Drought risk in the Anthropocene Special Issue published

Papers from the Science+ meeting held at the Royal Society and organised and edited by Professor Jim Hall, Associate Professor Jamie Hannaford and Professor Gabriele Hegerl is now available!

The impacts of droughts on people and the natural environment are increasing, due to climate change and over-exploitation of water resources. This Science+ meeting issue explored scientific understanding of changing drought risk and examined drought impacts on the environment, people and the economy. Policy-makers, practitioners and scientists explored policy options for management of droughts in the future.

Check out the special issue

Special Issue on Drought and Water Scarcity now finalised

The special issue in Frontiers in Environmental Science on Drought and Water Scarcity: Addressing Current and Future Challenges has been successfully finalised.

Water scarcity and drought are increasingly significant environmental challenges. Recent continental scale drought events in Europe have emphasized that the severity, significance and impacts of drought pose a substantial risk to society. Furthermore, climate change projections suggest that in many parts of the world, the frequency, duration and severity of drought events is likely to increase. Despite the immediacy of this risk, communication around drought and water scarcity is difficult, and effecting timely responses is challenging. Whilst there have been significant advances in drought forecasting, monitoring and impact mitigation, many challenges remain.

This Special Issue aims to consolidate cutting-edge, international research on drought and water scarcity, highlighting critical gaps in understanding and setting urgent priorities for research and action, providing an international platform for generating an integrated, systems perspective on this complex, multidimensional and socially constructed environmental hazard.

The special issue is available now as PDF or an e-book, comprising all the articles featured.

Download the Special Issue

Why we are still in drought despite recent rain

The UK experienced a prolonged period of dry weather in 2022 which culminated in a severe summer heatwave and record-breaking temperatures, posing challenges for water resources. Impacts of the protracted dry weather and low river levels included environmental stress in aquatic ecosystems, challenges for farmers in terms of irrigation, harvesting and drilling seeds, stressed terrestrial habitats and severe wildfires.

Steve Turner, hydrologist at the UK Centre for Ecology & Hydrology, reflects on this year’s record-breaking heatwave and long period of dry weather and looks at the status of the UK’s water resources as we move into autumn and winter…

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How does the 2022 Drought compare to past events in the UK and how might it evolve in the near future?

The UK Centre for Ecology & Hydrology’s blog post last month highlighted the precarious hydrological situation following a very dry spring and early summer. Low groundwater levels, reservoir stocks and especially river flows were already prompting concerns around the water resources situation.

One of the questions that’s commonly asked is how the current event compares to the 1976 drought which still stands as the benchmark episode in the UK. UKCEH’s Simon Parry explores the current hydrological situation, how this compares to previous drought episodes and what might be on the horizon.

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Groundwater’s role in the 2022 Drought

Groundwater plays an important role in water supply in the UK, both for agriculture and irrigation and for public supply. It provides around 30 per cent of public water supplies accross the UK, and sustains flows in rivers and wetlands during dry conditions. The British Geological Survey’s John Bloomfield and Andrew McKenzie explore the affect of the drought in groundwater in 2022.

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How is the 2022 Drought in the UK affecting farmers?

July 2022 was the driest July in England since 1935. Combined with record breaking temperatures, there are fears of disruption to public water supply and poor crop yields, especially for fruit and vegetables. Cranfield University’s Tim Hess and Ian Holman explore how the current drought is affecting farmers and how it compares to previous droughts in The Conversation.

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Heatwave increases pressure on water resources

Increased demand from the heatwave has put short-term pressure on water supply, and should river flows continue to fall, there will be growing threats to water supply later in the year. In his blog, Principal Hydrologist from the UK Centre for Ecology & Hydrology, Jamie Hannaford uses the Hydrological Summary, Hydrological Outlook and interactive water situation monitoring tools to look at the current water resources situation and how it may evolve in the coming months. 

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Westminster, water supply resilience and climate change: a POSTbrief for parliamentarians

Dr Jade Ward has recently finished an Academic Fellowship at the UK Parliamentary Office of Science and Technology (POST) writing a POSTbrief on water supply resilience and climate change in England. The Fellowship was funded by the UK Droughts and Water Scarcity Research Programme.

POST makes the latest scientific research accessible to parliamentarians through the publication of POSTbriefs and POSTnotes. POST publications are impartial, balanced, peer-reviewed and evidence-based, covering a diverse range of topics that are of interest to policymakers. POST publications are also freely available to the public.

Introduction

The extensive drought of 1976 in the UK is etched in the memory of those who lived through it. For those of us who are too young to remember, the stories of stand-pipes in the street have been recounted many times. But how many people realise that England is heading for more frequent and severe water shortages in the future if no action is taken?

Having completed this Fellowship, I know the answer is, not many.

