̽��ֱ�� of Cambridge - drought

Extreme drought contributed to barbarian invasion of late Roman Britain, tree-ring study reveals

ta385 — Thu, 17 Apr 2025 06:00:00 +0000

̽��ֱ��‘Barbarian Conspiracy’ of 367 CE was one of the most severe threats to Rome’s hold on Britain since the Boudiccan revolt three centuries earlier. Contemporary sources indicate that components of the garrison on Hadrian’s wall rebelled and allowed the Picts to attack the Roman province by land and sea. Simultaneously, the Scotti from modern-day Ireland invaded broadly in the west, and Saxons from the continent landed in the south.

Senior Roman commanders were captured or killed, and some soldiers reportedly deserted and joined the invaders. Throughout the spring and summer, small groups roamed and plundered the countryside. Britain’s descent into anarchy was disastrous for Rome and it took two years for generals dispatched by Valentian I, Emperor of the Western Roman Empire, to restore order. ̽��ֱ��final remnants of official Roman administration left Britain some 40 years later around 410 CE.

̽��ֱ�� ̽��ֱ�� of Cambridge-led study, published today in Climatic Change, used oak tree-ring records to reconstruct temperature and precipitation levels in southern Britain during and after the ‘Barbarian Conspiracy’ in 367 CE. Combining this data with surviving Roman accounts, the researchers argue that severe summer droughts in 364, 365 and 366 CE were a driving force in these pivotal events.

First author Charles Norman, from Cambridge’s Department of Geography, said: “We don’t have much archaeological evidence for the ‘Barbarian Conspiracy’. Written accounts from the period give some background, but our findings provide an explanation for the catalyst of this major event.”

̽��ֱ��researchers found that southern Britain experienced an exceptional sequence of remarkably dry summers from 364 to 366 CE. In the period 350 to 500 CE, average monthly reconstructed rainfall in the main growing season (April–July) was 51 mm. But in 364 CE, it fell to just 29mm. 365 CE was even worse with 28mm, and 37mm the following year kept the area in crisis.

Professor Ulf Büntgen, from Cambridge’s Department of Geography, said: “Three consecutive droughts would have had a devastating impact on the productivity of Roman Britain’s most important agricultural region. As Roman writers tell us, this resulted in food shortages with all of the destabilising societal effects this brings.”

Between 1836 and 2024 CE, southern Britain only experienced droughts of a similar magnitude seven times – mostly in recent decades, and none of these were consecutive, emphasising how exceptional these droughts were in Roman times. ̽��ֱ��researchers identified no other major droughts in southern Britain in the period 350–500 CE and found that other parts of northwestern Europe escaped these conditions.

Roman Britain’s main produce were crops like spelt wheat and six-row barley. Because the province had a wet climate, sowing these crops in spring was more viable than in winter, but this made them vulnerable to late spring and early summer moisture deficits, and early summer droughts could lead to total crop failure.

̽��ֱ��researchers point to surviving accounts written by Roman chroniclers to corroborate these drought-driven grain deficits. By 367 CE, Ammianus Marcellinus described the population of Britain as in the ‘utmost conditions of famine’.

“Drought from 364 to 366 CE would have impacted spring-sown crop growth substantially, triggering poor harvests,” Charles Norman said. “This would have reduced the grain supply to Hadrian’s Wall, providing a plausible motive for the rebellion there which allowed the Picts into northern Britain.”

̽��ֱ��study suggests that given the crucial role of grain in the contract between soldiers and the army, grain deficits may have contributed to other desertions in this period, and therefore a general weakening of the Roman army in Britain. In addition, the geographic isolation of Roman Britain likely combined with the severity of the prolonged drought to reduce the ability of Rome to alleviate the deficits.

Ultimately the researchers argue that military and societal breakdown in Roman Britain provided an ideal opportunity for peripheral tribes, including the Picts, Scotti and Saxons, to invade the province en masse with the intention of raiding rather than conquest. Their finding that the most severe conditions were restricted to southern Britain undermines the idea that famines in other provinces might have forced these tribes to invade.

