Wednesday, May 18, 2011

The Keeling Curve- And What It Portends for the Planet

When I first saw the "Keeling Curve" (see attached image superimposed on the Earth in a satellite view) it shook me to my core. It also sent me into despair realizing that nothing, nothing at all, would halt the ominous rise of CO2 in the Earth's atmosphere. To put it bluntly, in the image of the Keeling Curve I beheld the future of our planet: as a hothouse wasteland with little water, barely thousands of people able to survive and with no hope ever for a green or plentiful future. They could all as well be dead.

What Charles Keeling showed, from even his earliest measurements, is that there is a continuous, unabated increase of CO2 in the atmosphere. Right now the CO2 concentrations are approaching 480 ppm, but within a rather short time, maybe 40 years - they'll approach 550 ppm and the likely runaway greenhouse limit. From that point on there'll be no turning back, and Earth will be hurled pell-mell into becoming another Venus complete with eventual 450 C temperatures, or hot enough to melt lead.

For those looking at the curve the inevitable question became: How can the CO2 be contained or limited? This naturally led to discussion of means and methods of "carbon sequestration" or the separation of carbon (specifically in the form of CO2) from the human living environment.

Generally, two forms or categories of carbon sequestration can be considered: natural and artificial. In the first, the natural carbon reservoirs that abound on the planet suck up the excess CO2 and prevent it from doing too much harm. These reservoirs include: the oceans, forests (especially rain forests) and geologic formations, rocks such as calcium carbonates, etc. In the second, artificial means are sought to inject excess carbon - say deep into sedimentary formations.

The problem with the natural carbon sequestration is first, that the oceans naturally absorb more CO2 than all the world's vegetation, but second, the recent rates of emission from burning fossil fuels have exceeded the CO2 uptake rate of the oceans. Thus, even the oceans are now nearing their absorptive capacity, which may be just as well since their acidity has increased by 30% since the Industrial Revolution began. Already the lower pH has had deleterious effects on many forms of sea life, including corals, anemones, plankton and hundreds of species of fish. The effect of the higher CO2 absorbed then is to form carbonic acid via the chemical reaction: CO2 + H2O -> H2 CO3.

It has been suggested that one form of human-abetted artificial enhancement for the oceans might occur via deliberately injecting CO2 at a depth (See: Eos Transactions of the AGU, Vol. 92, No. 18, 3 May, 2011, p.156), but as noted in the cited piece, the potential local impacts on sea life make this approach infeasible. Certainly now, and I'd say for the near future given how many more people are added to the global population each day, all needing food. (Also since the news of how many larger fish species are already being fished out, including tuna).

What about artificial geological sequestration? Well, over months or years we could try to inject lots of CO2 into the subsurface leading perhaps to much vaster proportions sequestered compared to vegetation or the oceans. The problem here is you can't confine yourself to one location for injection, or even a hundred. You'd need basically "tens of thousands of point sources around the globe requiring a huge number of injection wells"(ibid.). Assuming say ten thousand such wells at minimum, and a minimum cost of $1-2 million to operate each well to inject at least 10,000 cubic ft. of CO2, that's a lot of moola. Without economic incentives or subsidies, matching funds from governments the cost would be prohibitive. And with most governments of the world now immersed and obsessed with deficits and bond defaults who can expect them to fret over the possible meltdown of the planet?

So, it looks as though we're headed onward for a catastrophic course that won't alter anytime soon. Perhaps, once money entered the human psyche and human history, its manipulations and accumulation (or losses) became more important than ensuring human survival.

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