The sobering science
Yesterday’s stunning news about sea level rise means that Florida can no longer enjoy the beach with its head in the sand. Two papers in the Proceedings of the US National Academy of Science showed with sobering clarity that the acceleration of global sea level rise over the 20th and 21st centuries has vastly outpaced the rate of rise in the previous 27 centuries. The rate of rise will continue to increase rapidly unless aggressive mitigation of climate change is implemented in the near term. We can slow the rate, but not stop it. Sea level will likely continue to rise for several centuries.
The first paper shows that if humans had not been warming the planet, the rate of rise would have been less than half of the observed rate. There is little doubt that the last 100 years, and especially the first part of the this century, are radically out of line with the rate of sea level rise since the great ice sheets began to recede and human agriculture was invented. A second study published in the same issue of PNAS confirmed these projections. Most alarming about these new estimates is that they are calibrated against historical rates that were driven by the melting of glaciers and thermal expansion of the oceans. The new wildcard that has not been fully considered is the rapid melting of the ice sheets of Antarctica and Greenland.
Taken together, these studies and several others indicate that it is reasonable to expect between 3 and 4 feet of sea level rise by 2100 relative to the year 2000, assuming there is no successful mitigation of greenhouse gas emissions. It should be noted that there is no wholesale infrastructure fix for Florida that could address such an extreme increase in sea level.
The implications for Florida are profound, if not outright catastrophic. The respected climate news organization Climate Central (the source of these figures) published an analysis showing that most of coastal flooding of the last fifteen years can be attributed to human caused climate change. Moreover, it has long been known that sea level rise amplifies hurricane storm surge. Work by Dr. Tim Frazier, who completed his doctoral studies at Florida State University, showed that Sarasota County is likely to be increasingly in harm’s way as the waters of Sarasota Bay continue to rise. It is not a question of if, but rather when. The odds will worsen quickly if we don’t act to slow the rate of sea level rise. It should be obvious at this point that coastal Florida can expect some tough years ahead.
Why this is an urgent matter for Florida
In March 2007 I was silenced and dismissed giving an invited talk on climate change and energy alternatives to a joint committee of the Florida legislature. Senator Cary Baker from Eustis considered me to be giving false information about climate change because I had shown the infamous hockey stick, which by then had been validated by the National Research Council. When I approached Mr. Baker after I had been dismissed, I found that he was not particularly interested in the opinions of the National Research Council. In another incident, while presenting at a conference at the UF School of Law in 2006, the former Speaker of the House lambasted me for defending science, which he felt had misled politicians. In the years since, the politics related to climate change in Florida have not improved.
The reality of sea level rise and its stunning acceleration means that our elected officials must now take action to fulfill their duty to serve the people. The science can no longer be ignored, even if it is politically inconvenient. The sooner that policy makers embrace this obligation, the less harm will be suffered by Floridians, irrespective of their proximity to the coast. The resulting economic and demographic shifts over the course of this century will affect every county in the state.
There are three primary areas of concern that need to be addressed in the near term:
(1) The frequency of coastal flooding is increasing and the economic damage from this can be expected to multiply rapidly. Efforts to control coastal flooding should not attempt to permanently forestall flooding or provide a long term infrastructure fix. Such efforts are futile in the face of such accelerating sea level rise. Instead we should begin the first stages of strategic retreat from the shoreline, moving those homes and businesses that are most vulnerable to coastal flooding first.
(2) Because of rapidly rising seas, amplification of storm surge is more of a looming threat from hurricanes. Hurricanes are generally projected to be stronger, but perhaps less frequent under the influence of warming seas and shifting trade winds. Regardless, we can expect a few very big Atlantic storms to hit Florida this century. Again, we should formally assess the engineering aspects of coastal infrastructure for resistance to amplified storm surge, and begin strategic retreat as soon as possible. Potential loss of life should be a serious consideration in such planning. Many coastal areas of Florida are occupied by aging populations that are largely dependent on public transportation. This is an emergency planner’s bad dream, and we should consider moving these folks in advance of catastrophe.
(3) Coastal property values will tank in the relatively near term. Although it is impossible to know precisely when this will occur, because of this new science, it will almost certainly happen sooner than previously anticipated. Certain properties will be more likely to drop in value sooner than others depending on exposure to coastal flooding. Reclassification of properties by FEMA, which is likely, could have a profound impact on property values throughout coastal Florida. My estimate is that property values will begin to selectively change within five years, and large scale changes will follow once the details of strategic planning become public knowledge. Failure to make such planning public is reprehensible, and failure to plan is immoral.
In light of this reality, Florida’s entire coastline should be strategically managed for competing uses through 2100. Indeed, Florida beaches are a clear example of the public domain. Certain activities such as beach nourishment should be phased out in certain vulnerable areas as strategic retreat is implemented. Recreational beach use can be allocated according to priorities that should include maintenance of mangroves and wetlands, which act as natural buffers against coastal flooding. Habitat restoration can be a valuable asset to protect human and natural communities on the coast.
In the longer term, all of Florida should become ready for large scale demographic and economic shifts that will unfold toward the middle of this century. Centers of population will shift inland, and the Everglades and existing agricultural lands and ranches will be radically affected. Agencies responsible for restoration of the Everglades and southwest Florida should carefully review the impacts of accelerating sea level rise on existing plans for adaptive management of water, wildlife, and ecosystems.
All county governments should be developing sustainability plans that include management of people, lands, public health, food, agriculture, transportation, and finance as these profound shifts unfold over the coming decades. Comprehensive planning should focus on nothing shorter than a 50-year horizon. Planners must make no assumptions that basic physical and economic factors will remain constant. A powerful tool to address such uncertainty is formal scenario analysis. Presently, only a few counties in Florida are having these discussions.
It is deeply concerning to me that developers and our political leadership continue with business as usual as if the Florida of the 20th century will always be. Nothing could be farther from the truth.
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