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Damaged cars line a waterfront street in Lahaina, Hawaii. Toxins released by burnt items could infiltrate the city’s water supply.Credit: Paula Ramon/AFP via Getty

As search crews wrap up the hunt for people missing after fires swept the Hawaiian island of Maui, scientists are gearing up for a challenge facing survivors: water contamination. Early indications suggest that the local water system has been compromised in places, and the sheer scale of the damage could pose unprecedented threats to Maui’s diverse coastal ecosystem.So far, more than 100 people in Maui have been confirmed dead, making the wildfire that devastated the city of Lahaina the deadliest in modern US history. Hundreds more people are still unaccounted for. The fire damaged or destroyed an estimated 2,200 buildings, creating a toxic environment that is likely to affect water quality. The carcinogenic chemical benzene has turned up in the public water system in Lahaina, and local officials have advised residents not to drink tap water. Scientists also fear that contaminated run-off will flow onto the island’s sensitive coral reefs.“We have had large fire events before, but this is a different beast,” says Chris Shuler, a hydrologist with the Water Resources Research Center of the University of Hawaii at Manoa, in Honolulu. “There’s no playbook for this. Everybody is just figuring it out as we go,” adds Shuler, who is based on Maui.A fire’s toxic legacyWorking in parallel with local water officials, scientists at the University of Hawaii have already started testing for a variety of contaminants that could be released by the incineration of plastics, vehicles, household chemicals and other sources.Initial results might not be available for several days, but there is every reason to suppose that the water system in Lahaina has been contaminated, says Andrew Whelton, an engineer at the Purdue University in West Lafayette, Indiana, who specializes in disaster response. The problem, Whelton says, is that when multiple buildings are destroyed, the water system not only loses pressure but also can develop a vacuum that pulls pollution from burnt areas into water-delivery pipes. Those pollutants can then circulate through the water system as firefighters and residents open hydrants and taps to keep the flames at bay.

Volunteers unload bottled water from a boat in Maui, where some residents have been advised not to drink the tap water.Credit: Rick Bowmer/AP via Alamy

“The pipes and water volumes are designed to handle one or two structure fires,” says Whelton, who spent more than a week in Maui to help coordinate relief efforts with the University of Hawaii and government agencies. “They are not designed for an entire city to burn down.”The university is testing for benzene, formaldehyde and 86 other chemicals that are classified as volatile organic compounds. It is also checking for dozens of other contaminants. Test results from the inland community of Kula, where a second fire destroyed several hundred structures, have turned up little contamination thus far, Shuler says. But it could be several days before the university team gets its first test results from Lahaina, where the Maui County water department discovered benzene.Whelton says contamination is likely to show up in Kula as well. Hundreds or even thousands of samples will need to be tested to fully assess the risk across the island, he says.Reefs at riskScientists and government officials are already starting to think about longer-term impacts on the coral reefs, which are core to Lahaina’s economy and cultural identity. For Steve Calanog, incident commander for the US Environmental Protection Agency (EPA), that means working to prevent ashes tainted with contaminants such as asbestos, lead and arsenic from blowing into the ocean.Now that search and recovery operations are coming to an end, the EPA is preparing to move through the burnt zone to recover hazardous materials such as household chemicals, batteries and propane canisters. The agency then plans to spray cleared areas with a biodegradable soil stabilizer that will create a temporary crust on the ash piles. The material is commonly used for dust control in construction and other industries, but its application in wildfire recovery is relatively new. Calanog says that Lahaina represents a particular challenge, presenting a complex and often hazardous mix of urban fire debris that is sitting immediately next to coral reefs.
Controlling pollution and overfishing can help protect coral reefs — but it’s not enough
Other researchers are already starting to think about how to monitor fires’ impacts on the ocean. Scientists will be watching for everything from algal blooms to changes in acidification — as well as long-term changes in ocean nutrients and chemistry, which could drive a shift from a coral-based reef to one that is dominated by algae, says Andrea Kealoha, an oceanographer at the University of Hawaii’s Maui campus, in Kahului.Kealoha and her colleagues are applying for a National Science Foundation grant to investigate the ecosystem impacts. They are also hoping for a separate grant from the Federal Emergency Management Agency, so that they can monitor contaminants in fish populations to ensure that the fish are safe to eat.But for now, Kealoha is planning to test seawater samples that she collected off the coast a little over a week after the initial fire. Days before her sampling trip, according to the captain of the boat she was on, the ocean had been covered in ash and gleaming with oily substances. When she went out, however, the water was crystal clear, suggesting that the initial wave of pollution might have been carried farther out to sea by the winds.It will take time to gather the data and understand the impacts, she says, and people in Lahaina are already starting to ask questions. “The community wants to know about the long-term impacts to our waters and to our ecosystems,” she says. “It’s time to start addressing these questions.” More

A rescuer helps a woman with a child disembark from a rubber boat as trapped residents evacuate through floodwaters in Zhuozhou in northern China’s Hebei province, south of Beijing, Wednesday, Aug. 2, 2023. China’s capital has recorded its heaviest rainfall in at least 140 years over the past few days. Among the hardest hit areas is Zhuozhou, a small city that borders Beijing’s southwest.Credit: AP/Alamy

The floods that swept through China’s capital this week were exacerbated by urban development and insufficient drainage systems, researchers say.Typhoon Doksuri hit southern China’s coast in Fujian province on 28 July. It then rolled north to Beijing, dissipating to a lower grade of storm, but in the process dumping up to 745 millimetres of rain on the capital over 5 days — 4 times the city’s average August rainfall. The tail end of the storm also soaked the nearby city of Tianjin and the nearby Hebei province. The deluge of rain was the heaviest to hit Beijing in 140 years, leading to floods killing more than 20 people, destroying roads, cutting off power and forcing thousands of residents to evacuate. “We didn’t expect that the typhoon could impact such a large, vast area,” says Junqing Tang, who focuses on urban resilience and disaster risk reduction at Peking University Shenzhen Graduate School in Shenzhen, China.But as tragic as this week’s events have been, Beijing is no stranger to flooding and disaster. Floods that have resulted in injuries and casualties have hit the capital at least seven times over the past two decades. The deadliest of these occurred in July 2012, when 190 millimetres of rain drenched the city in a day, leading to flash floods that killed 79 people.One factor behind Beijing’s recent vulnerability to floods is its rapid development, says Shao Sun, a climatologist at the University of California, Irvine. Over the past three decades, the city’s population has almost tripled. The result is a concrete sprawl of buildings, roads and other infrastructure.“China’s rapid urbanization has led to a proliferation of impermeable surfaces,” he says. “Green spaces such as parks and gardens play a vital role in water retention. Their dwindling presence due to urbanization diminishes their capacity to effectively manage excessive rainfall.”Duafang Lu, who specializes in urban development in China at the University of Sydney in Australia, says that urbanization has also wiped out many of Beijing’s wetlands, which reduce flood risk by capturing and absorbing excess rainwater.The drainage systems in Beijing have also not kept pace with its rapid development, says Tang. Many of these systems were not designed to handle such huge volumes of water and are not maintained or upgraded on a regular basis. “This can lead to waterlogging and exacerbate the impact of floods,” he says.

A vehicle was left on a bridge, which collapsed by torrential rain in the suburbs of Beijing on August 1st, 2023. Flooding and fierce rain have killed at least 11 people.Credit: AP/Alamy

Sponge citiesThe Chinese government has taken steps to reduce the risk of urban floods. In 2015, it introduced a plan to construct ‘sponge cities’ that can retain and reuse 70% of rainfall. The aim is to ensure that 80% of urban built-up areas in these cities meet this target by 2030. Since then, some 30 cities — including Beijing — have been testing various approaches to mitigate floods, such as using permeable materials for roads and pavements, restoring wetlands and natural waterways, and creating more green spaces.Although the sponge-cities strategy is “very ambitious”, the approach was not designed to handle extreme weather events like the Doksuri storm, says Hongzhang Xu, who specializes in urban planning and infrastructure development at the Australian National University in Canberra. “Its design is based on average annual rainfall,” says Xu. And given Beijing’s low-lying location, drainage systems need to ferry excess rainwater quickly, he says. “The most important thing is to divert the water away as soon as possible.”Urban drainage in Beijing and other cities in China will need to be improved to withstand more frequent extreme weather as climate change intensifies, says Sun. Although this will be challenging, he says it would “significantly reduce the risk of urban waterlogging during the rainy season”. He adds that cities across China will need tailored flood-management strategies. “A one-size-fits-all approach is not the most optimal choice,” says Sun.Tang adds that Beijing and other Chinese cities will also need to create infrastructure that facilitates evacuations and provides information to help people respond to extreme weather. “At the end of the day, it’s people who react to those kinds of disasters,” he says. More

Fog-catching nets (seen here in Lima) can collect enough water for daily use. This technology has the potential to be used on larger scales.Credit: Klebher Vasquez/Anadolu Agency/Getty

This year’s United Nations water conference — the first in nearly 50 years — did not lead to a binding agreement. But the event, held in March in New York City, provided a wake-up call: water crises are worsening and need our urgent attention.As of last year, some 2.2 billion people still lacked access to safe drinking water, according to a July report from the World Health Organization and the UN children’s agency UNICEF (see go.nature.com/3djb6tb). And some 653 million people did not have hand-washing facilities at home.Fixing these problems is among the targets of the sixth of the UN Sustainable Development Goals (SDGs): to “ensure availability and sustainable management of water and sanitation for all” by 2030. This editorial is part of Nature’s series looking at each of the SDGs, set in 2015, at their halfway stage. We are focusing on questions and gaps that researchers can help to address.
Progress towards the Sustainable Development Goals
When the SDGs launched, there was optimism that the water goal could be reached, and progress has been made on some of its targets. Since 2000, an extra 2 billion people have gained access to safe drinking water, and by 2020, some 56% of all households had their waste water treated.But overall progress has not been fast enough, and, as early as 2018, UN-Water, which coordinates the UN’s work on water and sanitation, warned that the world was not on track. Countries are not prioritizing this goal, either at the national or the global level. By the UN’s own estimates, to achieve SDG 6, the world will need to spend US$260 billion per year by 2030 — mostly in Asia and Africa, where the numbers of people without safe drinking water are highest. International development assistance for water-related projects is currently around $9 billion annually, and has been falling since 2017. When there’s no policy strategy, it becomes hard to demonstrate research or pilot projects on large scales. Yet that is what needs to happen if clean water and sanitation are to become universal.Generations of water-stressed communities have applied the results of knowledge and innovation to get water. But there has been, at best, partial success for attempts to systematically share techniques that are known to work on local scales, such as condensing water from clouds with giant nets, used in Chile and Peru, or storing snow for use in dry periods, as practised in parts of China.It’s the same for newer technologies. For example, membrane distillation is a low-temperature method of desalinating water. It’s greener than existing methods because it uses less electricity, as chemical engineer Mohammed Rasool Qtaishat at the University of Jordan and his colleagues reported last year1. However, it is struggling to break out of the research and pilot phases and be deployed at larger scales. In a study2 published in March, Patricia Gorgojo, a chemical engineer at the University of Zaragoza, Spain, and her colleagues recommend improving communication between those who undertake small-scale studies and those who implement larger-scale demonstration projects, because the two often have different needs.
Global action on water: less rhetoric and more science
When it comes to research in its broader sense, results can be scaled up, as medical anthropologist Sera Young and her team at Northwestern University in Evanston, Illinois, show3,4. They have developed inclusive measures of the experience of being water-stressed, called water insecurity experiences (WISE) scales.SDG 6’s sanitation target calls for “special attention to the needs of women and girls”. But the UN’s annual progress reports do not include data on this topic. The principal reason seems to be that surveys are typically conducted at the household level — rather than at the individual level — and therefore cannot be disaggregated by sex or gender. This is where the WISE scales are effective: they can collect data at the household or individual level. They examine how water insecurity affects daily activities, health and well-being, from cooking, hand washing and laundry to personal hygiene and feelings of anger and anxiety. Respondents are identified according to age, gender and income, among other characteristics.The WISE scales are being used by some 100 national, intergovernmental, research and civil-society organizations around the world. Their use as a policy tool was demonstrated last year in Australia, which officially, has relatively low levels of water insecurity, with just 1% of the population affected. But some communities don’t recognize this picture. In 2022, Yuwaya Ngarra-li, a partnership between the Dharriwaa Elders Group — an Aboriginal cultural organization in the rural town of Walgett — and the University of New South Wales in Sydney applied the WISE methodology to a survey of 251 people and found that around 44% of respondents reported water insecurity and 46% food insecurity (see go.nature.com/3dciovf). The communities and Walgett Shire Council are exploring how to bring about improvements.As the world gets closer to the 2030 SDG deadline, more ideas will undoubtedly emerge, with promising potential. But SDG 6 will not be achieved without attention to scale. This is a large missing piece of the water and sanitation jigsaw. Ultimately, implementation is what matters. More

Indigenous mother Rosalia Gomez with her child in Santa Victoria Este, Argentina, where the authors worked in May 2022.Credit: Ronaldo Schemidt/AFP via Getty

Fieldwork can be a nightmare of logistics. Nobody would increase the burden by taking their children along — would they? We did just that, embarking on a four-day field campaign in a remote village with our three children, all under four. Not only did it work out, but we recommend it.We met in 2015, when we worked in the same laboratory at the University of Buenos Aires. Both of us are biologists: V.L.L. is an ecotoxicologist and M.L.L. studies the ecology of shallow lakes.We’ve both also been involved in other projects. M.L.S. has worked on a study of drinking-water quality in neighbourhoods of Buenos Aires for the past 15 years. V.L.L. has worked with rural and Indigenous communities as part of the Argentinian arm of the international organization Vía Campesina. We’ve formed a strong friendship and enjoyed holidays together with our partners before we became mothers.
Collection: Diversity and scientific careers
We supported each other in our shared desire to embrace motherhood as working scientists, which posed certain challenges. In 2019, M.L.S. began a three-month internship at Michigan State University in East Lansing, and her partner, Fede, took on full-time caring responsibilities for their six-month-old daughter, Maite, when the family moved to the United States. At the same time, V.L.L. relocated to Salta, Argentina — 1,490 kilometres from Buenos Aires — to live with her partner, Nacho, when their daughter, Julia, was just two months old.Family tripDuring the COVID-19 pandemic, we applied for funding to combine our scientific interests. The idea was to collaborate on the quality of drinkable water available to Indigenous and rural populations in Santa Victoria Este, a remote area of northern Argentina, bordering Bolivia and Paraguay. Santa Victoria Este encompasses approximately 6,430 square kilometres and is home to around 7,000 families, from the Wichí, Chorote, Toba, Chulupi and Tapiete communities. The zone is very arid, with little rain, so access to safe drinking water is a huge problem. This is probably one of the reasons for the infant death rate in the area — among the highest in the country.Beyond our scientific and social interests, we were personally motivated to find a way to ease tensions between motherhood and our scientific careers. The project involved a four-day research trip to the area. V.L.L. was still breastfeeding her second daughter — now one year old — and was committed to nursing throughout. For both of us, it was our first time so far from home since the children were born. So when the project was approved, we agreed with the rest of the team that we would embark on the trip as an extended family, with two little girls and a baby. Any scientific campaign requires teamwork; in this case, our daughters and husbands would be part of it.
Collection: Fieldwork
There were challenges. Our partners had to take leave from their jobs, for example. And Santa Victoria Este has a precarious health-care system and the potential for extreme temperatures. We felt guilty about exposing our daughters to possible risks, both on the journey and during our stay. The pandemic had heightened everyone’s fears. We took all the precautions we could, from using secure child seats on the journey to preparing a fully stocked first-aid kit.Despite the complexities involved, one driving force for both of us is the belief that our daughters will be happier if their mothers pursue their aspirations. We want to give them the message that they should chase their dreams and never feel limited by being women or having children. We also believe that, even though our children were very young at the time, living through such an adventure with their mothers was a valuable life experience.Toddlers on tourFinally, in May 2022, M.L.S., Fede and Maite flew from Buenos Aires to Salta, where they met up with the rest of the team. We spent two days finalizing our plans with the other team members. The care of the girls was included in the planning: we needed to make some adjustments to ensure the baby’s breastfeeding, as well as provide activities to keep the children entertained and happy. Slightly behind schedule owing to the unpredictability of family life, we loaded specially equipped car seats into the van, along with a tablet, toys, books, pencils, children’s music and other essentials. We also made sure to pack nappies, cleaning wipes and other necessary equipment for the baby. With everything in place, we embarked on an 8-hour drive. We planned stops to eat, use the toilet and stretch our legs. Fortunately, our children became friends, and played a lot during the long trip.
Training: Persuasive grant writing
Once on site, we worked with the whole team to take water samples at various locations. During the fieldwork, the children stayed in the village with their parents, playing among themselves, although Julia — then aged four and the oldest among them — joined us on some occasions. Before setting off, we had collaborated closely with local team members to establish a laboratory, providing the communities with the resources to conduct microbiological and chemical analyses of the water. Besides the results of the campaign, which provided valuable information about the drinking water, we anticipated establishing a local monitoring system. The communities of Santa Victoria Este have been organizing themselves to address their challenges. In 2020, they achieved a landmark victory when an international court ruled that the national government is obligated to ensure the restitution of lands to Indigenous communities, along with access to safe water and other rights. This historic ruling presents an important opportunity for us to support the local people’s empowerment and autonomy by providing them with equipment and training to monitor the water quality periodically.Motherhood and scienceOur experience fortified our conviction that it is possible to navigate the roles of mother and scientist committed to societal welfare simultaneously. We honed our ability to overcome obstacles, innovated effective solutions and, above all, relied on the unwavering support of our families and dedicated team as a real safety net. It was crucial that our partners acted as the main carers during the trip, and that the rest of the team was flexible and patient about our need to adjust plans during travel. This gave us the confidence to carry forward this ambitious project.Having the girls with us undoubtedly caused more tiredness (mental and physical), but the experience and lessons we gathered were very positive. Nothing we had done before could compare. For V.L.L., it was a relief to be able to continue breastfeeding, because neither she nor her daughter desired to end it prematurely.We hope that our story serves as an inspiration for other women in the scientific community, motivating them to pursue their professional aspirations while finding meaningful ways to meet the demands of motherhood. In this way, we can propel scientific progress, and foster the well-being of the communities we endeavour to serve. More

On a warm day in March, ecologist Valeria Souza went into a temazcal, or sweat lodge, in Texcoco, Mexico, to pray for the wetlands that she had been studying in the Chihuahuan Desert for the past quarter of a century. She had been performing this shamanic ceremony for years, asking for guidance to help save the scientifically treasured basin in the northern reaches of the country — known as Cuatro Ciénegas — from human exploitation. But this time was different.
Mexico is seeding clouds to make rain — scientists aren’t sure it works
Souza, the region’s lead scientist, based at the National Autonomous University of Mexico in Mexico City, instead asked for permission to step away and forgiveness that she couldn’t do more. Despite the fight she’d put up, farmers and other local residents have been slowly draining water from the area for their crops and other sustenance. This has led to many of the basin’s pools drying up, turtles and plants dying, and prized microbes receding into the ground beyond researchers’ grasp. With climate change pushing the landscape’s temperatures ever higher, it has been an uphill struggle.Souza loves Cuatro Ciénegas. Researchers think that the isolated landscape has preserved microorganisms for hundreds of millions of years. “It’s a unique window into the past,” she says. But she is also tired, and says that it’s time to leave the task of protecting the basin to a new generation of scientists and advocates.A lost worldCuatro Ciénegas, which translates to ‘four marshes’, has long fascinated scientists. Although its name was inspired by springs located at the four cardinal points shaping the valley, in total, it contains more than 300 blue-green pools, or pozas, filled with microbes, bacterial mats and ancient microbial reefs called stromatolites. “It’s perhaps the most diverse place on the planet in terms of bacteria and archaea,” Souza says.

Valeria Souza, during a visit to Cuatro Ciénegas.Credit: Esteban Gonzalez de Leon

The wetland is fed by “an ancient sea” beneath the nearby Sierra de San Marcos y Pinos mountain, Souza adds. Rain on the mountain feeds the aquifer, which is heated by magma deep underground. The water then seeps upward, through ancient marine sediments, to form the pools.The region’s stromatolites have especially intrigued scientists. In other parts of the world, researchers usually come upon stromatolites as fossils — dried-out layers of ancient cyanobacteria containing trapped sedimentary grains. But those in Cuatro Ciénegas are alive, allowing scientists to study what early life on Earth must have been like. One way they do this is by extracting stromatolite DNA and analysing how it might have evolved.Drawn to the area in 1998, researchers funded by NASA’s Astrobiology Institute in Mountain View, California, went there to study the origins of life — with an eye towards understanding whether life could have once existed on Mars’s arid surface. James Elser, a limnologist who was one of the lead scientists on the project and who was at Arizona State University in Tempe, invited Souza to collaborate.Emptied oasisSouza confesses that the fight to save the place has been like a rock on her back.Because it is one of the most abundant sources of water in the Chihuahuan Desert, Cuatro Ciénegas has been tapped extensively by local residents. Three main canal systems — La Becerra, Santa Tecla and Saca Salada — siphon water from the wetlands, especially to grow alfalfa (Medicago sativa), a crop mainly used to feed cows.To halt this drainage, Souza brought in Mexican business magnate Carlos Slim, who partnered with the global wildlife charity WWF in 2009 to buy the land around the region’s largest lagoon, El Churince, and make it a protected area. She also successfully lobbied the dairy company Grupo LaLa, based in Gómez Palacio, to stop buying alfalfa from the region. But demand for water continues to soar, and the wetlands have steadily dried up.

This set of time-lapse aerial images shows El Churince, once the largest lagoon in Cuatro Ciénegas, dry up and disappear (images run from 1997 to 2022).Credit: Landsat data courtesy of the U.S. Geological Survey

By 2017, El Churince — which held the vast majority of fish species found in Cuatro Ciénegas and housed more than 5,000 species of bacteria, most of them only found in the region — was gone. Souza says that, after seeing the “graveyard of turtles and fishes” left behind, she mourned for years.Others have tried to protect the region. For instance, in 2000, the civil association Pronatura Noreste in Monterrey acquired the Pozas Azules ranch, whose roughly 2,700 hectares hold 100 of Cuatro Ciénegas’ pools. But the organization has similarly struggled to make headway. The land is protected, but the aquifer beneath it is not, says the association’s director, Rosario Alvarez.Souza would like to see Mexico’s National Water Commission (Conagua) take more stringent steps to protect the aquifer. The agency doesn’t keep a record of all the water that’s extracted from it, or the permissions for its use. This leads to over-extraction, which is collapsing the wetland, she says. “There is no inventory, and it’s urgent that [Conagua keep one] because the system cannot last five more years,” Souza adds.Conagua did not respond to Nature’s requests for comment.Saving an ancient worldSouza’s one hope is the generation of scientists and advocates she trained.When she became interested in Cuatro Ciénegas, she spent time educating children from the local school, CBTA 22, as well as the surrounding community, about the importance of preserving the wetland. Among the people she taught is Héctor Arocha, now a biotechnologist who is taking over research in the basin. Arocha works for 2040 Plan, a foundation in Cuatro Ciénegas that seeks to support the development of the community over the next 25 years.
The world faces a water crisis — 4 powerful charts show how
As part of that effort, on 4 April, Arocha opened Genesis 4C, the first scientific museum in the region, with the mission of creating a culture of conservation. “We gathered all the research that has been done in the valley in collaboration with Valeria and the whole team of researchers who have come over the years,” Arocha says. The museum has a research centre and plans to continue microbial-ecology projects on the origins of life, as well as to find uses for the wetland’s microorganisms in agriculture and medicine.Souza also sees ecotourism efforts in the area as promising. “Hoteliers and non-governmental organizations own the largest areas of Cuatro Ciénegas,” she says. One of the hotels, the María Elena, is donating to the 2040 Plan. There’s also an ecotourism park, called Las Playitas, that educates visitors about the marshes and donates money to the foundation.It’s hard to know whether the pools of Cuatro Ciénegas will survive, but Souza takes solace in the longevity of the bacteria that she loves. “Time is very relative” to the microbes living under the mountain, she says. The water in the pools might completely dry up, but the microorganisms are capable of patiently waiting millions of years underground before rising back up to the surface if the aquifer ever refills. Humans might never see that — “we will be extinct by then”, she predicts — but the microbes could endure. More

Up to 5.5 billion people worldwide could be exposed to polluted water by 2100, a modelling study has found.Researchers mapped surface water quality under three different visions of future climate and socio-economic development.In every case, sub-Saharan Africa was shown to be among the worst-affected areas.The predictions, published in Nature Water on 17 July1, offer “a temporal and spatial analysis of what has been, until now, anecdotal evidence regarding water quality in sub-Saharan Africa”, says Tafadzwa Mabhaudhi, who studies climate change and food security at the University of KwaZulu-Natal in Durban, South Africa.Without adequate investment in water infrastructure or treatment, “we are definitely sitting on a time bomb”, adds Joshua Edokpayi, a researcher in water-quality management at the University of Venda in Thohoyandou, South Africa.

Source: Ref 1.

According to United Nations estimates, two billion people worldwide already struggle to access safe drinking water. In the past few decades, East Asia and the Pacific region have had the most surface water pollution, owing to booms in industrialization and population that have led to increasing demand for water in areas that do not have the infrastructure to support it.Water forecastTo investigate the future effects of similar trends, researchers modelled water quality in 20-year chunks from 2005 to 2100, using existing models of global water quality.They considered three future climate scenarios used by the Intergovernmental Panel on Climate Change, known as SSP1-RCP2.6, SSP5-RCP8.5 and SSP3-RCP7.0. SSP stands for ‘shared socio-economic pathways’, and considers various societal factors, whereas RCP describes ‘representative concentration pathways’, referring to trajectories of greenhouse-gas concentrations. For example, SSP5-RCP8.5 denotes a ‘business-as-usual’ trajectory defined by continued strong technological progress with limited concern for global warming. SSP1-RCP2.6 defines an optimistic ‘green’ future where sustainability becomes globally prioritized.
The water crisis is worsening. Researchers must tackle it together
The team found that under all of the scenarios, water quality got worse in countries in South America and sub-Saharan Africa with emerging economies. By contrast, in many wealthy countries, levels of organic pollutants and substances that can cause disease tended to decrease, owing to improved water treatment.The SSP3-RCP7.0 projection, which describes an upcoming ‘bumpy road’ of increasing national rivalries coupled with slow economic and environmental progress, stood out as the worst-case scenario (see ‘Pollution predictions’). In this model, organic water pollution in sub-Saharan Africa more than quadruples by 2100, leaving 1.5 billion people exposed to unsafe water. Deterioration in water quality in South Asia, the Middle East and North Africa also leads to increased pollution exposure in those regions.This came as a surprise, says study co-author Edward Jones, a geoscientist at Utrecht University in the Netherlands. He adds that although a ‘business-as-usual’ scenario would involve unsustainable dependence on fossil fuels, it could also lead to improved water infrastructure and thus water quality, as has already been seen in some countries. The SSP3-RCP7.0 scenario is characterized by poor economic growth, severe climate change and population expansion, which leads to much worse water-quality management.Global effortBoth Edokpayi and Mabhaudhi say that the research highlights the need for better implementation of regional water-quality policies. Under the UN’s Sustainable Development Goals, everyone worldwide should have access to safe drinking water by 2030. However, Mabhaudhi says there is a disconnect between global policies and the reality on a smaller scale, and that the world needs joined-up approaches that “place people and planet outcomes at the core”.Pollution defies national boundaries, says Edokpayi, and cross-boundary collaborations will be crucial to keep the worst predictions from coming true. More

Pollution of surface waters and overexploitation of aquifers are making it harder for annual precipitation to fulfil most of the world’s water requirements. Drought preparedness therefore depends largely on local water management and foresighted governance.
Competing Interests
The authors declare no competing interests. More

International Women in Engineering Day

Nature is marking International Women in Engineering Day on 23 June by profiling two female engineers who are role models for the Liverpool Women in Science & Engineering (LiVWiSE) initiative, based at the University of Liverpool, UK. The accompanying profile of automotive engineer Imogen Howarth can be found here.

Esraa Tarawneh, a water resercher in the Civil and Environmental Engineering Department at Mutah University, Jordan, describes how growing up in Jordan made her passionate about research into hydrological extremes, flash floods and the impacts of climate change on water resources.How did your love of engineering begin?As a child, I liked to solve things. With a problem you make a plan, break the problem down into different aspects and try to solve each part on its own. Then you assemble the parts back together. This is what I enjoyed. Everyone around me said, “She’s an engineer.”The environment in our home was all ‘study, study, study’. I am the second of ten siblings and all of us are either medical doctors, engineers, pharmacists or computer specialists, bar one, a judge. Three of the six daughters are engineers — two civil engineers and an electrical power engineer.What does your research involve?I work on hydrological and analytical modelling, providing and developing scenarios of what can happen, and I predict change in water patterns. I also study how we can improve ways of harvesting water and managing floods.I went into hydrology to provide tangible solutions. Jordan is one of the most water-poor countries; there is a huge shortage. The severe water scarcity threshold, as defined by the United Nations children’s charity UNICEF, is 500 cubic metres of renewable water resources per person per year, but in Jordan we have less than 100 cubic metres per person per year. And it can actually be way below that — it varies from place to place. Often, we have just 2 cubic metres a week, sometimes over 2 weeks, per family.How did your career in engineering begin?In 1999, I started my undergraduate degree in civil engineering at Mutah University. It covered highway engineering, roads, bridges, construction, everything.But I always wanted to specialize in water, so after graduating I registered for a new master’s degree there, in water and environmental engineering. My thesis was on water and sediment yield for the Wala Dam catchment area located just to the south of Amman.I then spent four years at the Jordanian Ministry of Public Works and Housing before gaining a scholarship, in 2012, from Mutah University. It was to study at the University of Liverpool, UK, for a PhD in water and environmental engineering.I used modelling for various scenarios, including the feasibility of increasing the height of the Wala Dam for sustainable land and water management in an environment for which we do not have abundant data. I am very grateful for that chance to come to a world-class university such as Liverpool, which would never have happened without Mutah’s support.When I returned to Mutah University in 2018, I was the only woman with a PhD in a department of around 20; the only other woman was an architect. Now there are seven women with PhDs. That’s a positive move.As a woman, were you unusual among your peers in Jordan, in wanting to be an engineer?In Jordan, we do not distinguish between girls and boys doing engineering, unlike in the United Kingdom, where in my experience women do not want to do engineering as much as men do. But my youngest sister, the power engineer, has had difficulty in getting a job since she completed her studies at Mutah — the companies in Jordan seem to want men.What have been the main challenges or barriers in your career?Throughout my time as a university professor, I have faced a range of challenges including balancing the heavy teaching load while also striving to devote decent time to research. This requires some innovative solutions to maximize productivity and manage priorities.And I have faced the same challenges that affect women generally: stereotypes, a lack of female role models and unconscious biases. You have to find your own way and support yourself, which I have taken as an opportunity to improve, to find wider networks and collaborate with people from around the world. Studying in the United Kingdom gave me the confidence to seek professional development opportunities in countries including the United States, Germany, Belgium and the Netherlands, with financial support from international funding schemes.What does successful collaboration look like for you?When I came back to Jordan in 2018, I collaborated with my PhD supervisor on a joint project to link UK experts with peers in Jordan to work on sustainable catchment management and water security, which was implemented the following year. It was supported by the Newton Fund, which is managed by the UK government’s Department for Business, Energy and Industrial Strategy, and which builds research and innovation partnerships with countries in Africa, Asia and Latin America.We were able to use those links after a tragic, fatal event in October 2018, when a school bus was washed away in a flash flood near the Dead Sea. It was thought that in these very arid or semi-arid regions and with a tough environment and harsh topography, nothing could be done to prevent such incidents. But we can’t just stand there and say that nothing can be done.
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I wanted to predict the floods and propose scenarios for how to manage or mitigate them, using hydrological modelling. I started looking into that, trying to collect resources to reconstruct these floods and make data available to other researchers as well, to learn lessons. At one point we were stuck, so we called for a collaboration with Sheffield Hallam and Aberystwyth universities in the United Kingdom, to secure funds to continue. This led to an 18-month project with UK representatives carrying out fieldwork in Jordan, which contributed to developing greater awareness of and improved resilience to flood events in the region.How would you encourage women to study engineering?Look at the problems around us, for instance, climate change. It’s not the role of only men to work in these fields and contribute to mitigating the impact. We all have this responsibility, so, we must all share our knowledge and contribute.Women are powerful enough to stand shoulder to shoulder with men — they are not limited to humanitarian work, they can be astronauts or anything. We don’t want to be left behind while men are working on artificial intelligence in engineering, science and mathematics, and solving problems in the world.What advice would you give to your younger self?Believe in yourself and look for opportunities. Also, this might sound weird, but stop looking for perfection — 100% perfect things do not exist in life. Perfectionism can make you get stuck at some point and cause you to underestimate your work. My PhD supervisor, Jonathan Bridge, gave me this advice, saying that you can contribute to solving a problem if you do the best you can.What’s been the best advice you have had?My PhD was tough, owing to the lack of data and the fact that the project was in a remote place in Jordan. At one point I was really suffering, and Jonathan said, “As long as you succeed in this, you will be really strong-boned and nothing in life can break you easily.” That was really inspiring. I thought that I was the only one struggling and he told me, “A PhD is not meant to be easy because you’re contributing to knowledge and doing something that no one else has done before.” I feel I’m really strong-boned, and I really would like to thank him for that. I appreciate what he’s done for me.What does being a role model for the LivWiSE programme involve, and why did you agree to be one?Liverpool was a very supportive environment that sparked many of my current achievements, and I want to give back. My LivWiSE programme role is to actively engage with students and aspiring prospective engineers to share my experiences, knowledge and insights, and participate in mentoring programmes.If I’m experienced and skilful, but everyone around me is not having similar opportunities, then I cannot do much with my skills. So I try my best to contribute to building their capacity. More