Grassroots geoengineering

If there’s one concept that terrifies me almost beyond words in our energy and environmental future, it’s not peak oil or global warming or even that bottomless, stinking pit known as presidential election cycles [shudder]. It’s geoengineering.

Just to be clear, when I use that term I’m referring to overt actions taken with the primary (or sole) purpose of directly influencing global warming. Pumping many billions of tons of CO2 into the atmosphere by burning fossil fuels doesn’t count, as that was a mindless side effect of energy use. Likewise, any conservation, efficiency, or use of substitutes (e.g. natural gas instead of oil in generating electricity), even when carried out to reduce our greenhouse gas emissions, doesn’t count, as those are “merely” reductions in the damage we’re already doing.

To me, and to most people interested in such things, I suspect, geoengineering includes much more science fiction-y steps like seeding oceans to promote plankton growth, putting gigantic mirrors (or clouds of small mirrors) in orbit to reduce the amount of sunlight reaching the earth, or building many artificial “trees” that will capture CO2 from the atmosphere and lock it into a chemical form we can safely dispose of (forever! just like nuclear waste!).

The reason geoengineering scares me is that I think it’s abundantly, painfully, and trivially obvious that we don’t know nearly enough about how our planet’s climate works to start tinkering with it directly. I’m also convinced that we are so close to a true climate crisis that we will fail to find the political will to reduce CO2 emissions enough that we can avoid having to employ geoengineering. Whether you think the magic number, beyond which the impact of global warming is unacceptable, is 450 parts per million of CO2 in the atmosphere or 400 or 350. the simple fact is we’re already at 380+ ppm and nowhere close to making the kinds of changes necessary to hit any of those numbers in a useful time frame.

This is why I think it’s imperative that all of us, even the hard core geoengineering haters (like me), take a very serious look at our options. In particular, we should favor any technology/technique that has the following characteristics:

• Flexibility

  Ideally, we would want to employ techniques that can be fine tuned, in both the “more” and “less” directions. We don’t really know what the heck we’re doing, so it seems like a really good idea to maximize our options for responding to the inevitable errors.[1]

• Reversability

  Anything we resort to should be very easily reversed or completely canceled. This is really just a generalization of the “less” flexibility requirement to include a complete (or nearly complete) rollback of the project, possibly in a short time frame. Again, we have to be adult enough to park our pride and respect our own ignorance; it was ignorance and hubris that got us into this mess, so it might be a good idea to learn whatever lessons we can from history and try to avoid further aggravating the situation.

• Political convenience

  We need solutions that both governments and citizens (and powerful businesses, to the considerable extent that they influence those groups in some countries) will find acceptable. That means the US can’t put up orbiting mirrors that block sunlight from hitting some country that won’t like that, and China or Russia can’t seed the ocean to grow more plankton close to US shores and adversely affect commercial fishing.

• Economic

  Assuming we find more than one solution that meets at least the minimal requirements above, we will inevitably have to face the tough cost/benefit decisions that non-economists so detest. If you’re one of the people who likes to rant about economists “putting a dollar value on human life”, etc., then my advice is: Shut up and deal with it. We’ll have to make many such decisions in the coming years, some of them difficult to the point of perversity, as we try to unwind the incredible set of interlocked, cascading messes we’ve created. (And here’s a secret: Most economists don’t like those decisions any more than you do. We’ve just accepted that in a world of infinite possibilities and finite resources we’re faced with a lot of tough, and even distasteful, trade offs that have to be made the right way.)

For some time, I’ve been pondering a way we could meet these goals. One admittedly fanciful approach I came up with, more for the sake of a computational example than anything else, was to cover some dark areas of the Earth’s surface with CD’s, thereby substantially raising the reflectivity (or albedo). This could potentially be cheap–we make billions of these things per year already, most of which wind up in land fills–and it could be tweaked pretty easily, contained within political boundaries, etc.

I’ve been playing around with the numbers for a while, and luckily I can now say that someone with far more expertise has tackled this problem in a recently presented paper. The author, Hashem Akbari, is “a staff scientist and leader of the Heat Island Group” at the US’ Lawrence Berkeley National Laboratory. His paper was presented at the Fifth Annual California Climate Change Research Conference, and is titled, “Global Cooling: Effect of Urban Albedo on Global Temperature”. You can find the paper on this page [PDF], and the PowerPoint slides from his presentation here [PDF].

Akbari didn’t didn’t talk about anything as silly as CD’s strewn about the landscape, but something much closer to home (and business and government and…), namely making roofs and roadways more reflective. The results he gets are dramatic, to say the least. On slide 14 in the PowerPoint version he shows a cooling equivalent to reducing CO2 emissions by 24 billion tons/year for roofs, and another 20 billion tons/year for roads. The entire world emits about 28 billion metric tons of CO2 year currently, so we’re talking about some pretty hefty figures in Akbari’s analysis. Of course, these are global figures, but even if we assume that only some countries would employ public policy measures to encourage the use of much more reflective roofs and roadways, we could still be on the verge of making a huge, relatively cheap and painless change, one that could buy us a lot of time while we figure out how to reduce CO2 emissions.

The calculations show on page 12 of the PowerPoint slides that it takes about 10 square meters of roof conversion to offset one ton of CO2 emissions per year. If you assume the average single family home has a 100 square meter roof, and that the roofing job will last 10 years, that’s a heat reduction equivalent to eliminating the emission of 100 tons of CO2 over the life of the roof. Plus, the building’s owners get reduced air conditioning bills, which in many areas means less CO2 emitted thanks to reduced electricity consumption.

As for what those public policies might be–you can conjure up your own formulas pretty easily. A 100% government rebate on the cost of roof shingle for home owners who select a color that reflects at least X% of light, federal government grants to partially pay for lighter colored roadways, etc.

Admittedly, this form of geoengineering doesn’t completely meet my requirements spelled out above–you couldn’t very well ask everyone with a light-colored roof to quickly change it to a darker color, for example–but it’s simple, cheap, and effective enough that I think it clearly should (and will be) part of our policy response in the coming years.

[1] Do I really have to remind everyone that we freakin’ missed Mars with a space probe once, at least partially thanks to a screw up involving English vs. metric units?