Global experts discuss drought risk

A symposium was held in Oxford on 22 September, bringing together global experts on the causes and impacts of droughts. The speakers shared experience and expertise from Australia, America, Europe and the UK, providing interdisciplinary insights into the climatic and socio-economic factors that contribute to drought.

“If you do what you’ve always done, you’ll get what you’ve always got!” said Professor Donald Wilhite, University of Nebraska, stressing the need to change the way droughts are managed. Although drought is a normal part of climate variability, unprepared governments and vulnerable societies often react to droughts with shock and alarm. Professor Wilhite proposed that droughts can act as a window of opportunity to change from post-impact crisis response to a pre-impact drought risk management approach. The cost of preparedness action against drought is insignificant when compared to the cost of inaction, he said.

The speakers at the symposium are members of the International Advisory Board of the Oxford-led MaRIUS project on drought and water scarcity in the UK. Oxford University’s Professor Jim Hall presented the project which was launched earlier this year and adopts a risk-based approach to understanding droughts and water scarcity; analyses the impacts on people, the environment and the economy; and will develop methods to support decision-making and improve drought risk management.

Dr Henny van Lanen from Wageningen University in the Netherlands said that there is medium confidence that droughts will intensify in the 21st Century in some areas and during some seasons in southern and central Europe, central North America, Central America and Mexico, northeast Brazil and southern Africa. Elsewhere in the world inconsistencies in models make it difficult to draw any firm conclusions. The ability of scientists to identify future drought trends is constrained by available data, various definitions of droughts, different ways to quantify or identify a drought, and the inability of models to include all the factors that influence a drought.

Climate change poses a challenge to water planners, as drought risks in the future may be greater than in the past. Professor Casey Brown, University of Massachusetts, argued that the best approach to address these uncertainties is to focus on understanding the project and its vulnerabilities to climate change. By identifying the key climate variables to which the system is sensitive and the magnitude of climate changes that cause unacceptable outcomes, a water planner can incorporate the desired or acceptable level of resilience into the project.

Drawing on research in the Shale Hills / Susquehanna wetland catchments in northeastern United States, Professor Christopher Duffy from Penn State University presented a methodology for assessing the vulnerability of wetlands to climate change and droughts. Early results show that upland catchments are the most vulnerable based on depth to groundwater which acts as a buffer during periods of low rainfall.

Professor Lucia De Stefano stressed that stakeholder input is essential for understanding vulnerability and response to drought. Her research in Spain and on a pan-European scale found that there are inconsistencies in drought perceptions across scales and that improving communication could benefit drought management and address mismatches between policy objectives and implemented measures.

Dr Narendra Kumar Tuteja from the Australian Bureau of Meteorology shared experiences from Australia, a country that has faced around eight major drought events in the last century, with the Millennium drought (1997-2009) radically influencing national water reform. He talked about the need for water availability forecasts at a range of time scales for operational water planning and management, and the challenges in generating these. He underscored the importance of continued and extensive consultation with stakeholders and users in order to deliver useful research, data or tools.