More than 40 organizations have joined forces to launch the Global Call to Action on Strengthening Water and Sanitation Regulatory Systems, a coordinated effort to improve public health, equity and climate resilience by strengthening regulatory frameworks worldwide.
The need for acceleration in strong regulation was reinforced in the most recent UN-Water Global Analysis and Assessment of Sanitation and Drinking-Water (GLAAS) report, which found that many countries still lack adequate regulatory frameworks, particularly for sanitation. Where effective regulation does exist, the report noted, countries make faster progress toward their national WASH targets.
The Call to Action outlines practical steps for governments, regulators, donors and partners to build enabling environments for strong regulation. It emphasizes the importance of legally binding standards, autonomous institutions, inclusive oversight and sustainable financing. It also highlights the role of regional regulatory associations in driving progress and sharing tools, expertise and capacity across borders.
The launch event featured remarks from global leaders including Ms. Retno Marsudi, United Nations Secretary-General’s Special Envoy on Water, and Bruce Gordon, Head of Water, Sanitation and Hygiene at WHO and Vice-Chair of UN-Water, the UN’s inter-agency coordination mechanism for water-related issues.
The Call to Action is available for download in six languages – English, French, Spanish, Portuguese, Russian and Arabic – and is accompanied by launch videos in English, French, Spanish and Portuguese. All materials are accessible here.
Heat waves and cold spells are now more common on the Great Lakes, according to U-M research, with implications for the region’s weather, economy and ecology.
Summary:Extreme heat waves and cold spells on the Great Lakes have more than doubled since the late 1990s, coinciding with a major El Niño event. Using advanced ocean-style modeling adapted for the lakes, researchers traced temperature trends back to 1940, revealing alarming potential impacts on billion-dollar fishing industries, fragile ecosystems, and drinking water quality.
Great Lakes temperature extremes have surged since the late ’90s, threatening ecosystems, fisheries, and water quality. Advanced modeling now offers a detailed history back to 1940 and could help forecast future risks. Credit: Shutterstock
Heat waves and cold spells are part of life on the Great Lakes. But new research from the University of Michigan shows that is true today in a fundamentally different way than it was even 30 years ago.
“The appearance of these extreme temperatures is increasing,” said Hazem Abdelhady, a postdoctoral research fellow in the U-M School for Environment and Sustainability, or SEAS. “For most lakes, the appearance is up more than 100% compared with before 1998.” That timing is significant because it coincides with the 1997-1998 El Niño, which is one of the strongest on record, he added.To reveal this trend, Abdelhady and his colleagues developed a state-of-the-art approach to modeling the surface temperature of the Great Lakes, which allowed them to study heat waves and cold spells dating back to 1940. The surface water temperature of the Great Lakes plays an important role in the weather, which is an obvious concern for residents, travelers and shipping companies in the region.But the uptick in extreme temperature events could also disrupt ecosystems and economies supported by the lakes in more subtle ways, Abdelhady said.
“These types of events can have huge impacts on the fishing industry, which is a billion-dollar industry, for example,” Abdelhady said. Tribal, recreational and commercial fishing in the Great Lakes account for a total value of more than $7 billion annually, according to the Great Lakes Fishery Commission.
While fish can swim to cooler or warmer waters to tolerate gradual temperature changes, the same isn’t always true for sudden jumps in either direction, Abdelhady said. Fish eggs are particularly susceptible to abnormal temperature spikes or drops.
Hot and cold streaks can also disrupt the natural mixing and stratifying cycles of the lakes, which affects the health and water quality of lakes that people rely on for recreation and drinking water.Now that the researchers have revealed these trends on each of the Great Lakes, they’re working to build on that to predict future extreme temperature events as the average temperature of the lakes — and planet — continue to warm. In studying those events and their connections with global climate phenomena, such as El Niños and La Niñas, we can better prepare to brace for their impact, Abdelhady said.
“If we can understand these events, we can start thinking about how to protect against them,” Abdelahdy said.
The study was conducted through the Cooperative Institute for Great Lakes Research, or CIGLR, and published in Communications Earth & Environment, part of the Nature journal family. The work was supported by the National Science Foundation, its Global Centers program and the National Oceanic and Atmospheric Administration, or NOAA.
Capturing the greatness of the lakes
One of the challenges of this work was the size of the problem itself. Although researchers have developed computer models that can simulate processes in most lakes around the world, the Great Lakes aren’t most lakes.
