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Terraforming Earth, Part II

droughtplantcells.jpgI wrote recently about "terraforming Earth" as a way of discussing the potential need for large-scale engineering of geophysical systems in order to stave off the worst ravages of climate disruption. I was using the term "terraforming" largely metaphorically; although terraforming can mean simply making changes to a planet to render it more livable, its primary meaning is making geophysical changes to a planet to render it more Earth-like. The ideas are similar (after all, the places we would find livable are also apt to be Earth-like), but not identical.

But upon further consideration of the idea, it struck me that I was using "terraforming" correctly. Our goal with such megaprojects would be to restore the global environment to pre-disruption conditions, to return Earth to a general ecosystem status more-or-less characteristic of the Earth prior to the most problematic of the human-caused changes. Although none of the potential worst-case results of massive climate disruption (atmospheric carbon loads in the 600+ ppm, with corresponding temperature increases; "whiplash" ice ages; the melting of oceanic methane clathrates; widespread extinctions) are unprecedented in the history of the planet, they are by no means typical of the planet's history, and historical changes to the atmosphere do not normally happen with the speed we've seen for the human-induced disruption.

The goal of geo-engineering efforts would be, in short, to make Earth Earth-like again -- or, in other words, to terraform the Earth.

But given that many of the strategies which would fall under the rubric of terraforming would have grave consequences if they fail, many people would be understandably reluctant to embark on such efforts in any event. And if the results of too-slow or insufficient action now is bad but not catastrophic, many more people would argue that the benefits of success of these projects are outweighed by the risks of failure. If we are unable to divert the not-quite-worst-but-still-pretty-bad scenarios, but choose not to use dangerous geo-engineering alternatives, what are our options?

Setting aside dying off, the main choice is engineered adjustment. But we should be clear on what this means: changes to our own behaviors and material environments, sure, but changes to the ecological environment, as well, so as to make survival possible. And adjustment has its own implications.

Publication of a recent discovery this last week is an excellent example of what adaptation would look like, and was the proximate trigger for this short essay.

Researchers at the University of Toronto have found the genes coding for the way plants "breathe:"

The pores on the surface of plant leaves, called stomata, function like little mouths that open and close in response to cues such as light, temperature, and water availability. [...] The discovery is another step in understanding how plants respond to their environment. In hot temperatures, plants keep their mouths “shut” longer than usual, to avoid losing gases and water through evaporation. However, they must open their stomata at some point, both to pick up carbon dioxide needed for photosynthesis and to release oxygen back into the atmosphere. This new information will be important to plant breeders looking to improve crop resistance to drought, as well as to those seeking to understand plants’ evolutionary responses to climate, says Campbell.

The research was published in the July 12 Current Biology; abstract and supplemental data here.

The relevance of this discovery for our discussion is two-fold:

First, as temperatures rise, we are certain to have greater numbers and severity of droughts. Plants that might withstand a season or two of reduced rainfall would have a far harder time when the drought conditions last decades. It is highly likely that we will need to engineer crops for greater drought resistance; furthermore, as different plants now have different levels of resistance, it's likely that we'll have to do transgenic engineering, pulling the characteristics from highly-drought-resistant plants and working them into the less-resistant species. Smart breeding and traditional cross-breeding will help to an extent, but it will be hard to avoid the need for full-scale genetic modification of crops.

The second point is somewhat more subtle. The article indicates that, as drought conditions worsen, plants "breathe" less in order to maintain internal moisture. But when plants breathe less, that means that they take less CO2 out of the atmosphere. This means that droughts decrease the carbon sequestration action of affected plants and engineered adaptations to enhance that resistance would very likely further decrease sequestration in plants. This, in turn, would slow the recovery of the atmosphere to pre-disruption conditions.

This is a single, and likely minor, example of what "engineered adjustment" would mean. It's not a clear-cut case that adjustment is a safer path than terraforming, should we force our climate to the point that these become our only plausible options. As I indicated with the first Terraforming Earth piece, my goal is to get us thinking about these options now, to better understand the choices that we could face, and to use them to test the strength and weaknesses of other choices that might emerge.

In the end, though, the obvious lesson to take from all of this is that we're far better off avoiding these hard choices entirely by not letting the climate warm to disaster.


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Comments (3)

The problem is adaptation is a co-opted word, used by climate "skeptics" to mean basically "We'll figure something out when it happens."

I think "response" is a less loaded and more accurate word, myself.

Less loaded, perhaps. I disagree that it's more accurate, in that pretty much everything we'd be doing could be called a "response." Adaptation has a particular meaning of making changes to suit a changed environment; "skeptics" may have adopted it as a do-nothing argument, but that doesn't mean we should let them get away with it.

Some questions meant to help further the discussion:

Would large-scale engineering of geophysical systems be done by large-scale institutions? What processes do you envision that could accomplish this? What would guide and govern those processes? What indicators would provide feedback about the progress of the endeavor? How confident could we be in those indicators? What do you know about this that you could write as *instructions*?


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