Friday, April 21, 2017

Geoengineering to Fight Climate Change

Pretty good article by Jon Gertner in the Times on the scientific and ethical questions that surround climate manipulation. If our equations are right, it ought to be fairly simple to cool the planet:
Ten Gulfstream jets, outfitted with special engines that allow them to fly safely around the stratosphere at an altitude of 70,000 feet, take off from a runway near the Equator. Their cargo includes thousands of pounds of a chemical compound — liquid sulfur, let’s suppose — that can be sprayed as a gas from the aircraft. It is not a one-time event; the flights take place throughout the year, dispersing a load that amounts to 25,000 tons. If things go right, the gas converts to an aerosol of particles that remain aloft and scatter sunlight for two years. The payoff? A slowing of the earth’s warming — for as long as the Gulfstream flights continue.
Dumping iron into the Pacific Ocean is another scheme some have suggested, and there are many other plans. One or another of these schemes really ought to work. And honestly I just don't take seriously people who say it is somehow immoral to try to engineer the planet, considering all the ways we have already engineered it. If we are warming the planet, we really ought to cool it back.

Every serious person involved in this and other geoengineering efforts agrees that for now what we need is a lot more research. and even then we may never know if it will really work until we try it on a large scale:
David Battisti, an atmospheric scientist at the University of Washington, told me, “It’s not obvious to me that we can reduce the uncertainty to anywhere near a tolerable level — that is, to the level that there won’t be unintended consequences that are really serious.”
But what if we do the research and find that this stuff works?
What then? The world would need to agree where to set the global thermostat. If there is no consensus, could developed nations impose a geoengineering regimen on poorer nations? On the second point, if this technology works, it would arguably be unethical not to use it, because the world’s poorest populations, facing drought and rising seas, may suffer the worst effects of a changing climate.
Honestly if the planet gets much warmer somebody is going to do this; there are too many nations, and corporations and even individuals who could afford to fund it. If the US and the UN have not approved, what are we going to do? Shoot down the planes?

If I were a science fiction writer I think I might get to work right now on a story about a war between some tropical dictator who wants to dramatically cool the planet and northern countries who want to keep it warm.


G. Verloren said...

Well the supply side seems plausible.

The annual global production of sulphur in all forms is about 94,000,000 tons. Of that amount, only about 57,000,000 tons is in a raw form. Using up 25,000 tons of sulfur would only constitute 0.0004% of the annual global production.

So assuming we can actually manage to deliver it properly, and keep it in the atmosphere, and that it actually deflects sunlight to the extent we predict, then it certainly sounds mechanically feasible.

The question is, what would be the unintended side effects? What would dumping 25,000 tons of sulphur into the atmosphere do to the environment? If it has the cooling effect we seek, it will absolutely alter air currents and weather patterns simply through that mechanism, possibly in unpredictable ways.

But what about secondary effects? Could all that sulphur in the atmopshere affect things like cloud formation? How would precipitation be affected? That sulphur will eventually settle out of the atmosphere - what effects might it have on living organisms? Wildlife? People? Agriculture?

What if distribution is lopsided, and some areas are super saturated with sulphur in the air, while others receive nearly none? What if this produces lopsided cooling effects, causing weather patterns to become more extreme and destructive? If this sulphur plan demonstrably causes a "natural" disaster, who do we hold legally responsible for damages? How does insurance handle what is normally an "act of god", when suddenly it becomes an act of humanity, or of a particular government, or of a coalition of governments?

There are so many variables that need to be factored in to a plan like this, and so much of it is non-obvious or completely unknown.

G. Verloren said...

Typo correction: 0.04% of the annual global production

G. Verloren said...

As for the matter of "where we set the thermostat"...

This is a pretty good visual representation of the global temperature averages over the course of known history. For the majority of civilization's existence, we've had a pretty stable average, which that image pretty clearly displays. We just need to pick a reasonable point somewhere along that central line.

It'd probably be best to err on the side of caution, and make any changes be smaller rather than larger. We know from events like The Little Ice Age that even small changes in temperature can have drastic and far reaching effects, so we don't want to cool things too much.

It'd probably be best to simply rewind the clock no further than a century, or even less than that, and to stabilize things there. From there, we can monitor the situation and make further adjustments as needed down the line.