Wednesday, June 8, 2011

The Earth is full

Sometimes New York Times columnist Thomas Friedman really does hit the nail on the head, as he does in his column today, The Earth is Full.

Economists have been glorifying unending economic growth for half a century, while systematically discounting (quite literally) the social and ecological costs, especially in the long term. So much economic analysis seems to take place in a weird vacuum in which the laws of physics and biology don't apply, but an increasing number of scientists and economists have begin questioning this, as Peter Victor did last year in Nature. As Victor pointed out, questioning economic growth is typically viewed as heresy, even though it has obvious malign consequences for the physical and biological environment on which we depend. In pursuing growth, we've increased our total throughput of raw materials and fuel by a factor of nearly 10 in the 20th century alone, increasing our spillage of degraded waste (including waste heat energy, see below) into the environment by a similar factor. So it is perhaps not at all surprising that a different article in Nature, as Victor notes, concludes that...
"Humanity has gone beyond the 'safe operating space' of the planet with respect to climate change, nitrogen loadings and biodiversity loss, and threatens to do so with six other major global environmental issues."
Friedman puts the same point -- that we face real consequences from physical and biological limits, no matter how clever our economics -- in more vibrant terms:
"You really do have to wonder whether a few years from now we’ll look back at the first decade of the 21st century — when food prices spiked, energy prices soared, world population surged, tornadoes plowed through cities, floods and droughts set records, populations were displaced and governments were threatened by the confluence of it all — and ask ourselves: What were we thinking? How did we not panic when the evidence was so obvious that we’d crossed some growth/climate/natural resource/population red lines all at once?"
Of course, the natural response in confronting such red lines is to suggest that with sufficient cleverness we might find a way around them, perhaps even grow our way around them -- invest in business and technology now and by some miracle discovery perpetual motion machines. This explains, I think, we many people have treated with scorn Germany's decision to phase out its plans for nuclear energy in the next decade. Why would they restrict their options, especially given the real limits we face in CO2 emissions? Quite possibly or even probably the German decision was a feckless and emotional response in the wake of the Japanese Fukushima disaster, but it may also, even if unintentionally, respect some unalterable facts associated with Friedman's title -- The Earth is Full.

A couple of years ago, Nick Cowern and Chihak Ahn estimated the amount of energy we humans dissipate to the environment through our energy use as heat. Currently such energy plays a very small and largely insignificant role in the overall energy budget. But our energy use is growing at 2% per year globally, and in 100 or 150 years, they showed, will be enough to begin climate warming again, even in a dream world in which we control warming associated with CO2 emissions. The conclusion is that we will soon simply be using too much energy, which, by the laws of thermodynamics, will heat the Earth environment. We're becoming too big. The Earth is too full -- of us. So, we might well switch to nuclear energy, and doing so might help us counter warming from CO2 for a time, but it doesn't get us away from the rock bottom problem that we are (or will soon be) using and dissipating too much energy.  The abstract of the Cowern-Ahn paper describes the lesson of this analysis:
Global warming arises from 'temperature forcing', a net imbalance between energy fluxes entering and leaving the climate system and arising within it. Humanity introduces temperature forcing through greenhouse gas emissions, agriculture, and thermal emissions from fuel burning. Up to now climate projections, neglecting thermal emissions, typically foresee maximum forcing around the year 2050, followed by a decline. In this paper we show that, if humanity's energy use grows at 1%/year, slower than in recent history, and if thermal emissions are not controlled through novel energy technology, temperature forcing will increase indefinitely unless combated by geo-engineering. Alternatively, and more elegantly, humanity may use renewable sources such as wind, wave, tidal, ocean thermal, and solar energy that exploit energy flows already present in the climate system, or act as effective sinks for thermal energy.
The part I've marked in bold and italic is key. Nuclear energy brings another source of energy into play on Earth, by rapidly releasing energy which would otherwise be sequestered in nuclear forces for long periods of time. If we continue to increase our energy use, as growth enthusiasts assume we must, the only way to avoid climate warming will be to somehow counter our increased dissipation by reducing energy dissipation from other sources in the environment. Nuclear energy won't do that.

Just another way to see that there are indeed physical limits to growth, for us just as much as for a colony of bacteria expanding into a jar of sugar water. Why do so many people find this hard to accept?

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