Hullabaloo in the Great Karoo

South Africa’s desert is a battleground between astronomers and gas companies

Cosmos Environment Science
Worth its SALT: The Southern African Large Telescope in the Great Karoo

The Great Karoo, the semi-desert region which accounts for 400,000 square kilometres (or about one third) of South Africa, is a dry, empty and beautiful place, recalling Buzz Aldrin’s description of the moon — “a magnificent desolation”. For many millions of years it was an inland sea or swamp and the fossils reveal that strange creatures roamed there at least ten million years before the dinosaurs, such as the Pareiasaurus, a weird cross between a hippo and a crocodile. Its rocks, dating from the Permian and Triassic periods, contain fabulous coal deposits as well as an estimated 800 billion fossils. The world’s oldest people, the San, lived here and gave the area its name — Land of Great Thirst. Its few small towns — Calvinia, Carnarvon, Hopetown, Hanover — harbour a mainly coloured population and both they and the few hardy whites speak only Afrikaans: virtually no blacks live there. The trekkers had to make it through the Karoo and something of it has been burnt into the South African soul. People love coming here for its uncompromising landscapes, its quiet emptiness, a land that time forgot.

Now, however, the Karoo is alive with controversy. In 2005 the Southern African Large Telescope (SALT), the biggest in the southern hemisphere, was opened near Sutherland. Backed by an international consortium, SALT has become a tourist attraction as well as a major astronomical resource. Immediately there were proposals to build safari lodges and golf estates nearby, which were batted down because the whole point was that the Karoo has clear skies and no industrial or light pollution. Now it seems possible that the world’s biggest radio telescope, SKA (Square Kilometre Array) will be sited near Carnarvon for similar reasons. SKA, which will cost an international consortium 1.5 billion euros and be run by Jodrell Bank, will see 3,000 dishes each 15 metres wide at the centre of five spiral arms extending at least 3,000 kilometres, with further linked antennae all over southern Africa and as far afield as Kenya and Ghana. The result, a telescope more than 50 times as powerful as anything now extant, will see back almost to the Big Bang and thus study the formation of the earliest stars and galaxies. Surveying the skies 10,000 times faster than anything now possible, it will map a billion galaxies out to the edge of the universe and should be able to solve such riddles as dark energy, dark matter and even the existence of gravity waves. 

In effect what this will mean is the final experimental tracking down of all the theories and possibilities suggested by Einstein. By mapping the evolution of galaxies and studying their outward expansion SKA should be able to make definitive new findings about the dark energy driving them apart and the dark matter between them. Similarly, by using pulsars as monitoring devices SKA will be able to study the operation of gravity in areas on the edge of black holes where the curvature of space reaches extreme proportions. Thus far, all Einstein’s theoretical postulates have been borne out, but SKA could see us not only completing the process but pushing our knowledge further into a post-Einstein direction.

Already South Africa is building a precursor facility to SKA, MeerKAT, with 64 linked dishes, for the government is keen to have projects which put the country at the technological cutting edge. The only other possible SKA site (in Western Australia) lacks many of the Karoo’s advantages and linked antennae could be placed only in New Zealand. The final decision on SKA has to be made next year. It should start work in 2019 and be in full operation by 2024, with MeerKAT ready by 2012. SKA will have to have enormous computer and internet capacity, for the way modern astronomy works is by teams of scientists anywhere in the world sending immense amounts of data, observations and questions by email to those operating the telescope, who then feed these demands into the telescope and send the equally complex results back by email for analysis elsewhere.

However, the International Energy Agency reckons that the Karoo also has recoverable shale gas reserves of 485 trillion cubic feet. Shell has already begun what could become a major energy rush, though there is strong local resistance to the hydraulic fracturing — “fracking” — of the rock, which will use up scarce water reserves and possibly contaminate the water table. The government, panicked by the uproar, has declared a moratorium on the further application for shale gas mining licences, but this hardly solves the problem. South Africa is under fire for using dirty coal-power stations and can hardly turn its back on a clean energy source which could power the country for many decades to come. Shell, for its part, makes it clear that it knows there is a huge queue of other hydrocarbon companies keen to get their hands on the Karoo and claims, probably rightly, that it is likely to be more environmentally responsible than most. It insists that its exploration will not involve the use of any harmful, contaminating chemicals.

Thus far the opposition to “fracking” is led by Greens, conservationists, sheep farmers and those who just want things to stay as they are. Inevitably though, arguments are now being voiced that shale gas exploration would damage SKA. Thus Dr Adrian Tiplady of SKA warns that mining could create the sort of electromagnetic interference which would make SKA unworkable. Again, in a somewhat panicky move, the government has declared 12.5 million hectares of the Karoo to be an Astronomical Advantage Area, where astronomical imperatives will come first.

Closer examination suggests such fears may be misplaced. Dr Tiplady says an idling lorry can create electromagnetic interference up to 11 kilometres away (unless blocked by a hill) and mining operations could be worse. But such is the vastness of the Karoo that one could easily fit in any amount of fracking and stargazing. Fracking, after all, means pumping sand-laden slurry into rocks, fracturing them in order to allow the release of gas or oil, at depths of 5,000 to 20,000 feet. It is not clear that anything that happens that far down could have any effect on astronomers hundreds of kilometres away. A better question is, where will all the water for fracking come from? If one is not to tap into South Africa’s limited fresh water sources, the easiest thing to do would be to pump sea water in by pipeline from the Atlantic coast. That would be expensive but with nearly half a quadrillion cubic feet of gas at stake, perhaps not prohibitively so. No doubt there would be further uproar at the notion of pumping salt water into the Karoo’s deep water table, though of course the Karoo was long under the sea before. It might be best to hunker down and wait for a lot more such controversy as the world focuses in on Africa’s hydrocarbon bounty. The Seychelles, for example, has recently discovered Saudi-sized oil reserves just offshore. There’s going to be a lot more trouble in paradise.