Posts

Desertification: the environment gone pear-shaped?

On 17 June, World Day to Combat Desertification, Dr Troy Sternberg asks some important questions. What is desertification? Is it caused by climate or humans? Are deserts taking over? Can the process be stopped?

The Gobi Desert

The Gobi Desert. Photo by Nanel

The idea of desertification came in the 1970s when scientists noted that parts of the Sahara Desert appeared to be expanding by kilometres per year. News reports and popular imagination extrapolated the numbers and declared that deserts were spreading at alarming rates. Articles began, ‘at this rate, in 10 years (choose your favorite African city) will be covered in sand.’

In 1994 the United Nations created the Convention to Combat Desertification (UNCCD) to address the issue. Soon the term was applied to China and India, the American Southwest and the Middle East. Desertification had captured the public’s imagination and became the go-to term for ‘something’s happening in the desert.’

In time, science and climate knowledge diverged from popular perceptions of desertification. With interest, investigation and new techniques, like satellite imagery, researchers were able to better understand climate and landscape interaction in arid regions. Two important factors became clear: (1) climate variability, particularly in precipitation, resulted in fluctuations in land cover, and (2) humans had significant impact on desert environments.

The first point, now broadly acknowledged, highlights how climate affects vegetation patterns. With more rain plant cover increases, while in dry or drought years ecological productivity decreases. Thus in wetter years deserts ‘shrink’ whilst ‘expanding’ in drier years.

The second point stresses the huge impact people have on landscapes, especially drylands. Agriculture, livestock grazing, resource extraction, urbanisation and intensive land use all affect desert environments. Once damaged, marginally productive arid landscapes are unlikely to recover.

Soon the idea of desertification grew in complexity. It was not a simple case of ‘deserts taking over’ or just a ‘climate event’. One year’s ‘desertification’ might be replaced by the next year’s ‘greening’.

The UNCCD developed a definition of desertification as ‘land degradation in arid, semi-arid and sub-humid areas resulting from various factors including climatic variations and human activities’. The focus identifies a process resulting from many potential causes. Implicit is that desertification reflects a change in state, crossing a threshold in which original productivity is lost.

Much discussion uses the term ‘desertified’, where perhaps degradation would be more appropriate. This allows for changes in precipitation or land use (e.g. farmland left fallow or ending overgrazing) that may improve vegetation and pasture. As with several scientific terms that enter the popular lexicon, there is more nuance and shades of meaning to desertification than its usage suggests.

Two Oxford University researchers, Dave Thomas and Nick Middleton, wrote about this in ‘Desertification: Exploding the Myth’ in 1994, a book that highlighted the use and misuse of the term. Now over twenty years later the word is ever more popular and has become a shorthand way to say the environment has gone pear-shaped. Few writers take the time to look at contributory factors, from drought to conflict and war, poverty, intensive cultivation on unsuitable land and development pressures. Indeed, the term has become so generic that it has little real meaning.

A recent article of mine ‘Contraction of the Gobi 2000-2012’ showed how the size of East Asia’s largest desert has been decreasing due to increased precipitation (Sternberg et al. 2015). However, Chinese researchers were convinced that it was not precipitation but ‘good government anti-desertification policies’ that led to the shrinking of the desert.

In a recent visit to Oxford the UNCCD representative stressed ‘degradation in any environment’ rather than using the word ‘desert’. Where is the funding appeal for a dry or dessicated piece of land? Much better to rebrand desertification as a term for severe degradation. That implies the potential to change, reverse and improve landscapes through human action; a positive message the public can embrace.

On this day take a moment to think about the two billion people, predominantly poor, who live in marginal arid and semi-arid regions, to realise the implications of a term we use lightly.

Dr Troy Sternberg is a geographer researching desert environments and societies, based at the School of Geography and the Environment. His current focus is on how climate hazards impact landscapes and people across Asian drylands.

