Inequal Responses of Drylands to Radiative Forcing Geoengineering Methods

[Andrew Lockley]

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL084210

Inequal Responses of Drylands to Radiative Forcing Geoengineering Methods

Chang‐Eui Park Su‐Jong Jeong Yuanchao Fan Jerry Tjiputra Helene Muri Chunmiao Zheng

First published: 26 November 2019

https://doi.org/10.1029/2019GL084210

About

Sections

 

Share on

Abstract

Climate geoengineering has the potential to reduce global warming. However, the nonlinear responses of Earth's large‐scale circulation to climate geoengineering can exacerbate regional climate change, with potential inequality risks. We show noticeable inequality in the responses of drylands when three radiative forcing geoengineering (RFG) methodologies—cirrus cloud thinning (CCT), marine sky brightening (MSB), and stratospheric aerosol injection (SAI)—individually reduce the radiative forcing of the representative concentration pathway 8.5 scenario using a set of the Norwegian Earth system model (NorESM1‐ME) experiments. In North America, CCT and SAI alleviate drylands expansion, whereas drylands expand further under MSB. CCT induces significantly wetter conditions over the western Sahel. Wetting over Australia is enhanced and prevented by MSB and SAI, respectively. Our results suggest spatially inequal distributions of benefits and harms of individual RFGs on the projected distribution of drylands, which should be considered before any real‐world application of such RFGs.

[Stephen Salter]

Hi All

I have some comments on Chang-Eui Park et al.  at

 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL084210

They ignore the mobility of spray vessels and the short life of spray. We should not spray all the year round between 45 degrees north and south whether there was cloud or no cloud, monsoon or no monsoon.  It is like driving a car with the steering locked. For a month either side of the the summer solstice, being close to the Arctic ice is much better than at the equator. Please let me know if you would like calculations about the number of spray vessels needed to save Arctic ice  and reverse sea level rise.  

Spray vessel operations would be directed, by intelligent climate-control engineers with instant satellite data and super computers more powerful that we can now imagine.  For example sea surface temperature difference either side of the Indian Ocean have a profound influence on floods in Mozambique and droughts in Australia.  Moving marine cloud vessels either way gives us control.

The paper also uses the entire width of the accumulation mode when we want a mono-disperse spray of 0.8 micron liquid diameter which leaves salt residues just right for the Kohler nucleation and in the middle of the Greenfield gap for the lowest coalescence losses. The mass of a drop at the top of the accumulation mode, 3 microns, is 50 times higher.

They ignored the results in Stjern 2018 although it is in their references.   This paper used more intelligence than any previous computer model work by spraying only in sea areas with low cloud.  This alone would reduce the effort by a factor of about five.  Further gains might be available if fleet controllers mentioned above are using tactical spray patterns to avoid conditions where spray worked in the wrong direction.

The Stjern results for temperature and precipitation following a 50% increase in the concentration of condensation nuclei are shown below.

They look quite fairly benign and contradict table 4.7 of https://www.ipcc.ch/sr15/

The Chang-Eui Park results may be used by ignorant politicians to decide research policy.  I hope that can work on a second paper with the title 'Improvements to tactical spray patterns for marine cloud brightening' might offset the damage this paper may have done.

Stephen

Emeritus Professor of Engineering Design. School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3DW, Scotland S.Sa...@ed.ac.uk, Tel +44 (0)131 650 5704, Cell 07795 203 195, WWW.homepages.ed.ac.uk/shs, YouTube Jamie Taylor Power for Change

--
You received this message because you are subscribed to the Google Groups "geoengineering" group.
To unsubscribe from this group and stop receiving emails from it, send an email to geoengineerin...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/CAJ3C-05evDDTHGUARspMnk9%3D99Jg1H8L%2BDSAY8207%3DM9BJZhfw%40mail.gmail.com.