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Are the UK winter floods linked to climate change?

The general public are being called to take part in an Oxford University research project to find out what role climate change played in the UK’s record-breaking wet winter.

The rainfall from December last year through to February resulted in the wettest winter ever recorded at the Radcliffe Meterological Station in Oxford. The deluge caused widespread flooding across southern England, affecting thousands of people and resulting in an estimated £1bn or more in damage.

The project weather@home, led by Professor Myles Allen, will reveal whether climate change made the extreme rainfall and resulting floods more likely to occur, or not. Anyone can use their home computer to run weather simulations and contribute results to the experiment.

One set of weather model simulations will represent ‘real world’ conditions and possible weather, while another set of will represent the weather in an imagined world where humans have not changed the composition of the atmosphere through greenhouse gas emissions. By comparing the number of extreme rainfall events in the two sets, researchers can work out if the risk of a wet winter has increased, decreased or been unaffected by human influence on climate.

The models have to be run many thousands of times to ensure that the estimated probability of extreme events is robust. That’s why the researchers are asking for the help of the general public who can download the computer software and run the experiment from home. The results should be available within a month and will be published as they come in.

In the video below Nathalie Schaller, a researcher based at the Environmental Change Institute, explains the science behind the project.

Read the Guardian article ‘Home computers to help scientists assess climate role in UK’s wet winter’

Follow Damian Carrington’s blog on the Guardian website which discusses the science and its implications

Visit the weather@home project website and contribute to the experiment

Water shortages could disrupt Britain’s electricity supply

The Guardian reports on a team of academics from Oxford and Newcastle who say nuclear and gas-fired power stations could be forced to shut down during future droughts.

The electricity sector uses large quantities of water for cooling processes in thermoelectric power stations, accounting for around half of all water abstractions in England and Wales. As water resources come under increasing pressures from growing populations and climate change, shortages could have serious impacts on the country’s electricity production, warns a new study co-authored by Professor Jim Hall, Director of the Environmental Change Institute, Oxford University.

“The high dependency on water in electricity generation means there is a real possibility that in just a few decades some power stations may be forced to decrease production or shut down if there are water shortages”, said Ed Byers in the Guardian article, a researcher at Newcastle University and lead author of the study.

The research, published in the journal Global Environmental Change, assesses the water demand of the government’s proposed energy ‘pathways’ to 2050. While some pathways present opportunities to both reduce water dependency and carbon emissions, others increase the dependence on water resources. For example, using fossil fuels with high levels of carbon capture and storage (CCS) could increase freshwater consumption by up to 70%.

The research shows that up to the 2030s, water use performance improves for all pathways, in line with rapid decarbonisation. This is achieved as renewable energy production expands while older coal, gas and nuclear plants are decommissioned and new and more affordable nuclear and carbon capture-equipped generation begins to take shape.

In the 2030s the water security of the UK could be in the balance as the water intensity of the different pathways diverges, warn the researchers. Coal and gas plants would be forced to shut down if they do not adopt CCS, yet if CCS and nuclear power are deployed on wider scales, water intensity will rapidly increase. Developers could be forced to choose between using limited freshwater supplies or increasing abstraction from tidal and sea water, both of which could be problematic for the environment.

The energy pathway with the highest level of renewables uses the least freshwater. Hybrid or air cooling comes at a slightly high cost and more emissions, but minimises water consumption and therefore could reduce dependency on scarce resources.

Read the Guardian article

Reference

Byers, E.A., Hall, J.W. and Amezaga, J.M. (2014) Electricity generation and cooling water use: UK pathways to 2050. Global Environmental Change. DOI: http://dx.doi.org/10.1016/j.gloenvcha.2014.01.005

Action needed to reduce nitrogen and phosphorus pollution in the Thames

In a podcast on the NERC Planet Earth website, Paul Whitehead from Oxford University and Mark Barnett from the Environment Agency comment on the pollution challenge of the river Thames. They explain why the river will fail to meet European Union standards unless action is taken by farmers to reduce fertiliser use and water companies cut the amount of phosphorus being discharged by sewage works.