Andreas Rzepecki, from the Generaldirektion Kulturelles Erbe Rheinland-Pfalz, said: “Our findings align with the accounts of Roman chroniclers and the seemingly coordinated nature of the ‘Conspiracy’ suggests an organised movement of strong onto weak, rather than a more chaotic assault had the invaders been in a state of desperation.”

“ ̽��ֱ��prolonged and extreme drought seems to have occurred during a particularly poor period for Roman Britain, in which food and military resources were being stripped for the Rhine frontier, while immigratory pressures increased.”

“These factors limited resilience, and meant a drought induced, partial-military rebellion and subsequent external invasion were able to overwhelm the weakened defences.”

̽��ֱ��researchers expanded their climate-conflict analysis to the entire Roman Empire for the period 350–476 CE. They reconstructed the climate conditions immediately before and after 106 battles and found that a statistically significant number of battles were fought following dry years.

Tatiana Bebchuk, from Cambridge’s Department of Geography, said: “ ̽��ֱ��relationship between climate and conflict is becoming increasingly clear in our own time so these findings aren’t just important for historians. Extreme climate conditions lead to hunger, which can lead to societal challenges, which eventually lead to outright conflict.”

Charles Norman, Ulf Büntgen, Paul Krusic and Tatiana Bebchuk are based at the Department of Geography, ̽��ֱ�� of Cambridge; Lothar Schwinden and Andreas Rzepecki are from the Generaldirektion Kulturelles Erbe Rheinland-Pfalz in Trier. Ulf Büntgen is also affiliated with the Global Change Research Institute, Czech Academy of Sciences and the Department of Geography, Masaryk ̽��ֱ�� in Brno.

Reference

C Norman, L Schwinden, P Krusic, A Rzepecki, T Bebchuk, U Büntgen, ‘Droughts and conflicts during the late Roman period’, Climatic Change (2025). DOI: 10.1007/s10584-025-03925-4

Funding

Charles Norman was supported by Wolfson College, ̽��ֱ�� of Cambridge (John Hughes PhD Studentship). Ulf Büntgen received funding from the Czech Science Foundation (# 23-08049S; Hydro8), the ERC Advanced Grant (# 882727; Monostar), and the ERC Synergy Grant (# 101118880; Synergy-Plague).

Three consecutive years of drought contributed to the ‘Barbarian Conspiracy’, a pivotal moment in the history of Roman Britain, a new Cambridge-led study reveals. Researchers argue that Picts, Scotti and Saxons took advantage of famine and societal breakdown caused by an extreme period of drought to inflict crushing blows on weakened Roman defences in 367 CE. While Rome eventually restored order, some historians argue that the province never fully recovered.

Our findings provide an explanation for the catalyst of this major event.

Charles Norman

Adam Cuerden

Milecastle 39 on Hadrian's Wall

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Licence type:

Public Domain

How a drought led to the rise of skateboarding in 1970s California

sc604 — Tue, 12 Dec 2023 13:00:11 +0000

Why did professional skateboarding arise in southern California in the 1970s? Was it a coincidence, or was it a perfect storm of multiple factors?

Drought encouraged Attila’s Huns to attack the Roman empire, tree rings suggest

ta385 — Thu, 15 Dec 2022 09:00:00 +0000

Hungary has just experienced its driest summer since meteorological measurements began, devastating the country’s usually productive farmland. Archaeologists now suggest that similar conditions in the 5th century may have encouraged animal herders to become raiders, with devastating consequences for the Roman empire.

̽��ֱ��study, published in the Journal of Roman Archaeology, argues that extreme drought spells from the 430s – 450s CE disrupted ways of life in the Danube frontier provinces of the eastern Roman empire, forcing Hunnic peoples to adopt new strategies to ‘buffer against severe economic challenges’.

