The bad news about climate comes so frequently these days that it is difficult to remain focused on the existential challenges facing the East Coast. Now there is a new problem to think about: Throughout the region, the land is sinking. Recently published results of a study showed that of 172 counties from Maine to Florida, at least 8 out of 10 were subsiding. The culprit? Groundwater is being pulled from aquifers faster than it can be replenished. In some cases, communities have tapped into underground water sources from the last time glaciers reached this far south; these deeper aquifers will not refill within anyone’s lifetime.
On Long Island, the rate at which the land is sinking varies; the worst is in Nassau County. But Suffolk and the East End are not far behind. And it isn’t happening just along the shoreline, either. For example, the area around Poxabogue Pond in Sagaponack is dropping twice as fast as other places in Southampton Town.
The conditions were already alarming for coastal communities. Over the past 50 or 60 years, a massive population migration toward low-elevation shorelines continued accelerating. This shift multiplies the present vulnerabilities of these areas. As a combined threat, sea level rise and sinking land masses mean that problems once thought to be the next generation’s are now ours. Research indicates that subsidence increases the threat to coastal communities from sea level rise and may triple estimates of potential flooding over the next few decades.
To varying degrees coastal communities are trying to come up with ways to cope with sea level rise. This latest threat compounds the difficulties for government officials. It also adds urgency to the calls for abandoning the most at-risk places in favor of a policy of retreat. No spending of millions of dollars a year, as on the Montauk downtown oceanfront, will turn back the tide of this inevitable disaster.