The Limits of Climate Disaster
Posted in Unfounded Speculation
on February 27th, 2012 by
Stephen DeGrace
Topics:
Crystal Ball,
Science,
Energy,
Climate Change
The record will show that I am certainly not a climate change denier. However, I think that many scenarios of global warming make unwarranted assumptions about the rate of increase of green house gas levels in the atmosphere and hence don't paint a realistic picture of the future. A prime example of this genre, but by no means exceptional, is Under a Green Sky by Peter D.Ward, which I've just finished reading for the second time. I don't have any problem with the greenhouse extinction theory he describes, which is brilliant and convincing, but I have a problem with the way he extrapolates it into the future.
Within the genre, it is common to extrapolate a number of trends into the future:
The world's population is going to continue to grow to 9 billion, and beyond.
China and India will continue their inexorable march to a first world lifestyle, seriously aspiring to consume at American levels.
Americans will continue to consume at American levels.
Greenhouse gas emissions will continue to accelerate.
I don't have a problem with the projected consequences of unchecked greenhouse gas emissions per se. Even the eventual melting of the icecaps doesn't seem too radical. My complaint with these assumptions is not the optimist's complaint, that the world will respond to global warming with measures to control greenhouse gas emissions, or that technology will step in with a cheap and abundant substitute for fossil fuels. I think it's possible that that will happen, but not likely to happen before serious damage is already done.
The problem I have with these projections is that they depend on unchecked population and economic growth, which is just as much a fantasy when it comes from scientists as when it comes from terminally optimistic right wing ideologues. Climate change "alarmists" correctly point out that even the early stages of global warming can have devastating consequences, long before you get into serious melting of the polar ice caps. However, they seem oblivious to the tight coupling between greenhouse gas emissions and economic activity in a carbon economy and feel justified in extrapolating greenhouse gas emission growth into the indefinite future, right into the teeth of flood, storm, famine and war!
What models attempting to predict future growth of greenhouse gas emissions have to try and take into account negative feedbacks from a couple of different geopolitical and economic angles that usually seem to get short shrift.
One, peak oil. All the signs point to peak conventional oil having already happened, keeping oil prices permanently at a level making unconventional oil production (various kinds of synthetic oil including upgraded bitumen from the Alberta oil sands) profitable (these days typically floating around $100/barrel, even inflation adjusted an exorbitant price by historical standards). This will have a significant economic drag, especially if Jeff Rubin is right and oil price spikes actually cause recessions. Rubin predicts a near term future where anemic recoveries punctuated by recessions becomes the new normal, as each recovery sends oil prices shooting up to unsustainable levels, and a longer term future where the high price of oil, essentially functioning like a return to pre-globalization tariffs, causes the world's economy to reorganize into something more old-fashioned and localized. The implications of severely curtailed economic growth and sheer reduction in the volumes of hydrocarbons available in convenient form are a slowing of greenhouse gas emissions.
Then there's food. Growth of global food supplies have ceased to keep pace with population, leading to a frightening reduction in the world's grain reserves. Populations of countries like Bangladesh and Ethiopia simply can't continue to double. These countries cannot produce food to feed such populations, cannot afford to purchase the shortfall, and cannot be supplied by charity from outside in a sustained way. The spectre of mass starvation again haunts our future and limits growth. In more well-off countries, the problem of population growth has been miraculously self-correcting, and all things being equal we can probably feed our populations, but equally, can probably get our population growth under control. The fact the population can only grow so much before the problem is horrifically self-correcting must eventually curtail predictions of emissions growth in developing countries.
Then you get into the early consequences of global warming, with the beginnings of sea level rise and more severe storms and storm surges, plus the drying out of many important breadbaskets causing economic disruption and exacerbating existing problems with the food supply.
These economic and human disruptions must eventually lead to geopolitical disruptions and in all likelihood war, and early into the process of climate change. The potential for destruction is enormous. Lower economic output and you lower greenhouse gas emissions in any carbon economy, like clockwork.
As has been pointed out, it is not just the eventual level that CO2 levels reach, it is the rate that also matters. While the potential exists for humanity to put every single recoverable scrap of fossil carbon in the ground into the atmosphere, and using synthetic oil made from coal do it without substantial change to our technology and infrastructure, it seems exceedingly unlikely that under conditions of scarcity of the most convenient hydrocarbons and devastating stress to the systems of world civilization even the present rate of emissions could be maintained, let alone an accelerating rate.
All this assumes, of course, that we don't adopt an energy source other than fossil carbon, which would still leave significant challenges (and would in all likelihood be more expensive than a fossil carbon economy, limiting economic growth) but would at least make global warming significantly more manageable, especially over the long term. But let's make an extrapolation based on the idea that we're fundamentally lazy and selfish as a species, and as long as any alternative solution is cheaper than a carbon economy based on coal and synthetic hydrocarbon derivatives, we'll pick the easy way and cook the planet every time.
I believe that under this scenario, by mid century the global economy will be on average shrinking, and population may finally be heading down. Under this scenario, I think keeping the atmospheric CO2 level below 500 ppm by 2100 may be very reasonable, with the majority of the growth actually occurring during the first half of the century. Growth of greenhouse gas levels would continue until the point where the global economic system was no longer capable of sustaining a technologically advanced fossil carbon based economy and would eventually reach a very high level, but without the exuberance of models that don't take into account the feedback of global warming and other challenges faced by humanity on growth itself, carbon dioxide levels might grow slowly enough that the earth's feedback systems are more capable of dealing with them, leading to a much slower greenhouse extinction than the "pollyannas" are worried about.
To end on a more hopeful note, I think we have long passed the chance to avoid taking a horrific drubbing as a species during this century, but there is a seed of hope buried in there, because the slowing of emissions growth that this scenario implies, and the awful, undeniable consequences, may create a will to actually do something about the problem before it can have consequences for ourselves and the planet on the scale of a greenhouse extinction. If we can finally wean ourselves off fossil carbon and find a reasonably abundant and sustainable energy source for our economy, even if it means making due with less, we might have a long-term future as a species and even as a technological civilization.
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