It's Time to Start Talking About Geoengineering

http://keith.seas.harvard.edu/papers/148.Holmes.Keith.Contac... is probably the most advanced current geoengineering proposal currently; the estimated cost is US$60 per tonne of CO₂ removed, proposing to spend C$140M to construct a facility that removes 1 megatonne of CO₂ per year. (One of the authors constructed a small-scale prototype a few years earlier.) If this is correct, a facility to remove all of the 29 billion tonnes of CO₂ emitted by human activities annually would cost C$4 trillion to build (about one month of global GDP) and cost US$1.7 trillion per year to operate (about 5% of global GDP, comparable to the total amount currently being spent on energy.)

That is, unless Keith's analysis is wrong, low-risk geoengineering to completely remediate current CO₂ emissions is clearly economically feasible, but not as a skunkworks project — it's a project of a size comparable to the entire existing energy industry, so it would need to be supported by the full influence of the current Establishment. It clearly cannot be done as a market-driven project.

These costs, already somewhat pessimistic, should come down a bit as energy becomes cheaper with the proliferation of photovoltaic farms. Indeed, much of the operating cost is the energy used, which would have to come from non-carbon-burning sources.

Many of the other geoengineering approaches mentioned — cloud doping, ocean fertilization, stratospheric acid, space mirrors — would probably be cheaper. Unless they crash the Earth's climate system!

I listened to a talk by Clive Hamilton and Tim Flannery a few months ago, where they discussed geoengineering.

I liked Flannery's framing of geo-engineering. I'm probably slightly misrepresenting what he said, but it was something like this:

1. we need to be seriously pushing a transition to a decarbonised economy, i.e., actually reducing greenhouse gas emissions, before we start playing accounting games with negative emissions

2. then, as a secondary concern, at the same time as we're reducing our emissions, we also need to be pursuing geo-engineering options to remove carbon from the atmosphere

3. there are many different kinds of geoengineering options. some of these are more likely to strengthen or enhance existing earth systems, and other approaches will damage earth systems.

I am glad to see Morton agrees with point #2:

> I'm very keen to get across in this book is that I do not in any way see geoengineering as an alternative to a program of emissions reduction. I think that that would be a very foolish approach to the problem.

There is a very big risk that geo-engineering is perceived as a magical patch that will fix the problem - it can't fix the problem, but perhaps it can alleviate some of the symptoms. Any particular geo-engineering approach will have secondary implications (perhaps unanticipated, like the whole global warming thing).

It isn't realistic to think that we can completely reverse the changes we've set in motion - no reverse, only forward, into new and interesting (and potentially non-adaptable) conditions we haven't yet experienced as a species.

We are already removing carbon from the atmosphere at industrial scale, 550,000 tonnes per year with bio-energy with carbon capture and storage [1].

We can get a lot better at this, with engineered simple organisms like algae growing fuel to be consumed and the carbon captured.

“If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from [current levels] to at most 350 ppm.”

Dr. James Hansen

Right now we are at 398 ppm, and we are already seeing weird climate effects, more, bigger wild fires etc.. I don't think the modern, developed world will tolerate 450 ppm. Things will get too weird.

I think we will be forced to capture carbon.

> a facility to remove all of the 29 billion tonnes of CO₂ emitted by human activities annually would cost C$4 trillion to build

We will get these costs down, but to me, even 4 trillion looks downright affordable, the US spent that much invading and occupying Iraq.

[1] https://en.wikipedia.org/wiki/Bio-energy_with_carbon_capture...

> The atmosphere is becoming a greenhouse. The surface of our planet is now warming, with unpredictable consequences.

Our planet would be frozen solid if it weren't a greenhouse ;)

geoengineering as a concept operates with a High Modernist ideology, and overwhelming confidence in humanity's ability to reshape the natural world, society, the State, in a desired fashion. i think relying on policy and markets and the state makes sense public works cleanups, removing tax breaks and subsidies for industries that produce externalities, restructuring labor into environmentally-minded industries and sectors....but i'm ultimately skeptical of a technological fix, sprinkling oceans with lead or growing mass plankton farms or whatnot. sounds like snake oil to me.

Why not calling it "planetary engineering" from very beginning? The experience gained in here will not be limited to Earth!

Also, I think that the ambition of changing the atmospheric composition can be a little bit higher. The talk now is (only) about the removal of CO₂ from the atmosphere (releasing back the oxygen, I guess), but an increase in the atmospheric proportion of oxygen, from sources other than carbon dioxide, would be beneficial too (at least for humans, as the blood thickness would drop and so would do a lot of the cardiac related issues). Currently there is a great deal of oxygen trapped in different kinds of oxides (SiO₂ especially) that would to us more good in the atmosphere.

There's more to geoengineering than just aerosols. Ultimately, it'll be about giant mirrors and barriers in space to modulate the Sun's radiation in various places. It may sound fantastic, since these are huge surfaces involved, but you can block or reflect the Sun's light with very thin materials, which can be folded up on their way up.

The reason geoengineering scares me: https://xkcd.com/349/