This article reviews recent literature on drought of the last millennium, followed by an update on global aridity changes from 1950 to 2008. Projected future aridity is presented based on recent studies and our analysis of model simulations. Dry periods lasting for years to decades have occurred many times during the last millennium over, for example, North America, West Africa, and East Asia. These droughts were likely triggered by anomalous tropical sea surface temperatures (SSTs), with La Ni˜ na-like SST anomalies leading to drought in North America, and El-Ni˜ no-like SSTs causing drought in East China. Over Africa, the southward shift of the warmest SSTs in the Atlantic and warming in the Indian Ocean are responsible for the recent Sahel droughts. Local feedbacks may enhance and prolong drought. Global aridity has increased substantially since the 1970s due to recent drying over Africa, southern Europe, East and South Asia, and eastern Australia. Although El Ni˜ no-Southern Oscillation (ENSO), tropical Atlantic SSTs, and Asian monsoons have played a large role in the recent drying, recent warming has increased atmospheric moisture demand and likely altered atmospheric circulation patterns, both contributing to the drying. Climate models project increased aridity in the 21 st century over most of Africa, southern Europe and the Middle East, most of the Americas, Australia, and Southeast Asia. Regions like the United States have avoided prolonged droughts during the last 50 years due to natural climate variations, but might see persistent droughts in the next 20–50 years. Future efforts to predict drought will depend on models’ ability to predict tropical SSTs. 2010 JohnWiley &Sons,Ltd.WIREs Clim Change2010 DOI:10.1002/wcc.81

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Drought under global warming: a review

This paper presents a formal probabilistic framework for seismic design and assessment of structures and its application to steel moment-resisting frame buildings. This is the probabilistic basis for the 2000 SAC Federal Emergency Management Agency ~FEMA! steel moment frame guidelines. The framework is based on realizing a performance objective expressed as the probability of exceeding a specified performance level. Performance levels are quantified as expressions relating generic structural variables ''demand'' and ''capacity'' that are described by nonlinear, dynamic displacements of the structure. Common probabilistic analysis tools are used to convolve both the randomness and uncertainty characteristics of ground motion intensity, structural ''demand,'' and structural system ''capacity'' in order to derive an expression for the probability of achieving the specified performance level. Stemming from this probabilistic framework, a safety-checking format of the conventional ''load and resistance factor'' kind is developed with load and resistance terms being replaced by the more generic terms ''demand'' and ''capacity,'' respectively. This framework also allows for a format based on quantitative confidence statements regarding the likelihood of the performance objective being met. This format has been adopted in the SAC/FEMA guidelines.

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Probabilistic Basis for 2000 SAC Federal Emergency Management Agency Steel Moment Frame Guidelines

Cities are complex and interdependent systems, extremely vulnerable to threats from both natural hazards and terrorism. This paper proposes a comprehensive strategy of urban hazard mitigation aimed at the creation of resilient cities, able to withstand both types of threats. The paper reviews hazard mitigation practice, defines a resilient city, considers the relationship between resilience and terrorism, and discusses why resilience is important and how to apply its principles to physical and social elements of cities. Contending that current hazard mitigation policy, practice, and knowledge fail to deal with the unique aspects of cities under stress, the paper recommends a major resilient cities initiative, including expanded urban systems research, education and training, and increased collaboration among professional groups involved in city building and hazard mitigation.

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Urban Hazard Mitigation: Creating Resilient Cities

Collaboration is a necessary foundation for dealing with both natural and technological hazards and disasters and the consequences of terrorism. This analysis describes the structure of the American emergency management system, the charts development of the Federal Emergency Management Agency, and identifies conflicts arising from the creation of the Department of Homeland Security and the attempt to impose a command and control system on a very collaborative organizational culture in a very collaborative sociopolitical and legal context. The importance of collaboration is stressed, and recommendations are offered on how to improve the amount and value of collaborative activities. New leadership strategies are recommended that derive their power from effective strategies and the transformational power of a compelling vision, rather than from hierarchy, rank, or standard operating procedures.

Collaboration and Leadership for Effective Emergency Management

Social vulnerability refers to the socioeconomic and demographic factors that affect the resilience of communities. Studies have shown that in disaster events the socially vulnerable are more likely to be adversely affected, i.e. they are less likely to recover and more likely to die. Effectively addressing social vulnerability decreases both human suffering and the economic loss related to providing social services and public assistance after a disaster. This paper describes the development of a social vulnerability index (SVI), from 15 census variables at the census tract level, for use in emergency management. It also examines the potential value of the SVI by exploring the impact of Hurricane Katrina on local populations.

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A Social Vulnerability Index for Disaster Management

The Federal Emergency Management Agency (FEMA) assists states and localities overwhelmed by, or at risk from, disasters. FEMA also co-ordinates emergency management activities and planning for the continuity of government should national security be threatened. Since 1979 FEMA has administered a range of authorities that enable the agency to serve as the primary source of federal, technical, and financial assistance for emergency management. Among the types of aid provided through FEMA programs are grants and material to help disaster victims meet pressing needs such as food and shelter, education and training programs to improve the response capabilities of non-federal officials, and mobile communications equipment. FEMA exercises little regulatory authority, but directives that underlie the agency's mission authorise the agency to establish standards for reconstruction of buildings after a disaster declaration is issued, for the construction of federal buildings in earthquake-prone areas, and for the operation of first responder equipment. FEMA has responded to, and has helped communities prepare for, terrorist attacks in the United States. The Office of Homeland Security (OHS), established by President Bush subsequent to the attacks in 2001, has a similar, but more encompassing, mission related to disasters caused by terrorist actions. Congressional debate on the contours and framework for federal administration of homeland security might include consideration of FEMA's mission, the extent to which that mission overlaps with the assignments given the new OHS, and a new structure or set of authorities for that agency.

C. V. Anderson

Papers

The Federal Emergency Management Agency (FEMA)