Renowned geologist Chris Hartnady has resurrected concerns that Econometrix, the country’s largest independent macroeconomic consultancy, underplayed environmental consequences in its assessment of the potential macroeconomic benefits of hydraulic fracturing, or fracking, to extract gas in the Karoo.

The report, released earlier this month, estimated that 485 trillion cubic feet (tcf) of shale gas could be lurking in the Karoo – described as being equivalent to 400 years of oil consumption in South Africa.

Bonang Mohale, the chairman of Shell South Africa, which commissioned the report, said the findings were “bigger than the discovery of gold in Gauteng”.

The anti-fracking coalition Treasure the Karoo Action Group (TKAG) dismissed the 73-page report as “poorly researched in respect of the holistic facts on shale gas mining”, “lacking in substance” and ignoring social costs.

Speaking at the Shale Gas Southern Africa conference in Cape Town yesterday, Hartnady presented a case against shale gas development, arguing that the environmental impacts and geophysical risks of fracking were too costly.

He warned that the reassuring figures of available gas in the Karoo might be scaled back if the gas resource assessment of the Marcellus shale deposits in Pennsylvania and Ohio in the US was anything to go by.

“An original 2009 estimate of 489tcf, closely comparable to the Karoo estimate… has now been reduced to between 84tcf and 43tcf by the US Geological Survey, depending on the confidence level (50 percent or 95 percent, respectively) assigned to the estimate.”

In terms of damage to the environment, Andrew Venter, the chief executive of the Wildlands Conservation Trust, was also wary of the Econometrix estimates. “There is no doubt that Shell and its fracking allies are determined to persevere despite the concerns that have been raised… This is understandable, and it would be shortsighted for us to forego the associated economic opportunities (of fracking).

“However, there is significant doubt as to the realistic scale of this impact. The Econometrix report has been widely criticised as not only being biased (but) also unrealistic in its projections,” he said.

Hartnady said the exploration would lead to landscape degradation through the industrialisation of the rural habitat and noise pollution. More damaging to the country’s plight was that it would deplete the dwindling water supply.

The exploration phase in three areas of the Karoo would require 48 000 to 216 000 cubic metres of water to drill 24 wells and, should exploration be successful, actual gas production was likely to require about 10 000 wells.

“Shale gas production would become a serious competitor for water, requiring as much as four times the current annual usage of the groundwater in all three of the Shell exploration areas,” he said.

Surface water can be contaminated through improper disposal of recycled water, and groundwater could be contaminated due to fracking fluids being injected into rocks during the fracking process. In extreme cases in the US, this has led to flammable tap water.

Hartnady said fracking would be likely to increase the incidence of earthquakes. Referring to the 5.6 magnitude Oklahoma earthquake in 2011, he said the state previously experienced around 30 small earthquakes a year; a number which, since 2010, had soared to over 1 000 a year.

“The 2011 ‘hydroseismic’ events in Oklahoma and Ohio bear important lessons for the Karoo, especially since – though not common knowledge – significant earthquake activity is established in this part of the country. The earthquake catalogue of South Africa shows many epicentres within and around the Karoo,” he said. - Sungula Nkabinde