Related links

/0 Comments/by

New EU project on coastal hazards and an Oxford ‘Think-Shop’

Professor Edmund Penning-Rowsell, Distinguished Research Associate at the School of Geography and the Environment, is managing a new research and knowledge transfer project to better protect society from coastal hazards.

coastal-hazards

The EcosHaz project will develop a framework to assess the costs and benefits of prevention and response to coastal hazards such as flooding, shoreline erosion, storm surges, sea level rise and oil spill accidents.

Until now, investment decisions in Europe in this field have been based more on local or regional political agendas than logical risk assessments.

Professor Penning-Rowsell, also Pro Vice-Chancellor for Research at Middlesex University said: “Coastal hazards are a major concern for authorities and populations as they can have severe impacts on the economy as well as the health and safety of people. The project will provide state of the art guidance on assessing the costs and benefits of risk prevention measures, compared to the costs for response and rehabilitation. This will enable decision-makers to make sensible choices based on sound evidence.”

The project team will train up personnel in coastal authorities and their consultants or advisers, so that they can adopt economic assessment tools in their work and reduce the damage caused by coastal hazards.

Partners within the consortium are: Sigma Consultants, Greece; the University Pablo de Olavide, Seville, Spain; the Flood Hazard Research Centre, Middlesex University, UK; the Maritime Institute in Gdansk, Poland; the Department of Economic Theory at University of Santiago de Compostela, Spain; and the Università degli Studi di Catania, Italy.

A ‘Think-Shop’ (the antidote to the proverbial “Workshop”) will be held in Oxford on 7 October 2015, to brainstorm coastal protection and conservation issues. Those interested should contact Edmund Penning-Rowsell at Edmund@penningrowsell.com.

Visit the EcosHaz project website

Ecoshaz

eac logo

Project co-funded by the EU Humanitarian Aid and Civil Protection.
The sole responsibility of this communication lies with the author.
The Commission is not responsible for any use that may be made of the information therein.

 

 

/0 Comments/by

Oxford University water research at the 2015 European Geosciences Union General Assembly

There was a great turnout for the School of Geography and the Environment at the European Geosciences Union (EGU) General Assembly, where eight students and staff presented their latest water and climate related research findings.

sdsd

Map of a global topographic index developed by Toby Marthews and colleagues.

The annual EGU General Assembly is the largest European geosciences event and took place this year on 12-17 April in Vienna. The meeting covers all fields of science dealing with planet Earth, including volcanology, the Earth’s internal structure and atmosphere, climate, as well as energy, water and other resources.

Our students and staff were among the 11,000 scientists at the event from 108 countries. Oxford University presence included oral and poster presentations by Associate Professor Simon Dadson, post-doctoral researchers Emily Barbour, Gianbattista Bussi, Benoit Guillod, Rachel James, Toby Marthews and Daniel Mitchell, and doctoral candidate Franziska Gaupp.

Franziska Gaupp presented research on the role of storage capacity in coping with water variability in large river basins. Using a global water balance model, her analysis shows that current storage is able to buffer water variability in most basins. However, hotspots of water insecurity were found in South Asia, Northern China, the West Coast of the United States, Spain, Australia and several basins across Africa.

Emily Barbour’s research examines the complex relationship between water resource management and poverty in the Bangladesh Ganges-Brahmaputra-Meghna Delta. Her poster shares experience with engaging policymakers and stakeholders to discuss the impacts of climate and socio-economic change on water availability and quality.

The map featured on this page shows a topographic index developed by Toby Marthews and colleagues – a measure of the ‘propensity for soil to become saturated’ – which will be an invaluable resource for use in large-scale hydrological modelling. In a second poster, Toby presented findings from a study which sought to find out if human-induced climate change contributed to the devastating 2014 drought in the Horn of Africa. The modelling results suggest no human influence on the likelihood of low rainfall but clear signals in other drivers of drought.

It’s difficult to study extreme weather events such as floods and droughts, because, by definition, they don’t occur very often. A way to overcome this issue is to use large ensembles of climate model simulations to produce ‘synthetic’ weather events. This was the topic of Benoit Guillod’s talk which he illustrated with an example of synthetic drought events in the UK being generated for the MaRIUS project (Managing the Risks, Impacts and Uncertainties of drought and water Scarcity) in order to better understand and predict droughts. In a second talk Benoit presented results on the impact of soil moisture on rainfall – an important interaction in the climate system.

