Policy: Hurricane Katrina’s Lessons for the World

Ten years after the devastation of the US Gulf coast, Edward B. Barbier calls for coastal protection plans like that adopted by Louisiana for the world's most vulnerable nations.

Ten years ago, Hurricane Katrina devastated the US Gulf coast states.  It caused around US$110 billion in damages, more than 1,800 deaths, and displaced 1.2 million people.

The disaster led to a rethink of the management of the Gulf coastline.  In the seven decades preceding 2005, Louisiana had lost coastal lands, mainly marshes, totaling around 4,900 square kilometers (1,892 square miles) — an area the size of Trinidad and Tobago.  Following the hurricane, the President's Gulf Coast Ecosystem Restoration Task Force recommended extensive wetland re-establishment, noting that they “provide a natural flood attenuation function”.

After the hurricane season in 2005, the Louisiana state legislature created the Coastal Protection Restoration Authority (CPRA) and tasked it with coordinating the local, state and federal efforts.  The CPRA embarked on five-year coastal master plans to guide policymakers in developing a more sustainable coast.  I served on the science and engineering board that oversaw the scientific analysis for the 2012 master plan.  This plan was charged with evaluating, prioritizing and integrating coastal protection and restoration projects over the next 50 years, with a total budget of $50 billion.  The plan accounts for how coastal restoration and protection in Louisiana may have to adapt to differing climate-change and sea-level-rise scenarios.
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Flaws and merits aside, Louisiana's 50-year coastal-planning strategy represents a new way of thinking about the long-term management of coasts.  Resilience is the new aim — against short-lived natural disasters that have immediate and often extreme impacts, such as flooding and storm surges, and against long-term climatic changes that have more gradual impacts, such as sea-level rise, saline intrusion and erosion.

Other parts of the world urgently need such a long-term strategy.  Around 38% of the global population — 2.5 billion people — live within 100 kilometers of the coast.  More than three-quarters of these people are in developing countries.  The frequency of flooding associated with cyclones and other major coastal storms is likely to increase by the 2050s as a result of accelerated sea-level rise.  Coastal areas are the front lines of climate change.

The most vulnerable are poor, rural populations in developing countries that live less than 10 meters above sea level, in low-elevation coastal zones (LECZs).  In 2010, around 267 million people lived in the rural areas of LECZs.  By 2100, the figure is projected to be 459 million.
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A long-term global resilience strategy for coasts needs three lines of defense.  First is the restoration of 'green' infrastructure — robust coastal ecosystems, such as salt marshes, oyster and coral reefs, mangroves, seagrass beds and beaches.  These are essential, especially in remote, rural parts of developing countries.  Second is the right 'grey' infrastructure, such as seawalls, dikes, barrages and diversions as well as raising the elevation of buildings and flood-proofing structures.  Third is to involve key local stakeholders throughout; this builds institutional and coastal community capability.
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The next step should be for the COP21 UN climate summit in Paris this December to earmark multilateral adaptation funds to support developing countries in their efforts to devise a long-term global planning strategy for enhancing and protecting coasts and populations vulnerable to damaging storms.  The World Bank, UNDP, and the UN Environment Program should also commit to assisting local and national authorities through a coordinated effort.

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