“Nitrogen and phosphorus come from a range of different sources,” said Paul Whitehead, Professor of Water Science at the School of Geography and the Environment. For example, phosphorus comes through sewage works, from the soap we use in everyday in dishwashers and washing machines, as well as from agricultural and rural diffuse sources.

“They create eutrophic conditions in the river, where you get excessive blooms of algae and growth of unwanted plants” explained Paul. “It is possible to kill a river, meaning the oxygen levels in the river are reduced down to zero and fish and macroinvertebrates can’t survive.”

Mark Barnett, Catchment Coordinator for the Environment Agency said that although a lot of work has been done over the last few decades to reduce nitrates and phosphates, there is still quite a long way to go to meet European Union targets.

Climate change could have significant impacts on river pollution in the future as the distribution of rainfall changes, with more rainfall predicted in the winter and reduced rainfall and river flows in the summer. “This means that in the summer there will be less dilution of pollutants coming into the river system, so that could raise phosphorus levels, and in winter more nitrogen and phosphorus could be flushed out of the catchment into the river system,” warned Paul Whitehead.

Building riparian buffer strips is one measure that could be taken to cut down pollution levels – these are zones of land next to the stream channel which effectively act as a filter for the sediments and nutrients found in water running off the fields. There are also technologies available for removing phosphorus at sewage treatment works, enabling it to be recycled and sold back to farmers rather ending up in the river.

“I’m reasonably confident that things will improve” said Paul Whitehead. “They’ve improved massively over the last 50 years in the Thames so I’m sure that will continue. Technology is improving the whole time, the water companies are quite keen to actually extract phosphorus and sell it back to the farmers, it’s potentially a source of money for them and at the same time farmers want to use less and less fertiliser because it is more expensive.”

Listen to the Planet Earth podcast

Managing phosphorus water pollution in an uncertain future

An Oxford-led study suggests that multiple strategies may be needed to manage phosphorus in rivers. Sources of phosphorus pollution vary depending on future changes in rainfall and runoff under different scenarios of climate, land use and water resource management.

Phosphorus causes eutrophication or over-fertilisation of rivers, a serious problem that leads to excessive growth of algae, having a harmful effect on plant and animal life. Managing phosphorus levels in rivers is therefore a major global, national and European concern. Phosphorus can come from diffuse sources such as agricultural fertilisers or point sources such as sewage treatment works.

The study, led by Dr. Jill Crossman and Prof. Paul Whitehead, assesses how the water quality and hydrology of the Thames River system respond to future changes in climate, agricultural land use and water resource allocations. It then evaluates the effectiveness of phosphorus management strategies under these scenarios of future change.

The authors of the study found that the relative contribution of phosphorus from diffuse and point sources vary according to future rainfall and runoff. During high flow periods, agricultural diffuse sources are the main problem, and during low flow periods point sources dominate.

The study suggests that the best approach to phosphorus management may be to adopt multiple strategies for use at different times and locations in order to target the dominant source.

Read the full journal article in Science of the Total Environment

New tool launched to calculate nitrogen footprint

Scientists at Lancaster, Virginia and Oxford universities have produced a web-based tool that allows anyone living in the UK to calculate their own ‘nitrogen footprint’.

The tool, known as the N-Calculator, asks you to input certain information on what you eat, how you travel and how much energy you use in your home, and then calculates the likely effects on the environment in terms of nitrogen pollution. It is hoped that the tool will encourage people to choose more sustainable ways of living.

Scientists have warned that reactive nitrogen pollution is already a major environmental problem that is causing significant damage to air and water quality across the UK. Nitrogen runoff from farms and man-made effluents are largely responsible for algal blooms that affect river systems, whilst atmospheric nitrogen pollution is leading to significant losses of biodiversity. Most of the nitrogen pollution arises out of agricultural processes used in the growing of crops or grazing of animals. In addition, a significant proportion of the average UK nitrogen footprint comes from vehicle emissions.

