Sunday 3 September 2017

We need to talk about a geo-intervention

Photo NASA: Filament Eruption Creates 'Canyon of Fire' on the Sun

There was a time to work on (the technologies for) reducing emissions of greenhouse gasses (mitigation), now is the time we also need to work on adaptation and now is the time we need to start having a serious conversation about a geo-intervention. The journalistic hook is a new interesting commentary in the scientific journal Nature. It makes the surprising, at least for me, case that a geo-intervention to reduce the insolation will also reduce greenhouse gas concentrations and ocean acidification.

Geo-intervention is the more accurate term for what is commonly called geo-engineering. We cannot engineer the climate, but we may be able to make the climate crisis less harmful. Also our emissions of greenhouse gases are a geo-intervention and by now we cannot even say anymore that it is an unintended intervention. We know what we are doing and are doing it anyway.

The best known geo-intervention is called Solar Radiation Management, that is, a reduction of the amount of sun that is absorbed at the Earth’s surface. This is possible by making the Earth brighter, especially the dark oceans, it may be possible to make clouds brighter or we could install mirrors in space. The most considered Solar Radiation Management method is creating large amounts particles high up in the air in the stratosphere. We know this works, large tropical volcanoes cool the Earth by emitting sulphur dioxide creating small particles in the stratosphere.

Advantages of Solar Radiation Management would be that it is relatively cheap. A medium sized economy like The Netherlands would have to spend a few percent of its gross domestic product to keep the global mean temperature stable. That sounds like a much better deal than having your culture disappear in the waves and more countries will likely be willing to chip in and join such a coalition of the chilling.

The Nature comment makes the interesting case that reducing the warming, will also reduce the concentrations of carbon dioxide in the atmosphere. It would do so as vegetation would take up more carbon dioxide if they are less stressed by the heat. The Arctic would warm less, which would reduce emissions from thawing permafrost. And also humans tend to use less energy when the planet is colder (for example, less air conditioning). Compared to other methods to remove carbon dioxide from the atmosphere solar radiation management is cheap.

Disadvantages are that this would hurt the ozone layer in the stratosphere. Volcanoes use sulphuric dioxide for their Solar Radiation Management, this would make acid rain worse. However, there is ongoing research on alternative particles and hopefully acid rain becomes better anyway due to the energy transition away from burning fossil fuels, which emits sulphuric dioxide in the troposphere where we live. In the dry stratosphere the particles are not removed as fast (for example due to precipitation) as in the troposphere. So we would need much less sulphuric dioxide emissions to cool the planet in the stratosphere than in the troposphere.

Solar Radiation Management can also not stop all climatic changes. Global warming due to greenhouse gases will mostly warm the Arctic (polar amplification), while solar radiation management would mostly cool the tropics where the sun is the strongest. Thus the temperature difference between equator and pole would become smaller and the circulation and water cycle would still change (although probably less).

The Nature comment argues that we should also talk about using Solar Radiation Management to partially offset global warming. Most studies look at bringing the temperature down to pre-industrial levels, but we could also make smaller reductions. For example, we could stabilise the temperature in the tropics. Then the rest of the planet would still warm, but the impacts in poor and thus vulnerable countries would then be reduced.

Goe-interventions are typically accompanied by academic debates about global governance of such a system. We have seen how good that works for the original problem, geo-engineering by carbon dioxide. In case of carbon dioxide the response has been limited by the people willing to take the largest risks with other people's lives and property. (Hopefully economic forces will now block them.) The only possible climate treaty was one without any obligations beyond reporting back. Still the incompetent president of the historically largest polluter said fuck you to the entire world for no other reason than the pleasure of saying Fuck You!

Similarly the coolest coalition of the chilling will set the temperature. If the hotheads do not like that, I am sure the reasonable cool people will be willing to talk, if the talks are also about carbon dioxide emissions.

