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Now & Next: Solar geoengineering: is it worth it?– in partnership with The Economist

Posted on 21 April 2022

The premise is simple: if the world is getting too hot, why not give it some shade? Solar geoengineering is a radical response to global warming which could rapidly halt rising temperatures. But is it too good to be true and how does the world decide whether it is a risk worth taking?

If the world is getting too hot, why not give it some shade?  That’s the simple idea behind solar geoengineering.  A radical response to global warming which could rapidly halt rising temperatures.
 

Prof David Keith, Solar Geoengineering Research Programme, Harvard University
It would reduce those peak temperatures that are very destructive.
But is it too good to be true?
 

Raymond Pierrehumbert, Professor of Physics, University of Oxford
It would be like living underneath a hundred ton boulder ready to fall at any time.
As the debate heats up how does the world decide if this technology is a risk worth taking?
 

NOW&NEXT
 

Solar Geoengineering: Is it worth it?
Norbotten County, Sweden
Like many indigenous groups the Saami people are on the front line of climate change and it’s Asa Larsson Blind’s job to stand up for their way of life.
 

Asa Larsson Blind, Vice President, Saami Council
The traditional livelihoods like reindeer herding have survived through industrialisation and modern society development and land encroachments and we are still here but when people talk about the future of climate change, it’s not a future; we are already dealing with it and coping with it, all seasons, all year round.
But the Saami Council is concerned that one area of scientific research aiming to counter climate change could backfire on the world.  The Council is worried about the impact of a controversial but potentially life changing technology known as solar geoengineering.
Think of volcanic eruptions, sulpha dioxide released into the atmosphere creates particles which reflect sunlight back into space and cool the earth.  Scientists have suggested it may be possible to reduce global warming by using high flying aircraft to release particles into the stratosphere bouncing the sun’s rays back in the same way.
In 2021 scientists from Harvard University researching solar geoengineering plan to test fly a balloon from a nearby space centre over territory where the Saami live.
 

Asa Larsson Blind, Vice President, Saami Council
This is the testing area, is in the mountain area.  So this is the area where the testing would have taken place.
Although the first balloon wouldn’t have released any particles a complaint from the Saami Council ensured it didn’t take off and helped persuade Sweden’s Space Agency to cancel the project.
The Saami Council objects to the message this research project sends out about climate change.  Like many, it worried that a successful technology could discourage the urgent need to reduce greenhouse gas emissions.
 

Asa Larsson Blind, Vice President, Saami Council
The notion of a plan B, the notion of technology saving us might put a pause on the needed climate action.  If the fossil fuel industry leans back just a little and said ‘well we’ll wait and see a bit’ – just that notion might be the thing that makes us not reach the Paris Agreement and that would be devastating.
But models suggest that current political action is insufficient to limit global warming to the Paris Agreement’s target of 1.5 degrees centigrade.
So what about the case for doing at least more research into solar geoengineering?
Harvard University
David Keith is one of the scientists in charge of the Harvard Project.  He argues the risks from solar geoengineering must be weighed against the chance it could save millions from heatwaves.
 

Prof David Keith, Solar Geoengineering Research Programme, Harvard University
[basically your temperature noise is too big]
The Saami Council are entirely within their rights to make a statement which effectively says that this whole line of research is unethical and a bad idea.  My views is a point of view with its own ethical implications because the benefits of solar geometry would most be felt by poor people in hot countries because you reduce those peak temperatures that are very destructive.
Like most geoengineering researchers, Professor Keith doesn’t believe the idea should be a substitute for cutting emissions.
 

Prof David Keith, Solar Geoengineering Research Programme, Harvard University
I think there is a certain kind of mono media that we can only talk about one thing.  I just don’t think that’s ethical or good public policy.  Of course we have to cut emissions but that can’t be all that climate policy comprises.
He argues that stifling research into solar geoengineering now could increase the risk of negative consequences in the future.
 