“Nitrogen is essential for growing crops for food or high quality grass for cattle, as any farmer knows,” said Paul Whitehead, Professor of Water Science at the School of Geography and the Environment, and Director of the NERC-funded Macronutrients Cycles Programme. “However, the widespread use of nitrogen fertilizer to boost crop production has resulted in a runoff of excess nitrogen from farms into our rivers, lakes and groundwaters.”

The researchers used publicly available data such as national atmospheric data, national land use and farm statistics, to make the calculations. The N-Calculator website also makes recommendations for how to lessen your ‘nitrogen footprint’. Lifestyle choices affect your nitrogen footprint: reducing your nitrogen footprint means cutting back on road and air travel, choosing renewable energy and, most importantly, altering the balance of the foods contained in your diet.

“Unlike your carbon footprint, what you eat is the most important factor determining your nitrogen footprint,” said Dr Carly Stevens of Lancaster University. “By altering the amount and type of food that you eat, you can make a big difference to your impact on the environment.”

The tool, first developed in the US, has been updated and adapted for UK users by researchers from Lancaster University under a project funded by the NERC Macronutrient Cycles programme at Oxford. The device was originally created by award-winning scientist James N Galloway and his research colleagues, Allison Leach, at the University of Virginia, Albert Bleeker of ECN and Jan Willem Erisman of the Louis Bolk Institute, both of The Netherlands.

Calculate your N Footprint

Visit the Macronutrients Cycles Programme website

Experts discuss changing extremes in hydrology in the UK

The conference ‘Changing extremes in hydrology’ was held at Exeter College in Oxford on 15 April 2013, and examined the characteristics and impacts of the extreme hydrological conditions experienced in the UK during 2012.

The conference’s theme was inspired by the extraordinary nature – in hydrological terms – of 2012. The first three months of 2012 were marked by the on-going drought which began in 2010. In early April water companies were forced to issue water use restrictions, affecting 20 million users. Then just a few days after the restrictions were imposed, a period of intense rains commenced and continued for the entire summer period, making it the wettest summer in the past 100 years. This prolonged period of rain resulted in widespread flooding across the country throughout the remainder of the year.

The aim of the conference was to review the meteorological and hydrological conditions that characterised 2012, to review the economic damages associated with the drought and flooding, and to provide a broader conceptual framework for understanding how the occurrence of extreme hydrological events might change in the future as a result of climatic changes and other drivers.

Mike Kendon from the Met Office opened the event by describing the characteristics of the 2010-2012 drought and placing it within the context of previous droughts across England and Wales. The drought was one of the ten most significant of the last century, but what was really remarkable was its sudden end in the spring of 2012 with the onset of greater than average rains.

This sudden transition from too little water to too much water was discussed by Simon Parry from the Centre for Ecology and Hydrology. Parry explained how a shift in the jet stream in the spring of 2012 provided the climatic conditions necessary to produce two of the wettest months on record. This rapid change from drought to flood conditions had massive impacts on farmers, explained Tim Hess from Cranfield University. He pointed out that very few farmers are insured against flood damage and recommended a series of measures to make the UK agricultural industry more resilient to weather-related shocks.

Stuart Hyslop from the Environment Agency spoke about the effects of the 2010-2012 drought on water supply in the Thames region. He pointed to the increasing sectoral competition for water for agriculture, domestic use, recreation and wildlife during low flow periods. In order to resolve this conflict, the Environment Agency has a role in monitoring and coordinating the different water users to ensure that an equitable balance is struck between users wherever possible. Edmund Penning-Rowsell, Visiting Research Associate at Oxford University, described the damages caused by the 2012 floods.  Comparing the damage with that of historical floods, he showed how economic losses caused by flooding are overestimated in the UK.

Bill McGuire, University College London, addressed the problem of extremes from a broader perspective, providing examples of how changing climate triggers geological events such as volcanic eruptions and tsunamis. He suggested that changes on the Earth’s surface induced by climatic changes, such as ice sheet melting and sea level rise, may trigger geological catastrophes. This may imply that in the future we might witness “geological mayhem as well as climatic mayhem”, he said.