We would have to keep on managing the insolation for millennia or until someone finds a cheap way to remove carbon dioxide from the air. The largest danger is thus that humanity gets into trouble over these millennia and would no longer be able to keep the program up, the temperature would jump up quickly and make the trouble even worse. Looking back at our history since Christ was born and especially the last century, it seems likely that we will be in trouble once in a while over such a long period.

This danger could also be an advantage, just as the mutual assured destruction (MAD) with nuclear arms brought us a period of relative peace, the automatic triggering of Mad Max would force humanity to behave somewhat sensibly and make people who love war less influential.

My impression is that the main objection from scientists against geo-interventions is their worry about creating such an automatically triggered doomsday machine. Those people seem to think of a scenario without mitigation, where we would have to do more and more Solar Radiation Management. While carbon dioxide accumulates in the atmosphere over millennia, the stratospheric particles (after a volcanoes) are removed after a few years. So we would need to keep adding them to the stratosphere and if we do not reduce greenhouse gas emissions increasingly many particles.

I do not think humanity will forgo mitigation, but we will likely be too slow. My expectation is that we will stabilise the temperature, but after quite a lot of warming. Renewable energy is getting very cheap and still rapidly declining in price. Also batteries are declining in price. Thus I would see the energy transition as unstoppable for electrical power and private transport. That would break the political power of the fossil fuel industry and then make the rest of the transition (heating and industrial processes) a lot easier.

About 20 percent of historical warming is due to methane, which is mostly due to animal husbandry (read burping cows) and rice paddies. The residence time of methane is about a decade. It thus accumulates thus much less than carbon dioxide and would be something we could fight with a modest and importantly stable amount of Solar Radiation Management. Hopeful was a recent study that feeding cows seaweed reduces their methane emissions almost to zero. (There are many other ethical and environmental problems with industrial agriculture, but the global warming part of it would then be solved.)

Thus I expect us to stabilise the climate, but at a level that will be harmful. If we stabilise at 3°C of warming, would it not be better to reduce the warming to 2°C, 1.5°C, or our current 1°C. The internationally agreed upon 1.5 and 2°C levels are not "safe" levels, below them there are clear damages (and above them the word will not suddenly end).

There are scientific justifications for the 2°C level, for example looking at some tipping points in the climate system, but this level is not set by science. In the end it is a political compromise between the risks of climate change and political difficulty of changing the energy system. As a Dutch person, my compromise is to go back to the old temperature. Also if the warming would stop now immediately, sea level rise would continue for millennia.

The question is not whether it would be nicer not to have climate change, but whether a geo-intervention can improve the situation. Some worry that a geo-intervention would reduce the pressure to reduce greenhouse gas emissions. In a rational world that may partially be the case, although a geo-intervention would not stop the market forces moving us to renewable energy. In the real, not rational, world it may well do the opposite.

Most people like to see the world become a better place, some for all, some for a large group they identify with, some for their community, some for their family. That may make these people blind for the possibility that some do not mind if their own situation becomes worse, as long as it becomes even worse for others and relatively they “win”. Let’s call these people supremacists or fascists.

The term supremacy or Trump’s slogan “America first” is already a hint that these people want to be on top, it does not say that the top is a nicer place, it is a relative measure. When the Second World War still went "well" for the Nazi’s, they were on top, but the suffering was enormous, less so, but also for the Germans. The Nazi’s did not care, for them war and violence is a natural state. They call normal people “Good people”, seeing themselves as bad people, as people who enjoy bringing about suffering of humans they perceive as less valuable. America’s white supremacists dream of a race war, which will also bring a lot of suffering on the people they claim to love.

When these people hear Greenpeace argue that vulnerable people will suffer most from climate change, it would make sense that they like this and want more of this. It is not possible to convince these people that climate change is real, they already accept it is real, they only claim they do not. The best way to get more climate change is to claim that you do not accept the science of climate change. That way you can also convince some conservatives who do not like to see others suffering, but are naturally sceptical of any claim that powerful corporations can do something wrong and trust their politicians who work for the fossil fuel companies (campaign contributions, cosy jobs afterwards).

