So between reading Stewart Brand's book Whole Earth Discipline (a very mixed bag, you can get some good points out of it but also take it with a grain of salt) and hurricane Sandy, combined with the fact that climate change has up to the point of this disaster gone totally unmentioned this election - I've been thinking about what, practically, we really need to do to maximize our chances of surviving the carbon dioxide we have, and will at least for some time yet continue to put in the atmosphere.
In the very shortest term, anything we can do to convert coal use to oil use is good. Still in the short term, anything we can do to convert oil use to natural gas use is good. Natural gas carries the largest amount of extractable energy per carbon atom, and coal the least, so even before we escape the fossil fuel paradigm there are ways to minimize damage. "Clean coal" is not one of them and should be considered an embarrassment to Obama's administration.
In the medium-longer term, anything we can do to trap natural gas that would otherwise be released into the atmosphere, such as from livestock waste, and burn it for fuel, is good. Fossil fuels that are stable in the ground and/or non-gaseous should be left where they are, but methane has more greenhouse impact than carbon dioxide per molecule even over a 500 year timeframe, and the conversion ratio is 1:1. Carbon dioxide is the biggest problem right now because we produce the most of it, but if we have a choice between greenhouse gases, it is usually the lesser of evils.
As the immediate arm of long-term strategy, we need to ramp up nuclear energy. Hydro, wind, and solar are all great to the extent they can be utilized, but hydro and wind have inherent capacity/infrastructure limitations, as well as non-carbon environmental impacts that scale with increased implementation, and solar is hindered by materials scarcity and conversion efficiency. We already have the ability to use nuclear fuel for fission reactors, and insofar as we improve solar technology, we are merely harnessing our favorite extraterrestrial fusion reactor. The fact is that nuclear reactions have the capability to produce orders of magnitude more power than chemical or mechanical energy generation.
The elephant in the room when it comes to nuclear is the radioactive waste. What the hell do you do with waste that is dangerous for 10,000 years? The intuitive, but perhaps somewhat blockheaded, way to look at it is that we need to seal it up so well that it can't leak and nobody will stumble across it in the next 10 kYr. But whatever else I may have thought of Stewart Brand's book, he did do a nice job of reframing that issue: if society collapses so badly that we lose the knowledge of what the waste is and how to deal with it for-the-moment, then we'll have other problems killing us quicker than trace radioactivity. So what we really need is flexible planning that allows each generation to monitor and relocate or re-protect, if necessary, the waste. In the meantime, it will decay fastest at the beginning, becoming less dangerous over time; we may come up with better storage strategies that do meet the 10 kYr dream; and even now there is research into ways to use the "waste" for another cycle of fission, all the way down to stable products - which, if sufficiently developed, could remove the problem entirely.
High energy density situations, however, lend themselves to runaway failure. Brand argues that we learned from Windscale, Three Mile Island, and Chernobyl and reactor safety is "solved." He was writing in 2009; in 2011, Fukushima seriously challenged that point. Hurricane Sandy did not cause any meltdowns, but there was some concern before landfall about nuclear plants in the way. The earthquake causing the Fukushima tsunami is as much a fluke as it would have been 50 years ago, but crazy storms like Sandy are only going to increase in the near future, and we will need our infrastructure, especially higher risk operations, to routinely withstand disaster conditions.
Therefore, in the shorter-medium term, we need to seriously hash out nuclear operating standards and risk management so that we can safely maintain reactors and begin replacing carbon-derived electricity. In the medium-longer term, we need to continually improve the state of nuclear waste management, with an ideal goal of recycling all the way down to stable isotopes, or even down to Fe-56.
In the long term, we need to develop carbon sequestration. We are already at 387 ppm of CO2, well above the 350 hypothesized to be "climate-safe," which is in turn well above the preindustrial 280 or so. Extreme measures would be necessary to level off as low as 450 ppm, and more realistic scenarios project 550 or even 650. In other words, we are likely to end up with way more carbon than we can afford in our atmosphere, and we desperately need a way to pull it back out, or better yet, sequester it in non-gaseous form after creating but before releasing it.
Another long-term project should be optimizing solar energy conversion. There isn't unlimited uranium any more than there's unlimited oil, and if we developed fusion reactors, we would need hydrogen fuel, which would likely come from water, a resource we do not want to irreversibly deplete (though I suppose space technology could eventually support hydrogen harvesting from Jupiter or something). Solar powered electrolysis of water to give combustible hydrogen fuel, however, would result in a closed-loop process, regenerating water upon use. In theory, we could use photoelectricity to power any fuel-generating reaction we wish. It could even be coupled to the carbon sequestration issue, if a reasonably efficient mechanism were found to reduce CO2 back to organics.
Finally, we need short-term shims besides energy. Fossil to nuclear isn't going to happen overnight, and neither are solar-generated transportation fuels or carbon sequestration - so we need to give the climate OTHER negative feedbacks. We can boost albedo simply by painting all our roofs white, and that has pretty much no consequences, so we should do it. Light-colored aerosols are another way to boost albedo, and although I'm wary of sulfates causing as many problems as they solve, I like the idea of boats that churn and increase sea spray. Sea salt and water make one of the lowest potential impact types of aerosol, and the method is quickly and easily reversible if unintended negative effects were to be observed.
And of course, as a matter of sustainability not just on the energy front, but also in terms of materials and the rates of natural recycling processes, we need to create a culture of conservation, reuse, repurposement, and durability. We need to do away with planned obsolescence and ever-changing fashion. We need to make shoes that will last 10 years and then wear them for 10 years and then when they're really and truly done use the material to make a patchwork handbag. We need appliances that can be repaired over and over again instead of just getting a new one full of freshly extracted metal and plastic. This is itself a complex issue, but to end this post I must at least raise the point that non-carbon energy will not solve our problems forever, and carbon dioxide is not the only problem created by "business as usual."
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