Sea level rise in Miami, here now... by gimleteye

Global warming is a major focus of scientific inquiry, with real consequences to Florida.

On sea level rise, we're waiting. For the most part the local conversation is not whether sea level rise will occur but when. And in this context, "when" is usually framed as an abstract matter of decades hence. The low end of estimates is a foot rise by the end of the century. The high end, five to twenty feet. The science committee of the Miami Dade Climate Change Advisory Task Force-- manned by an array of volunteer and professionals with the support of a few county planners-- is "at least three to five feet" by century's end. "This does not take into account the possibility of a catastrophically rapid melt of land-bound ice from Greenland, and it makes no assumptions about Antarctica."

With the economy in such shambles, no one needs more bad news. But... what if projections of sea level rise decades from now when many of us will be gone are wrong? I have something to show you.

A long-time resident of downtown and keen observer of the local marine environment (used to be a lot more of them, relative to our overall population) sent me this photo with the following note:

"This is high tide in the 1700 block of North Bayshore Dr. Miami FL. Unfortunately, this flooding is not associated with storm surge or any other exceptional tidal or weather event. It has become the regular twice a day occurrence of the tide. ... low lying streets all over Miami and Miami Beach are experiencing increasingly regular, non weather event, flooding."

(Photo taken 9/27/2008 9:19 am, high tide at Dodge Island was at 8:20 am) To me, the photo is extraordinary because it shows one of the brand new additions to the downtown skyline. In other words, this flooding is a very recent phenomenon otherwise the condo's foundation and surrounding infrastructure could never have been completed.

I asked the photographer: is this a photo after a rainfall, or, on a moon tide? He replied, no: you can observe salt water flooding this and other areas downtown regularly.

I showed the photo to a scientist who is involved with climate change on a daily basis and asked for comment. This is the response I received, "Well just a quick look at the NOAA tidal data shows that tides are running about 6-8 inches above that predicted (see graph below). I was out at Cape Sable last Friday and there were extremely high tides. The flood tide at Middle Cape Canal was more turbulent than at any time I can remember."

The graph represents a data set from the last few days, but let's put these eight inches in perspective: according to the Miami-Dade climate change science subcommittee, beginning in 1930 the rate of relative sea level rise increased about eight fold over that of the past 2,000 years. Its report states, sea level is "presently rising at 30 cm (1') / 100 years!"

Does this photo show that something else is happening, much faster and in support of a basic theory: that sea level rise will not happen gradually and imperceptibly but rapidly.

Theories for the future aside, the long record is clear as a bell: Cape Sable, at the very southern tip of the Florida peninsula, is disappearing. It's only 30 miles from here and it takes some work to get there, but Cape Sable is disappearing like frontage of the Louisiana and Mississippi bayou. These changes in the southern Everglades are off-the-chart.

Just last week, after a considerable period of observation, the National Park Service decided to press the issue with the public, although it has not yet arisen to a level of broad public attention. The NPS on September 25th issued an advisory that should make everyone wake up: the federal agency is preparing an environmental assessment of "options for mitigating the impacts from failed dams on the East Cape and Homestead Canals at Cape Sable in Everglades National Park." (read full text, below).

This is not subjective and is not a matter of land subsidence; dams placed decades ago have failed-- salt water over-topping the dam, twice a day. According to the USGS, "During the early decades of (the 20th) century, when the drainage of the Everglades accelerated, the southern glades frequently dried out, reversing the hydraulic gradient and allowing the Homestead Canal to become a conduit for the inland flow of salt water. In addition to the free exchange of salt water through the outlet near Flamingo, saline water also entered the canal at Whiskey Creek." Today, the entire area is saline. The dams have failed. The sea is pouring in.

If every one of Miami-Dade's 2 million residents could see the power of an incoming tide breaching a canal dam that once held the sea back, our politics would not be so complacent.

Local government is continuing to permit and allow zoning in flood plains despite the fact that elevations show the invasion of the sea will be from the south and the west, not incoming through downtown streets. When the Miami Dade Climate Change Advisory Task Force made its powerpoint presentation (a version of this one, available on the web), most the county commissioners could be observed on the dais nodding and dozing off to sleep.

I understand that most people shrug; sea level rise that affects distant habitat for crocodile and various wading birds is more or less off the radar. Many of those sleeping county commissioners were just re-elected without a breath of comment on global warming.

The point is this: real sea level rise at the Homestead Canal means it must be observable elsewhere in Miami-Dade. That is why I believe these photos show that global warming is hitting Miami now.

The rate of change is an open question. Here, the prospect of twice-daily high tides inhibiting people from their property will require immensely expensive adaptation: who will pay for elevated roadways, for instance, so people can get in and out of their condos? Or, for maintenance of water or fire and safety service? What will the impact be to insurance rates, for personal property and for municipal debt, too?

On the following two photos; notice the location of the storm drain and the fact the drain is not working. This is the new Opera Condo, on NE 17th Street two blocks east of Biscayne Blvd.




In conclusion-- if you have made it this far-- you will wonder how Republican VP candidate and Alaska governor Sarah Palin (Drill, baby, drill!) could be from the state that has suffered the most damage and loss from a warming climate and still doubt the science of global warming.

But never mind Anchorage, we have plenty to be concerned about with global warming, right here and now. Don't shoot the messenger: in Miami, where a porous underlying geology is a sponge not a barrier, sand bags and walls will not deter the implacable sea.

"September 25, 2008
Everglades National Park

Dear Friends:

The National Park Service (NPS), in compliance with the National
Environmental Policy Act of 1969 (NEPA), plans to prepare an environmental
assessment (EA) of options for mitigating the impacts from failed dams on
the East Cape and Homestead Canals at Cape Sable in Everglades National
Park. The purpose of the project is to prevent saltwater intrusion into
freshwater marshes that are habitat for the threatened American crocodile
and various wading birds by restoring the failed dams on the two canals. A
detailed description of the site and some potential alternatives that could
be selected for the project are provided in the attached newsletter.

The NPS is requesting public input on the proposed action and any issues,
concerns or alternatives that should be considered in the environmental
assessment. There are several ways to participate in this process and make
your voice heard.

You may submit your comments electronically at the NPS Planning,
Environment, and Public Comment website http://parkplanning.nps.gov. Once
on the website, select "Everglades NP" from the drop down box, then "Cape
Sable Canals Dam Rehabilitation EA," and finally "Open For Public Comment."

If you are unable to access this website, please submit written comments by
October 23, 2008 to:

National Park Service
Attention: Patrick Malone
Denver Service Center, Planning Division
P.O. Box 25287
Denver, CO 80225-0287

Finally, we invite you to attend a public meeting on October 8, 2008, from
5:00 p.m. to 8:00 p.m. The meeting will be held at:

South Dade Regional Library
10750 SW 211th St.
Miami, Florida 33189

The first hour of the meeting will be an open house and NPS staff will be
available to discuss the project, answer questions and record your
comments. At 6:00 p.m. there will be a brief presentation on the project,
followed by a public comment session.

Once the environmental assessment is completed, it will be made available
for public review for a 30-day period.

Your opinions matter a great deal to us, and we want to hear from you.
Please share your ideas, suggestions and concerns about this project with
us by providing written comments and attending the open house.

Please provide your input on or before October 23, 2008.

We look forward to hearing from you.

Sincerely,

Brien F. Culhane"