Florida Keys Prepare For Sea Level Rise

An Associated Press report details how the Florida Keys are starting to prepare for seasonal flooding and rising water levels overall. "A tidal gauge operating since before the Civil War has documented a sea level rise of 9 inches in the last century, and officials expect that to double over the next 50 years." Flooding used to be a much rarer occurrence, but now many businesses are finding it necessary to have plans in place to deal with it. "The Keys and three South Florida counties agreed in 2010 to collaborate on a regional plan to adapt to climate change. The first action plan developed under that agreement was published in October and calls for revamped planning policies, more public transportation options, stopping seawater from flowing into freshwater supplies and managing the region's unique ecosystems so that they can adapt, too." The Keys are one of many places beginning to seriously evaluate their options for dealing with flooding after witnessing the damage caused by Hurricane Sandy.

Comments

Options

[drinkypoo]

The Keys are one of many places beginning to seriously evaluate their options

Like relocation to higher ground? Awesome vacation spot, not such a good idea to move in. Of course, I support people being able to live in inherently unsafe places, the only time I get grumpy is when people get disaster relief and spend it on rebuilding in those places. I'm not against the relief, I'm against it being so damned temporary.

Re:Options

[Black Parrot]

The Keys are one of many places beginning to seriously evaluate their options

Like relocation to higher ground?

They should move to North Carolina, where the legislature outlawed sea level rise.

Re:Options

[Capsaicin]

They should move to North Carolina, where the legislature outlawed sea level rise.

Too right. I can't fathom these Global Warming advocates... who in their right mind actually wants catastrophic climate change?!!

I say we vote to keep the climate just as it is thank you very much.

Re:Options

[drinkypoo]

Sure, the story talked about that. But what caught my eyes was "has documented a sea level rise of 9 inches in the last century, and officials expect that to double over the next 50 years". It's a typical climate change non-story.

It takes a special kind of stupid to not believe that eighteen inches of sea level rise will cause significant effects. As well, "Over the next 50 years" means nothing. Anything that happens in the next five years also happens in the next fifty. Note that ice on land is still melting faster than expected. That means sea level rising faster than expected. But I would appreciate it if you would move to The Keys.

perspective

[stenvar]

To put this into perspective:

http://en.wikipedia.org/wiki/Florida_keys

The Florida Keys have taken their present form as the result of the drastic changes in sea level associated with recent glaciations or ice ages. Beginning some 130,000 years ago the Sangamonian Stage raised sea levels to approximately 25 feet (7.5 m) above the current level. All of southern Florida was covered by a shallow sea [...] Starting about 100,000 years ago the Wisconsin glaciation began lowering sea levels, exposing the coral reef and surrounding marine sediments. By 15,000 years ago the sea level had dropped to 300 to 350 feet (110 m) below the contemporary level.

The Florida keys are an environment that's neither stable nor safe from flooding, and when you live near the water, you have to live with the fact that you need to move sooner or later. Even without anthropogenic warming, there would have been substantial sea level rise over the last century, and these precautions would be necessary and prudent.

Re:perspective

[garyebickford]

I don't know the specific geology of the Keys, but most places with ocean interfaces are either raising or lowering with respect to sea level. For an example of short term movement, the shore of Japan close to the quake and tsunami in some cases is feet lower than it was before the quake because as the pressure built up over centuries, that land bowed upward, and when the stress was released the land dropped again. And on the Oregon coast there is a shallow marsh that before January of 1700 was a cedar forest, but it dropped six feet in that earthquake.

Other areas are dropping or rising more gradually. Many Pacific islands would be gradually going under water over the next few centuries regardless of the global sea level change.

Basically, the entire surface of the Earth is a bunch of scum piles being shifted around on an ocean of semi-liquid material, bumping into each other and tilting in various ways. As the Asian and Indian Ocean plates collide and tilt up to form the Himalayas, the other ends of those places are dropping. And there is now evidence that the Atlantic plate is cracking in the middle, offshore of Portugal because of similar activities.

Re:perspective

[Anonymous Coward]

...the entire surface of the Earth is a bunch of scum piles being shifted around on an ocean of semi-liquid material, bumping into each other and tilting in various ways

Generally, yes, but that ignores the fact that there are no plate boundaries nor obvious tectonic processes operating within any distance of the Florida Keys that can account for more than the most inconsequential sea level change over the last 150 years. In short, the keys are tectonically stable. A nine inch in rise in sea level over the last hundred years or so is consistent with the change in global sea level over the same period.

More generally, many ocean/continent boundaries are active margins, but far from all of them. Consider as counter examples the east coasts of North America and South America, the west coasts of Europe and Africa (despite evidence for incipient subduction off Western Europe, as it certainly doesn't currently dominate tectonic regime there), three sides of Australia, the east coast of Africa, the entire coastline of Antarctica, the northern coast of North America along the Arctic Ocean, and most of the northern coasts of Asia, are all passive margins. These areas as not devoid of tectonic activity, but it's usually mild compared to areas around the Pacific Ocean and other active continental margins.