I think the fascists are stupid to listen to Greenpeace. Yes, more people will die in poor countries, that means they will have more kids and multiply faster. Living in a harsh environment makes you flexible and strong. Our power and pampered life style is based on a fragile just-in-time economy, where everything is optimised and thus every change produces damages. Where a mid-sized bank going bust can produce a decade long recession. If civilisation goes down, the poor will have the more useful skills.

The mitigation sceptical movement seems to be against all types of geo-intervention, except for emitting greenhouse gases. Reading between the lines when they complain that scientists spread too much fear, one almost gets the impression they fear climate change more than most. That could be because they are fighting to make the worst case scenario happen and expect to be “successful”.

The fascists among them would hate it when geo-interventions would make their life’s work mostly futile. If they are no longer fighting for a bad world that would make the transition again a lot easier.

Hopefully they will move on to lie about other stuff, preferably claims that are easily checkable, like the size of inaugurations. (It is a sad state of affairs, that I thought is was worthwhile to add a link.)

Let me end this post with a And-Then-There's-Physics-style last paragraph. I know a little about the quality of climate data, but this post is just written as a participant in the climate debate. As far as I can judge nearly all scientists worry about geo-interventions and many do not even like doing research on it. So even if pro-intervention people are very present in the media, I am an outlier. Feel free to point out my thinking mistakes and alternative solutions.

Related reading

Do dissenters like climate change?

Nature commentary: solar geoengineering reduces atmospneric carbon burden. (Open Access with this link.)

Gernot Wagner co-author of the book Climate Shock: It's time to take solar geoengineering seriously, even though it seems outlandish.

Raymond T. Pierrehumbert in The Bulletin of Atomic Scientists The trouble with geoengineers “hacking the planet”.

Reto Knutti, Joeri Rogelj, Jan Sedláček & Erich M. Fischer, 2016: A scientific critique of the two-degree climate change target. (pay-walled)

Frieler, K., Mengel, M., and Levermann, A.: Delaying future sea-level rise by storing water in Antarctica, Earth Syst. Dynam., 7, 203-210, doi: 10.5194/esd-7-203-2016, 2016.

* Top photo by NASA, Filament Eruption Creates 'Canyon of Fire' on the Sun used with a Creative Commons Attribution 2.0 Generic (CC BY 2.0) license.

Photo of thawing permafrost by NPS Climate Change Response used with a Creative Commons Attribution 2.0 Generic (CC BY 2.0) license.

Photo Collecting salt under desert sun by Armando G Alonso used with a Creative Commons Attribution-NonCommercial 2.0 Generic (CC BY-NC 2.0) license.

Photo of a strong African lady Use No Hooks by Michał Huniewicz used with a Creative Commons Attribution 2.0 Generic (CC BY 2.0) license.


  1. Thank you for the interesting advocacy for other geo-interventions than carbon emission.
    What I found interesting about it is, that the ethical abandoning of this technology might be combined to societal optimism and pessimism at the same time. Optimist that mitigation can be effective and pessimist that possible geo-interventions might hamper mitigation measures.
    What actually is problematic is that the regional impacts of geo-interventions might turn out to be regionally unfair, therefore some kind of global governance seems to be desirable, if such an option is taken or considered seriously.

  2. I'd comment, but blogger keeps telling me I'm limited to 4096 characters, even though my comment is less than that!

  3. As a last line of defence "SPACE MIRRORS" would seem better than pushing "stuff" into the atmosphere.

    They would need to be adjustable to tune the cooling - a useful feature
    They would need a method of repositioning to allow for photon pressure.
    they are not cheap!!

    However putting aerosols in the atmosphere has problems
    get it wrong and will take time to disperse and correct.
    what effect on communications
    what effect on flight
    what effect on astronomy

    But as you pointed out how do you tell cold climate occupants that it will get colder again. Balancing pros and cons with every nation will be virtually impossible.