̽��ֱ��authors, Associate Professor Susanne Hakenbeck from Cambridge’s Department of Archaeology and Professor Ulf Büntgen from the ̽��ֱ��’s Department of Geography, came to their conclusions after assessing a new tree ring-based hydroclimate reconstruction, as well as archaeological and historical evidence.

̽��ֱ��Hunnic incursions into eastern and central Europe in the 4th and 5th centuries CE have long been viewed as the initial crisis that triggered the so-called ‘Great Migrations’ of ‘Barbarian Tribes’, leading to the fall of the Roman empire. But where the Huns came from and what their impact on the late Roman provinces actually was unclear.

New climate data reconstructed from tree rings by Prof Büntgen and colleagues provides information about yearly changes in climate over the last 2000 years. It shows that Hungary experienced episodes of unusually dry summers in the 4th and 5th centuries. Hakenbeck and Büntgen point out that climatic fluctuations, in particular drought spells from 420 to 450 CE, would have reduced crop yields and pasture for animals beyond the floodplains of the Danube and Tisza.

Büntgen said: “Tree ring data gives us an amazing opportunity to link climatic conditions to human activity on a year-by-year basis. We found that periods of drought recorded in biochemical signals in tree-rings coincided with an intensification of raiding activity in the region.”

Recent isotopic analysis of skeletons from the region, including by Dr Hakenbeck, suggests that Hunnic peoples responded to climate stress by migrating and by mixing agricultural and pastoral diets.

Hakenbeck said: “If resource scarcity became too extreme, settled populations may have been forced to move, diversify their subsistence practices and switch between farming and mobile animal herding. These could have been important insurance strategies during a climatic downturn.”

But the study also argues that some Hunnic peoples dramatically changed their social and political organization to become violent raiders.

From herders to raiders

Hunnic attacks on the Roman frontier intensified after Attila came to power in the late 430s. ̽��ֱ��Huns increasingly demanded gold payments and eventually a strip of Roman territory along the Danube. In 451 CE, the Huns invaded Gaul and a year later they invaded northern Italy.

Traditionally, the Huns have been cast as violent barbarians driven by an “infinite thirst for gold”. But, as this study points out, the historical sources documenting these events were primary written by elite Romans who had little direct experience of the peoples and events they described.

“Historical sources tell us that Roman and Hun diplomacy was extremely complex,” Dr Hakenbeck said. “Initially it involved mutually beneficial arrangements, resulting in Hun elites gaining access to vast amounts of gold. This system of collaboration broke down in the 440s, leading to regular raids of Roman lands and increasing demands for gold.”

̽��ֱ��study argues that if current dating of events is correct, the most devastating Hunnic incursions of 447, 451 and 452 CE coincided with extremely dry summers in the Carpathian Basin.

Hakenbeck said: “Climate-induced economic disruption may have required Attila and others of high rank to extract gold from the Roman provinces to keep war bands and maintain inter-elite loyalties. Former horse-riding animal herders appear to have become raiders.”

Historical sources describe the Huns at this time as a highly stratified group with a military organization that was difficult to counter, even for the Roman armies.

̽��ֱ��study suggests that one reason why the Huns attacked the provinces of Thrace and Illyricum in 422, 442, and 447 CE was to acquire food and livestock, rather than gold, but accepts that concrete evidence is needed to confirm this. ̽��ֱ��authors also suggest that Attila demanded a strip of land ‘five days’ journey wide’ along the Danube because this could have offered better grazing in a time of drought.

“Climate alters what environments can provide and this can lead people to make decisions that affect their economy, and their social and political organization," Hakenbeck said. "Such decisions are not straightforwardly rational, nor are their consequences necessarily successful in the long term.”

“This example from history shows that people respond to climate stress in complex and unpredictable ways, and that short-term solutions can have negative consequences in the long term.”

By the 450s CE, just a few decades of their appearance in central Europe, the Huns had disappeared. Attila himself died in 453 CE.

