GeoExtreme module D: Socioeconomic consequences and implications
|Location||International Geological Congress,oslo 2008|
|Author||Aaheim, Asbjّrn; Mestl, Heidi; Sوlen, Hهkon|
|Holding Date||11 October 2008|
This paper addresses the potential increase of damage caused by landslides and avalanches as a result of future climate change. Damages from landslides and avalanches are subject to a broad range of factors, but we concentrate only on two of them. One is the probability of slide events. The other is decision makers’ ability or willingness to take precautionary action in hazardous areas. The purpose is to apply scientifically founded estimates of changes in the probability of slide events to give recommendations for adaptation strategies for national authorities. The potential damage from an increased risk of landslides and avalanches is estimated by combining results from studies of local climate scenarios, relationship between climate indicators and slide events and determination of hazard zones in selected locations in Norway. The distribution of costs is estimated with reference to a mapping of wealth in terms of fixed capital (buildings and constructions) in hazardous areas. Preliminary results indicate that climate change will lead to a significant increase in the expected annual damage caused by landslides and avalanches due to an increase in the number of larger slides.
The estimated costs are zero if there is no fixed capital in hazardous areas. Damages may therefore be fully controlled by human decisions also under a change of hazard, at least in principle. There are, however, severe constraints to the decision making. Fixed capital analyzed in this study is already in place, and it is mainly new developments that can be controlled. Moreover, the decision making process is complex: private agents apply to local authorities for development of a certain area. Local authorities take the final decision, but they act, in principle, on the behalf of national authorities and standards. The interests of local and national authorities are not always coordinated, however. In Norway, local authorities are often unconcious about their economic responsibility in case of landslides, while national authorities have a relatively clear responsibility and have explicit guidelines for what hazard levels to be considered acceptable, but few policy instruments.
The cost of an increase in the landslides and avalanche hazard therefore depend on how responsibilities are distributed among the involved parties. This study looks, in particular, at the added cost of having final decisions about development made by local agents and developers with a highly limited responsibility for damages. Such a system already increases the present day costs of landslides and avalanches in comparison to a situation where public guidelines for risk acceptance were followed. But it also adds to the costs of climate change, in particular in expanding regions with potential landslides and avalanche hazard.