C. MooreSteven J. PhippsShingo Watanabe
First published: 23 April 2020 https://doi.org/10.1029/2020GL087348

Solar geoengineering that aims to offset global warming could nonetheless alter atmospheric temperature gradients and humidity and thus affect the extratropical storm tracks. Here, we first analyze climate model simulations from experiment G1 of the Geoengineering Model Intercomparison Project, in which a reduction in incoming solar radiation balances a quadrupling of CO₂. The Northern Hemisphere extratropical storm track weakens by a comparable amount in G1 as it does for increased CO₂ only. The Southern Hemisphere storm track also weakens in G1, in contrast to a strengthening and poleward shift for increased CO₂. Using mean available potential energy, we show that the changes in zonal‐mean temperature and humidity are sufficient to explain the different responses of storm‐track intensity. We also demonstrate similar weakening in a more complex geoengineering scenario. Our results offer insight into how geoengineering affects storm tracks, highlighting the potential for geoengineering to induce novel climate changes.

Read more: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL087348

A 2018 study covered by WUWT suggested solar geoengineering is bad for plants.

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

Geoengineering would kill plants directly by starving them of sunlight, and now we learn any plants which survive sunlight starvation will die in the geoengineering induced drought.

What seems clear is climate sulphate aerosol injection geoengineering is an incredibly bad idea. Let us hope nobody ever attempts it on a meaningful scale.

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