By Sarah Hamilton

Groundwater sustains nearly half of the world’s irrigated agriculture and supplies drinking water for roughly four billion people, yet over 150 years of large-scale extraction, weak governance regimes have repeatedly permitted unsustainable use. Over time, this has depleted major aquifers in arid regions around the world, producing falling water tables, land subsidence, and widespread well failures. These problems are frequently described in deterministic terms that emphasize the unknowable nature of the underground and the impossibility of effective regulation. Such depictions elide the fact that poor groundwater management is a political outcome that can be traced to specific historical decisions. In arid regions around the world, major groundwater users have repeatedly captured and deflected regulatory oversight to continue overexploitation long after its consequences were widely recognized.

Groundwater basins are a classic example of what political scientist and Nobel laureate Elinor Ostrom described as common-pool resources: resources from which it is difficult to exclude users, and in which each user’s access reduces what remains for others. Ostrom identified several conditions necessary for the effective governance of such resources, including clear resource boundaries, accurate monitoring, mechanisms for collective decision-making and conflict resolution, and, in the case of large systems, “nested” or polycentric institutions in which local authorities operate within broader regulatory frameworks.

The Southern California groundwater basins that formed the core of Ostrom’s doctoral work in the 1960s met many of these conditions and developed comparatively durable forms of local groundwater governance. But this stood in stark contrast to the rampant overexploitation occurring slightly farther north in the San Joaquin Valley, one of the most productive agricultural regions in the world. Over the course of the twentieth century, the heavily capitalized groundwater users of the San Joaquin routinely captured local institutions and kept groundwater pumping off the statewide legislative agenda, successfully lobbying for massive public works projects that transferred water from the wetter northern regions of the state in order to relieve pressure on rapidly depleting aquifers. Such projects proved Sisyphean, as the new water largely went to newly irrigated land and thirstier permanent crops while groundwater pumping continued to increase. By the 1970s, with major infrastructure projects completed and irrigators continuing to call for more water transfers, groundwater levels in many parts of the San Joaquin Valley had fallen by hundreds of feet from their prewar levels, while the land itself was subsiding by as much as a foot per year.

Unlike the municipalities and water agencies that dominated groundwater use in Southern California, the major groundwater users of the San Joaquin Valley had little incentive to pursue collective management of their aquifers. Without statewide regulation or collective-choice arrangements, the largest operations could simply dig deeper wells and pump more water while their less heavily capitalized neighbors’ wells ran dry. San Joaquin groundwater governance was carried out by more than a hundred fragmented local institutions, most of them organized around property lines, surface water systems, or both, rather than hydrogeological realities. The problem was not the absence of local institutions, but the absence of institutions capable of coordinating groundwater management at the scale of the aquifer itself. The mismatch between governance institutions and the boundaries of the shared resource itself made effective local management all but impossible.

It was not until California passed the Sustainable Groundwater Management Act in 2014, becoming the last western state to comprehensively regulate groundwater, that it established the conditions for a more genuinely polycentric system of groundwater governance. Even now, the profound mismanagement of the twentieth century has left the San Joaquin Valley on a path-dependent trajectory of overuse and resistance to sustainable management. Read more broadly, the history of groundwater in the San Joaquin Valley demonstrates that unsustainable groundwater use often persists not because the resource is unknowable or inherently ungovernable, but because powerful interests successfully resist the creation of institutions capable of managing it collectively. Ostrom’s framework also helps identify the specific historical junctures and institutional failures that produced these unsustainable but deeply embedded practices.

Sarah Hamilton is an Associate Professor of environmental history and leader of the Environmental Humanities Research Group at the University of Bergen. Her work on water history engages with questions of regulation, conservation, and the generation and deployment of knowledge and ignorance. Her first book, Cultivating Nature: The Making of a Valencian Working Landscape (Washington University Press 2018) received the Turku Book Award from the European Society for Environmental History. This talk is part of a larger project on large-scale groundwater exploitation around the world, which has also produced publications in The Journal of Modern History, Modern American History, and Hydrogeology Journal.

By Haozhi Pan, Professor at the School of International and Public Affairs, Shanghai Jiao Tong University.

Taming an Ocean of Information

Imagine trying to solve a global puzzle where the pieces are scattered across decades, written in hundreds of languages, and buried in thousands of dusty archives, diplomatic cables, and satellite data. This was the monumental challenge facing scientists seeking to understand what makes water cooperation between nations succeed or fail. Now, our study tries to crack the code, not with more diplomats, but with Artificial Intelligence. By harnessing the power of Large Language Models (LLMs), over 70 years of “messy” historical text are transformed into a predictive roadmap for global peace.

The study draws on more than 2,000 documented cases of transboundary water conflict and cooperation worldwide between 1951 and 2019. These cases range from high-profile disputes, such as tensions over the Nile or Indus rivers, to quieter examples of long-term collaboration, like joint river basin organizations in Europe and West Africa. Traditionally, scholars have studied such cases through qualitative analysis or statistical summaries. What makes this study different is its forward-looking ambition. Instead of only explaining the past, it asks what kinds of cooperation are most likely to prevent future conflicts under climate change.

The team employed a technique called Retrieval-Augmented Generation (RAG). They essentially trained their LLM system on a vast library of interdisciplinary literature, from political science theories of cooperation to numerical models of hydrology and climate science. Then, it is unleashed on the messy historical texts. The AI could read a short, ambiguous description of a 1960s water meeting, understand its context through the lens of international relations theory, and codify it in a way that allowed for systematic comparison with satellite-derived water stress data from the same region and period. For the first time, the nuanced “story” of diplomacy could be quantitatively linked to environmental and socioeconomic drivers.

Six Patterns Forged from Data

From this large body of evidence, the study identifies six distinct modes of water-related cooperation that have repeatedly appeared in real-world practice.

Some are formal and legalistic, such as cross-border basin agreements, which establish treaties, rules, and dispute-resolution mechanisms for shared rivers or aquifers. Others are more flexible, such as collaborative planning and adaptation, where countries jointly plan for floods, droughts, and climate uncertainty. There are also more technical forms of cooperation, including joint water allocation models, shared data and monitoring systems, transboundary water quality standards, and coordinated hydropower operations.

Each of these modes reflects a different theory of how cooperation works. Treaties emphasize rules and stability; planning processes emphasize learning and participation; data-sharing emphasizes transparency and trust. Importantly, the study does not treat these as abstract categories. Each mode is grounded in concrete historical examples, from the Mekong River Commission’s data exchange to the Senegal River Basin Organization’s integrated management approach.

Why combinations matter more than single solutions

One of the study’s most important findings is that no single cooperation mode is a silver bullet. Instead, the strongest reductions in conflict risk occur when multiple modes are combined. In high-risk settings, combining cross-border basin agreements, collaborative planning, and joint water allocation is associated with roughly one fewer conflict over five years. This insight matters because many international efforts still focus on one-off solutions. signing a treaty, building a dam, or launching a data platform.

Looking ahead to a warmer, riskier world

The study goes beyond historical analysis by linking its findings to future climate scenarios, using the widely adopted Shared Socioeconomic Pathways (SSPs). Under high-emission, high-stress scenarios, water-related conflicts are projected to rise sharply in parts of South America, Africa, and Asia. Yet the study also shows that targeted cooperation could offset more than half of these projected conflicts in regions such as Europe, North America, and parts of East and Southeast Asia.

The picture is less optimistic for some low-income, highly water-stressed regions, where institutional capacity and diplomatic leverage are limited. In these contexts, even well-designed cooperation frameworks struggle to deliver the same benefits. This finding highlights a crucial equity issue: the places most vulnerable to climate-driven water stress are often the least equipped to implement effective cooperation on their own.

Haozhi Pan, Professor at the School of International and Public Affairs, Shanghai Jiao Tong University.

Att få varmt vatten direkt ur kranen är en självklarhet i svenska hem. Men denna bekvämlighet har ett högt pris: enorma mängder energi går förlorade i de system som ständigt håller vattnet varmt. Samtidigt måste temperaturen vara tillräckligt hög för att förhindra tillväxt av den skadliga legionellabakterien. Ny forskning från KTH och Chalmers visar nu hur vi kan lösa denna ekvation – genom att spara energi utan att kompromissa med säkerheten.

Varmvattnets dolda energitjuv

I ett genomsnittligt svenskt flerbostadshus står uppvärmning av tappvarmvatten för cirka 25–30 kWh per kvadratmeter och år. Ungefär en tredjedel av detta, eller 8–10 kWh per kvadratmeter, är rena förluster från den så kallade varmvattencirkulationen (VVC). VVC-systemet pumpar konstant runt hett vatten i fastigheten för att säkerställa kort väntetid vid kranen. Dessa förluster motsvarar mellan 2,5 och 4,3 TWh årligen i Sveriges flerbostadshus – lika mycket energi som fjärrvärmen till en medelstor svensk stad.

Dilemmat: Energi vs. Bakterier

För att undvika tillväxt av Legionella pneumophila, en bakterie som kan orsaka allvarlig lunginflammation, kräver svenska byggregler att temperaturen i VVC-systemet är minst 50 °C. Men en hög temperatur driver oundvikligen upp värmeförlusterna. För att hitta den optimala balansen byggde forskarna en fullskalig testanläggning på KTH som exakt simulerar systemet i ett flerbostadshus med 20 lägenheter.

Resultat: Pumpen är den verkliga boven

Forskarna testade två scenarier: ett med högt vattenflöde (0,5 m/s) och ett med lågt flöde (0,2 m/s). Den mest relevanta analysen gjordes när systemet, precis som i verkligheten, justerades för att uppfylla lagkravet om en returtemperatur på minst 50 °C.

Resultatet: den årliga värmeförlusten var i praktiken identisk oavsett flöde. Lågflödesdriften förlorade 4276 kWh per år, medan högflödesdriften förlorade 4253 kWh. Anledningen är att två effekter tar ut varandra: lågflödessystemet kräver en lite högre starttemperatur, men det långsammare flödet ökar samtidigt rörets inre värmemotstånd, vilket bromsar förlusterna.

Den verkliga skillnaden låg istället i energin som krävdes för att driva cirkulationspumpen. Högflödesdrift krävde en effekt på 108 W, vilket var 3,4 gånger mer än de 32 W som lågflödesdriften behövde. På ett år innebar detta en besparing på 666 kWh i ren elenergi. Detta ledde till en total energibesparing för hela systemet på cirka 12 %, där hela vinsten kom från den minskade elanvändningen för pumpen.

Effektiv legionellakontroll utan slöseri

Parallellt med energimätningarna undersöktes hur legionellabakterien beter sig i systemet. Forskarna fann att:

1. Legionella uppstår inte av sig själv. Trots ideala temperaturer (41–43 °C) kunde bakterien inte etablera sig i det rena kommunala dricksvattnet. Det krävdes en “smitta” utifrån för att en koloni skulle växa fram.
2. Periodiska värmechocker fungerar utmärkt. När bakterien väl var etablerad, visade sig kortvariga temperaturhöjningar till 60–65 °C vara effektiva för att slå ut den. Detta bevisar att man inte behöver hålla en konstant hög temperatur för att garantera säkerheten.
3. Legionella återkommer efter en tid utan värmechocker. Om legionella är etablerad i systemet och man värmechockar systemet försvinner eller begränsas förekomsten kraftigt. Effekten visade sig att tillfällig, efter en tid på 2 veckor noterades att Legionella bakterier hade börjat att växa till. Därmed är det viktigt att man har periodisk temperaturhöjning.

Verkligheten bekräftar: Problemen finns där man tror

För att se hur det ser ut i praktiken analyserades 56 vattenprover från system i flerbostadshus. Resultaten bekräftade bilden från labbet: legionellaproblemen är inte generella i ett system, utan starkt lokala. Medan 10% av alla stickprov innehöll spår av bakterien, fanns nästan alla höga och problematiska halter i byggnader med kända konstruktionsfel. Den vanligaste orsaken var handdukstorkar som kopplats direkt på VVC-systemet, vilket skapar zoner där vattnet blir stillastående och får en perfekt temperatur för bakterietillväxt.

Vägen framåt: Smart styrning och mindre klimatpåverkan

Forskningen visar att det kan finnas en smartare väg framåt som balanserar både energi och hälsa. Genom att kombinera en lågflödesdrift för att minimera pumpenergin med periodiska temperaturhöjningar för att hålla bakterierna i schack, kan fastighetsägare spara energi utan att tumma på säkerheten.

– Det handlar inte om att sänka säkerheten, utan om att styra klokare, säger Jesper Knutsson, en av forskarna bakom studien. Med rätt teknik och kunskap kan vi både skydda hälsan och nå våra nationella energimål.

Jesper Knutsson, Tekn.Dr. Chalmers Tekniska Högskola, Architecture and civil engineering

Jörgen Wallin. Docent, KTH, Energiteknik

Till Jörgen Wallins profil

Till Jesper Knutssons profil

Dr. Louis Delannoy is a Researcher for the Global Economic Dynamics and the Biosphere programme (GEDB) of the Royal Swedish Academy of Sciences, and the Stockholm Resilience Centre. A transdisciplinary researcher, Louis combines various tools to understand how crises are transferred, absorbed and linked across space, time and sectors of society. He specifically focuses on the conceptualisation and formalisation of polycrisis, and the development of a long-term multi-scale database on historical shocks and crises.

“Polycrisis” has become a buzzword to describe today’s overlapping challenges – from COVID-19 and the war in Ukraine to climate extremes and social turmoil. The intuition is clear: crises no longer come one at a time, but interact and mostly amplify each other. Yet the term is often used without precision. What does polycrisis really mean, how can we study it, and what does it imply for governance? At the Royal Swedish Academy of Sciences and the Stockholm Resilience Centre, our team is working to answer these questions. In my seminar, I present three strands of our research: (I) a conceptual framework for polycrisis, (II) a global database of crises across five decades, and (III) an analysis of how institutions perceive risks compared to how they actually unfold.

First, it is crucial to understand what we mean by “crisis”. According to our social-ecological systems approach, a crisis emerges from two interrelated processes: shocks (diseases outbreaks, terrorist attacks, droughts, etc.) and creeping changes (democratic backsliding, biodiversity loss, etc.). The latter are considered much slower than the former, yet they must be regarded as critical. For example, intergenerational inequalities (which, when measured in terms of exposure to extreme weather events, have been steadily increasing since 1980 and are expected to worsen over time) are considered one of the factors contributing to Trump’s return to power. A polycrisis emerges when several crises overlap and reinforce one another. For example, when a heatwave worsens food insecurity or when a pandemic exposes long-standing weaknesses in health systems and social inequities. However, and as we found out in our first study, several interpretations of polycrisis co-exist. Yet if they disagreed on causes, they agreed on two points: polycrisis spans multiple scales, and it is more than a buzzword.

To see how polycrisis unfolds in practice, we built a database of shocks in 175 countries between 1970 and 2019. It tracks six types of disruptions – climate, conflict, economic, ecological, geophysical, and technological – year by year. The results show that shocks became increasingly entangled until around 2000, with combinations like climate–conflict–technology especially frequent. After that, patterns diverged by region: Asia experienced rising co-occurrences, while other regions plateaued or declined.

Figure 1 – The share of shocks per category per year in each region. REF = the reforming economies of Eastern Europe and the former Soviet Union, OECD = the Organisation for Economic Co-operation and Development 90 countries and the European Union member states and candidates, MAF = the Middle East and Africa, LAM = Latin America and the Caribbean, ASIA = Asian countries except the Middle East, Japan, and the former Soviet Union states. Source: Delannoy et al. (2025).

To complement this effort, we are conducting an expert elicitation process mapping creeping changes. The overarching goal consists in mapping where and when crises take place in the world, and what kind of interactions can we measure through empirical studies. A critical caveat is of course the inclusion in the process of several perspectives, especially from marginalized communities, often disproportionately affected by crises. Another caveat is the recognition of the risks of misinterpretation in how we conceptualize crises and communicate our findings, and our responsibility in this regard.

To bridge the gap with governance, we looked at how global institutions perceive risks, focusing on the World Economic Forum’s Global Risks Reports. These reports heavily emphasize economic risks, while downplaying ecological and long-term systemic ones. Additionally, they frame risks as complex, regulatory challenges rather than opportunities for systemic transformations. This creates a dangerous gap, where governance can end up preparing for the wrong risks while overlooking the creeping changes that quietly erode resilience.

Taken together, our work shows three things. First, polycrisis is best understood as the interplay of shocks and creeping changes. Second, history reveals recurring patterns of how crises cluster and diverge across regions. Third, governance often misjudges these dynamics, focusing on the visible while neglecting the systemic. Polycrisis is not just a buzzword. It is a call to rethink how we study, anticipate, and govern crises in the Anthropocene. By combining conceptual clarity, long-term data, and critical analysis of risk perceptions, we can begin to build the foundations for more resilient responses.

Authored by Professor Zaini Ujang, Hon. DSc, PhD, PE, CEng (UK), FCIWEM (UK), FIChemE (UK), FRSP (Lund), AMP (HBS).

At the age of 60^th recently, I have decided to start a new venture in life. In the past, with PhD in environmental engineering from University of Newcastle, England, and certified as a chartered engineer, I have successfully completed two phases of professional life: Phase 1 as a tenured academic for 25 years (1988-2013) at Universiti Teknologi Malaysia, and Phase 2 as Secretary General of six ministries in Malaysia (2013-2025).

Phase 1 was completed to satisfy my curiosity in the scientific principles on environmental science and engineering, mainly related to water ecosystem and sustainability. I had opportunities to work closely with leading figures, not only within Malaysia, but global outreach including Sweden and Denmark. In line with global academic norms, we had ventured into sustainability of water management and tried to provide range of innovative solutions for both developed and developing countries. My approach was to work with leading authorities on relevant issues to the needs of developing countries, and tropical climate in particular.

With Mogens Henze from Denmark Technical University, for example, we co-authored many research papers mostly related to the applications of activated sludge models in tropical conditions, and co-edited two books related to environmental biotechnology and wastewater management for developing countries. With Gustaf Olsson from Lund University, we co-supervised at least 10 doctoral students since 2005 on various topics related advanced bioprocess engineering for water and wastewater technologies. And many other research collaborations with leading figures such as Mark van Loosdrecht (Delft), Tom Curtis (Newcastle), Masa Goto (Japan) and Norio Sugiura (Japan).

The lessons learned: Collaborate on pressing scientific issues and working closely with leading academic figures to catch-up with latest scientific methods and its applications.

My full time career in academia officially ended upon the completion of my tenure as Vice-Chancellor (in other countries it is known as President or Rector) of Universiti Teknologi Malaysia in July 2013.

Phase 2 was more excitement and challenging as a Secretary-General of six ministries (in some countries, the title is Vice-Minister or Permanent Secretary). The roles of Secretary-General is to lead senior officials to translate ideas into policy, from policy into legal instruments, from legal instruments into practices. Indeed with dedication and strong managerial skills, it was a smooth sailing to lead senior officials in big organisations, such as ministries, provided the political climates are positive in encouraging new framework and promote innovation. But often, political systems have been customised to conventional framework and approach in order to minimise political risks. For example, the polluters pay principle is a good idea. However when environmental services such as water and energy pricing, and carbon tax to be introduced and sustainably enhanced using polluters pay principle, the systemic polluters used their political cards to object.

My observation has shown that mere scientific mastery and administrative authority might not be able to bring significant change or transformation in a society, particularly in developing world. Scientific community can provide evidences, promote appropriate solutions and outreach to policy makers. Often, policy makers themselves have other priorities in their political agenda, and placed environmental issues, such as water sustainability and climate change at the bottom of their to-do-list.

Therefore, we should learn from experiences in other regions where environment and climate have been considered among the top priorities in nation building and political agenda. Scandinavia and Japan could be good examples.

In 2018, I have written a book, entitled Eco-Shift: Holistic Transformation towards Environmental Sustainability. It was a reflection on bringing cultural transformation, instead of small changes in policy, practices and lifestyle towards green growth and climate action. Eco-Shift is defined as a transformative change, more than mere regulatory and organisational transformation, towards environmental sustainability. It covers personal domain, targeting behavioural and habitual changes. Organizational domain covers planning, strategy, execution and improvement, often limited to targeting “outputs” in the forms of key performance indicators, ratings, rankings, budgets, time-frame etc. For holistic transformation to occur, it requires significant changes in personal domain, targeting “outcomes” which involve values, attitudes, behaviours and habits. This lecture at KTH on 16 May 2025 was based on a sequel books by Zaini Ujang (2018, 2019 and 2020) to direct present discourse on ecology towards ecological philosophy, or ecosophy, on top of environmental policy. A special focus will be given by comparing ecosophy from a Scandinavian perspective, with respect to Asian perspectives, particularly Japanese.

Many countries within the Paris Agreement 2015 framework have agreed to adopt Net-Zero Emission (NZE) by 2050. However, climate action, as shown in series of annual COPs, has been excessively focus towards state-actors. Efforts to mitigate and adapt climate change by reducing greenhouse gas emissions and adapting to its current and future impacts should involve all sectors and actors. These actions are crucial in addressing global challenges in all sectors, including water and energy sectors. This lecture will explore the potential of non-state actors, mainly non-governmental international and national organisations, trade chambers, scholarly institutions, academies, conventional and new media, individuals and influencers.

Issues and outstanding challenges to improve the design and management of safe and reliable supply chains that are accessible and sustainable by creating predictive analytical tools and technologies, with examples on water-energy nexus. The framework of Eco-Shift will be highlighted through holistic transformation in thinking, public policy, cultural change and lifestyle in supply chain and market optimization, human health risks in the goods and services, and access to healthy ecosystem.

The speaker’s wide experience both in developing environmental and climate policy from national to international levels, and actively engaging various climate actors – particularly non-state actors – will open up wider opportunities, thus enhancing this discourse towards sustainable futures. In many ways, the roles of non-state actors could be more impactful and efficient, compared to politically-tied state-actors.

Bio

Zaini Ujang, 60, is a “professor-at-large” serving more than ten universities around the globe as a visiting professor.

He is also the non-executive Chairman, Malaysia Qualification Agency since March 2025. He was appointed as Secretary-General for six ministries in Federal Government of Malaysia within 12 years (2013-2025) on portfolios related to higher education, human resource, climate, energy, environment, water, energy and health. He was chairing many technical committees to formulate national policies, such as higher education blueprints (2015-2025 and 2035), green technology (2016-2025), green sukuk (2016), climate adaptation (2021-2030) etc.

He was a professor in environmental sustainability and President/Vice-Chancellor of Universiti Teknologi Malaysia (2008-2013), and assigned to head the Malaysian delegation and chief negotiator at COP26 (Glasgow) and COP27 (Sham El-Sheikh). 

Prior to his appointment in leadership roles at various institutions in Malaysia, since 2006, Zaini was Vice-President, International Water Association (based in London, 2004-2006) and had delivered more than 300 invited and keynote lectures including at MIT (June 2019), Imperial College London (almost annually since 2012), Lund (Sweden), Tokyo, Tsukuba and Kyoto universities. He has written more than 300 scientific papers and 52 books.

From April 16 to July 26, 2025, Zaini is undertaking a life challenge by traveling around the globe for 100 days, visiting and delivering lectures at 40 universities, including Imperial College London, MIT and Harvard. 

#100DayWorldLectureTour