The melting of the polar ice caps gets a lot of attention for global sea level rise. But another contributing factor to higher tides is groundwater depletion.
More than 6 percent of the sea level rise in the last century is from the movement of land-locked water to the oceans. That’s according to a new study by the U.S. Geological Survey and published in the most recent edition of the journal Geophysical Research Letters.
Groundwater depletion for human consumption and agricultural and industrial uses is known to have many negative outcomes, including land subsidence, a reduction in surface water as underground springs dry up, the depletion of wetlands, and threats to long term water supplies.
Pumping groundwater to the surface also adds to sea levels as the water is used and then discharged into sewer systems and storm drains, which ultimately empty into the oceans. How much this is happening has been a bit of a mystery because of insufficient data and previous estimates have been all over the map, says the study’s author Leonard Konikow.
Konikow set out to find the answer by developing the first comprehensive estimate of changes in groundwater storage using “volumetric accounting.” He found that ...