Geology Reference
In-Depth Information
aid to give us a literal breathing space whilst we work on the full spectrum of tasks to
be tackled if we are to live well with Gaia. I am referring to the capture and storage of
carbon dioxide as it comes out of the chimney-stacks of power stations and factories.
Once captured, the gas can be pumped into large underground spaces capable of hold-
ing it safely in place over geological time scales. The large caverns left over from the
extraction of oil and natural gas might work well, and there appear to be enough such
places available in the USA alone to hold 100 years of its carbon dioxide emissions.
Technically, carbon capture and storage is not a difficult task, and is already being done
successfully in a handful of pilot projects around the world. STATOIL, the Norwegian
state oil company operating in the Sleipner gas field, captures and stores one million
tonnes of carbon dioxide every year from natural gas purification in a sandstone aquifer
800 metres underground, thereby reducing Norway's total carbon emissions by three per
cent. But to make a major contribution, the technology will have to be rolled out very
quickly and be linked to coal-fired power stations, a step that planners seem reluctant to
take—the vast numbers of new power stations in the pipeline for India and China (713
in all), have no built-in capacity for carbon capture and storage. Some experts estimate
that even under the best of circumstances it could take 20 years to put this technology
in place on a sufficiently large scale—far too long to save the earth from severe climate
change.
There is of course a great danger that this technology will be used to stimulate even
more economic growth by removing all impediments to the use of fossil fuels. If so, the
strategy would have failed and the band-aid would have turned into a noose, for, as we
have seen, material growth will eventually destroy the biosphere as we know it, and with
it our equable climate. Furthermore, capturing carbon from power stations wouldn't help
to cool the earth; it could, at best, only slow down the rate of warming.
There is no escaping it—vastly reducing the burning of fossil fuels (especially coal)
will not be enough to cool the earth; we must also extract carbon directly from the at-
mosphere. There is no industrial technique that can do this efficiently, but there is a pro-
cess under scrutiny right now that is claimed to show great potential: the production of
a kind of carbon known as biochar. The raw material is plant biomass, which, by defin-
ition, contains carbon removed from the atmosphere by photosynthesis. Under normal
circumstances much of this carbon is rapidly returned to the atmosphere by decompos-
ing organisms such as fungi and bacteria. But if the biomass is treated in the right way
(with no oxygen at high temperature) deep black, carbon-rich biochar is the result. Wood
makes the best biochar, but some kinds of agricultural waste work fairly well as long as
they are not too wet.
So far, what little research has been done leads one to doubt that biochar really is an
effective long-term store of carbon atoms that would otherwise warm the atmosphere.