Patrick McSharry from the Smith School of Enterprise and the Environment, Oxford University, discussed the contribution of mathematical statistics and the theory of extreme values to quantifying risks associated with extreme weather events, enabling better estimates of the levels of risk associated with catastrophic events.

Bruno Merz from the German Research Center for Geosciences discussed the linking of observed changes in flood frequency with specific drivers. While it may be easy to detect changes in flood frequency, separating the effects of drivers such as climate change, dam building or land use change on flooding is much more difficult and requires further research effort. This issue was also taken up by Thomas Kjeldsen from the Centre for Ecology and Hydrology, whose research investigates the effects of urbanisation on a catchment’s flood response. Comparing pre-urbanisation and post-urbanisation flood data has increased understanding of how urbanisation affects flooding frequency.

The final presentation by Harvey Rodda, Hydro-GIS Ltd, considered the nature of floodplain development in the UK and how flood risk is incorporated within the planning process. A number of examples showed how flood risk may, in some instances, be used as a lever against problematic planning applications.

The conference demonstrated clearly the need for further research to link observed changes in flood frequency to drivers, and to better understand and manage rapid shifts from drought to flood conditions. At the intersection between research and policy, thinking should be devoted to investigating risks associated with extreme events, and to means of financing these risks and sharing the burden of extreme hydrological events across society. In terms of policy-relevant findings, a better understanding and an unbiased representation of the damages caused by hydrological extremes is required to prioritise flood protection investments and also to reduce the chances of inappropriate use of flood risk information in planning.

The conference was organised by Hydro-GIS Ltd, a UK-based hydrology and GIS consultancy company, and received sponsorship from Oxford University’s Smith School of Enterprise and the Environment. Visit the conference website

By Edoardo Borgomeo, DPhil student at the Environmental Change Institute

Economic Rights and Regulatory Regimes: is there still a ‘right’ to water?

On Tuesday 19 March, a workshop at Oxford University gathered 55 participants from the Department for the Environment, Food and Rural Affairs (Defra), the Environment Agency, the National Farmers’ Union, water companies, along with academic experts to discuss the right to water in the light of increasing regulatory intervention.

 

The event was convened by Dr. Bettina Lange, Centre for Socio-Legal Studies, Oxford University and Dr. Mark Shepheard, McGill University, in association with the Foundation of Law, Justice and Society and Wolfson College.

The workshop’s theme was inspired by increasing concerns about water scarcity issues in the face of pressures from climate change and reforms to the abstraction licensing system currently being discussed for England and Wales.

The first panel, which invited speakers to ‘rethink’ water rights through stewardship, was opened by Professor Karen Morrow from Swansea University who provided an extensive overview of the common law applicable to water regulation. Morrow highlighted the links that water regulation has not only with property law but also with administrative environmental and human rights law. She introduced the new and more radical approach of granting rights to nature to protect water resources. Dr. Bettina Lange and Dr. Mark Shepheard shared their findings from empirical socio-legal research which mapped how farmers think about a right to water and identified key factors that shape such conceptions.

Henry Leveson-Gower, Head of Defra’s Future Water Resource Management Project, opened the second panel which explored the use of market mechanisms for promoting water stewardship. He explained the need for a reform of the current water abstraction licensing system, highlighting that the current system is not flexible enough to respond to alternating floods and droughts due to climate change. Leveson-Gower urged the need for more efficient use of water resources and outlined three economic incentive-based options currently being considered by the government. 

Alice Piure, Strategy & Policy Analyst at Anglian Water, presented interesting findings from a research project that explored the use of various types of water trading and their contribution to promoting water stewardship. Finally, Jon Stern from City University London discussed market-based approaches to dealing with periodic water scarcity, in particular the sale of raw water from one region to another.

The third panel offered academic perspectives on state regulatory approaches to water stewardship. Donald McGillivray of Sussex University gave a historical overview of the approach taken by the common law to regulate water stewardship. He argued that the current regulation gives mixed legal messages about water rights and sustainability as there is no real clarity regarding the regulatory goals.

