Droughts in the Anthropocene

United Kingdom – Understanding the complexities of drought

While the UK is generally regarded as a wet country, some parts are dry, experience intensive water exploitation and can already be considered water stressed. The continuing vulnerability of the UK to drought has been demonstrated in recent years. In 2012, the country was hit by a serious drought amounting to the driest spring in over a century, following two dry winters [1]. Again, in summer 2018, parts of England and Wales hardly experienced rain for months and between May 2018 and April 2019, most areas of the country received below-average rainfall [2]. Shifting rainfall frequency and rainfall patterns, along with the effects of climate change, have made it difficult to accurately predict the occurrence, duration and intensity of drought events, as well as to minimize their impacts [3]. Increasing demand and over- abstraction of water to meet the needs of industry, agriculture and a growing population put even more pressure on freshwater resources, posing a serious challenge for water management. Traditionally, the meteorological and societal causes of drought and water shortages were considered in isolation in the UK. However, recent drought events have made their interconnectedness highly visible and widely acknowledged in the UK [4]. Taking this into account, researchers have called for a more integrated approach to understanding the multifaceted nature of water shortages and how to predict, prepare for and mitigate the effects. The UK Droughts &Water Scarcity research programme, a five-year interdisciplinary programme, was launched in 2014 [3]. It includes a number of partners from research institutions across the UK, with the aim of supporting improved decision- making in relation to droughts and water scarcity by providing research that identifies, predicts and responds to the interrelationships between

multiple drivers and impacts. The programme is divided into four projects – Historic Droughts, IMPETUS, MaRIUS and DRY – and a knowledge exchange follow-on called ENDOWS. Together, the distinctive project has set out to address three major scientific goals: (1) Characterize the drivers and nature of droughts and water scarcity; (2) Examine the multiple and inter-linked impacts of UK droughts and water scarcity on the environment, agriculture, infrastructure, society and culture and the trade-offs between them; (3) Develop methods to support decision-making for drought and water scarcity planning and management, and to assess opportunities to reduce their occurrence and severity [3]. One of the key characteristics of the droughts programme has been its emphasis on supporting decision-making through co-development of research outputs with stakeholders engaged in UK drought management. This has led to a number of key transformations in UK drought and water resources management. One important outcome of the programme has been the UK Drought Portal, a tool to help visualize the current meteorological conditions across the country [5]. The portal can be used to understand the severity and magnitude of drought at different spatial scales across the UK over the past half century through interactive maps and graphics. The portal provides an assessment of drought severity based on a single precipitation data set and one particular indicator (the Standardized Precipitation Index, SPI). The portal was used extensively by water managers (including private water utilities, regulators and agricultural and conservation organizations) during the 2018–2019 drought episode, which helped put the emerging situation in a historical context, thereby providing key information to support drought management actions.

More recently, a more comprehensive monitoring and early warning tool has been co-developed alongside regulators and water companies, namely the UK Water Resources Portal [6]. This has the same functionality as the Drought Portal but also covers river flows, including daily updated real-time information and soil moisture, using a network of in situ real-time and wide-area soil moisture observation stations (COSMOS-UK). The forecasting work from within the programme was also used to help stakeholders during the 2018–2019 drought. Another key transformational area is long-term drought planning. The Historic Droughts and MaRIUS projects, in particular, have delivered comprehensive national data sets of past drought severity and potential future drought risk under climate change and have also delivered major advances in national-scale hydrological and water supply system modelling. Within ENDOWS, the teams have been working closely alongside water companies and regulators to embed these data sets and tools into the process for the next round of water resource planning, especially in helping pave the way for the more improved regional to national-scale planning that is currently being adopted. The scientific advances which have been made in relation to drought in the UK over recent years are closely aligned with the IHP-VIII Themes of “Water-Related Disasters and Hydrological Changes” and “Addressing Water Scarcity and Quality”. UK researchers have engaged with drought experts across the world through the IHP-FRIEND programme in order to share scientific knowledge and solutions.

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