    If you cannot get nations to agree on energy efficiency (why are people still buying SUVs in UK?)/moderation in fossil fuel use etc what chance do you have of global agreements for geo-engineering

  4. @Victor Venema:
    You have claimed that Solar Radiation Management is cheap.
    This may be true, but it has very expensive effects.

    It reduced the incoming solar radiation to the ground, which reduced evaporation and so worsening droughts and reducing power from solar and hydro electric plants.

    The cost for offsetting 2°C warming f.e. by this method may be a damage of tens to hundreds of billions $ per year in the agricultural sector.

    And for the power sector even today the economic loss for hydro and solar power plants would exceed ten billions $ per year and it may be hundreds of billions to trillions $ per year, if the solar power sector is the main source of energy in the future.

    Due to this would have been done for ten thousands of years, from the energetic point of view, the loss of solar energy could be far greater than the energy get from fossil sources in the first place.

    So Solar Radiation Management may be far to expensive to be considered as a possible option.

  5. In your article it is stated, that SRM would lower the temperatures especially in the tropics. Might this result in unexpected weather as the atmosphere is in large scale by the temperature gradient between the poles and the tropics. As warming would continue at the poles but ofsetted in the tropics this might produce surprises in general circulation. Is this a relevant possibility?
    Additionally, I am not sure that the effects in the topics are that simple, that smaller warming there produces smaller harms at this very region?

  6. Dear anonymous posters, you can also use the option "Name/URL" (and leave the URL open) to make a comment with a random name. That makes the conversation easier.

    Anonymous 1, global governance/cooperation would also have been nice for the original geo-intervention with CO2. This also has regionally varying consequences. Here is would also have been just if the people who benefited the most would have asked for permission and compensate the people who suffer the most.

    I do not see why we should be more strict with making the situation less bad with solar radiation management than we were with making the situation bad.

  7. Sorry about the problems submitting your comment Mal. If you saved it, please try again or send it to me by mail and I will try to submit it. Has not happened before. If it was close to the threshold, maybe Blogger also counts white space as characters?

  8. Perfect Ford, do you have any reasons to expect problems with communications, flight, astronomy or even links? I see no obvious reason to expect problems with communication and with flight. For optical astronomy orbiting mirrors would be just as bad, at least in case of many "small" ones?

    I do not expect large problems with not getting the temperature right. If I recall correctly Pinatubo cooled the Earth by about half a degree Celsius, one degree Fahrenheit. So we know the order of magnitude and like with the volcanoes the particles would be gone again after one or at most a few years. In other words, we have a good first guess and can slowly increase the concentration to get it right.

    That we could change the mirrors could also be a problem. This would lead to more conspiracies about weather warfare (then suddenly chaos theory does not exist for the conspiracy theorists, while they do acknowledge its existence for climate change and pretend it means climate projections are impossible). In case we could change regional climates that way more accurately than with particles in the stratosphere (no idea if that is possible), that would make the problem of needing global governance larger.

  9. Uli, do you have sources for your cost estimates? In case of hydropower we would restore the energy balance at the surface and make evaporation normal again. Thus they have no disadvantage compared to the situation before climate change. Evaporation/rain increases by 1 to 2% per degree Celsius, so I think they will be just fine.

    I was unaware that sunlight was the main restricting factor for global agriculture. I thought they were nutrients, soil, temperature, water. Only very close to the poles I could imagine sunlight being a factor and more likely it would be the temperature. So I would be very interested in any quality resources you may have. There would be advantages to agriculture due to less heat waves.

    The reduction in sunlight would be about 1%. Just install a few solar panels more. I think human lives and well being should be worth that.

    It would also be nice to contrast your cost estimates to the damages from climate change. I would expect these costs to be much higher, especially for The Netherlands and tropical countries. The end of The Netherlands has some economic costs to The Netherlands. American critics of climate science may not care about the annihilation of The Netherlands, but we do have to right to defend ourselves.

  10. Anonymous 2, yes I mention that temperature difference between the equator and the poles will become small and that that will change the circulation in the above post. There is no other way to get back to the old situation than stopping greenhouse gas emissions and removing past emissions from the atmosphere.

