Drylands occupy 41% of the earth's landmass and are home to more than two billion people—a third of the world population. Most of these people are poor, located at the bottom of the economic pyramid. The nature–society interactional system is among the most vulnerable to the projected increase in frequency of various kinds of extreme weather events. In particular, drylands at middle-high latitudes (such as those in Eurasia) have a harsh environment, coupled with a cold, arid climate. The livelihoods of people inhabiting these areas have long been jeopardised by repeated natural hazards associated with this climate.
Hazards in Mongolia are characterised by the '4Ds': drought, dzud (harsh cold-season conditions), dust storms and desertification that occur interactively (Fig. 1). However, these were not fully integrated into previous efforts to elucidate disaster mechanisms and implement appropriate land management techniques, as these have typically focused only on individual disasters. Against this background, a new project, 'Integrating Dryland Disaster Science' has been implemented for FY 2013–2017 under the Grants-in-Aid for Scientific Research Program supported by the Japan Society for the Promotion of Science.
The project's dual aims are (1) interrelating 4D disasters in dry inland areas of Eurasia in terms of their causal mechanisms (especially drought memory) and the timescales of their occurrence, and (2) developing comprehensive proactive countermeasures and making policy recommendations designed to mitigate multi-disaster impacts.
Fig. 1 4D disasters in arid Eurasia. Photos: dust storm (S. Otani), drought (T. Ito), desertification (N. Yamanaka) and dzud (R. Tsolmon),
The first objective can be achieved by correlating the impacts of extreme weather events producing the 4Ds in terms of the drought memory concept; evaluating risks for each disaster as the product of impact (hazard or forcing); and evaluating vulnerability (expressed through the three elements of exposure, sensitivity and resilience) of the nature-society system (Fig. 2). Assessments of vulnerability should be made using socioeconomic, public health and environmental data. The second objective can be achieved by implementing approaches that integrate the opinions of various stakeholders on countermeasures needed to reduce the vulnerability of both people and the environment to 4D disasters.
In Fig. 5, drought as a hazard (forcing) is linked to other hazards with different timescales by the drought memory mechanism (shown in Fig. 4). Drought is a background factor that influences dust storms and dzuds, and the accumulated effect of multi-year droughts leads to desertification. Its risk (influence) is calculated as the product of hazard and vulnerability of the natural environment-society system. In this conceptual model, each type of hazard is related to specific types of risk. Sporadic and intensive hazards such as dust storms and dzuds are related to economic and/or infrastructural losses and mortality, while drought has a longer timescale and desertification an even longer one, leading to famine and poverty, respectively. The vulnerability of both the natural world and of society is expressed by the three elements: exposure, sensitivity, and resilience in a clockwise sequence of a disaster cycle involving the social and natural domains. Damages caused by disasters provide feedback relating to vulnerability.
Fig. 2 Interrelationships between 4D disasters (dust, dzud, drought and desertification) and the drought memory mechanism
Expected achievements are (1) prediction of 4D disasters based on integrated risk assessment and (2) policy recommendation of proactive disaster management with countermeasure options.
・Shinoda, M.: Land: Proactive Management of Drought and Its Derived Disasters. In R. Shaw and T. Phong eds.: Environment Disaster Linkages. Community, Environment and Disaster Risk Management, Vol. 9, Emerald Publishers, Bingley UK, 61-78, January 2012.
FY2013-2017 and 168,400 Thousand Yen