|
A WWF report lists 11 major Asian cities most vulnerable to climate change and says the impacts are already being seen and felt. Action must be taken now to mitigate the effects on the large populations of these cities
With their large populations, Asian cities need particular attention when the impacts of climate change are considered. A recently released World Wide Fund for Nature (WWF) report ‘Mega-Stress for Mega-Cities: A Climate Vulnerability Ranking of Major Coastal Cities in Asia’, focuses on 11 key Asian cities most likely to be affected by climate change. These are Dhaka (Bangladesh), Jakarta (Indonesia), Manila (Philippines), Kolkata (India), Phnom Penh (Cambodia), Ho Chi Minh (Viet Nam), Shanghai (China), Bangkok (Thailand), Hong Kong (China), Kuala Lumpur (Malaysia), and Singapore. The report lists Dhaka in Bangladesh as the most vulnerable to climate change impacts. It is a large but relatively poor city and is located just metres above current sea levels. It is regularly impacted by tropical cyclones and flooding and has very limited adaptive capacity. Jakarta and Manila are also extremely vulnerable cities and tie for second rank, largely because of their size, degree of exposure (both experience frequent flooding), and relatively low adaptive capacity. Kolkata and Phnom Penh tie for third most vulnerable city, largely because Kolkata is prone to saltwater intrusion and the effects of sea level rise, while Phnom Penh has very low adaptive capacity. Each city is given a score card that lists particular vulnerabilities: to environmental exposure (storm threat, sea level rise, flooding/drought), socio-economic sensitivity (population, assets threatened) and inverse adaptive capacity, that is, its inability to adapt. Some cities score high on environmental exposure -- Manila, for example, tops the list as it is extremely prone to flooding. During tropical storm Ketsana, floodwaters reached nearly 7 metres and hundreds of deaths occurred. Dhaka, Ho Chi Minh City, and Shanghai are also vulnerable in this respect says the report. Though Hong Kong ranks third highest in terms of exposure to climate change impacts, it has relatively high adaptive capacity and therefore is less vulnerable overall. Adaptive capacity was arrived at by examining the overall willingness of the city to implement adaptation strategies (calculated by the number of available adaptation examples and/or responses to previous impacts) and per capita GDP. Dhaka and Phnom Penh top the rankings as having the lowest adaptive capacity to climate change. This is not a surprise as both countries, Bangladesh and Cambodia, are classified as ‘least developed countries’ by the United Nations, says the report. Kolkata, Jakarta and Manila have the second lowest adaptive capacity; Bangkok is next, with Kuala Lumpur and Ho Chi Minh following. Shanghai has the second highest adaptive capacity; Hong Kong and Singapore tie for highest capacity. Kolkata has a high overall vulnerability score of 7/10. On environmental exposure it scores 6, with the threat from sea level rise being a dangerous 8 and flooding/drought being 7. Its ability to adapt is also rated as low. Being situated on the banks of the Hooghly river, and within the Ganges delta, Kolkata is vulnerable because it is only metres above current sea levels. As it expanded, it reclaimed significant amounts of surrounding wetland. Consequently, the city sits on alluvial deposits and within a considerable seismic zone. It is thus prone to earthquakes. The report says Kolkata has seen an increase in temperature of around 0.68°C over the last century. Annual mean temperatures are higher after the monsoon season and during winter. Increases in sea level accompanied by ground subsidence are the biggest threat to the city, says the report. ‘In fact, a 1 metre rise in sea level could potentially inundate 5,763 km in India. In addition to sea level rise, a ground subsidence of 0.6 to 1.9 mm per year is adding to the risk in the Ganges delta. Due to the combined effects of sea level rise and subsidence, the Ganges delta will likely see saltwater intrude 100 km from the coast, greatly impacting groundwater supplies,’ the report says. Compounding the effects of saltwater intrusion, over-exploitation of groundwater in and around Kolkata has led to a drop in its level, leading to further intrusion of seawater, thus making the sub-surface groundwater saline. Droughts have been more frequent in the last few decades and are projected to get worse, which will lead to even more saltwater intrusion and thus deteriorate surface and groundwater quality. In fact, India may reach a state of severe water shortage and stress before 2025 when the water availability per capita is projected to drop below 1,000 metres per year, compared to the level in 2001 of 1,820 metres per year. The report suggests adaptation solutions for the affected cities. Manila, for example, which is at high risk of tropical storms, floods, drought, and sea level rise, needs early warning systems to alert residents of approaching tropical cyclones, appropriate infrastructure to better protect citizens and allow for massive evacuations if necessary, weather prediction and hazard warning systems, etc. Dhaka, which is both low-lying and subject to violent storms, needs to stop building on its waterbodies and wetlands and manage its water resources better. For Kolkata too, better water management is crucial to minimise the effects of salinity and over-extraction of groundwater. The city needs increased protection, enforcement and restoration of mangroves and wetlands to limit the impact of saltwater intrusion and storm surges. These are relatively low-cost but effective strategies, the report points out. Read the full report here: http://assets.panda.org/downloads/mega_cities_report.pdf Infochange News & Features, November 2009
|