Reference

S.E. Hakenbeck & U. Büntgen, ‘ ̽��ֱ��role of drought during the Hunnic incursions into central-east Europe in the 4th and 5th centuries CE’, Journal of Roman Archaeology (2022). DOI: 10.1017/S1047759422000332

Hunnic peoples migrated westward across Eurasia, switched between farming and herding, and became violent raiders in response to severe drought in the Danube frontier provinces of the Roman empire, a new study argues.

People respond to climate stress in complex and unpredictable ways

Susanne Hakenbeck

Stefan Lefnaer

Devínska Kobyla Forest steppe in Slovakia

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Licence type:

Attribution-ShareAlike

Cambridge experts on UK drought and climate change

lw355 — Tue, 16 Aug 2022 09:25:55 +0000

From pollinators to profits, food to fires, here's what Cambridge experts say about the impacts of water scarcity – and what it signals about our changing climate.

European summer droughts since 2015 unprecedented in past two millennia

sc604 — Mon, 15 Mar 2021 14:37:48 +0000

Recent summer droughts in Europe are far more severe than anything in the past 2,100 years, according to a new study.

Scientists measure severity of drought during the Maya collapse

sc604 — Thu, 02 Aug 2018 18:00:00 +0000

Researchers from the ̽��ֱ�� of Cambridge and the ̽��ֱ�� of Florida developed a method to measure the different isotopes of water trapped in gypsum, a mineral that forms during times of drought when the water level is lowered, in Lake Chichancanab in Mexico’s Yucatán Peninsula where the Maya were based.

Based on these measurements, the researchers found that annual precipitation decreased between 41% and 54% relative to today during the period of the Maya civilisation’s collapse, with periods of up to 70% rainfall reduction during peak drought conditions, and that relative humidity declined by 2% to 7% relative to today. ̽��ֱ��results are reported in the journal Science.

“ ̽��ֱ��role of climate change in the collapse of Classic Maya civilisation is somewhat controversial, partly because previous records are limited to qualitative reconstructions, for example whether conditions were wetter or drier,” said Nick Evans, a PhD student in Cambridge’s Department of Earth Sciences and the paper’s first author. “Our study represents a substantial advance as it provides statistically robust estimates of rainfall and humidity levels during the Maya downfall.”

Maya civilisation is divided into four main periods: the Preclassic (2000 BCE – 250 CE), Classic (250 CE – 800 CE), terminal Classic (800 - 1000 CE) and Postclassic (1000 CE – 1539 CE). ̽��ֱ��Classic period was marked by the construction of monumental architecture, intellectual and artistic development, and the growth of large city-states.

During the 9^th century however, there was a major political collapse in the central Maya region: their famous limestone cities were abandoned and dynasties ended. And while the Maya people survived beyond this period, their political and economic power was depleted.

There are multiple theories as to what caused the collapse of the Maya civilisation, such as invasion, war, environmental degradation and collapsing trade routes. In the 1990s, however, researchers were able to piece together climate records for the period of the Maya collapse and found that it correlated with an extended period of extreme drought.

Professor David Hodell, Director of Cambridge’s Godwin Laboratory for Palaeoclimate Research and the senior author of the current paper, provided the first physical evidence of a correlation between this period of drought at Lake Chichancanab and the downfall of the Classic Maya civilisation in a paper published in 1995.

Now, Hodell and his colleagues have applied a new method and estimated the extent of this drought. Using a new geochemical method to measure the water locked within gypsum from Chichancanab, the researchers have built a complete model of hydrological conditions during the terminal Classic Period when the Maya collapsed.

̽��ֱ��researchers analysed the different isotopes of water trapped within the crystal structure of the gypsum to determine changes in rainfall and relative humidity during the Maya downfall.

They measured three oxygen and two hydrogen isotopes to reconstruct the history of the lake water between 800 and 1000 CE. When gypsum forms, water molecules are incorporated directly into its crystalline structure, and this water records the different isotopes that were present in the ancient lake water at the time of its formation. “This method is highly accurate and is almost like measuring the water itself,” said Evans.

