In 2040 We Will Collectively Decide to Flood the Atmosphere With Aerosols

[Andrew Lockley]

https://jabberwocking.com/in-2040-we-will-collectively-decide-to-flood-the-atmosphere-with-aerosols/

In 2040 We Will Collectively Decide to Flood the Atmosphere With Aerosols

AuthorKevin DrumPublished onFebruary 9, 2021 – 9:21 am23 Commentson In 2040 We Will Collectively Decide to Flood the Atmosphere With Aerosols

I see that Ezra Klein is reading my mind today:

Should We Dim the Sun? Will We Even Have a Choice?

That’s the central theme of the Pulitzer Prize-winning author and journalist Elizabeth Kolbert’s new book, “Under a White Sky: The Nature of the Future.”...In my conversation with her on my podcast, “The Ezra Klein Show,” I wanted to focus on one [subject] that obsesses me: solar geoengineering. To even contemplate it feels like the height of hubris. Are we really going to dim the sun? And yet, any reasonable analysis of the mismatch between our glacial politics and our rapidly warming planet demands that we deny ourselves the luxury of only contemplating the solutions we would prefer.

Fifteen years ago my view on climate change was conventionally liberal: we needed bold policies to fight global warming. This included things like carbon taxes; federal initiatives to spur investment in solar and wind; regulations to reduce power consumption, and so forth. One of my earliest magazine pieces for Mother Jones represents this kind of thinking. You can read it here.

For fifteen years I waited for evidence that the world would make even the mildest efforts to enter this fight. But this is a global problem that demands a global response, and on that score we've gotten almost nothing. We all signed the Paris Accord, but compliance is voluntary and few countries have any real hope of meeting their goals. Extraction of fossil fuels continues apace in virtually every country where it's possible: Canada has oil sands, Norway has offshore oil, the United States has fracking, Germany has coal, China has coal, and even Britain, which gave up mining coal years ago, is now set to open a new coal mine. No matter how green a country claims to be, it will extract all the fossil fuels it can if it means generating a few more jobs or making a small dent in its balance of trade figures. In the meantime, carbon levels in the atmosphere continue to rise like a metronome:

A couple of years ago I finally gave up on this: It was obvious there was no hope for an adequate global response in anywhere close to the necessary time frame. I now believe that our only option is to invest massive amounts of money in technology solutions, hoping against hope that enough of them succeed to reverse warming before it destroys the planet. You can read all about that here.

But there's one more thing. Technological progress may be our best hope right now, but how likely is it to work? Since it requires no big personal sacrifice other than trainloads of cash—which can be put on national credit cards if push comes to shove—it could gain enough public support. And since it will produce technology that everyone can use, other countries might well pitch in. And finally, since it does nothing one way or the other about the Uighurs, even China might get on board. It has a legitimate chance.

By "legitimate," however, I mean that my personal guess is that it has maybe a 10% chance of panning out. If you're an optimist, you might give it 20%.

Which brings us to this: what do I predict will happen? The answer is that I think around 2040 or so we will collectively conclude that we're screwed. Global temps will already be 2ºC above the historical average and we'll be on an irreversible path to 3ºC. The future will look so horrific that we simply have no choices left. And so we will shoot gigatons of aerosols into the atmosphere. This will dim the sun's heat just enough to halt, and then reverse, global warming.

This is not the only possible form of geoengineering. There are lots of others, many of them fascinating and some of them far better, in theory, than aerosols. But all of them are pipe dreams right now, and even in the future will probably be prohibitively expensive and intrusive. Aerosols, by contrast, are surprisingly well understood and surprisingly cheap.

They're well understood partly because every few years a volcano dumps a huge load of ash and aerosols into the atmosphere, which has given us a chance to study their impact. And they're cheap because, well, because they are. Roughly speaking, all it takes is a fleet of about a hundred aircraft spraying loads of sulfate aerosols 24/7. The cost would be in the range of $5-10 billion a year, which is peanuts, and it would lower the temperature of the earth by about a twentieth of a degree per year. We would slowly get back to a manageable level, and then continue spraying to keep temps steady.

