Managing natural disaster risk, naturally

The occurrence of a coastal natural disaster, such as a hurricane or typhoon, evokes a feeling of environmental instability. However, as the name suggests, these events are in fact part of natural environmental cycles – up to a point. Climate change, poorly planned coastal development and environmental degradation have increased the frequency of many natural disasters and continue to exacerbate their devastating impacts. As recognition of these worrying trends has increased, there has been a growing acknowledgement of the capacity of natural ecosystems to aid in managing this risk.

Ecosystem-based adaptation (EbA) describes the process of managing and protecting ecosystems to aid in climate adaptation and reduce natural disaster risk. There is a growing recognition, both nationally and within the UNFCCC process, of the services provided by healthy ecosystems and the importance of maintaining them. As a result, recent efforts (by the IUCN and others) have focused on gathering a database of EbA projects around the globe, in order to develop a framework that connects these projects to other adaptation initiatives within the UNFCCC.

EbA has a large role to play in natural disaster risk management for two main reasons: First, healthy ecosystems buffer against the deleterious effects of natural disasters and reduce the associated risk. Second, ecosystem-based approaches to natural disaster mitigation are simply cost-effective.

1. Reducing natural disaster risk

If a hurricane hits the coast and no one is there to experience it, did it happen? Well…probably, but there is no doubt that hurricanes are much more real when they make landfall on a populated coastline. However, even on the most populated coastlines, preserving the presence and function of wetlands can buffer against the effects of hurricanes. When coastlines are maintained in their undeveloped state, the natural barricades formed by barrier islands, saltmarshes and interior wetlands serve to absorb floodwater, dampen wind speed and reduce storm surge.

Diagram: Southeast Louisiana Flood Protection Authority-East

For example, during Hurricane Katrina in 2005, wetlands are estimated to have reduced the speed of water coming inland from 7 feet/second to 3 feet per second. Following this disaster, the state of Louisiana acknowledged that the hurricane problem could not be solved by building more levees (manmade levees did not stand a change during Katrina), and instead mandated the Coastal Protection and Restoration Authority (CPRA) to implement restoration projects to combat the dramatic loss of coastal wetlands.

On the other side of the globe in the Philippine town of General MacArthur, coastal mangrove systems have proven to be an irreplaceable defense against storm surge and winds – especially after the recent Super Typhoon Haiyan. While the nearby city of Tacloban was destroyed in the storm, General MacArthur was largely undamaged due to the buffering capacity of the mangroves. Residents have recognized the value of this ecosystem, designating it a protected area. Unfortunately, mangrove systems nearby continue to be destroyed to make way for resorts and other coastal development.

2. A cost-effective approach

As Katrina demonstrated, man-made barricades and levees are not sufficient to protect coastal regions from powerful hurricanes. Further, these flood protection systems will become less effective as coastal land continues to erode. The CPRA’s plan, if carried out in its entirety, would cost $50 billion over 50 years. If that seems like a lot of money, think about this: the CPRA estimates that if nothing is done to restore the coastal ecosystems, sea level rise and continued coastal loss could increase flooding damage in Louisiana to $23.4 billion annually.

While the monetary benefits of the coastal mangrove systems in the Philippines are harder to quantify, the value of this ecosystem to the residents is clear in their reverence for it. Further, mangroves contribute to local economies through the provision of fisheries, wood and charcoal – something that man-made coastal defenses cannot do.

Diagram: Mangrove Action Project

Natural disasters are indeed natural. Coastal ecosystems have developed in tandem with the menacing presence of hurricanes and typhoons for eons, and the structure and function of these systems plays a large role in absorbing storm energy and reducing inland damage. However, these important functions are not served when marshes are drained, wetlands developed and mangroves cut down. The role of EbA, therefore, lies at the intersection of mitigating natural disaster risk, and managing and protecting ecosystems. As climate change and coastal development continue, the importance of maintaining and protecting healthy coastal ecosystems will only grow.

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