For starters, they’re an interconnected system of five lakes. They also contain more than a fifth of the world’s fresh surface water. And the length of their shoreline is comparable to that of the U.S.’s entire Atlantic coast — including the gulf states.In many regards, the Great Lakes have more in common with coastal oceans than with other lakes, said study coauthor Ayumi Fujisaki-Manome, who is an associate research scientist with SEAS and CIGLR.
“We can’t use the traditional, simpler models for the Great Lakes because they really don’t do well,” Fujisaki-Manome said.
So Abdelhady turned to modeling approaches used to study coastal oceans and tailored them for the Great Lakes. But there was also a data hurdle to overcome in addition to the modeling challenges.
Satellites have enabled routine direct observations of the Great Lakes starting about 45 years ago, Fujisaki-Manome said. But when talking about climate trends and epochs, researchers need to work with longer time periods.
“The great thing with this study is we were able to extend that historical period by almost double,” Fujisaki-Manome said.
By working with available observational data and trusted data from global climate simulations, Abdelhady could model Great Lakes temperature data and validate it with confidence back to 1940.”That’s why we use modeling a lot of the time. We want to know about the past or the future or a point in space we can’t necessarily get to,” said coauthor Drew Groneworld, an associate professor in SEAS and a leader of the Global Center for Climate Change and Transboundary Waters. “With the Great Lakes, we have all three of those.”
David Cannon, an assistant research scientist with CIGRL, and Jia Wang, a climatologist and oceanographer with NOAA’s Great Lakes Environmental Research Laboratory, also contributed to the study. The study is a perfect example of how collaborations between universities and government science agencies can create a flow of knowledge that benefits the public and the broader research community, Gronewold said.
The team’s model is now available for other research groups studying the Great Lakes to explore their questions. For the team at U-M, its next steps are using the model to explore spatial differences across smaller areas of the Great Lakes and using the model to look forward in time.
“I’m very curious if we can anticipate the next big shift or the next big tipping point,” Gronewold said. “We didn’t anticipate the last one. Nobody predicted that, in 1997, there was going to be a warm-winter El Niño that changed everything.”
Summary:Deep beneath the Antarctic seas lies a hidden network of 332 colossal submarine canyons, some plunging over 4,000 meters, revealed in unprecedented detail by new high-resolution mapping. These underwater valleys, shaped by glacial forces and powerful sediment flows, play a vital role in transporting nutrients, driving ocean currents, and influencing global climate. Striking differences between East and West Antarctica’s canyon systems offer clues to the continent’s ancient ice history, while also exposing vulnerabilities as warm waters carve away at protective ice shelves.
Submarine canyons are among the most spectacular and fascinating geological formations to be found on our ocean floors, but at an international level scientists have yet to uncover many of their secrets, especially of those located in remote regions of the Earth like the North and South Poles. Now, an article published in the journal Marine Geologyhas brought together the most detailed catalogue to date of Antarctic submarine canyons, identifying a total of 332 canyon networks that in some cases reach depths of over 4,000 meters.
The catalogue, which identifies five times as many canyons as previous studies had, was produced by the researchers David Amblàs, of the Consolidated Research Group on Marine Geosciences at the Faculty of Earth Sciences of the University of Barcelona, and Riccardo Arosio, of the Marine Geosciences Research Group at University College Cork. Their article shows that Antarctic submarine canyons may have a more significant impact than previously thought on ocean circulation, ice-shelf thinning and global climate change, especially in vulnerable areas such as the Amundsen Sea and parts of East Antarctica.Submarine canyons: the differences between East and West Antarctica
The submarine canyons that form valleys carved into the seafloor play a decisive role in ocean dynamics: they transport sediments and nutrients from the coast to deeper areas, they connect shallow and deep waters and they create habitats rich in biodiversity. Scientists have identified some 10,000 submarine canyons worldwide, but because only 27% of the Earth’s seafloor has been mapped in high resolution the real total is likely to be higher. And despite their ecological, oceanographic, and geological value, submarine canyons remain underexplored, especially in polar regions.
“Like those in the Arctic, Antarctic submarine canyons resemble canyons in other parts of the world,” explains David Amblàs. “But they tend to be larger and deeper because of the prolonged action of polar ice and the immense volumes of sediment transported by glaciers to the continental shelf.” Moreover, the Antarctic canyons are mainly formed by turbidity currents, which carry suspended sediments downslope at high speed, eroding the valleys they flow through. In Antarctica, the steep slopes of the submarine terrain combined with the abundance of glacial sediments amplifies the effects of these currents and contributes to the formation of large canyons.The new study by Amblàs and Arosio is based on Version 2 of the International Bathymetric Chart of the Southern Ocean (IBCSO v2), the most complete and detailed map of the seafloor in this region. It uses new high-resolution bathymetric data and a semi-automated method for identifying and analysing canyons that was developed by the authors. In total, it describes 15 morphometric parameters that reveal striking differences between canyons in East and West Antarctica.
