Munich Re: Climate change effects increasingly influencing US thunderstorm losses
Changing climatic conditions are having a considerable influence on the increase in severe thunderstorm losses in the USA. This correlationship is documented by a scientific study covering the period from 1970 to 2009 and produced in connection with a cooperation project between Munich Re and the German Aerospace Center (DLR).
Munich. In 2011, the current record year,
severe thunderstorms caused US$ 47bn in economic losses in the USA,
i.e. about as much as a medium hurricane. From the long-term
perspective also, on average severe US thunderstorm losses
increased significantly from the end of the 1980s in particular,
and the fluctuations between the years were more extreme.
In this respect, this peer-reviewed study examines hail, tornado,
thundersquall and heavy rainfall losses in the USA. The result of
the study is that, after adjusting the losses to take account of
socio-economic changes, increases still remain which cannot
therefore be explained by changes in exposed values. They are,
however, correlated with the increase in meteorological potential
for severe thunderstorms and its variability revealed by the study.
It has thus been possible for the first time to scientifically
prove that climatic changes have already influenced US thunderstorm
losses.
Eberhard Faust from Munich Re's Geo Risks Research and a co-author
of the study: "It is therefore clear that the change in losses
during the period in question is largely driven by changes in
climatological boundary conditions. "In particular, the potential
energy required in the atmosphere for the formation of severe
thunderstorms has increased in the course of time".
The study was not able to conclusively differentiate in the
climatological forcing of loss changes between the natural and the
man-made components of climate change. But the results are
consistent with the anticipated effects of anthropogenic climate
change.
Dr. Peter Röder, member of Munich Re's
Board of Management: "This scientific study shows, on the one hand,
that some regions already need to adapt to changing weather risks.
This concerns the insurance industry as risk carrier, first and
foremost, but also those in the private and public spheres
responsible for deciding on prevention measures".
The study examines events with losses exceeding US$ 250m in the
period 1970–2009, past losses being
extrapolated to current socio-economic conditions using a
normalisation technique. These losses account for some 80% of all
severe thunderstorm losses in the USA to the east of the Rocky
Mountains. Using this technique, the distorting effect of small
losses, the reporting of which is improving in the course of time,
is eliminated.