Water supply resilience and climate change is a vast and diverse topic, as evidenced by the wide-ranging and diverse work and content of About Drought, the UK’s Droughts and Water Scarcity Research Programme, funded by NERC. The POSTbrief I completed explores the drivers of drought and water scarcity, the water resource management framework and options to consider for building resilience into England’s water supply system. Climate change impacts will be similar across the UK, but as the environment is a devolved issue in Parliament, the nations of the UK manage their water resources in different ways. In England, private water companies have been responsible for water supply since privatisation in 1989.

The issues of water resilience and climate change

The public are, in general, unaware of the impending water scarcity crisis that could impact some areas of the UK as soon as the 2040s. Around the world, England is perceived as a place that gets a lot of rain, and it is no secret that everyone rejoices when the sun comes out, but in reality England is facing a water scarcity crisis. In fact, it doesn’t rain as much as you might think, especially in Eastern and Southern areas of the country, and population growth is putting increasing pressure on natural resources and the supply system. Climate change projections forecast hotter, drier summers and warmer, wetter winters in the UK. This increases the chances of extreme drought and flood events. The south east of England, with its high population density and drier climate, is already classed as a water stressed region and is likely to be the first to experience water shortages, but the whole country is at risk.

Over the past couple of decades, evidence for climate change and its impacts on water resources has been building, with researchers, water companies, trade associations, consultancies, non-governmental organisations and governmental departments all producing literature on the topic. The National Audit Office, The Public Accounts Committee and the Climate Change Committee have all given stark warnings about the risk to water supply if we don’t act now. However, to date, little progress has been made in policy to set targets and implement mechanisms to achieve them, from reducing carbon emissions to improving water supply infrastructure and water efficiency. Recent developments include the Environment Bill, the Government’s 25 Year Environment Plan and the legally binding net zero carbon emissions by 2050 but implementation strategies will be key to meeting the targets.

In recent years, the impacts of climate change have become reality, with the UK experiencing more frequent severe flood and drought events. In addition, the COVID-19 pandemic has exposed the vulnerability of many systems, which have struggled to adapt to such an extreme global event. There is a growing understanding that such extreme events do occur, and the consequences are severe if our systems are not resilient. The water supply system suffered from increased demand during the first lockdown in March-July 2020 due to most people spending all their time at home coinciding with hot weather and the sunniest spring on record.

Building resilience in England’s water supply system

There is an established process for water resource management planning, with water companies required to produce 25-year water resource management plans (WRMPs) and revise them every 5 years. Until recently, this process has focussed on individual water companies managing water within their own area. However, the next review of water company plans, due in 2024, requires input from the new national framework for water resources and regional planning groups.

This new approach enables collaboration between regions and water companies, which will be required in the future to minimise the risk of shortages across the country. For example, large-scale inter-regional water transfers could be set up if droughts are forecast to occur at different times in different regions. The regional planning groups facilitate cross-sector collaboration for water resource management for the first time, recognising that the issues of water scarcity would have impacts across society. Water security is closely linked to food and energy security and the wider environment. For example, if ensuring the provision of public water supply led to water shortages for agricultural use this could reduce crop yield with impacts for food security, farming businesses, the food and drink supply chain and ultimately the public. Bringing the stakeholders together ensures that improving resilience in one sector does not leave another more vulnerable. This is called a systems approach, where cross-sector risks and trade-offs are explored under different management scenarios to develop integrated management plans.

Analysis of historic droughts continues to improve our understanding of such events and develop early warning systems for the future. These results can be used to inform the planning process. Going forward, a more integrated approach to modelling the water cycle – from rainfall, river and groundwater flow to water supply distribution systems – would better support the move to a systems approach for water resource management planning. These models would require sufficient data, with the potential to include real-time monitoring data in the future, which would enhance forecasting and decision-making.

Improving water efficiency, by reducing water consumption for individuals and businesses and making our appliances and properties more efficient, would ease demand on water resources.  This is likely to require an increased awareness of water consumption rates, as the majority of the public are not aware of how much water they use in a typical day or how much water their appliances use. Effective communication of water scarcity issues and the social, economic and environmental impacts, could help to empower citizens and businesses to be part of the solution.

Working with POST

My work began with a literature review of scientific papers, government reports, POSTnotes and more, to establish the key areas of focus and who I should interview for more information. Interviewing researchers (including the principal investigators and others across the DWS programme), stakeholders, regulators, and government departments is a key part of developing the POSTbrief. I really enjoyed speaking to such a wide range of people with different perspectives. Although I have been working in the water industry for nine years, I learnt a lot about different areas of research. My task was then to put it all together in a coherent, simple, impartial briefing to present an overview of the topic. Once complete, the POSTbrief was sent out to over 30 external reviewers, the majority of whom I had interviewed as part of the process. Their comments were incorporated into the final POSTbrief.

At the beginning of my Fellowship, I completed training in the POST style of writing and then learnt how to put this into practice throughout the editing and internal review process. It was sometimes quite a challenge to reduce such a complex topic into a short summary and make sure the main point is not missed. This is the true art of a POST publication!

