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Climate change will mean more landslides, experts warn

Almost 100 experts from 14 nations, representing scores of global institutions and governments, gathered at UN University in Tokyo January 18-20 to set international priorities for mitigating human and financial landslide losses and to promote a global network of International Programmes on Landslides.

The meeting marks the first anniversary of the landmark UN World Conference on Disaster Reduction in Kobe, Japan.

Asia suffered 220 landslides in the past century – by far the most of any world region – but those in North, Central and South America have caused the most deaths and injuries (25,000+) while Europe’s are the most expensive – causing average damage of almost $23 million per landslide.

And experts attending the Tokyo conference warned that climate change-related increases in the number and intensity of typhoons and hurricanes will produce in tandem a rising danger of landslides in future.

"Increasing rainfall intensities and frequencies, coupled with population growth can drastically increase landslide-associated casualties, especially in developing countries, where pressure on land resources often lead to slope cultivation and slope agriculture which are very much prone to landslide disasters," according to the International Consortium on Landslides (ICL), United Nations University, Kyoto University and UNESCO scientists organizing the three-day international meeting on landslide prevention and damage mitigation.

Climate change may promote landslides in other ways as well. A December landslide that claimed 60 lives in Yemen was blamed on mountain boulders shifting due to changes in temperature. Other landslide inducements include earthquakes, volcanic eruption, poorly planned developments, and mining.

Among natural disasters, landslides are the seventh ranked killer, after windstorms, floods, droughts, earthquakes, volcano and extreme temperature, claiming 800 to 1,000 lives on average in each of the last 20 years. An average of 940 people annually were killed by landslides in the decade 1993 to 2002, most of those victims from Asia.

Large-scale landslides along coasts or in oceans can cause tsunamis; the deadliest on record was caused by a landslide in the Unzen volcano in 1792 which killed 16,000 Japanese, due to landslide debris and the resulting tsunami. Landslides occurring at the top of a volcano can trigger eruptions, most famously that of the USA’s Mount St. Helens in 1980.

Landslides also threaten some of the world’s most precious cultural sites, including Egypt’s famous Valley of the Kings, home to the Pharaohs Tombs; Lishan China, site of the Huaqing Palace, built in the Tang dynasty (618-907); and Machu Picchu, Peru, the mountaintop fortress city of the ancient Incas.

"While all regions experience landslide disasters, the harm they cause is most acute in developing countries, where the knowledge base required to identify landslide prone areas is often either non-existent or fragmentary," says Badaoui Roubhan, Chief of the UNESCO's Disaster Reduction section.

Experts worry that in many places:

  • Available resources are insufficient to carry out adequate investigations to understand risks and identify hazard zones;
  • There is no strong political commitment for risk reduction measures such as land use planning;
  • Appropriate building codes, safety regulations, and response plans are not developed and applied;
  • Appropriate financial incentives are not utilized; and
  • Expertise in landslide risk reduction is not fostered in local
    institutes and universities.

While the Tokyo conference discussed several strategies to reduce landslide losses “there is no one-size-fits-all strategy,” said UNU Rector Hans van Ginkel. "The question is, short of recommending unrealistic bans on development in areas that could some day be affected, what would best protect people against the high costs of landslide disasters?"

Officials at the meeting formalized an international network of national landslide programmes, its world centre to be headquartered at Kyoto University (at the UNESCO-Kyoto University-International Consortium on Landslides UNITWIN Cooperation Programme), to promote common approaches and share best practices.



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