In periods of drought, more water evaporates from lakes such as Chichancanab, and because the lighter isotopes of water evaporate faster, the water becomes heavier. A higher proportion of the heavier isotopes, such as oxygen-18 and hydrogen-2 (deuterium), would indicate drought conditions. By mapping the proportion of the different isotopes contained within each layer of gypsum, the researchers were able to build a model to estimate past changes in rainfall and relative humidity over the period of the Maya collapse.

This quantitative climate data can be used to better predict how these drought conditions may have affected agriculture, including yields of the Maya’s staple crops, such as maize.

̽��ֱ��research was supported by the European Research Council.

Reference:
Nicholas P. Evans et al. ‘Quantification of Drought During the Collapse of the Classic Maya Civilization.’ Science (2018). DOI: 10.1126/science.aas9871

Inset image: Lake Chichancanab, the site of the study. Chichancanab means “Little Sea” in Yucatec Maya, reflecting its relatively salty water composed dominantly of calcium and sulfate. (Credit: Mark Brenner)

̽��ֱ��severity of drought conditions during the demise of the Maya civilisation about 1,000 years ago has been quantified, representing another piece of evidence that could be used to solve the longstanding mystery of what caused the downfall of one of the ancient world’s great civilisations.

̽��ֱ��role of climate change in the collapse of Classic Maya civilisation is somewhat controversial, partly because previous records are limited to qualitative reconstructions.

Nick Evans

Edzná ruins, Campeche

Yes

Opinion: Droughts and floods: India’s water crises demand more than grand projects

Anonymous — Mon, 06 Jun 2016 16:17:48 +0000

India is facing one of its most serious droughts in recent memory – official estimates suggest that at least 330m people are likely to be affected by acute shortages of water. As the subcontinent awaits the imminent arrival of the monsoon rains, bringing relief to those who have suffered the long, dry and exceptionally warm summer, the crisis affecting India’s water resources is high on the public agenda.

Unprecedented drought demands unconventional responses, and there have been some fairly unusual attempts to address this year’s shortage. Perhaps most dramatic was the deployment of railway wagons to transport 500,000 litres of water per day across the Deccan plateau, with the train traversing more than 300km to provide relief to the district of Latur in Maharashtra state.

̽��ֱ��need to shift water on this scale sheds light on the key issue that makes water planning in the Indian subcontinent so challenging. While the region gets considerable precipitation most years from the annual monsoon, the rain tends to fall in particular places – and for only a short period of time (about three months). This water needs to be stored, and made to last for the entire year.

In most years, it also means that there is often too much water in some places, resulting in as much distress due to flooding as there currently is due to drought. So there is a spatial challenge as well – water from the surplus regions needs to reach those with a shortfall, and the water train deployed in Maharashtra is one attempt to achieve this.

Grand ambitions

̽��ֱ��current crisis has led the Indian government to announce that it hopes to resurrect an ambitious plan to try and link the major river basins of the country, under the Interlinking of Rivers (ILR) Project. ̽��ֱ��scale and magnitude of this exercise, both financial (it is estimated to cost more than £100 billion) and in engineering terms (involving the transfer of 174 billion cubic metres of water annually) is unprecedented.

Critics suggest that it is unlikely to work and is likely to create further ecological and social disruption, especially due to the uncertainties in weather and precipitation patterns due to climate change. There is a risk that other alternatives, perhaps less dramatic in their scope, might be neglected in the rush for the big headline-grabbing schemes.

A specific way forward might be to work more directly with natural processes to secure the regeneration of water sources at the local level. In the dry plains, this involves the revitalisation of aquifers and the replenishment of groundwater through recharge during the monsoon, as has been attempted already in some regions. In the hilly areas, there is considerable scope for investment in spring recharge and source sustainability, as has been undertaken on a significant scale in the Himalayan state of Sikkim.

