Global projections of drought hazard in a warming climate: a prime for disaster risk management
Clim Dyn
Global projections of drought hazard in a warming climate: a prime for disaster risk management
Hugo Carrão 0
Gustavo Naumann 0
Paulo Barbosa 0
0 European Commission, Joint Research Centre (JRC), Directorate for Space, Security and Migration, Disaster Risk Management Unit , Via E. Fermi 2749, I-21027 Ispra, VA , Italy
1 Paulo Barbosa
Projections of drought hazard (dH) changes have been mapped from five bias-corrected climate models and analyzed at the global level under three representative concentration pathways (RCPs). The motivation for this study is the observation that drought risk is increasing globally and the effective regulation of prevention and adaptation measures depends on dH magnitude and its distribution for the future. Based on the Weighted Anomaly of Standardized Precipitation index, dH changes have been assessed for mid-(2021-2050) and late-century (20712099). With a few exceptions, results show a likely increase in global dH between the historical years (1971-2000) and both future time periods under all RCPs. Notwithstanding this worsening trend, it was found that projections of dH changes for most regions are neither robust nor significant in the near-future. By the end of the century, greater increases are projected for RCPs describing stronger radiative forcing. Under RCP8.5, statistically significant dH Vol.:(011233456789)
Drought hazard; Risk management; Global warming; CMIP5 models; ISI-MIP project; RCP scenarios
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This research received support from the EUROCLIMA regional
cooperation program between the European Union (European
Commission; DG DEVCO) and Latin America. Research by
Gustavo Naumann was funded by the European Union Seventh
Framework Programme FP7/2007-2013 under Grant Agreement
No. 603864 (HELIX: High-End cLimate Impacts and eXtremes).
The authors are grateful to the modeling groups and the CMIP
projects for making the model data available, and acknowledge
the ISI-MIP project for providing the bias-corrected datasets.
changes emerge for global Mediterranean ecosystems and
the Amazon region, which are identified as possible
hotspots for future water security issues. Taken together,
projections of dH changes point towards two dilemmas: (1) in
the near-term, stake-holders are left worrying about
projected increasing dH over large regions, but lack of
actionable model agreement to take effective decisions related
to local prevention and adaptation initiatives; (2) in the
long-term, models demonstrate remarkable agreement, but
stake-holders lack actionable knowledge to manage
potential impacts far distant from actual human-dominated
environments. We conclude that the major challenge for risk
management is not to adapt human populations or their
activities to dH changes, but to progress on global
initiatives that mitigate their impacts in the whole carbon cycle
by late-century.
1 Introduction
Drought is a recurring and extreme climate event that is
originated by a temporary water deficit and may be related
to a lack of precipitation, soil moisture, streamflow, or any
combination of the three taking place at the same time
(Wilhite and Glantz 1985)
. Drought differs from other
hazard types in several ways. First, unlike earthquakes,
floods or tsunamis that occur along generally well-defined
fault lines, river valleys or coastlines, drought can occur
anywhere (with the exception of desert regions where it
does not have meaning)
(Goddard et al. 2003)
. Secondly,
drought develops slowly, resulting from a prolonged period
(from months to years) of water supply conditions that are
below the average, or expected value, at a particular
location
(Dracup et al. 1980)
.
The immediate consequences of short-term droughts (i.e.
a few weeks duration) are, for example, a fall in crop
production, poor pasture growth and a decline in fodder
supplies from crop residues, whereas prolonged water
shortages (e.g. of several months or years duration) may, among
others, lead to a reduction on hydro-electrical production
and an increase of forest fire occurrences
(Mishra and
Singh 2009)
. Because of their long-lasting socioeconomic
impacts, droughts are by far considered the most damaging
of all natural disasters
(Sivakumar et al. 2014)
. Over the
United States, droughts cause $6–8 billion per year
damages on average, but as much as 22 events between 1980
and 2014 resulted in over $200 billion costs (NCDC 2015).
Current estimates by the European Commission
(CEC
2007)
indicate that the damages of droughts in Europe over
the last 30 years are at least €100 billion. On top of that, the
European Environmental Agency
(EEA 2010)
reported that
the annual average economic impact from droughts doubled
between 1976–1990 and 1991–2006, rising to €6.2 billion
per year in the most recent period. In India a drought has
been reported at least once in every 3 years in the last five
decades
(Mishra et al. 2009; UNISDR 2009a)
. Moreover,
the country has suffered a financial loss of a (...truncated)