Taking a more local perspective, Gianbattista Bussi spoke about his research on water quality in the River Thames basin which analyses the dynamics of fine sediments. Another strand of the work models the growth and movement of phytoplankton – microscopic algae which are an important food source for river wildlife, but over-growth can lead to algae bloom, depleted oxygen levels and the death of fish and other species.

It was fantastic to see so many of our researchers in Vienna sharing their insights and knowledge about the Earth’s water and climate systems.

Visit the EGU General Assembly website

Presentation files

/0 Comments/by

Report shows how water insecurity is a drag on the global economy

A new report shows floods, droughts and a lack of investment in providing good quality, reliable water supplies is dragging down the global economy. The report, published today and entitled ‘Securing Water, Sustaining Growth’, was written by an international Task Force chaired by Claudia Sadoff and co-chaired by Professors Jim Hall and David Grey from the University of Oxford.

cover with borderThe Task Force was established by the Global Water Partnership (GWP) and the Organisation for Economic Co-operation and Development (OECD). The report and new scientific analysis examines not only water’s destructive force but also how it contributes to human health and prosperity. It was launched at the start of the Seventh World Water Forum in South Korea, the international summit at which the world’s water challenges are addressed.

The report draws on research led by the University of Oxford and feeds into a policy statement released by GWP and OECD calling on governments to invest in strengthening the world’s institutional capacity to manage water security, with much improved information systems and better water infrastructure. It urges that special attention be paid to social risks, with a focus on vulnerable segments of society.

According to the report, South Asia has the largest concentration of water-related risks. East and Southeast Asia face rapidly increasing flood risk, although the United States has the greatest exposure to flood risk. Sub-Saharan Africa is the only region where the risks of inadequate water supply and sanitation are rising. North Africa has the greatest percentage of population at risk of water scarcity.

The international Task Force is comprised of leading academics, researchers and practitioners from around the world.

Claudia Sadoff, Distinguished Visiting Scholar at the Environmental Change Institute, said: ‘Both our empirical and theoretical analyses demonstrate the importance of investment in water security for development and the importance of development for investment in water security.’

‘Effective ways of achieving water security involve combinations of investments in information, institutions and infrastructure’, says Professor Hall, report co-author and Director of the Environmental Change Institute. ‘Not all investments have been beneficial or cost-effective. Investment must be designed to be robust to uncertainties and to support adaptive management as risks, opportunities, and social preferences change. All of this will require refined analytic tools, innovation, and continuous monitoring, assessment, and adaptation.’

Report co-author and Visiting Professor at the School of Geography and the Environment, David Grey said: ‘Our analysis shows that the countries that depend on agriculture for their economies are often the worst affected by floods or water scarcity. Some countries will need to think about how they can diversify from an agriculturally focussed economy to one less dependent on water. They will also focus on how better use can be made of the limited water supplies available to them.’

Read the report
Read the GWP news release
Water insecurity costs global economy billions a year, Bloomberg, 13 April 2015
Water insecurity costing global economy billions, Japan Times, 25 April 2015

 

/0 Comments/by

Climate extremes: moving from physics to solutions

Professor Paul Whitehead joined over 35 scientists in the Swiss mountains to discuss how to assess and adapt to extreme climate events.

delegate

Delegates at the climate extremes workshop, Riederalp, Switzerland

The most significant impacts of climate change are likely to be due to the increasing intensity and frequency of extreme weather events, such as droughts, floods, heat waves and wind storms. The costs of damage caused by these events could be extremely high.

The University of Geneva organised the workshop in Riederalp, Switzerland on 24-28 March 2015, bringing together a wide range of expertise on the science of climate extremes. The scope of the workshop also moved beyond physical science to consider impacts and adaptation policies for reducing climate-related risks and the costs of extreme events to vulnerable societies.