Prof. Bill Howarth of Kent University pointed to the significant advances that have been made in regulation to anticipate and manage the risks of unpredictable events such as floods or droughts, but argued that much more must be done to effectively enhance ‘water security’.  Dr. Sarah Hendry from Dundee University closed the session with some contrasting insights from Scottish water regulation.

The final panel involved a round-table discussion regarding the future research agenda in water stewardship. Various themes were raised, including the challenge of reconciling potentially different competing regulatory goals, specifically ‘water security’ and ‘food security’, as well as challenges to and opportunities for developing cross-disciplinary perspectives on water stewardship.

By Sebastián Castro, DPhil Student, Centre for Socio-Legal Studies, Faculty of Law, University of Oxford.

View workshop presentations and podcasts

More severe and widespread UK droughts expected with climate change

UK droughts are projected to be more severe and affect larger areas of the country over the next 100 years, according to a new study by Muhammad Rahiz and Prof. Mark New published in the journal Water Resources Management.

The team made a detailed analysis of regional climate data from the Met Office’s Hadley Centre to investigate future drought trends. “Both drought intensity and the spatial extent of droughts in the UK are projected by these climate models to increase into the future”, said Professor Mark New, Professor of Climate Science at the School of Geography and Environment and co-author of the study.

The findings of the study could have implications for the way water is managed, particularly in the South East, one of the most vulnerable regions. “If you have small, localised droughts, that’s not so important from a water management point of view, because most utilities can move water in from another place,” said Professor New. “But if a drought affects a whole region like the South East of England, then you’ve got a more significant problem.”

Read the full article on the Natural Environment Research Council website

Reference

Rahiz, M. and New, M. (2013) 21st Century drought scenarios for the UK. Water Resources Management, 27(4): 1039-1061.

Open innovation in the water sector

Professor Carolyn Roberts, Director of the Environmental Sustainability Knowledge Transfer Network, calls for major shifts in the way we think about water and wastewater. She writes about open innovation and the principles of collaboration for water management in the Water and Sewerage Journal.

Roberts notes that a recent surge of interest in innovation in the water sector is an encouraging sign. The impetus for change comes from emerging pressures such as the Water Framework Directive, carbon reduction targets and growing concerns about sustainability. Water companies are starting to rethink their approaches but Roberts suggests that a fundamental paradigm shift may be needed.

“Government backing and open innovation principles of collaboration and partnerships have underpinned the changes in the waste sector, but despite the rhetoric, a steer clear for water management is yet to emerge” she writes.

Progress is being seen in some areas, such as leakage control and anaerobic digestion for treating waste. But imagination is limited, says Roberts, and planning for cities where water, energy and waste sytems are monitored and managed together is far from the norm.

According to Roberts, the solution must be like an orchestra creating great music. The various and overlapping sectors, such as water, energy and land management, along with the cross-cutting themes of resource efficiency and carbon management, need to be managed collaboratively and creatively to produce a harmonious whole.

Read the full article in Issue 1 / 2003 of Water and Sewerage

Find out more about the Environmental Sustainability Knowledge Transfer Network’s Sustainable Water Management Group

Simon Dadson wins grant to study the impacts of urbanisation on water security in the Thames

Dr. Simon Dadson from the School of Geography and the Environment has been awarded a £160k NERC grant for a project which aims to advance understanding of the fine-scale impacts of urbanisation on water resources and pollution in the Thames river basin.

Over the past 50 years changes in UK land use have been considerable and this trend is likely to continue. The UK population is projected to increase by 16% to 2035 which will bring about change to the size and structure of urban areas and increased pressure on land management. These changes have significant implications for water resources.

The three-year project ‘Changes in urbanisation and its effects on water quantity and quality from local to regional scale’ will focus on water security in the Thames river basin, a region facing serious water stress.

A novel integrated modelling approach will be developed and tested for detailed local case studies, and then scaled up for testing across the entire basin. Future impacts on water resources will be quantified, taking into account projections of urban development, land management, and climate change.

The project is a collaboration between Oxford University, the Centre for Ecology and Hydrology, and the University of Surrey.