    Global warming does the same and there are people who claim that this changes the circulation in the midlatitudes and may be a reason for cold air outbreaks in America in the winter and makes heatwaves more likely by reducing the movement of high pressure areas.

    Nothing in the real world is ever simple. Also when we do nothing to reduce the temperature there will be surprises. At the equator the situation would not be that same than before climate change. We could get the same energy balance there, but after the geo-intervention a larger part of the energy would be as infra-red radiation (CO2 still there) rather than solar radiation. That would change the daily cycle and the annual cycle.

    It would likely still be a smaller change then doing nothing or making a larger geo-intervention to return to the old global mean temperature, which would mean cooling at the equator.

  11. Victor Venema, sorry for the late answer.

    I have no external sources for my cost estimates, because they are rough estimates by me, done in a few minutes.

    The energy balance at the surface will not be restored that way. I had remembered a threefold decrease of the global evaporation/precipitation in the case of SRM compared to the same temperature change from GHGs.

    The temperature depends on the energy balance at top of atmosphere but the evaporation depends on the surface energy balance. Because the solar radiation is reduced, there is lesser need for energy transport from surface to the upper atmosphere due to evaporation/precipitation.

    Now, I tried to calculate approximately the surface energy balance and got only a decrease in evaporation two times as large as the increase due to GHGs.

    This is consistent with the results in AR5 WG1 Ch. 7.7.3 around 1% increase of precipitation per degree warming due to GHGs but 2% decrease of precipitation per degree of cooling due to SRM.

    So the effect of precipitation change on agriculture there is about three times less than I've assumed in the last comment.
    So in the case of CO2 as GHG, the negative effects are probably more then offset by positive effects of CO2 on agriculture. But these effect are also present without SRM.
    But there may be regional effects of precipitation.

    I did not claim a large influence of sunlight change on agriculture.

    I got a reduction in sunlight and non concentrated solar power by 1.5% per degree Celsius cooling, much more for concentrated solar power. So it would be 3% in the case of 2°C, not just 1%.

    For the cost compared to other options I got more than ten times higher cost, due to solar power loss of 3% from assumed future 75 TW of continuous solar power (in the case where solar power is the main energy source) for SRM than direct air capture cost of CO2 today. If solar power including storage will be very cheap, the cost may be lower than my estimate.

    In the case of low areas threatened by sea level rise as The Netherlands, there may be additional factors. F.e. some areas are sinking fast due to human induced removing of mass from the ground, like water, oil, natural gas, coal, salt or ore.
    I don't know if this is the case for The Netherlands. But if, it may be worth to consider to stop these and maybe even reverse it by rising the land level by pumping mass into the ground, f.e. captured CO2.

  12. "Our power and pampered life style is based on a fragile just-in-time economy, where everything is optimised and thus every change produces damages. Where a mid-sized bank going bust can produce a decade long recession." Is this the rationale behind Neil DeGrasse Tyson's latest interview, where he explains that the US might not be able to recover from the effects of climate change?

  13. Uli, I thought the increase in evaporation was 1 to 2% per degree Celsius of warming. Thus if the decrease due to solar radiation management is 2% per degree of cooling, they would mostly even out. And if you do not fully go back to the old temperature, the global average evaporation could stay about the same.

    A few percent less solar energy, with the energy sector being about 6% of the economy would be an economic impact of 0.03*0.06=0.0018=0.2%. That seems to be a small effect relative to the damages of climate change.

    There are some people thinking of injecting, I think, Sulphur in the ground in The Netherlands, which would change it to gypsum, which takes more space and would lift the ground. No idea how serious those ideas are and whether you can pull it off without destroying the infrastructure. Would probably also be a large project and it would only help The Netherlands.

  14. Serrara Fluttershy, I found the video of the interview on YouTube. The automatically generated transcript is to the side and I put it on Reddit.

    Hard to say what Neil DeGrasse Tyson was thinking of and when it comes to questions of how society responds to climate change I really only speak as a citizen.

