Last year, we had covered a study on the non-trivial contribution of groundwater depletion to sea level rise. It concluded that humans have pumped enough water from underground sources to account for up to 13 percent of the rise in ocean levels that occurred between 2000 and 2008.
A caveat, from a related paper, was that this might be offset by an increased retention of surface water in large reservoirs behind new dams. That would make the net effect of these human activities a wash. In fact, the 2007 IPCC report left out groundwater depletion when projecting sea level rise because of the uncertainty of existing estimates and the presumed balance with reservoir impoundment.
A new estimate, published recently in Geophysical Research Letters, takes a closer look at dam building and projects current trends into the future. While groundwater depletion continues, dam construction is on the decline. The result should be an increasing contribution to sea level rise.