Paul Whitehead, Professor of Water Science at the School of Geography and the Environment, presented his research on modelling the Ganges, Brahmaputra and Meghna river systems in India and Bangladesh, which together form one of the largest river basins in the world, providing water to over 650 million people.

The Oxford University research, which forms part of the ESPA Deltas project, assesses how future climate change and socio-economic change in the river basin will impact the flow of water and nutrients into the Ganges-Brahmaputra-Megha Delta. The results show that climate change could have significant impacts on river flows, both increasing wet season flows and leading to more frequent droughts. Socio-economic changes could impact flows during droughts, when irrigation will further reduce water availability. The modelling work also explores how management and policy interventions can reduce these impacts.

Participants at the workshop shared case studies of a variety of extreme events, from glacier lake dam bursts in the Himalayas, to heat waves in Moscow, wind gust events in Switzerland, and extreme snow storms in Austria.

An important outcome from the workshop will be a policy document for the 21st Conference of Parties (COP) in Paris in December 2015. The meeting’s discussions will also be presented to the EU Science Managers to inform them of this key area of research, which is largely missing in the major EU Horizon 2020 research programme.

Visit the climate extremes workshop webpage

Read more about the ESPA Deltas project

View Paul Whitehead’s powerpoint presentation on modelling climate change and socio-economic pathways in the Ganges, Brahmaputra and Meghna rivers

Academic publications on modelling the the Ganges, Brahmaputra and Meghna rivers, in the Journal Environmental Science: Processes and Impacts:

/0 Comments/by

A new era of cooperation on the Nile River

Kevin Wheeler, DPhil candidate at the Environmental Change Institute, presented his work on the Grand Ethiopian Renaissance Dam at Chatham House of the Royal Institute of International Affairs.

The workshop, held on 25 March 2015, brought together experts to discuss infrastructure developments in the Horn of Africa and whether governments are working with local communities to balance the costs and benefits of these projects.

Kevin’s talk ‘The Grand Ethiopian Renaissance Dam and regional energy security’ was particularly timely given the well-publicised ‘Declaration of Principles’ signed between Egypt, Sudan and Ethiopia last week over future management of the Nile. Now the attention of the region is shifting to how the new Ethiopian dam might be operated and how this might positively or negatively affect the downstream countries of Sudan and Ethiopia.

Kevin presented potential strategies of filling and operating the dam, which is located on the Blue Nile River, and how this new infrastructure might meet the needs and development objectives of these countries. His DPhil research explores the costs and benefits of various degrees of coordinated management of Nile reservoirs, and how these potential agreements might be affected by climate change.

/0 Comments/by

Oxford University and UK Government to lead research to improve global water supply

A global research project led by the University of Oxford and backed by the British Government will help millions of people in Africa and South Asia to have reliable access to water.

Photo credit: Rob Hope

Researcher sampling water quality at a water pump in Kenya

Announced by International Development Minister Baroness Northover, the seven year research project will receive a £15 million grant from the Department for International Development.

A changing and variable climate, increasing demand for water, crumbling infrastructure, unaffordable bills and water contamination have caused a chronic lack of safe, reliable and clean water in the developing world.

Baroness Northover said: ‘Access to water is a defining challenge for the 21st century. The UK has already helped 43 million people to access clean water, but there is far more to be done. Research into how water resources can be better managed will help millions of the world’s poorest and most vulnerable people.

‘Oxford University’s expertise will ensure we can generate new ways to give up to 5 million more people secure water resources in some of the world’s poorest countries.’

The programme’s initial focus will be on fragile states which face great water security risks. Some of the world’s poorest and most vulnerable people live in fragile states, rural hinterlands, floodplains and rapidly growing urban slums where they have very low resilience to water shortages and the least capacity to cope.

The announcement comes ahead of World Water Day on 22 March 2015 and the release of the 2015 United Nations World Water Development Report, which calls for urgent action in managing the earth’s water resources.

The researchers aim to create a risk-based framework for policy-makers, assessing risk at global, national and individual household scales. Researchers will generate data on climate, hydrology, health, poverty and demographic trends to provide an overarching context for governments and international organisations to inform future decision-making to improve water security. Ensuring the research translates into real influence and change leading to improvements for the poorest will be a priority for the programme.

The University of Oxford Vice-Chancellor, Professor Andrew Hamilton, said: ‘This research programme is an outstanding example of how the University of Oxford can contribute to the international effort to improve water security globally. Our researchers work to provide innovative solutions to the pressing challenges of climate change, population growth and sustainable development. They are helping to ensure that more people living in poverty can rely on safe water supplies and working to minimise the impact of droughts and floods on lives and livelihoods.’

The Programme Director Dr Rob Hope, from the Smith School of Enterprise and the Environment in the School of Geography and the Environment, said: ‘Living in poverty has long been synonymous with the struggle for water security. This programme establishes a global science-practitioner partnership to design, test and replicate more effective policy, methods and technologies to improve water security and reduce poverty.’

The global science-practitioner partnership will work with UNICEF global, regional and country programmes to provide the capacity and expertise in delivering water security for children and communities in the greatest need.

Sanjay Wijesekera, UNICEF’s Chief of Water, Sanitation and Hygiene said: ‘Water security will be one of the major challenges in making sure that the poorest and most vulnerable children gain access to drinking water and sanitation. We are excited to be partnering with the University of Oxford to help countries access the best possible evidence for making decisions that will improve the lives of millions of people.’

Media coverage

/0 Comments/by

Learning to live with floods and droughts

A panel discussion on Living with Floods and Droughts: Adapting to Hydro-Climatic Extremes was held at the School of Geography and the Environment on 1 December 2014, and brought together a number of water and climate experts in the field.

Dr Simon Dadson, School of Geography and the Environment, chaired the event and highlighted the huge impacts that floods and droughts can have in both developed and developing countries. Examples include the 2013/14 floods in the UK and the 2011 floods in Thailand which caused an estimated $43 billion in economic losses.

At the other end of the hydrological spectrum, a severe drought in 2008 led the city of Barcelona to import water in tankers from France. East African droughts in 2010/11 brought about a devastating humanitarian crisis which counted 260,000 deaths and 1 million refugees.

Dr Dadson invited the panel to reflect on how flood and drought risks might change under future scenarios of climate change, and what actions could be taken to adapt to these changes.

Professor Jim Hall, Director of the Environmental Change Institute, said that we have tended to cope with floods and droughts reactively in the past, with extreme events triggering policy action only after they have occurred.

However, he said that a transition is underway to a risk-based approach which bases decision making on a much broader range of possible events and consequences that might occur in the future. This “quiet revolution of thinking and methodology” in risk analysis means that we are better than ever equipped to live with floods and droughts, he said.

“The single most important asset we have to manage present and future risks from extreme floods and droughts is the long-term observational record” said Professor Rob Wilby from Loughborough University. He stressed the value of using historic records and information from climate models to understand the processes driving extreme events and how risks change through time.

Climate models can be used to predict future risks. However as Dr Richard Betts, Head of Climate Impacts at the Met Office pointed out, different models can produce widely varying results and it is impossible to test their accuracy. There is work to be done both in improving the science, and in improving the communication of uncertainties, he said.

Drawing on expertise in climate change adaptation in developing countries, Professor Declan Conway from the London School of Economics and Political Science reminded the audience that the adaptation process has many steps and the production of climate scenarios is just one step.

Professor Conway reflected on what lessons from climate change adaptation in the UK might be relevant for developing countries. In this country, legislation has played an important role in forcing institutions to assess and act on risks facing society. He also mentioned the importance of monitoring – of changes that are occurring now, the consequences of those changes, and the effect of adaptation policies.

Professor Mike Acreman of the Centre for Ecology & Hydrology said that natural ecosystems are completely adapted to floods and droughts as these events are all part of the natural cycle. Floods or droughts can only been seen as ‘good or ‘bad’ when considering how they impact human uses of the environment.

The natural environment can play a role in influencing the hydrological cycle, Professor Acreman said, but only on a small scale and to a limited degree. For example, restoring wetlands can help store floodwater and release it slowly during drier periods. Payments for ecosystem services may provide a mechanism to fund conservation and restoration of the natural environment to help combat future floods.

/0 Comments/by

Coping with the curse of freshwater variability

Oxford scientists say that institutions, infrastructure and information are the key ingredients for coping with freshwater variability and enabling economic growth, in an article published in Science.

The authors, which include Prof Jim Hall, Prof David Grey and Dr Simon Dadson, say that a key challenge to achieving water security is managing the risks posed by variable and unpredictable freshwater resources. Building resilience to these risks requires a transformation in the way investments are made.

Extreme events such as floods and droughts are hard to predict and future changes in variability are highly uncertain. The article highlights three dimensions of freshwater variability: change within the year (seasonal and monthly), year-to-year, and the unpredictable timing and intensity of extremes. When these three dimensions combine the situation is “most challenging – a wicked combination of hydrology that confronts the world’s poorest people,” say the authors.

The article warns that the inability to cope with variability can place serious burdens on society and the economy. Extreme events such as droughts and floods have ripple effects through the economy. For example, floods in Thailand in 2011 caused $43 billion in losses. Meanwhile in Ethiopia economic growth is 38% less that what would be expected based on average rainfall, due to the country’s complex hydrology.

Countries can do very little about their natural endowment of water: when and where it rains and how much water evaporates, infiltrates into the ground, and runs into rivers and lakes. However for those countries burdened with highly variable hydrology, investment in water management can help buy their way out of water insecurity.

The study’s analysis shows that countries that have achieved economic growth, despite high variability in freshwater resources, have invested heavily to reduce risk. In river basins with complex hydrology where there has been low investment, the economy suffers.

Countries along river basins with less variability are more wealthy, even though investments have sometimes been quite modest. Where the hydrology is highly variable, additional investment is needed to transition from water-insecure to secure, but this is least affordable and hardest to deliver in the poorest countries. Climate change may increase variability further, making water security an even more distant goal for countries already underequipped to cope.

F2

 

The authors highlight “the three ‘I’s” as essential for adapting to freshwater variability: institutions and good governance (such as river basin organisations, legal systems, and water pricing), infrastructure (such as water storage, wastewater treatment, groundwater wells) and information (including monitoring, forecast and warning systems, and modelling tools).

Crucially, coping with variability involves a combination of institutions, infrastructure and information – rarely will they generate their full benefits alone.

The article calls for a new approach to investing in water security. A broader and longer-term vision is needed that looks beyond individual projects to the sequence of investments that can create a pathway to water security. Context also matters when it comes to what combination and sequence of investments are needed.

This new approach will focus on risks, trade-offs and uncertainties to enable decision-makers to choose between alternative investment pathways and build a more water secure future.

This research stems from the work of a global Task Force on Water Security and Sustainable Growth, an initiative of the Global Water Partnership and OECD, co-chaired by Oxford University’s Professor Jim Hall and Professor David Grey.

Reference

Hall, J.W., Grey, D., Garrick, D., Fung, F., Brown, C., Dadson, S.J. and Sadoff, C.W. (2014) Coping with the curse of freshwater variability. Science, 346(6208): 429-430.

/0 Comments/by

Attributing extreme weather to climate change in real-time

Dr Friederike Otto examines the question of how extreme weather events might be linked to climate change in this blog entry for the Carbon Brief.

The question of how extreme weather events might be linked to climate change is a key one.

It’s particularly important because in many regions, extreme weather like heatwaves, floods and droughts cause more damage than other, more predictable consequences of climate change, such as sea-level rise.

Scientists know that an increase in average temperature as the climate changes will lead to an increase in the number or magnitude of some extreme events, while others will get less likely.

But the chaotic nature of weather means it’s generally impossible to say, for any particular event, that it only happened because of climate change.

Read more on the Carbon Brief website

Dr Friederike Otto is a research fellow in the ECI Global Climate Science Programme at the Uiversity of Oxford and scientific coordinator of climateprediction.net.

/0 Comments/by