    If the damages get larger than the typical growth of the economy due to efficiency gains, market societies would have real problems. That would quickly lead to mass unemployment, fascism and a command economy controlled by the powerful.

    It beats me why it are the people who claim to love markets that are willing to take that risk with their object of adoration. One sometimes wonders if the love is real.

    Locally the case is stronger. Close to the coast you have most impacts from sea level rise and hurricanes. Once insurance companies are no longer will to take the risk because the events are too large for them the bear or the risks too hard to quantify this will have an impact on coastal communities and their economies.

    And you cannot simply move such cities and communities. Their productivity comes from networks of trust and complementary companies. Building that complexity up again takes decades, while the rest of the world continues and may sap away investment capital. If it were just a matter of hard work, the developing countries would long have been similarly affluent as we are.

    The farmers that left the dust bowl for the big cities mostly did not return. Gaveston never recovered from the Galveston hurricane. A third of the population of New Orleans is still gone. Is that "recovered"?

  15. Victor Venema, the don't even out. The solar radiation reaching ground is reduced and so evaporation. If the increase in evaporation is 2% per degree Celsius of warming, that is more sensitive, the reduction due SRM would be larger. It's about twice as large. It's not that the reduction due SRM is fixed and if the increase due to warming by GHG is large enough they may cancel out.

    The economic impact is in the right order of magnitude. I get about 0.1% probably being more energy efficient.
    But you have to take in account that this is for about 20000 years. As the impact of climate chance. Where the cost of other measures as re-movement of GHG from the atmosphere or a faster transition to non fossil energy sources need only paid ones.

    So I think that the cost in the order 'cheapest first' are:

    Fast reducing of fossil fuel use.

    CCS from fossil fuel and biomass.

    Air capture of CO2 and storage, to remove to much emitted CO2 from atmosphere.

    Solar radiation management due aerosols in the upper atmosphere.

    Do nothing of this, and adapt to the climate change.

    Ok. Do nothing and do not adapt is even more expensive.

  16. Compared to other methods to remove carbon dioxide from the atmosphere solar radiation management is cheap.

    Okay, let's be clear. The word "other" in that sentence does not belong there. Sure, by containing increases in temperature, knock-on effects from temperature-related releases of greenhouse gases from vegetation will be avoided. This will realize an improvement over the do-nothing scenario. But nothing SRM does will remove greenhouse gases. The atmospheric lifetime of half of the fossil fuel carbon dioxide is a thousand or more years. (Archer and Brovkin, 2008, and figure below. Updated 2009, and see Solomon, et al.)
    Worse, although CO2 concentrations will decay to a long-lived asymptote in a couple of centuries were emissions to be ended completely, global mean temperature will not, due to thermal inertia of the climate system.

    So, the only two real choices are mitigation, or stopping emitting, and clear air capture of CO2 and sequestration of it. The second choice actually subsumes the first, because there is no conceivable scenario where direct capture makes any sense if emissions are continuing. We do not know how to do direct capture at scale or at a price which is affordable. I did a calculation. We need to be something around US$0.33 per tonne CO2 (2010 dollars) to extract and sequester to make the technology feasible. We are presently at about US$300-US$600 per tonne.

    Sure, SRM is cheaper, but even setting aside its complications and possible side effects, it is a stopgap for a world where emissions are zeroed, and direct capture has been scaled and implemented. Zeroing emissions is harder than most imagine because 4 GtCO2e is pure agriculture, without fossil fuel emissions for planting, harvesting, processing, and transport. Especially in a scenario where SRM is deployed, and major protein sources from for a billion or so people on the planet have been killed off by ocean acidification, this 4 GtCO2e is a lower bound, since these people are going to have to eat.

    The final sobering fact is that we are not at 405 ppm CO2 but, actually, 490 ppm, since there are a large number of species in atmosphere, like methane, which decompose into CO2 in the long term and if that calculation is done, it's 490 ppm.

    To monitor our continued lack of progress, the Global Carbon Project is the definitive source.


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