Read the POSTbrief in full

Dr Jade Ward

A Nationally Consistent Approach to Assessing Accumulated Rainfall Rarity

Accumulated rainfall totals are an important variable for a range of hydrological applications, including monitoring and forecasting, and long-term planning. A new report has been published which identifies the most appropriate, nationally consistent approach to quantifying return periods of long duration rainfall.

A comparison of the suitability of nine distribution families for estimating the relative rarity of accumulated rainfall periods across the UK provides opportunities to further improve the accuracy of return period estimation in many areas such as the water resource planning and the Hydrological Summary for the UK, and elsewhere.

Whilst distribution families that are commonly applied in extreme value estimation, such as the generalised extreme value, were demonstrated to be suitable in a lot of cases, overall Pearson Type III outperformed all other assessed distributions. Closer inspection of the performance on accumulation periods of 12 months or less provided further support for the suitability of Pearson Type III, as did the strong performance of Pearson Type III across accumulation periods, start months and regions.

Presentation of return level plots for two potentially appropriate distribution families demonstrated the sensitivity of return period estimates to distribution family, and thus the importance of this question. With this in mind, the approaches presented in Eastman et. al. (2021) provide opportunities to further improve the accuracy of return period estimation and uncertainty quantification.

The full report is now available

Figure 1 Northumbrian 12-month accumulation period beginning in October: return period plots for The Pearson Type III (pe3) and Generalised Extreme Value (GEV) distributions, with associated 95% confidence interval bands, and highlighted return periods corresponding to 48.09, 45.83, and 44.56 mm of rainfall per month. Points correspond to the Weibull plotting positions of the observed rainfall accumulation data.

REF: Eastman, MichaelParry, SimonSvensson, CeciliaHannaford, Jamie. 2021. A nationally consistent approach to assessing accumulated rainfall rarity. Wallingford, UK Centre for Ecology & Hydrology, 42pp.

Far reaching influence of MaRIUS research into water risks

By Dr Helen Gavin, Project Manager for MaRIUS

Research from the MaRIUS project is widely recognised as having transformed how water risks are managed by the Government, water suppliers and regulators.

MaRIUS (Managing the risks, impacts and uncertainties of droughts and water scarcity) developed the first national-scale water resource model for England and Wales, triggering a transition in government policy and industry practice. Between 2014 and 2020 MaRIUS research involved new theory, the creation of new datasets and models, validation and demonstration in case studies of how the risk of droughts can be assessed and better managed through system modelling and ‘outcomes-based’ approaches to decision making. To date, four major reports have drawn on its work: ‘Water UK Long Term Planning Framework (2016); the National Infrastructure Commission’s ‘Preparing for a drier future, England’s water infrastructure needs’ (2018); the Committee on Climate Change’s CCRA3 Water Availability study (2018-19) and the Environment Agency’s report ‘Meeting our Future Water Needs: A National Framework for Water Resources’ (2020).

Prof Jim Hall, Principal Investigator (PI) of MaRIUS and Professor of Climate and Environmental Risks at the University of Oxford, is a member of the Prime Minister’s Council of Science and Technology and an Expert Advisor to the National Infrastructure Commission. The project was based at the Environmental Change Institute in Oxford.

“Our research has caused a transition in government policy and industry practice for water resource management in England. It has shown how drought risks can be assessed and better managed through system modelling and ‘outcomes-based’ approaches to decision making.

“We have achieved a significant shift in thinking and practice by the regulators, through interaction over eight years with water companies, the Environment Agency, Ofwat, Defra and the National Infrastructure Commission.”

Professor Jim Hall, University of Oxford

The increasing frequency of droughts and water scarcity in our warming climate, combined with our growing population and increasing demands for supply present huge challenges for national and local government, water suppliers, energy, agriculture, infrastructure, industry and communities.

MaRIUS’s work has provided conceptual frameworks and methodologies that have enabled government and its agencies to address these challenges and has provided data, systems models and other evidence that are transforming policy and practice. The new water resource system simulation model integrates public water supplies with use of water in agriculture, power generation and other industries. It has been used to explore different future scenarios of drought and assess the frequency, duration and severity of water shortages now and in the future. Tools have been developed to explore trade-offs between different aspects of risk and the cost of alternative management plans.

Key to the take-up of MaRIUS’s research was a series of well-managed and effective workshops where potential users sat down with the leading researchers to explore datasets, models and tools in development, sharing their real-world decision-making and communications processes.

“We are continuing to work very closely with the Environment Agency and Ofwat, at their request. We are undertaking joint resilience assessments and exploring the impacts on water resources. We continue to train Environment Agency staff on our model and will transfer this tool to them as they wish to use it to fulfil their regulatory responsibilities.”

Professor Jim Hall, University of Oxford