A UN report launched here on Thursday says few of the world's coastal cities will be spared by climate change.

In the 20th century, sea levels rose by an estimated 17 centimeters, and global mean projections for sea level rise between 1990 and 2080 range from 22 centimeters to 34 centimeters. The low elevation coastal zone -- the continuous area along coastlines that is less than 10 meters above sea level -- represents 2 percent of the world's land area but contains 10 percent of its total population and 13 percent of its urban population, says the report "State of the World's Cities 2008/9: Harmonious Cities" launched by the United Nations Human Settlements Program (UN-HABITAT) after analyzing urban inequalities in 28 developing countries.

But at a time when over 50 percent of the world's population lives in urban areas, the report sets out to determine which cities are in danger and which communities might well be drowned out.

There are 3,351 cities in the low elevation coastal zones around the world. Of these cities, 64 percent are in developing regions; Asia alone accounts for more than half of the most vulnerable cities, followed by Latin America and the Caribbean (27 percent) and Africa (15 percent). Two-thirds of these cities are in Europe; almost one-fifth of all cities in North America are in low elevation coastal zones, according to the report which UN- HABITAT publishes every two years.

Aimed at policy makers and planners, the new UN report warns that few coastal cities will be spared.

In the developed world, 35 of the 40 largest cities are either coastal or situated along a river bank. In Europe, rivers have played a more important role in determining the growth and importance of a city than the sea; more than half of the 20 largest cities in the region developed along river banks.

Quoting a report by Organization for Economic Cooperation and Development, the authors note that the populations of cities like Mumbai, Shanghai, Miami, New York City, Alexandria, and New Orleans will be most exposed to surge-induced flooding in the event of sea level rise.

In Asia, 18 of the region's 20 largest cities are either coastal, on a river bank or in a delta. Some 17 percent of the total urban population in Asia lives in the low elevation coastal zone, while in South-Eastern Asia, more than one-third of the urban population lives there. Japan, with less than 10 percent of its cities in low elevation zones, has an urban population of 27 million inhabitants at risk, more than the urban population at risk in North America, Australia and New Zealand combined.

The report points out that by 2070, urban populations in cities in river deltas, which already experience high risk of flooding, such as Dhaka, Kolkata, Rangoon, and Hai Phong, will join the group of most exposed populations. Also, port cities in Bangladesh, China, Thailand, Vietnam, and India will have joined the ranks of cities whose assets are most exposed.

Major coastal African cities that could be severely be affected by the impact of rising sea levels include Abidjan, Accra, Alexandria, Algiers, Cape Town, Casablanca, Dakar, Dar es Salaam, Djibouti, Durban, Freetown, Lagos, Libreville, Lome, Luanda, Maputo, Mombasa, Port Louis, and Tunis.

An assessment of the vulnerability of Alexandria, the most important economic and historic center along the Mediterranean coast suggests that, with a sea-level rise of 50 cm, more than 2 million people would have to abandon their homes, 214,000 jobs would be lost, and the cost in lost property value and tourism income would be over 35 billion U.S. dollars, which does not include the immeasurable loss of world famous historic, cultural and archaeological sites.

In her foreword to the report, Anna Tibaijuka, Executive Director of UNHABITAT, calls on cities and national governments to address these challenges and opportunities by adopting innovative approaches to urban planning and management that are inclusive, pro-poor and responsive to threats posed by environmental degradation and global warming.

"From China to Colombia, and everywhere in between, national and local governments are making critical choices that promote equity and sustainability in cities. These governments recognize that cities are not just part of the problem; they are, and must be, part of the solution," she added.

(Xinhua News Agency October 24, 2008)