“Some of the submarine canyons we analyzed reach depths of over 4,000 meters,” explained David Amblàs. “The most spectacular of these are in East Antarctica, which is characterized by complex, branching canyon systems. The systems often begin with multiple canyon heads near the edge of the continental shelf and converge into a single main channel that descends into the deep ocean, crossing the sharp, steep gradients of the continental slope.”
Riccardo Arosio noted that “It was particularly interesting to see the differences between canyons in the two major Antarctic regions, as this hadn’t been described before. East Antarctic canyons are more complex and branched, often forming extensive canyon-channel systems with typical U-shaped cross sections. This suggests prolonged development under sustained glacial activity and a greater influence of both erosional and depositional sedimentary processes. In contrast, West Antarctic canyons are shorter and steeper, characterized by V-shaped cross sections.”According to David Amblàs, this morphological difference supports the idea that the East Antarctica Ice Sheet originated earlier and has experienced a more prolonged development. “This had been suggested by sedimentary record studies,” Amblàs said, “but it hadn’t yet been described in large-scale seafloor geomorphology.”
About the research, Riccardo Arosio also explained that “Thanks to the high resolution of the new bathymetric database — 500 meters per pixel compared to the 1-2 kilometres per pixel of previous maps — we could apply semi-automated techniques more reliably to identify, profile and analyse submarine canyons. The strength of the study lies in its combination of various techniques that were already used in previous work but that are now integrated into a robust and systematic protocol. We also developed a GIS software script that allows us to calculate a wide range of canyon-specific morphometric parameters in just a few clicks.”
Submarine canyons and climate change
As well as being spectacular geographic accidents, the Antarctic canyons also facilitate water exchange between the deep ocean and the continental shelf, allowing cold, dense water formed near ice shelves to flow into the deep ocean and form what is known as Antarctic Bottom Water, which plays a fundamental role in ocean circulation and global climate.
Additionally, these canyons channel warmer waters such as Circumpolar Deep Water from the open sea toward the coastline. This process is one of the main mechanisms that drives the basal melting and thinning of floating ice shelves, which are themselves critical for maintaining the stability of Antarctica’s interior glaciers. And as Amblàs and Arosio have explained, when the shelves weaken or collapse, continental ice flows more rapidly into the sea and directly contributes to the rise in global sea level.
Amblàs and Arosio’s study also highlights the fact that current ocean circulation models like those used by the Intergovernmental Panel on Climate Change do not accurately reproduce the physical processes that occur at local scales between water masses and complex topographies like canyons. These processes, which include current channeling, vertical mixing and deep-water ventilation, are essential for the formation and transformation of cold, dense water masses like Antarctic Bottom Water. Omitting these local mechanisms limits the ability that models have to predict changes in ocean and climate dynamics.As the two researchers conclude, “That’s why we must continue to gather high-resolution bathymetric data in unmapped areas that will surely reveal new canyons, collect observational data both in situ and via remote sensors and keep improving our climate models to better represent these processes and increase the reliability of projections on climate change impacts.”
The fifth annual SDG 6 Water Action Agenda Special Event, co-hosted by UN‑Water and the United Nations Department of Economic and Social Affairs, took place at the 2025 High‑Level Political Forum on Sustainable Development (HLPF) in New York on 22 July 2025.
The event reviewed progress on Sustainable Development Goal 6 and its interlinkages with broader UN priorities.
UN-Water launched the fourth series of the SDG 6 Country Acceleration Case Studies, spotlighting practical examples from Bhutan, Rwanda, and Saudi Arabia, showing how targeted policy interventions and coordinated UN support helped drive results.
The event featured a fireside chat between UN-Water Chair Alvaro Lario and Bob Rae, President of the 2025 session of the UN Economic and Social Council, reflecting on the transformative potential of Artificial Intelligence (AI) for sustainable water management.
Looking ahead to the 2026 UN Water Conference, the event included a dialogue where commitment-holders and Member States explored how to sustain momentum through inclusive, collaborative processes.The fifth annual SDG 6 (clean water and sanitation) special event during the High-Level Political Forum (HLPF) launched three new SDG 6 Country acceleration case studies. The half-day event also hosted a dialogue on the interconnections and expectations for AI and water, followed by statements about countries’ commitments to water action. The Special Event took place alongside the High-Level Political Forum (HLPF), on 22 July 2025, in New York, US.
