James Lovelock’s Gloomy Vision

This does not seem to me an unreasonable conclusion, I must admit. Consider Biosphere II. This was a sealed greenhouse in the Arizona desert, an attempt to create a managed, self-contained biosphere. A very humbling effort it turned out to be, all in all. Biological control proved to be completely out of reach. Several species of birds were introduced into the system, based on rational design of ecological balance, and all of them went extinct. The only birds that flourished in BII were a local species that invaded the structure while it was under construction that they never managed to eradicate. Ants and cockroaches became so abundant in BII that the biospherians took to sucking them up into vacuum cleaners and feeding them to their domesticated chickens. Geochemically, the oxygen concentration plummeted and nitrous oxide rose, until the structure became uninhabitable.

At this point in the book, about half-way through, Lovelock diverts from the question of our impending doom into various other, much smaller issues like whether nitrates in food are really bad for you. It felt surreal, like the serving staff on the Titanic arguing about whether a time card had been properly punched or not. Lovelock uses this material to make the point that people worry about all the wrong stuff. OK, that’s a legitimate point, but I was left wishing for some discussion of what shape the catastrophe might take.

Based on the experiences of the Biospherians, I would imagine that the wildest instabilities might be biological. We can cope with bacteria, at least better than humankind could back in the days of the Black Death in Europe, but bacteria are adept at evolving defenses to our chemical weapons, and viruses are much more difficult to attack. A new plague would spread globally, much faster than it did in the middle ages. A biological collapse might be attributable to human overpopulation, or monoculture agriculture, perhaps more so than to climate change.

Geochemically, I could imagine the chemistry of the atmosphere shifting to a new equilibrium, in which (say) carbon monoxide could suddenly rise up to harmful levels. The oxidation chemistry of the atmosphere has been altered in all different directions by human emissions of organic compounds, nitrogen compounds, and methane. No one understands why the lifetime of methane in the atmosphere is as stable as it appears to been over the past decades. Surprises could lurk here.

Methane hydrates seem dangerous, because there is so much methane. If all of the hydrates were to melt within a few years, we would have a methane spike in the atmosphere that would be catastrophic, because methane is such a powerful greenhouse gas. But it seems more likely that the hydrates would melt slowly, over centuries and millennia. If that is the case, the climate impact might be comparable to fossil fuel CO2 combustion. It could double the human climate impact, but probably not make it 10 times worse or anything like that.

Physically, there have been abrupt climate changes in the past, which we are just beginning to figure out. Transitions between stable climate states may be sudden. Some transitions are driven by sharp changes in physical properties of substances like water. There is a sharp boundary between a stable and a runaway greenhouse effect, because of the sharp phase boundary between water vapor and liquid. Abrupt climate changes in the glacial North Atlantic may have been amplified by freezing of sea ice. Dynamical systems may also change states quickly. Ocean circulation seems to have multiple configurations, also apparently generating abrupt glacial North Atlantic climate changes. The dynamical balance in hurricanes on earth is between latent heat and wind friction with the ground, but if the pressure dropped low enough, ground friction fails as a regulator and a new beast, called a “hypercane”, could arise [Emanuel et al., 1995]. No one is suggesting that hypercanes will arise on Earth, but this is an example of a sharp transition in a dynamical system. It would be extremely difficult to forecast abrupt climate changes such as this for the future.

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