A Swiss report appearing at www.20min.ch claims that the extraction of groundwater for communities and agriculture is adding massively to global sea level rise.
According to a yet to be published paper by the America Geophysical Union, 2000 cubic km of freshwater are consumed yearly – with 1500 cubic km coming from lakes, ponds, rivers etc., and the remaining 500 cubic kilometers of freshwater being extracted from the ground. According to 20min.ch:
Scientists now have calculated how much of this extracted water returns from where it came: only 3%. The remaining 97% flows into the oceans via evaporation and precipitation.
Of course, the scientists say, this bodes extremely ill for groundwater levels and pose a serious threat to arid regions.
Adding to sea level rise
Moreover the AGU paper claims that the extraction of freshwater is contributing to an annual 0.8 mm rise in sea level, 0r more than 25% of the overall 3.1 mm/yr. It goes without saying that there are uncertainties involved here, as dams act to slow the entry of freshwater into the oceans. But 20min.ch writes:
Scientists are convinced that the relation between groundwater reduction and sea level rise will gain importance. Simply because global water consumption will continue to increase and for that reason groundwater reserves will continue to sink.
Uncertainty always allows alarmists to be convinced of anything they claim. Sceptic Edgar L Gärtner at eigentümlich freicomments in a piece called: Climate Lies: How geo-scientists are abandoning their expertise. Leaky faucets are causing the oceans to overflow, writes:
It can be certain that pumping out groundwater has no measureable impacts on sea levels. But perhaps US scientists are tying it to climate change in order to bring attention to the risks of exhausting groundwater reserves.
Drawing attention to potential groundwater depletion problems is legitimate. But claiming it is leading to sea level rise sounds absurd.