Miami: A Sinking City
There is perhaps no city in the United States today in which the effects of climate change are more visible than in Miami. Rising sea levels, one of the most commonly cited impacts of our warming climate , coupled with the geology of south Florida, has resulted in the common occurrence of what we locals like to call “sunny-day flooding.”  Underneath the cranes pushing Miami luxury developments higher into the sky is a bed of porous limestone. Because the city is built so close to sea level, as sea levels rise, the water makes its way through the limestone, posing a threat to the fresh water supply, and driving sewage into the streets.  The stereotypical image of a high-heeled fashionista strutting down Alton road on Miami Beach is being replaced by one of a frustrated fashionista wading through ankle deep water and floating trash.
While this peculiar scene certainly catches the eye, it is the island in the distance which marks the Port of Miami where I want to draw your attention. While Miami’s port does not rank high relative to other US ports with respect to shipping volume,  it remains the busiest passenger cruise port on the planet,  having served 4.8 million multi-day passengers in 2014.  Miami’s tropical climate and proximity to Latin America and the Caribbean have enabled the port to rise to this standing, but climate change poses a significant threat to the long term viability of the port.
- The port is located on an island that is composed of the same porous limestone as the rest of the city. As sea levels continue to rise, the infrastructure at the port will increasingly come under the threat of flooding. While the useful life of major port infrastructure such as docks and terminals ranges from forty to fifty years,  ports operate in a competitive industry, making it less likely that decision makers will opt to make the necessary infrastructure investments given the uncertainty of sea level rise estimates.
- Because the infrastructure investments made at ports are intended to generate benefits for decades, the challenge of anticipating how climate change will impact cruise ship volume is compounded. On the one hand, it would be prudent to protect the port from rising seas and storm surges, but if rising temperatures and other threats to Miami undermine its centrality as a hub for tourism in the Americas, then perhaps those investments are less worthwhile. As we’ve seen in finance, determining the proper discount rate can be a real challenge, and port PP&E investments are a great example of how long time horizons and the uncertainty of climate change’s multiple, intersecting consequences complicate the calculus significantly.
- In addition to sea level rise, the port of Miami is likely to be significantly impacted by the increasing frequency of extreme weather events brought on by climate change. Given the port’s reliance on tourism, more severe weather events might generate more frequent operational delays and slowdowns. The extreme weather events may also dampen demand at the port if customers decide that cruising to cities in Latin America and the Caribbean is less attractive as a result of severe weather risks.
What is being done at the port?
Despite a lack of political will to acknowledge or act to mitigate the effects of climate change at the state level,  there have been some efforts at the local level to prepare the port for a future with higher seas. Specifically, the port has developed plans to raise the height of its new infrastructure projects, using FEMA flood maps to project elevation requirements. And yet, port officials appear to have not made significant changes to their operational plans to account for broader effects .
What else can be done
While the port cannot predict how future fluctuations in tourism and cruise ship volume will impact its operations, it can build more resilient infrastructure and operational systems that will make it better able to adapt to changing conditions over time. Firstly, the port should be sure to use the most accurate scientific estimates of sea level rise when designing future structural investments on the site. Secondly, the port can work with other ports around the world to collectively share best practices for mitigation. While some of the challenges that the Port of Miami faces are unique, many are shared by other ports around the world. Finally, the port should coordinate with local agencies to ensure access to the port remains uninhibited in the future. Because the port is located on an island, bridges and tunnels designed to reach the port likewise need to be built with the capacity to handle storm surge and sea level rise.
 Henderson et al., “Climate Change in 2016: Implications for Business.” Harvard Business School Publishing (October 14, 2016.)
 Kamp, David. “Can Miami Beach Survive Global Warming?” Vanity Fair (November 10, 2015).
 McKie, Robin. “Miami, the Great World City, is Drowning While the Powers that be Look Away.” The Guardian, (July 11, 2014.)
 U.S. Army Corps of Engineers, Waterborne Commerce of the United States, Part 5, National Summaries (New Orleans, LA: Annual Issues).
 PortMiami Breaks Another Cruise Passenger Record with 4.8 million Multi-day Passengers in 2014,” Miami Dade County News Release (December 3, 2014) <http://www.miamidade.gov/portmiami/press_releases/2014-12-03-cruise-passenger-record.asp>
 US Environmental Protection Agency White Paper: “Planning for Climate Change Impacts at U.S. Ports” (July 2008.)
 Bump, Philip. “Why Climate Change is Such a Big Issue in Florida.” The Washington Post. March 10, 2016.
Cover Photo: http://www.newyorker.com/magazine/2015/12/21/the-siege-of-miami