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3 ObservedandProjected Impacts fromExtremeWeatherEvents… 71
In sum,while increasing trends are found for losses frompast extremeweather
events, increasing exposure has been the main driver, and climate change (both
anthropogenic climate change aswell as natural climate variability) could have an
additional role, but this role was not substantiated. The confidence of the role of
anthropogenicclimatechangeasdriver in theupward trend indisaster loses ishow-
ever low. Results from these previous reviews, as well as more recent studies on
disaster loss databases, are displayed inTable 3.2. In total 34 studies are included.
Mostof thesestudieshaveanalysedmonetised losses fromextremeweatherevents,
although in some cases the losses concern quantified impacts, such as volume of
damaged timber wood. Andmost studies account for increasing exposure, using
eitherdataonexposedcapital assets, population,wealth indicators, andan inflation
correction.
While this overview is perhaps neither exhaustive nor complete, it provides a
comprehensiveoverviewofscientificstudiesonimpactsfrommajorextremeweather
types,suchastropicalandextra-tropicalcyclones,rainfallflooding,hailstorms,wild-
firesandconvectiveweathertypes.Whilecoastalfloodingisoftenincludedintropical
cyclone losses, drought events areunderrepresented in these studies.A fewstudies
detect trendsat the regionalornational level, theoverall conclusion is thatvery few
upward trendsare found, afternormalising for changes inexposure.
Thereareseveral issuesrelatedtothenormalisationapproach,aswellastheinter-
pretationofnormalised losses.Firstofall, thegeneralassumption is that thechange
in themajor driver of losses, that is increasing exposure of assets, has a propor-
tional(linear)relationwiththelosses(e.g.PielkeandLandsea1998;Bouwer2011a;
Handmeret al. 2012).Butalternativeapproaches suchas fromEstradaet al. (2015)
show that alternative formulations of statisticalmodelswith explanatory variables
may lead to different trends in losses, such as forUShurricanes. Such approaches
arehowevernotyetconclusive,andneedfurtherconfirmationinconsecutivestudies
(Hallegatte2015).
Inaddition, theinterpretationofthenormalisedrecordisalsonotstraightforward.
As Visser et al. (2014) and Visser and Petersen (2012) show, different statistical
methodsfortrenddetectionmayleadtodifferentinterpretationofupward,downward
or no trends found in the normalised loss records of extremeweather events. And
howfluctuations in the normalised loss-record are interpreted, possibly related to
natural climatevariability, is anothermatterofdiscussion.
What is clear from the normalisation studies listed here (Table 3.2) is thatmost
donotfindan increasing trend in losses, after the recordshavebeennormalised for
increasingexposure.This implies that themaindriver of theobserved losses likely
has been an increasing number of population and assets, and not a change in the
hazardfrequencyorseverity.Afewstudieshoweverdofindincreases in losses,also
afternormalisation.Theseincludemostnotablyconvectiveweatherevents,including
thunderstorms and hailstorms, where three studies find increasing trends for over
several decades.With increasing temperatures, there is a possibility that extremes
related to convectiveweather couldbecomemore frequent.However, IPCC(2012)
Loss and Damage from Climate Change
Concepts, Methods and Policy Options
- Title
- Loss and Damage from Climate Change
- Subtitle
- Concepts, Methods and Policy Options
- Authors
- Reinhard Mechler
- Laurens M. Bouwer
- Thomas Schinko
- Swenja Surminski
- JoAnne Linnerooth-Bayer
- Publisher
- Springer Open
- Date
- 2019
- Language
- English
- License
- CC BY 4.0
- ISBN
- 978-3-319-72026-5
- Size
- 16.0 x 24.0 cm
- Pages
- 580
- Keywords
- Environment, Climate change, Environmental law, Environmental policy, Risk management
- Categories
- International
- Naturwissenschaften Umwelt und Klima