Is science sometimes in danger of getting tunnel vision? Recently published ebook author, Ian Miller, looks at other possible theories arising from data that we think we understand. Can looking problems in a different light give scientists a different perspective?

Carbon Dioxide Storage

The decision to do something is always preceded by a theory, which usually involves a proposition of the "if … then" form, i.e. if I do A and the conditions G apply, then the outcome P will follow. The premise of this blog is that there are usually alternatives B, C, D . . .  What we want is for our politicians to make the best choice from the set of alternatives, but if scientists want decisions to be made based on evidence, then they must provide the necessary information to the decision makers and the public in a form they can understand. I think you are a little deluded if you think that happens often enough.
Consider the issue of carbon dioxide storage. On one side, the coal industry states: if all the carbon dioxide made by burning coal is buried permanently, then there is no adverse environmental effect from that carbon dioxide, therefore we can continue burning coal. Based on what is available to the general public, is this sound policy or a case of "Out of sight, out of mind"?
Compound propositions such as that are usually bad; the proper procedure is to separate the steps, then draw conclusions by procedure rather than lurch into it. Suppose we rewrite the first part as: if all the carbon dioxide made by burning coal is buried permanently, then there is no adverse environmental effect from that carbon dioxide entering the atmosphere. I think that is justifiable, but there is a subtle difference.
One problem involves the word "permanent". Where do we store it? If it is deep enough, say, approaching 1 km, the pressure will convert the gas into a supercritical fluid. The ideal situation is isolation by containment by non-permeable rock, but how easy is it really to find that? Something that traps heavy oil does not necessarily trap supercritical carbon dioxide. Can we guarantee it will not travel through porous rock, or, if an old oil structure is used, through an abandoned well whose cap fails? What about faults or breaks in rock structure? I would question anyone who states we know where all the faults are. As evidence, Christchurch in New Zealand is now undergoing an extremely prolonged sequence of earthquakes, due to a sequence of faults that were completely unknown two years ago. They are now being found because they are active; inactive faults can go undetected for a very long time. Suppose the carbon dioxide clathrates in water, and suppose the clathrate can move to a region of lower pressure? Could the resultant decomposition of the clathrate widen a gap, and thus accelerate leakage?
The ultimate in containment would be where it reacts with rocks to form carbonates. Olivine is one of the better weathering rocks, while peridotite (an olivine/pyroxene blend) in Oman apparently weathers very quickly. The problem, of course, is that basalt is not one of the easiest rocks in which to find storage spaces and it is somewhat unyielding while the world's emissions are not centred on Oman.
Does this process make sense other than as a special case? Old oil fields are often cited as disposal points, but these are often far from coal burning plants, and very frequently there will have been a number of test wells drilled which are sealed with unknown reliability. The oil is usually under sandstone, which usually comprises the remains of weathered rock. The collection, transport, compression and injection of the carbon dioxide requires considerable energy (I have seen an estimate that almost 30% more power stations are required.) and the construction of the necessary pressurized piping also generates carbon dioxide.
The issue here is, if the public decide to reduce carbon dioxide emissions from the atmosphere, is this concept a sensible part of the solution, or is it simply "smoke and mirrors"? Are scientists making all the relevant information available to the public on this matter? If a member of the public wants to find out what is critical, can he or she? You may protest that my analysis above is superficial, but if I cannot readily find what is needed to reach a proper conclusion, how can the public? If you argue the public does not matter, then you must argue against democracy. In my opinion, if science is to make a proper impression on our future, scientists have to lift their game.
Posted by Ian Miller on Jun 21, 2011 11:05 PM Europe/London

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