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Shoreline Surety
Coastal Development Under Scrutiny
July, 2009
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URBAN DWELLERS CONCENTRATED IN THREATENED ZONES
LECZ – low elevation coastal zones – is an acronym we will see more and more. LECZ, which are areas less than 10 metres or 33 feet above sea level, constitute only 2% of the earth’s land area, but are home to 10% of the global population and 13% of urban dwellers. Every global region is threatened, but the highest numbers of threatened urbanites are in Asia, Oceania, the Middle East and North Africa.
Coastal flooding threatens some large cities and will become more dangerous as sea levels rise. Salinity may also penetrate the water table and make water undrinkable. However, coastal cities are not the only ones with freshwater problems: supplies are inadequate in one major market after another from Las Vegas to New Delhi.
Apart from Venice’s periodic aqua alta, one of the most extreme examples is the tiny Micronesia nation of Kiribati, which is severely threatened by the rising Pacific Ocean. As salt gradually pollutes the groundwater, islands become uninhabitable long before they are submerged. Over time Kiribati’s population is being restricted to fewer and fewer islands.
Numerically, Asia’s population is at greatest risk with more than 250 million people living in LECZ urban areas, some of which are growing rapidly. One of the most vulnerable is Dhaka, the capital of Bangladesh, where the population of 13.5 million is expected to reach at least 22 million by 2025. Dhaka’s elevation ranges from 2 to 13 metres above seal level. Almost 60% of the city’s extremely dense slums have poor or no drainage and are already susceptible to frequent flooding.
Source: Global Demographics 2009, the Urban Land Institute.
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Changing climatic conditions pose an unprecedented threat to coastlines. Sea level rise, temperature increases, changes in precipitation patterns and other climate-related changes are expected to occur and to become increasingly severe over the coming decades.
As coastal developing is intensifying, so are coastal property losses. The higher wind speeds, storm surge, flooding and erosion hazards intrinsic to coastal regions increase the likelihood of property damage, degradation of coastal ecosystems and subsequent social costs.
Reducing the physical and economic risks associated with coastal hazards is not only critical, but also cost-effective. An analysis from the US National Institute for Building Safety concluded that investments made to minimize the impact from earthquakes, flood and wind yielded $4 of benefit for $1 spent.
Priority must be placed on providing local governments with the predictive capacities and other tools they need to adapt land use and infrastructure for an uncertain future. The need to adapt is also an opportunity to restore coastal ecosystems, which are a critical complement to defensive infrastructure. The Resilient Coast Blueprint is envisioned as a first step toward reconciling the ecological, social and economic health of coasts.
RISK ASSESSMENT
Calculating future risks based on forecasts of climate change are fraught with uncertainties that make effective adaptation planning difficult. A critical step toward better quantifying future change is to advance scientific understanding and develop the methodologies necessary to refine forecasts and make them useful for adaptation purposes.
Current estimates of sea level rise have uncertainties both in terms of timing and extent. This could delay implementation of adaptation plans or lead planners to address only the higher-probability, lower-impact scenarios. Improving technologies and methodologies to reduce uncertainty would prove invaluable.
In the case of sea level rise, as one example, the relationship between rising temperatures and ice sheet breakdown must be better understood. Current flood, shoreline and inundation maps used for land use and infrastructure planning and mortgage due diligence do not accurately reflect current risks, let alone future risks, posing significant challenges for adaptation. In the case of sea level rise, the development and dissemination of high-definition, digital flood and coastal maps, based on assessment of data from LIDAR (a light detection and ranging remote sensing system used to collect topographic data) surveys and other data gathering techniques is essential.
These maps should be created to include a variety of scenarios for potential future sea level increases. There is also strong need for climate change models and other tools that enable improved predictions of future coastal storms, and that clearly describe the uncertainties of those predictions.
PLANNING AND BUILDING STANDARDS
During the land use planning process, government entities should consider climate related risks including the likelihood and extent of climate change related hazards, and identify actions to protect or adapt in specific geographic locations. In especially vulnerable coast areas, government entities might designate no-build and no-rebuild zones similar to floodway zones in riverine areas and/or provide private property owners with incentives to relinquish property or development rights in these areas through land exchanges, land banks and the transfer or trading of development rights.
Construction, retrofit and operational standards for new and existing public and private infrastructure should be routinely assessed and modified. New approaches to infrastructure might be considered, such as decentralized energy and water treatment systems that would be less susceptible to catastrophic loss or disruption than the traditional centralized systems.
The risk mitigation strategy should recognize the enormous protective value of ecosystems and other natural infrastructure such as coastal wetlands, barrier islands, trees, mangroves and other vegetation. This natural infrastructure is essential to society’s efforts to address climate change and these systems must be included as part of any adaptation strategy.
Public and private entities should protect and restore these natural features to mitigate threats to built and natural systems. For example, government entities can establish incentives and/or regulations to make ecosystem preservation and enhancement part of adaptation funding, risk-based land use planning and post-disaster rebuilding.
Adaptation plans must be flexible and amendable to incorporate higher levels of climate change protection as required. For example, a bridge built to function under five-foot storm surge conditions might be designed so it could be modified should higher levels actually occur.
DILIGENCE
While not every risk is insurable regardless of the price, a resiliency strategy must recognize insurance as an indispensible tool and maximize its effectiveness. Insurance cannot play its role if land use regulations, building codes and physical protection are not sufficiently robust. In turn, the insurance industry must give appropriate consideration and weight to the demonstrable reduction in risk provided by improved building standards and other risk mitigation efforts.
A stable private insurance market should provide the right price signals and incentives for risk mitigation. As the risk to property grows because of location and other climate related factors, the associated insurance premiums will increase because of the greater likelihood of damage, providing an incentive to build in less risky areas and/or build or retrofit properties to higher standards.
Wise investing will involve asset managers understanding the impacts of climate change on their investments and managing that risk, especially in real estate, infrastructure and other financial instruments. Responsible banks will need to understand the levels of exposure with their investment and lending portfolios by incorporating climate risks into their due diligence.
The preceding article is excerpted from Resilient Coasts: A Blueprint for Action, a joint report of the Heinz Center (see www.heinzctr.org) and Ceres (see www.ceres.org.) |
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