The 10 Asian cities most threatened by climate change flooding
Climate change will bring flooding to the world’s coasts, and it’s becoming clearer which cities are most threatened.
Cities with the worst exposure to coastal flooding in the coming decades are overwhelmingly located in Asia, according to a comprehensive analysis by leading climate scientists, with port cities in India and China particularly vulnerable.
Researchers at the OECD, climate risk modeling firm RMS and Tyndall Centre for Climate Change Research, among others, cited four major factors creating the threat: the deepening climate emergency, the gradual cave-ins of land, rising populations, and the migration of people from the countryside to urban areas.
The threat comes as the United Nations’ climate panel warns of increasingly extreme weather events, with some of the changes that are already in motion — such as continued sea level rise — thought to be “irreversible” for millennia to come.
U.N. Secretary-General António Guterres described the Intergovernmental Panel on Climate Change’s landmark report as “a code red for humanity.” He added: “There is a clear moral and economic imperative to protect the lives and livelihoods of those on the front lines of the climate crisis.”
Here, CNBC takes a look at the 10 Asian cities most exposed to coastal flooding through to 2070:
The most important port and manufacturing center of northern China, Tianjin straddles the Hai River near an inlet of the Yellow Sea. Much of the city is less than 3.5 meters (12 feet) above sea level, and some less than 2 meters (6 feet). The Hai River acts as a major outlet for the waters of the immense North China Plain, and Tianjin has long had to carefully manage drainage. Tianjin is home to much heavy industry, including iron, steel, shipbuilding and chemicals.
China's most heavily populated city is also one of the world's most important cities. Shanghai is the financial capital of China and the country's most important industrial hub. With more than 27 million people, Shanghai is about two-and-a-half times the size of New York City. It's home to one of the biggest seaports on Earth and is a critical export center. Most of Shanghai juts into the East China Sea on a wedge-shaped peninsula, with the Yangtze River to the north and the bay of Hangzhou to the south. That peninsula is a level plain that averages 3 to 5 meters (10 to 16 feet) above sea level.
Guangzhou is one of China's most important trading cities. In recent years, it has been trying to transform into a tech hub through central planning and the encouragement of start-ups. Guangzhou lies at the head of the massive Pearl River Delta, about 145 km (90 miles) north of the South China Sea. It's one of China's most densely populated cities, drawing migrants from around the country.
Haiphong is located only 16 km (10 miles) from the Gulf of Tonkin on the Red River Delta, and it serves as the port for the Vietnamese capital, Hanoi. Haiphong has become an increasingly important tech and manufacturing center for foreign companies. Domestic companies there make consumer goods, textiles and other products.
Known as Saigon until after the Vietnam War, Ho Chi Minh City is the largest city in Vietnam by population. The city lies about 50 km (31 miles) up the Saigon River from the South China Sea, just north of the agriculturally critical Mekong River Delta. By itself, Ho Chi Minh City accounts for more than a fifth of Vietnam's total GDP.
Bangkok is the capital, biggest city and main port of Thailand. It's also the country's commercial and cultural center. It accounts for a third of the country's manufacturing output, and its financial institutions hold three quarters of Thailand's deposits. Population density is high, with housing dominated by small, detached buildings. The city lies within the Chao Phraya River delta, about 40 km (25 miles) north of the Gulf of Thailand.
Yangon is the largest city in Myanmar and the country's commercial center. It lies along a ridge on the east bank of the Yangon River, surrounded by delta and floodplain. The Andaman Sea is 40 km (25 miles) to the south. Yangon is home to the Shwedagon Pagoda temple complex, revered in the Buddhist faith.
The capital of Bangladesh is also the country's most populous city, home to 21.7 million people. Dhaka lies above the confluence of two major rivers, and its metro area straddles three smaller ones. It's bounded on all sides by a wide, level plain. Dhaka is heavily industrialized, producing chemicals, pharmaceuticals and electronics, as well as traditional textiles and jewelry.
Formerly called Calcutta, India's seventh-largest city is renowned for grand architectural monuments dating to the British colonial era. Kolkata is located on a low bank of the Hooghly River and is fewer than 100 km (62 miles) north of the Bay of Bengal. A third of the city's population lives in groupings of huts called bastis, and Kolkata has a very high population density. A major industry is the processing of jute for textiles.
Mumbai is India's biggest city and one of the world's largest and most densely populated urban areas — roughly 32,300 people per square mile. It also is India's financial capital and main commercial center, making it economically one of the most important cities in the world. It lies on a peninsula that was created by drainage and reclamation work that linked a scattering of once-separate islands.
This interactive graphic is based on the results of a global screening study citing the exposure of the world’s largest port cities to coastal flooding.
Lead authors of the study, first published in 2007, told CNBC in August that the assessment remains the clearest listing of port cities at risk.
The analysis was based on the exposure of population and economic assets in cities to a 1-in-100-year, surge-induced flood event, assuming no defenses.
It assessed 136 port cities worldwide that have more than 1 million inhabitants and ranked them in terms of population exposed to coastal flooding in the 2070s, including both climate change and socioeconomic change, and reflected present-day exposure.
Writers: Ted Kemp and Sam Meredith
Editors: Matt Clinch and Ted Kemp
Design and code: Bryn Bache
Images: Getty Images
Data sources: OECD Ranking of the World's Cities Most Exposed to Coastal Flooding Today and in the Future, World Population Review, Our world in Data and www.citypopulation.de.