Disasters // infrastructure protectionWorld Bank: Coastal cities in Asia face devastating floods

Published 12 January 2011

Thirteen of the twenty largest cities in the world are located on the coast, with more than a third of the world’s population living within 100 miles of a shoreline; a World Bank report finds that Asia’s major coastal cities will experience more devastating floods; damage due to flooding could be as high as 6 percent of regional GDP in 2050; developing cities will be most heavily affected; the report urges the threatened cities immediately to begin developing and implementing long-term plans to harden critical infrastructure to withstand and mitigate the effects of increased flooding

A recent report by the World Bank finds that major coastal cities in Asia are unprepared for coming weather trends that will result in more frequent and more extreme floods. These floods will affect far more people and cause even greater economic damage relative to past floods.

Working with the Asia Development Bank and the Japan International Cooperation Agency, the World Bank’s report found that a confluence of factors in Asia’s major coastal cities will result in greater economic damage and human hardship as a result of more frequent extreme weather-induced disasters.

Current climate trends such as accelerated sea level rise, increases in sea surface temperatures, intensification of storms, and extreme waves and storm surges are just some of the threats facing major coastal cities around the world.

These trends are particularly worrisome for disaster planning efforts because a significant percentage of the world’s population lives near the coast – an area highly susceptible to natural disasters like flooding, storms, and tsunamis.

Currently, thirteen of the twenty largest cities in the world are located on the coast, with more than a third of the world’ population living within 100 miles of a shoreline. Rapid urbanization and population growth will dramatically increase the number of people living in vulnerable areas. It is projected that by 2070, nine of the ten most populous cities will be located in Asia in developing countries near coast lines.

In 2009 floods wreaked havoc in Manila and exposed its susceptibility to extreme weather patterns. After tropical storm Ketsana, Manila experienced the heaviest flooding it had seen in nearly 40 years, with flood waters reaching nearly twenty-three feet leaving more than 80 percent of the city underwater. The floods resulted in millions of dollars in economic damage to buildings, housing, and infrastructure and displaced 280,000 to 300,000 people.

Incidents like this were not just isolated to Manila. In 2007 nearly twenty million people were displaced as floods swept across northern India, Bangladesh, and Nepal washing away roads, entire villages, and farm land. Laos, in 2008, experienced record flooding with water reaching as high as forty-five feet above its lowest level in the dry season. Most recently Australia has been hit by devastating floods that may cost more than $5 billion to repair.

Using several climate change models, the report projected by 2050 that these floods would only get worse, causing even more damage and affecting an even wider area.

It is estimated that damage from floods in East Asia would negatively affect regional GDP by as much as 6 percent, cost billions to clean up, and disproportionately affect the urban poor.

The World Bank was troubled by the fact that the increase in exposure to coastal flooding will mostly occur in developing countries in East and South Asia. These developing countries are generally at a disadvantage when it comes to the strength of existing infrastructure, disaster preparedness, and relief efforts.

In Ho Chi Minh City, roughly 26 percent of the population is currently affected by flooding, but that could climb to more than 60 percent in 2050. Additionally, in Manila a worst case scenario flood could damage that would cost nearly 25 percent of the metropolitan area’s GDP.

Despite the clear dangers posed by these natural disasters, these cities have not incorporated appropriate countermeasures into their planning scenarios. The World Bank, in a press release, strongly urged these cities to “take targeted, city-specific and cutting edge approaches to meet these challenges.”

The report recommends a greater focus on environmental implications in urban planning as these cities continue to experience rapid urban growth. In particular, cities should focus on the urban poor as they will be disproportionately affected in addition to constructing more resilient buildings as a significant portion of the cleanup costs will be the result of damage to structures.

The report also recommends that cities begin investing in hard infrastructure interventions as well as “eco-based solutions.” These include the construction of dykes and levees as well as the rehabilitation of mangrove systems and reforestation of upper watersheds.