Prof David Keith, Solar Geoengineering Research Programme, Harvard University
What blocking research does is it means that when the decisions about deployment come on to the agenda, whenever that is, people will make that with less knowledge about the side effects, less knowledge of how to do this in a way that might be more effective and probably with less serious discussion about how to govern it.
Some studies have suggested that solar geoengineering deployed equitably could provide climate benefits to all countries.  But without global cooperation a technology designed to cool the climate could instead stoke international conflict.  Because solar geoengineering could disrupt rainfall patterns and increase droughts, some countries may lose out.
University of Oxford
 

Raymond Pierrehumbert, Professor of Physics, University of Oxford
[what happens if you dim the sun by geoengineering and remove solar energy from the surface]
Scientists such as Raymond Pierrehumbert believe a technology aimed at countering one global problem could create others by ramping up disputes and sparking new ones.
 

Raymond Pierrehumbert, Professor of Physics, University of Oxford
What if Russia likes an ice free arctic and wants less solar geoengineering but what if India is labouring under killer heatwaves so often that they really want to chill their climate down?  Anything that increases the level of international tension in a world where nuclear arms are already proliferating is going to be a threat multiplier.
Some also fear being locked into solar geoengineering without any reverse gear.
If humans fail to reduce emissions and rely on solar geoengineering alone it could mean having to do it forever.  In the worst case scenario stopping it abruptly could bring a disastrous termination shock.
 

Raymond Pierrehumbert, Professor of Physics, University of Oxford
The word is terror.  If anything forces the solar geoengineering to stop we are hit with catastrophic warming.  It would be like living underneath a hundred ton boulder just perched over your head ready to fall at any time.
Some scientists advocating research into solar geoengineering argue that termination shock could be avoided by gradually winding it down over decades.  But would thinking less globally and more locally about solar geoengineering help to balance some of the risks associated with it.
Great Barrier Reef, Australia
On the Great Barrier Reef a group of scientists lead by oceanographer, Daniel Harrison are doing just that. 
They are testing a kind of solar geoengineering called Marine Cloud Brightening.  The first time it has been tried outside of a laboratory.
 

Dr Daniel Harrison, Cloud Brightening Project Leader, Southern Cross University
Cloud Brightening is one of the ideas that if it scales up how we hope that it may, it is potentially usable over the entire reef and can help all of the coral and all of the eco system.
Using a custom design turbine with 320 nozzles they release a cloud of trillions of nano-sized sea water droplets above the ocean.  If the droplets can reach the clouds above the theory goes that they will make them more reflective.
 

Dr Daniel Harrison, Cloud Brightening Project Leader, Southern Cross University
What we are really interested in looking at is the behaviour of that plume of sea salt droplets as it drifts away from the boat.  We have a big focus on using drones as sampling platforms to measure the plume not just in a horizontal dimension but also in a vertical dimension.
If it works the cooling effect could protect the reef from bleaching, damage done to the coral during heatwaves.  Dr Harrison’s vision for marine cloud brightening is targeted and temporary rather than an attempt to alter the climate on a larger scale.
 

Dr Daniel Harrison, Cloud Brightening Project Leader, Southern Cross University
One of the great advantages of the cloud brightening concept applied regionally is that in the very low chance there were some unexpected or undesirable consequences, you could stop producing the sea salt spray and everything would go back to normal after only a few days.
Yet other proponents of solar geoengineering research argue that if cloud brightening were used more widely, regional and unequal benefits could become a problem.
 

Prof David Keith, Solar Geoengineering Research Programme, Harvard University
My only concern is that this will kind of be a thin end of the wedge that allows geoengineering technology that’s inherently quite patchy and therefore unequal therefore more likely if used at scale to actually make some people worse off.
Arguments look set to intensify about the balance of risks and rewards of solar geoengineering as well as whether and how it could be deployed equitably.  It is the kind of debate that is all too familiar when parts of the scientific community press the case for progress.
 

Prof David Keith, Solar Geoengineering Research Programme, Harvard University
In any disputed area of science it is entirely legitimate for different civil society groups to raise objections.  It is the job of Governments and democracies to ask a bunch of questions and make an overall decision in the public interest.
 

NOW&NEXT
Catherine Brahic

Hi I am Catherine Brahic, Environment Editor for The Economist.  If you’d like to learn more about this topic, click on the link opposite and if you’d like to watch more of our Now & Next series, click on the other link.  Thank you for watching and don’t forget to subscribe.

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