It may also be worth observing that some parts of the world, especially Northern Europe and parts of North America, even where the tectonic environment is mild, are still isostatically rebounding upwards following the last glacial maximum. The ice sheets were so massive that they depressed the continents underneath them. Now that the ice has melted, the land is slowly rising back up from the viscous mantle upon which the continents float. In those places, with the land rising, local sea level may be falling. Isostasy can also locally affect other areas where there's a lot of geographic relief, such as in high continental plateaus where erosion unloads the land surface, or where high relief upstream contributes large volumes of sediment. The Florida Keys are not, however, subject to these processes.

The global average sea level, or sea level measured against an artificial reference point, is called eustatic sea level. Over hundreds of millions of years tectonic processes can affect eustatic sea level, but on shorter time frames the tectonic variation averages out: if rock is rising in one place, it's falling in another, so the contribution to sea level changes by tectonic processes are generally only local. For example, the sea level in the Florida Keys won't be affected by changes in the local sea level along the coast of Japan.

The biggest general contributor to most sea level change on the timescale of our species is climate, not deeper geologic processes. There is a minor component related to the thermal expansion of seawater, which accounts for probably about half the currently observed sea level rise, but the dominant longer term factor is variation in the amount of ice sequestered in continental ice sheets -- like the those that once covered much of North America and Europe, as well as the extant Antarctic ice sheets and Greenland Ice Sheet. Broadly speaking, throughout geologic history the amount of water impounded in continental ice sheets will tell you more about eustatic sea level than any other single factor. Back through the Pleistocene, if you had to guess how much water covered any random point on the globe, knowing the level of glaciation would on average give you a better answer than anything else. Sea level tracks very closely with glaciation.

You can look at the Greenland Ice Sheet as a remnant of the much larger Pleistocene ice sheets in the northern hemisphere during the last glacial maximum. The Greenland Ice Sheet contains enough water that if it were to melt or flow in to the ocean, eustatic sea level would rise a couple dozen feet even without contributions from other reservoirs. Since the late Pleistocene, eustatic sea level has ris

Re:perspective

[Intrepid imaginaut]

The key word here is anthropogenic I would guess. Nobody can deny that there is global warming, we're in an interglacial period, where I'm sitting now used to be under a kilometer depth of ice, the main discussion is how much of it we are responsible for.

Re:Just asking questions.

[Ziest]

Shouldn't you be at your AA meeting?
 

Re:Just asking questions.

[ZarathustraDK]

When are these folks going to blame their breathing on Obama and stop their socialist respiration which supports the agenda of the illuminati?

Re:Well duh!

[Barsteward]

but .. but ...but...but... climate change is a lie....... the sky is falling, not the water levels rising.... (maybe that'll be a good rationale for the climate change deniers of this planet)

Re:Just asking questions.

[vilanye]

I lived in Key West for several years. It is a fun place, the entire keys are great. Mainland Florida can sink into the ocean for all I care, just leave the keys alone. They are pretty open to anyone, as long as you aren't an ignorant, uptight redneck. Decent rednecks are welcomed.

No Where To Turn

[b4upoo]

For those that don't know the Florida keys are only a few inches above ocean levels even before the 1800 era. An 18 inch rise in sea levels would put the keys under water. these keys stretch for well over 100 miles and involve hundreds of islands. The area is also vital as a nursery for sea life. A slight rise in ocean levels is a clear cut disaster.

Re:And all I know...

[Thud457]

More sophisticated societies ask Where shall we have lunch?

the first one blew away. the second one sank into

[Thud457]

It's all about the storm surge
two thirds of Key West was underwater during Wilma.
That used to be a once in a generation thing. Then it's going to be every 20 years. Then every 5. Even if it doesn't turn into New Atlantis, that's gonna put a real crimp in the island lifestyle.

Re:Just asking questions.

[fyngyrz]

They threw him out when he accused the doughnuts of spying on anyone with more than a 30-day token.

Faster rise than the rest of the ocean

[tompaulco]

MSL has risen 7.7 inches in 135 years in the rest of the world, but somehow has risen another 1.3 inches in the Keys in less time. I suspect that they are experiencing ocean water rise in conjunction with the natural eroding away of the islands themselves. You certainly wouldn't want to build any permanent (in terms of centuries) buildings on those islands.

Re:Not what I saw there

[jbengt]

I don't know about the keys, but the everglades' water levels are dropping because of a combination of less rainfall than in the past (climate change?) and agricultural and other diversions of the water that should be flowing into the everglades. It has nothing to do with sea levels.