Alvaro Lario, UN-Water Chair and President of the International Fund for Agricultural Development (IFAD), opened the special event and highlighted the recent launch of the Collaborative Implementation Plan (CIP) for the UN System-wide Strategy for Water and Sanitation. He also looked forward to discussions on the 2026 UN Water Conference, which will be co-hosted by the United Arab Emirates (UAE) and Senegal and will take place in the UAE, and the 2028 UN Water Conference, which will take place in Dushanbe, Tajikistan.
Li Junhua, Under-Secretary-General for Economic and Social Affairs, noted that the following themes for the 2026 UN Water Conference had been agreed on 9 July: Water for people, Water for prosperity, Water for planet, Water for cooperation, Water in multilateral processes, and Investments for water.
Launch of the SDG 6 Country Acceleration Case Studies
Mary Matthews, UNDP and UN-Water Senior Programme Manager, presented the three country case studies and highlighted recommendations and lessons learned in each country. Leaders from the three countries then commented on their national experiences.
In the Bhutan case study, Matthews highlighted that drivers of progress were identified as: the national prioritization of water; the establishment of a legal and policy framework; progressive implementation of plans and programmes; empowerment of local authorities to lead WASH initiatives; diversified sources of financing; and a low level of corruption.
In the Rwanda case study, Matthews noted the report indicates progress has been made due to the intersectoral coordination of policy under the Office of the Prime Minister and scaling planning and evaluation down to the district level, among others.
In the Saudi Arabia case study, Matthews noted the country’s Vision 2030 has inspired reform in all sectors, its National Water Strategy 2030 has provided a policy framework, and the government began purchasing desalinated water from the private sector.
Across the case studies, Matthews noted that: people and businesses were major sources of the solutions; non-conventional water is playing a key role; public investment has been critical in almost all case studies; and political leadership is essential.
Tshering Tobgay, Prime Minister, Bhutan, highlighted that his country has:
prioritized governance and let it be people centered, with its water vision based on consultations and governance not just focusing on policies, but listening to people;
financed “boldly and intelligently” by combining international loans, development grants, and user fees that help regulate demand;
built institutions and human capacity;
let data speak; and
trusted and empowered youth and let them lead.
He said climate change is Bhutan’s next challenge, with 21.4% of its water sources drying up. He concluded by recommending that other leaders “Listen to your people, back vision with values, empower youth, and never take water for granted.”
Abdulaziz Al-Shaibani, Deputy Minister for Water, Saudi Arabia, and Tshering Tobgay, Prime Minister, Bhutan
Abdulaziz Al-Shaibani, Deputy Minister for Water, Saudi Arabia, highlighted the following lessons:
secure high-level political will and commitment;
set goals, indicators, and assign responsibilities across the value chain;
engage the private sector as a partner in service delivery and infrastructure;
leverage data and innovation to improve delivery; and
forge partnerships and international cooperation, such as with G20 and UN-Water, and convene global events, such as Saudi Water Week.
He invited participants to participate in the 2027 World Water Forum, which will take place in Saudi Arabia.
Gemma Maniraruta, Director General of Water and Sanitation, Ministry of Infrastructure, Rwanda, noted the benefits of intersectoral coordination, including by ensuring that water-related policies and decisions align with Rwanda’s broader development priorities. Efforts on transboundary water resources cooperation have also been undertaken, and noted that cooperative transboundary river management is a contribution to regional integration and diplomacy, builds trust, and ensures equitable resource use. She highlighted efforts to invest in human resources, including through support for the education and training of Rwandan nationals in internationally accredited institutions.
Gemma Maniraruta, Director General of Water and Sanitation, Ministry of Infrastructure, Rwanda
Ligia Noronha, Assistant Secretary-General and Head of the New York Office of the UN Environment Programme (UNEP), offered closing remarks for the session, highlighting that SDG 6 is not a stand alone goal but is central to achieving the other goals. She noted links between the strategies and the environment, and noted in particular Bhutan’s efforts to protect forests and adopt nature-based solutions, Saudi Arabia’s efforts to integrate governance, and Rwanda’s efforts to link its efforts to global objectives. She noted that UNEP develops tools to support countries.
During a discussion, a representative from the Children and Youth major group noted that water security is linked to biodiversity, food and climate. Other speakers noted that water is a human right and asked how synergies between the UN Water Conferences and other multilateral environmental agreements could be built.
Bob Rae, President of the 2025 session of the Economic and Social Council, and Alvaro Lario, UN-Water Chair and President of IFAD
Fireside chat: Water and Artificial Intelligence
Aarathi Krishnan, founder of AI firm RAKSHA, moderated a conversation between Bob Rae, President of the 2025 session of the Economic and Social Council, and Alvaro Lario, UN-Water Chair and President of IFAD, on questions related to water and AI.
