Global projections of drought hazard in a warming climate: a prime for disaster risk management

Climate Dynamics, Jun 2017

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 (2071–2099). 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 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.

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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 - 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)


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Hugo Carrão, Gustavo Naumann, Paulo Barbosa. Global projections of drought hazard in a warming climate: a prime for disaster risk management, Climate Dynamics, 2017, pp. 2137-2155, Volume 50, Issue 5-6, DOI: 10.1007/s00382-017-3740-8