Among the many controversies raised by Hurricane Sandy, one incontrovertible fact is that sea levels are rising and that higher sea levels increase the risk of damage from storms. For, despite the extraordinary devastation caused by Sandy, it was not particularly severe as storms go.  


To give a point of reference, when Hurricane Katrina, a Category 3 hurricane, landed in New Orleans on August 29, 2005, it had a top wind speed of 125 miles per hour compared to Sandy’s top wind speed on landfall of 94 miles per hour, according to a comparison by Scientific American. Sandy, a Category 1 hurricane when it landed, was more than twice the size of Hurricane Katrina, but its storm surge was “only” 12.5 feet [3.8 m] (though it may have been higher in some places). The storm surge caused by Katina was 14 feet [4.3 m] and as it funneled up to New Orleans, it reached 28 feet [au: 8.5 m]. That the level of damage from a moderately intense storm could be so devastating shows how vulnerable the Middle Atlantic coastal region is. The damage could easily have been far worse. For example, some estimate that with winds only 10 to 15 percent more severe, still less than Katrina’s top speeds, windows would have been blown out of many of New York’s tall office and residential towers. 

There is considerable debate about whether Sandy, and Hurricane Irene, which hit the area and caused great damage last year, are precursors of more frequent and intense weather events. Regardless, the ongoing rise in sea levels means that this area, and all coastal regions, is becoming more vulnerable each year. 

Sea levels have been rising since the glaciers began retreating 10,000 years ago, but the rate has increased significantly since the dawn of the industrial age. The New York State Department of Environmental Conservation reports on its website that: “Global mean sea level has been generally rising since the end of the last ice age. In the 18th and 19th centuries the rise was small, but during the 20th century the seas rose faster, primarily because ocean waters have warmed and expanded, and larger volumes of meltwater from mountain glaciers are now reaching the sea.” 

During the past century the rate of global mean sea level rise averaged 1.7 millimeters [.07 in] per year or 18 millimeters [0.7 in] per decade. But sea levels rise differently in different regions, and based on tide measures in New York Harbor, they have risen by close to a foot [0.3 m] over the last century. 

Recent observations indicate that the rate of rise is accelerating, and the Intergovernmental Panel on Climate Change (IPCC) projects a faster rate of rise during the 21st century. In 2007, the panel estimated that over the course of the century sea levels would rise 7 to 23 inches [17.8 to 54 cm] in total. This projection, however, now appears to be too low, as the extent of the melting of the Greenland and west Antarctic land-based ice sheets are far greater than predicted in 2007. More recent predictions are that the seas will rise by a total of 20 to 55 inches [50.8 to 134 cm]  by 2100, based on the increased amount of melt and faster sea warming. 

There have been a number of studies of the significance of rising seas on coastal development in the U.S. and around the world.  For the U.S., these include the U.S. Global Change Research Program, a coordinated effort of 13 federal departments and agencies mandated by Congress in 1989, that assesses a variety of risks in addition to sea level rise in all U.S. regions.   

In the New York region alone there have been many studies and reports, including studies by:

Other regions have also prepared studies. For example, there is the Southeast Florida Regional Climate Change Compact, the intention of which is to support an on-going collaborative effort among the counties in southeastern Florida “to foster sustainability and climate resilience at a regional scale.”  Just this October the Compact issued a Regional Climate Action Plan.  Its 110 action items combine both adaptation and mitigation strategies and set priorities for investments going forward.

The point here is that the potential for the kind of damage done by Sandy’s surge has been well known, and there are plenty of excellent recommendations on what to do to reduce damage in the future. The costs of many of the recommendations are significant, controversial, and often considered unaffordable in today’s constrained economy, though this does bring to mind the old Fram oil filter slogan: “You can pay me now or pay me later.”  For instance, current estimates for recovering from the damage caused by Sandy have reached $50 billion.

While major plans and projects are being considered and debated, there also are many smaller, practical recommendations in these reports that are less expensive.  Instead, they offer guidance on where to invest in new housing and other development, and where and how to build new infrastructure. 

It would seem obvious, for instance, that the New York City Department of Housing Preservation and Development should take into account evacuation and flood zones in determining where to invest funds and develop future housing; currently it does not. Likewise, it should now be obvious that any development in such areas be resilient with regard to flooding. For example, boilers and electrical equipment should be required to be placed above flood levels, not in the basement as currently required by the city’s building code. There are many examples like this of outmoded plans, zoning, and codes, and of the failure to incorporate simple but fundamental modifications that will enhance resilience in flood-prone areas in New York and in other coastal communities.

Harder to fund are the actions needed to adapt existing development to the changing circumstances caused by a rising sea level.  Indeed, there are many tough choices that will inevitably have to be made. That said, many recommendations made in the studies do not need to be re-studied and can be implemented now and become ingrained in the day-to-day planning fabric at the local government level. 

There are many tough issues to be addressed in finding the best ways to build resilience into coastal regions. But there is also much that has already been studied, is well known, is practical and can be implemented now without the need for new studies. What is needed is for these recommendations to be enacted and to become part of zoning and building codes and the process of approving new development and infrastructure. If not they are not, there is the risk that little will be accomplished as the memory of Sandy fades, just as did the memory of the damage caused by Hurricane Irene only a year ago.