Ris­ing sea lev­els threaten Ever­glades

Cli­mate change mak­ing ecosys­tem less re­silient to events like hur­ri­canes

The Dallas Morning News - - Nation - Chelsea Har­vey, The Washington Post

As res­i­dents of the South­east are re­turn­ing home and as­sess­ing the dam­age left by Hur­ri­cane Irma, Florida sci­en­tists are anx­iously wait­ing to eval­u­ate the storm’s im­pact on one of the state’s most valu­able — and vul­ner­a­ble — ecosys­tems: the Ever­glades.

Al­ready threat­ened by the con­tin­u­ous pro­gres­sion of sea-level rise — which pumps dam­ag­ing salt wa­ter into the habi­tat, jeop­ar­diz­ing ground­wa­ter re­sources, con­tribut­ing to ero­sion and threat­en­ing wildlife and veg­e­ta­tion — some sci­en­tists worry that the weak­ened Ever­glades are be­com­ing less re­silient to dis­rup­tive events like hur­ri­canes. The is­sue is a prime ex­am­ple of the way cli­mate change can ren­der ecosys­tems more vul­ner­a­ble to even nat­u­ral dis­tur­bances.

In­deed, it’s an is­sue that Pres­i­dent Barack Obama chose to high­light two years ago dur­ing his last term. On a visit to Ever­glades Na­tional Park in April 2015, timed to co­in­cide with Earth Day, Obama em­pha­sized the grow­ing threat of cli­mate change and pointed to the im­pact of the ris­ing seas in Florida as an ex­am­ple.

“Cli­mate change is threat­en­ing this trea­sure and the com­mu­ni­ties that de­pend on it, which in­cludes al­most all of South Florida,” he said in a speech de­liv­ered at the en­trance of Ever­glades Na­tional Park. “And if we don’t act, there may not be an Ever­glades as we know it.”

Ever­glades Na­tional Park con­sists of about 1.5 mil­lion acres, or more than 2,300 square miles, of wet­land area, con­tain­ing pine wood­lands, saw grass marshes and ex­ten­sive man­grove forests, which help to nat­u­rally build up the land and buf­fer the coast against the ris­ing seas. It’s home to a di­verse va­ri­ety of wildlife — in­clud­ing croc­o­diles and al­li­ga­tors, as Obama pointed out in his speech — and it’s part of the fresh­wa­ter sys­tem that feeds South Florida’s Bis­cayne Aquifer, a source of drink­ing wa­ter for mil­lions of peo­ple.

Hur­ri­canes, in and of them­selves, are not nec­es­sar­ily dev­as­tat­ing events for the Ever­glades, ac­cord­ing to Harold Wan­less, an ex­pert on coastal ge­ol­ogy at the Univer­sity of Mi­ami. They have long been a nat­u­ral and com­mon oc­cur­rence in South Florida. They can even some­times ben­e­fit the land­scape by throw­ing mud onto the coast and help­ing to build up the land.

Over the last cen­tury, how­ever, sea-level rise — ac­cel­er­ated by hu­man-in­duced global warm­ing — has be­gun to de­grade the Ever­glades by al­low­ing salt wa­ter to seep into the sys­tem, sci­en­tists say. This is bad news for the fresh­wa­ter plants and an­i­mals that live there, but it’s also a ma­jor threat to South Florida’s drink­ing wa­ter sup­plies.

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