Our current research is examining the need to invest in source protection and sustainability in detail, especially in the Himalayas, which have been described as the “Water Towers of Asia”. Urbanisation trends in the region suggest that there will be a growing number of small towns and settlements that will need water infrastructure to meet their needs – and there is a critical need to secure these water sources.

Deforestation, land conversion and degradation, as well as urban encroachment due to illegal construction, pose major threats to the water bearing capacity of the Himalayan landscape. There is an urgent need to invest in the identification, protection and restoration of these “critical water zones”.

Potential for conflict

̽��ֱ��Himalayan context also demonstrates the transboundary nature of the water issue. ̽��ֱ��Hindu Kush Himalayan region extends across eight countries, from Afghanistan to Myanmar, and supports ten major river systems, potentially affecting the lives of more than 1.5 billion people. Cooperation across political boundaries is vital to manage these fragile resources, further threatened by the uncertain impacts of climate change.

̽��ֱ��Hindu Kush Himalayan region is the source for ten major river systems in Asia. Author provided

There is some hope, despite three major wars since independence, that India and Pakistan have managed to maintain some semblance of cooperation under the Indus Waters Treaty, which was negotiated in 1960. However, analysts suggest that regional conflict over water is going to worsen – and much depends on the role of China, which is the dominant upstream water controller in the region.

̽��ֱ��other key response is managing water demand – and making explicit choices over alternative uses. This year, the shifting of Indian Premier League cricket matches away from water-scarce Maharashtra was a high-profile, though somewhat symbolic, example of an explicit prioritisation of water use.

More generally, though, managing water demands has rarely been prioritised. Water-thirsty crops – sugarcane, for example – dominate the landscape in the dry regions of Marathwada and Vidarbha in Maharashtra. Farmers receive subsidies on energy, which allow them to pump dry the already-depleted aquifers in other parts of the country. And, there are important issues of distributional equity – the poor in many urban contexts pay significantly more per litre for erratic and unreliable water, while their richer neighbours luxuriate in swimming pools and spend weekends on plush golf greens.

Water is an issue that cuts across all aspects of social and economic life in India. Compartmentalised responses are unlikely to be adequate to address the current crises. There is a need for an integrated approach, which addresses source sustainability, land use management, agricultural strategies, demand management and the distribution and pricing of water. With growing pressures due to climate change, migration and population growth, creative and imaginative governance is needed to manage this precious resource.

Bhaskar Vira, Reader in Political Economy at the Department of Geography and Fellow of Fitzwilliam College; Director, ̽��ֱ�� of Cambridge Conservation Research Institute, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

Bhaskar Vira (Department of Geography and ̽��ֱ�� of Cambridge Conservation Research Institute) discusses ways of dealing with the crisis affecting India’s water resources.

Rita Willaert

Brahmaputra - Assam

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Licence type:

Attribution-Noncommerical

Opinion: Paying people to stay away is not always the best way to protect watersheds

sc604 — Thu, 24 Dec 2015 08:00:00 +0000

In the American West, unprecedented droughts have caused extreme water shortages. ̽��ֱ��current drought in California and across the West is entering its fourth year, with precipitation and water storage reaching record low levels.

Such drought and water scarcity are only likely to increase with climate change, and the chances of a “megadrought” – one that lasts 35 years or longer — affecting the Southwest and central Great Plains by 2100 are above 80% if greenhouse gas emissions are not reduced.

Droughts are currently ranked second in the US in terms of national weather-related damages, with annual losses just shy of US$9 billion annually. Such economic impacts are likely to worsen as the century progresses.

As the frequency and severity of droughts increases, the successful protection of watersheds to capture, store and deliver water downstream in catchments will become increasingly important, even as the effective protection of watersheds becomes more challenging.

Since the early 2000s, the prevailing view in watershed protection is that paying upstream resource users for avoiding harmful activities, or rewarding positive action, is the most effective and direct method. This is the case of the Catskills watershed in New York, where environmentally sound economic development is incentivized.

