Posts

Drought—no longer uncommon topic in England, 1976 drought now 4x more likely to occur

Henny van Lanen, a guest speaker, mentioned in his opening remarks in Oxford’s 2019 conference on Drought and Water Scarcity, water regulators in northwest Europe are biased towards floods and usually do not think about the effects of drought. And yet, Prof. Len Shaffrey, a specialist in meteorology and climate change also at the conference, announced that now the drought of 1976 is 4 times more likely to occur. There is a growing realisation however of the impacts of not having enough water, with the conference occurring in the wake of the speech by Sir James Bevan, the head of the Environment Agency, in which he warned that England could be in the jaws of death due to water scarcity within twenty-five years—no surprise to this audience of experts.

During a two-day conference, over 140 participants discussed the impacts of drought in the UK and throughout Europe and Turkey and the Americas—particularly in the summer of 2018. Comparing challenges and solutions in the international context gave perspectives regarding research in the UK and ideas for new solutions like the use of satellite data. Many sessions honed on technical details around planning and management, climatology, hydrology, and drought impacts, but also flagged the need for more governance and communication, and to place a greater value on water and its use.

This fourth annual conference was organized by the UK Droughts and Water Scarcity programme, which is  composed of five projects: Historic Droughts, Impetus, MaRIUS, DRY (Drought Risk and You), and ENDOWS. ENDOWS was responsible for a vibrant part of the conference where university students from Falmouth University shared their innovative media campaigns to raise issues of drought and water scarcity with the public. Ideas included racing to finish showering before a three-minute song ends. One afternoon breakout session was dedicated to a series of talks on how research can help communities and risk perception through communication to assist in behavioural changes.

 

/0 Comments/by

Ebro River’s Lessons for WSPM students

By Lucy Chen, WSPM ’18-’19

How can we equitably and efficiently manage and allocate scarce water resources in a river basin with high hydrological variability and competing demands among a multitude of stakeholders? On Sunday March 10, this was the question that MSc students from the Water Science, Policy and Management (WSPM) programme kept in the back of their minds as they embarked on a sun-drenched, week-long field trip across Spain’s Ebro River basin.

At 910 km, the Ebro is the longest river in Spain and its basin covers 17% of the country’s territory, spanning nine of its seventeen autonomous regions. Since the early 20th century, Spain’s national government under Franco funded ambitious dam projects to smooth out the steep hydrograph that brought unpredictable floods and droughts, promoting economic development and fostering nationalism. Today, vast stretches of vineyards, as well as almond and olive plantations in Ebro’s semi-arid central valley testify to this legacy while tensions between domestic and industrial supply, power generation, agriculture, recreation and conservation form an ongoing challenge for the Ebro Basin Water Authority, the Confederación Hydrograficá del Ebre (CHE).

The WSPM students took a plunge into the Ebro’s hydrological past to understand its future. They travelled to the once vibrant village of Ruesta, which was displaced by the construction of the Yesa dam in the 1950s; to the infamous Flix reservoir, which is still wrangling with more than half a century of mismanagement of industrial waste; to the Ebro Delta wetlands, where rice agriculture, tourism and conservation collectively face the threat of rising sea levels; and finally to the Llobregat desalination plant—a 235m € solution to Catalonia’s water scarcity problem that currently only operates at 10% of its full capacity—raising questions about the true cost of resilience. The field trip ended with an expert panel discussion on water management trade-offs with Michael Hanemann, David Grey, Dustin Garrick and Lucia de Stefano. The students came away with the important insight that trade-offs are ultimately an issue of balancing between objectives, the choice of which entails deep philosophical reflections about rights and entitlements. Although finding the suitable objectives can be achieved at a community level by inviting citizens to reflect upon their common future, balancing benefits and costs between the local and national levels will remain a perpetual challenge.

 

/0 Comments/by

Exploring whether water shortages are due to climate change or local factors

Human-induced climate change plays a clear and significant role in some extreme weather events but understanding the other risks at a local level is also important, say research studies just published. Oxford researchers examined serious droughts in Brazil, East Africa and the eastern Mediterranean.

The Jaguari Reservoir in Brazil. The left side image shows the area on August 3, 2014; the right side image shows the same area on August 16, 2013, before the recent drought began. Credit: NASA.

The Jaguari Reservoir in Brazil. The left side image shows the area on August 3, 2014; the right side image shows the same area on August 16, 2013, before the recent drought began. Credit: NASA.

Oxford researchers found that while there was a clear influence of human-induced climate change being responsible for the failing rains in the Levant region, the fingerprint of human activity was not detected in the other two where causes of water shortages were found to be local factors, such as increased water demand, population growth or methods used for irrigating the crops.

A study of a severe drought in São Paulo, the largest city in South America with a population of about 20 million, found that human-induced climate change was not a major influence. The researchers, led by Dr Friederike Otto of the Environmental Change Institute, examined the drought in terms of lack of rainfall, water availability, and water demand. They found the consequences of the drought – which included temporary water shut-offs, a spike in dengue fever cases, and higher electricity prices – were a result of low water availability combined with the numbers of people involved and damage to the infrastructure system. They also concluded that the lack of rainfall in southeast Brazil in 2014 and 2015 while unusual was not unprecedented, with similar dry periods occurring before, with the most recent being in 2001.

Dr Otto said: ‘It’s clear that a lack of rain and changes in evaporation were not the only players in the Brazilian drought. We therefore looked beyond the weather and found that the increased demand for water caused by a quadrupling of the city’s population since 1960 and rising water use increased risks of water shortages in this area.’

The second Oxford-led study by Dr Toby Marthews focused on the Horn of Africa and showed that droughts are a natural part of the climate in this region; yet, despite this, the population is heavily dependent on rain-fed agricultural methods. This made the population extremely vulnerable when there was no rain – as happened in the 2014 growing season, says the study. It adds though there was no influence of human-induced climate change causing a lack of rain that year, although it had led to higher temperatures and incoming radiation, making the population more vulnerable.

The third study focused on a lack of rainfall in what should have been the raining season in the Levant region in 2014. The researchers found human-induced climate change increased the risk of such a severe and unprecedented drought occurring by around 45%. Co-author Daniel Mitchell, from the Environmental Change Institute, said: ‘We used local station data and the modelling framework provide by the weather@home project to find clear signals for human influence on this uniquely persistent drought. The study suggests those living in the southern Levant region should be considering adaptations and ways of reducing the risks of extreme weather events, particularly if weather is set to become increasingly extreme in the future.’

Researchers from the ECI have led and co-authored five of the published studies that appear in the Bulletin of the American Meteorological Society’s annual special report, Explaining Extreme Events of 2014 from a Climate Perspective, which investigates the causes of a wide variety of extreme weather and climate events from around the world. All of the five rely on simulations provided by members of the public in the distributed computing framework weather@home. This project uses the combined power of tens of thousands of home computers to simulate the risks of human influence in extreme weather events.

Dr Otto, who leads the weather@home project, said: ‘The field called “extreme event attribution”, which looks for the fingerprints of human-caused warming in extreme weather events, has made considerable advances over the past decade. The goal of extreme event attribution science is to provide this evidence and we are in a unique position to provide the necessary modelling framework to look into the changing statistics of rare and unprecedented events.’

Read the report

Visit the weather@home website

/0 Comments/by