By Marta Arbinolo and Catherine Gamper, OECD Environment Directorate
Coastal zones have always been one of the most attractive settlement areas because of their access to the ocean, their richness in natural resources, and the high quality of life they offer. As our new policy paper shows, today coastal zones are home to 2.4 billion people, or 40% of the world’s population, with a density three times higher than the global average. Many of the world’s largest cities lie along the coast, including Tokyo, New York and Mumbai.
Coastal zones are also global economic hubs: maritime transport is responsible for 80% of all goods traded globally, and a large share of global tourism flows depends on the coasts. In the United States, for example, 85% of tourism revenues are generated by coastal areas. Coastal zones also harbour some of the world’s richest ecosystems, such as mangroves and coral reefs, which sustain many economic activities and provide natural protection against natural hazards such as storm surges. At the same time, coastal ecosystems, such as mangroves, store up to five times more carbon (per km2) than mainland tropical forests, thus contributing to mitigate climate change.
Rapid socio-economic expansion has had harmful impacts on coastal ecosystems. Water pollution has altered the natural hydrological cycle and undermined ecosystems’ ability to regulate water flows and quality. The overexploitation of natural resources (e.g. sand and gravel) has contributed to rapid coastal degradation and erosion: globally, 25% of shorelines are eroding by half a metre annually and over half of coastal wetlands have been lost since 1990. Coastal groundwater extraction has also facilitated land subsidence, threatening low-lying agglomerations such as Bangkok and New Orleans. In addition, today, over 90% of waste entering the sea remains near the shore. While coastal ecosystem degradation harms coastal communities most directly, global economic activities that depend on the coast are equally at risk.
The high concentration of people, assets, economic activities and ecosystems along the world’s coasts makes them some of the most exposed regions to the impacts of climate change. And while all countries along the sea are set to experience the damaging impacts of climate change, low-lying areas such as river deltas, coastal plains and small island states will be particularly affected. Climate change affects coastal zones in multiple ways:
To respond to the growing and interlinked challenges of climate change and ecosystem degradation along the coast urgent policy is action is needed:
Through the work of the Task Force on Climate Change Adaptation, the OECD will continue to examine the issue of climate risks in coastal zones and how adaptation policies can best address them in the future.
For more information, please visit our website: https://www.oecd.org/environment/cc/climate-adaptation/
OECD (2021), “Adapting to a Changing Climate in the Management of Coastal Zones”, OECD Environment Policy Papers, No. 24, OECD Publishing, Paris, https://doi.org/10.1787/b21083c5-en.
OECD (2019), Responding to Rising Seas: OECD Country Approaches to Tackling Coastal Risks, OECD Publishing, Paris, https://doi.org/10.1787/9789264312487-en.