There are, however, many different ways communities can invest in watersheds to harness the benefits they provide downstream communities.

In a recently published paper in the journal Ecosystem Services, we highlight an alternative option with the example of Salt Lake City’s successful management of the Wasatch watershed. Instead of offering financial incentives for the “ecosystem services” provided by this watershed, planners use regulations to secure the continued delivery of water, while allowing for recreational and public use.

̽��ֱ��successful management of the Wasatch demonstrates that an overreliance on markets to deliver watershed protection might be misguided.

Perhaps part of the reason for this overreliance on market-based tools is a paucity of alternative success stories of watershed management. We note that the Wasatch story has been largely absent from much of the literature that discusses the potential of investing in watersheds for the important services that they provide. This absence results in an incomplete understanding of options to secure watershed ecosystem services, and limits the consideration of alternative watershed conservation approaches.

̽��ֱ��Wasatch management strategy

̽��ֱ��Wasatch is a 185-square-mile watershed that is an important drinking water source to over half a million people in Salt Lake City. This water comes from the annual snowmelt from the 11,000-foot-high peaks in the Wasatch range, which act as Salt Lake City’s virtual reservoir.

Salt Lake City’s management of the Wasatch watershed is somewhat unusual in contemporary examples of watershed protection in that it is focused on nonexclusionary regulation – that is, allowing permitted uses – and zoning to protect the urban water supply. For instance, the cities of Portland, Oregon and Santa Fe, New Mexico have worked with the US Forest Service to prohibit public access to source water watersheds within forests to protect drinking water supplies. In contrast, the governance of the Wasatch allows for public access and both commercial and noncommercial activities to occur in the watershed, such as skiing and mountain biking. It also imposes restrictions on allowable uses, such as restricting dogs in the watershed.

This permitted use, socially negotiated, helps mitigate the potential trade-offs associated with protection activities.

̽��ֱ��suite of policies that protect the Wasatch do not include a “payments for ecosystem services” or other market-based incentives component, nor has there been any discussion of compensating potential resource users in the watershed for foregone economic opportunities. By not having a market-based incentives component, the Wasatch example provides an alternative regulatory-based solution for the protection of natural capital, which contrasts with the now prevalent market-based payments approach.

Importantly, the Wasatch example reinforces the rights of citizens to derive positive benefits from nature, without these being mediated through the mechanism of markets. In most payment-based systems, potential harm to a watershed is avoided by organizing beneficiaries so that they can compensate upstream resource users for foregone activities. In contrast, reliance on regulation and permitted activities supports the ‘polluter pays principle,’ which might be more appropriate in many circumstances.

Why we need alternative strategies

With the American West facing ever-increasing droughts, policymakers will be faced with the increasingly difficult task of protecting and preserving water supplies. Thus, awareness of alternative, successful strategies of watershed protection and management is crucially important.

̽��ֱ��Wasatch offers an important example of how natural capital can be instrumentally and economically valued, but conserved via regulatory approaches and land use management and zoning, rather than a reliance on the creation of water markets, which are often misplaced and not suitable. Bringing stakeholders together to negotiate allowable uses that preserve critical watershed functions is an additional option within the policymaker’s toolkit, and one that is at risk of being forgotten in the rush to payment-based systems.

Libby Blanchard, Gates Cambridge Scholar and PhD Candidate, ̽��ֱ�� of Cambridge and Bhaskar Vira, Reader in Political Economy at the Department of Geography and Fellow of Fitzwilliam College; Director, ̽��ֱ�� of Cambridge Conservation Research Institute, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

Libby Blanchard and Bhaskar Vira from Cambridge's Department of Geography argue that we need to consider alternative approaches in order to protect watersheds.

̽��ֱ��successful management of the Wasatch demonstrates that an overreliance on markets to deliver watershed protection might be misguided.

Bhaskar Vira

Silver Lake, Wasatch watershed, Utah

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes