[PHOTO -Manila, like most of the world's large cities, suffers from a huge and problematic urban sprawl.]

MANILA, AUGUST 11, 2012 (PHILSTAR) A unit of the United Nations has warned that rapid and unplanned urban expansion exposes cities to severe flooding and other disasters.

"As the urban sprawl of rapid urbanization expands outwards and upwards, it prvides ready opportunities for hazards such as floods, storms and earthquakes to wreak havoc. Half the world's population now lives in urban areas, and that figure is estimated to rise 70 percent by 2050. That's a lot of vulnerable and exposed people given that urban floods will represent the lion's share of total flood impact because of infrastructure, institutions and processes that are not yet up to the task ahead," said Margareta Wahlström, chief of the UN Office for Disaster Risk Reduction (UNISDR).

She said governments, countries and communities should be alarmed by the increasing flood risk and frequency of massive flooding and that measures to address them are ineffective.

The Philippines has seen three recent catastrophic floods - first in 2009 when tropical storm Ondoy dumped half a month's rain fell on Metro Manila in 24 hours; typhoon Sendong which led to floods that killed more than 400 people in Mindanao; and the recent monsoon rains that caused landslides and deep floods in many parts of Luzon.

UNISDR noted that Metro Manila's population includes millions of informal settlers, who were forced to flee the huge shantytowns lining rivers and sewers following relentless rains that began Monday night.

Citing statistics from the Emergency Events Database (EM-DAT) of the Centre for Research on the Epidemiology of Disaster, USIDR added that the Philippines suffered economic losses worth $730 million, affected 11.6 million people and claimed 1,904 lives in 2011.

Wahlström's observations find resonance in a new report just out by the World Bank and the Global Facility for Disaster Risk Reduction, Cities and Flooding -- A Guide to Integrated Urban Flood Risk Management for the 21st Century, which states that "poorly planned and managed urbanization contributes to the growing flood hazard due to unsuitable land use change. As cities and towns swell and grow outwards to accommodate population increase, large-scale urban expansion often occurs in the form of unplanned development in floodplains, in coastal and inland areas, as well as in other flood prone areas."

Besides the Philippines, the UN unit also said destructive floods have occurred over the past 18 months in Pakistan, Australia, Brazil, Japan, South Africa. Sri Lanka, Thailand and the US. In Thailand, the Bangkok floods caused $40 billiion in economic losses.

"What's happening in Asia is alerting us about what is going to happen more regularly everywhere in the world. The new climate situation requires more disaster risk reduction investments in urban planning as unplanned urbanization is increasing flood impacts, "Wahlström said.

She said governments must ensure that new investments would address these problems.

"Economic and human losses as well as the disruptions to economies are increasing rapidly and substantially. Surely, this should be unacceptable to all concerned? There must be an all out push for to increase knowledge and expertise that will enable countries of and communities to build more robust urban evironments," said Wahlström.

The UNISDR has launched the World Disaster Reduction Campaign - Making Cities Resilient, which calls for substantial investrments by both national and local governments in disaster rick reduction if cities are to better adapt to climate variability. The project sees the intergration of disaster risk reduction in all urban planning as a critical component of reilience building.

Chief News Editor: Sol Jose Vanzi

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