Do I think this is a good idea? Absolutely not. For one thing, it doesn't solve all the problems of climate change. Ocean acidification, for example. For another, different areas of the planet have different ideal temperatures. Who's going to decide what our global goal should be? And what's to stop any country from spraying its own aerosols if it thinks temperatures should be even lower?

So of course it's not a good idea. It's a terrible idea. But is it a worse idea than warming of 3ºC? Nope. And it's not even close.

The things we're doing now will probably have an impact by 2040. That's good, since the less spraying we have to do the better. But they most likely won't be anywhere close to what we need, and the pressure to adopt a cheap, fast, and decently understood second-best solution will eventually become irresistible. And so we'll spray 

[Alan Gadian]

Andrew, 

The answer to your question is to understand meteorology, which few climate scientists seem to do nowadays. In fact there is still a lot we don’t know.  They ignore small scale ( < 20km) processes. 

If you look at the last Iccp report aerosols will only produce 0.9 W /m2  difference /error bars on radiation balance.  Aerosols are often washed out in the boundary layer ( except in high pressures and under SC clouds).  Clouds are incredibly important in radiation balance.  Look at Mars and Venus. 

Put aerosols in the stratosphere , they last a long time but can do funny things like remove the ozone (protecting layer ) and last for years like cfcs and produce skin cancers, as found in South American toad workers. 

One has to understand the atmosphere!!

Alan 

T ---

Alan Gadian,  UK. 

Tel: +44 / 0  775 451 9009 

T ---

On 10 Feb 2021, at 18:27, Andrew Lockley <andrew....@gmail.com> wrote:



--
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-07idNQJE3LeoAuJPOfsOeOQwuoZUOz8wvbigMU-S36kKA%40mail.gmail.com.

[Daniele Visioni]

Meteorology is important, but so is atmospheric chemistry.

Saying that sulfate would “remove the ozone” (it’s complicated, and there are chemical and dynamical factors, and in also depends on the current amount of CFCs in the atmosphere, and on latitude) and that it “last for years like CFCs” (which are gases, and are hard to remove and stay for decades and centuries, whereas sulfate grows in aerosol particles and it is fully removed in 12 months from the stratosphere) are both wrong statements. There’s plenty of works on this subject.

Furthermore, considering that the decrease in CFCs + the cooling of the stratosphere produced by CO2 will result in a super-recovery of stratospheric ozone by mid to late century, the assertion that it will “produce skin cancer” is also heavily dependant on scenario and location. And, too little UV (as it might result from a ozone super-recovery) at mid-latitude may also have adverse health effects.

Exactly like the word “flooding the atmosphere with particles”, which is a gross exaggeration (we currently emit over 50 Tg-SO2 per year in the troposphere due to anthropogenic activities). Only 1/10th in the stratosphere would cool the planet much more.

I wish we could all be more careful with the words we use, here and elsewhere, to describe things. There are multiple reasons why SRM is not desirable, so there is no need to exaggerate and misinterpret results casting doubts on climate science - that’s what climate deniers do.

Daniele

To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/EA9C882D-867A-4085-9763-853A170574B7%40gmail.com.

[Adrian Hindes]

I do wonder about the uncertainty on small-scale processes like cloud formation though. I seem to recall David Keith mentioning in a presentation that one of the possible "unknown unknowns" (or partially known unknowns? IDK) is how sulphur falling back to the troposphere could interrupt cloud formation, ultimately backfiring and increasing total solar insolation. I can't remember the precise details and haven't come across discussion on that potential effect in any SRM papers I've read, but it does sound like a plausible example of a process on <20km scale which should warrant attention.

Although conversely, as I'm sure Alan and other MCB folks might like to point out, marine cloud brightening could aid in understanding cloud processes, so maybe that's interesting. Not sure how that would work experimentally, but seems promising regardless.