Rae recalled that AI is a tremendous user of energy, which he said represents a serious problem. He also noted that utilities have been assuming energy use would decline. Rae highlighted that AI has been expected to help us use water more efficiently, for example by informing us when leaks occur. He said AI should be seen as a tool that can be helpful in using a scarce resource more efficiently, but added that whether that happens is a political question that involves money, resources, and financing.
Alvaro said we need some guardrails for the technology, and its clear and present harms need to be addressed. He said water utilities need capacity and expertise to use AI, and that such capacity should not only be available to the private sector.
In closing, speakers noted that AI brings unprecedented potential along with profound responsibilities.
Li Junhua, Under-Secretary-General for Economic and Social Affairs, and Alvaro Lario, UN-Water Chair and President of the International Fund for Agricultural Development (IFAD)
Sustaining Momentum: Building toward the 2026 UN Water Conference
Representatives from the 2023 UN Water Conference host countries offered reflections on lessons from the 2023 conference.
Jonibek Hikmat, Permanent Representative of Tajikistan to the UN, noted that the Water Action Agenda gathered over 800 commitments. He recalled that the 2023 UN Water Conference led to the appointment of a Special Envoy on Water and the UN System-Wide Strategy on Water and Sanitation.
Anna Pot, Ministry of Foreign Affairs, the Netherlands, noted that Voluntary National Reviews (VNRs) are one area in which countries can share their experiences on water. She said the water conferences need to evolve into a platform for action and impact.
Diamane Diome, Deputy Permanent Representative of Senegal to the UN
Water Action Agenda Commitment Holders: Rapid Progress Pitches
Representatives from a number of countries and organizations then discussed their commitments and progress. They noted the importance of water diplomacy and the need to focus on implementation. Germany and Finland indicated their interest in co-chairing an interactive dialogue during the 2026 Water Conference.
Efforts of 10 multilateral development banks (MDBs) to collaborate on water funding was discussed, as was the recent launch of the first joint MDB report on water. The World Bank Group reported it has a new global water strategy.
A representative from UNDRR noted that water connects 90% of disasters worldwide, either because of too much or too little water. She said UNDRR is working to improve the data on hazardous events. The need to change behaviors was mentioned, with a call for reaching people through their faith traditions.
During the discussion, representatives from youth cautioned against the commodification of water and called for including them in decision making. Speakers also suggested developing case studies on tribal and First Nations water policies.
Fatema Yousuf, Deputy Permanent Representative of the UAE to the UN
2026 UN Water Conference Co-hosts Closing Remarks
Fatema Yousuf, UAE Deputy Permanent Representative to the UN, said the next step for the 2026 Conference will be the selection of co-chairs for the interactive dialogues. She said the co-hosts will work with stakeholder groups in the lead up to conference.
Diamane Diome, Deputy Permanent Representative of Senegal to the UN, said his country wants to make water be at the heart of the UN, including through regular meetings on water.
Representative of the Major Group for Children and Youth
When Kristine Wojnovich and her husband bought their home 20 years ago in Washington Crossing, Pennsylvania, it was everything they wanted — until one day in 2023, when she turned on her kitchen faucet.
“It tasted weird and smelled like oil,” Wojnovich said. “It was very disconcerting.”
Wojnovich called Sunoco Pipeline, operator of the Twin Oaks pipeline that runs just across their street. It carries jet fuel underground from a fuel terminal outside Philadelphia to Newark Terminal near the airport.Sunoco tested her water, but she says they didn’t find anything.
“[They said], ‘We’re so happy to tell you, there’s no oil, no gas, no propane, nothing in your water,'” Wojnovich said.
When she pressed further about the cause, Wojnovich said Sunoco Pipeline told her they didn’t know, but it could be “some kind of bacteria” unrelated to the pipeline.
“I feel like we’re being poisoned every day,” Wojnovich said.
People in the community don’t use water piped in from a reservoir far away. Instead, they use wells that draw from underground aquifers for their cooking and drinking water.When their well was finally opened earlier this year, Wojnovich was shocked at the amount of jet fuel on top of it.
“It was 15 gallons…and it’s been gathering there since September 2023,” Wojnovich said.
Sunoco removed that fuel, but Wojnovich says Sunoco still sends workers each day to skim off new fuel seeping into her well.
She’s not alone. The number of wells impacted has risen to at least 38, according to the Pennsylvania Department of Environmental Protection.
In 2024, Sunoco Pipeline spilled more fuel than any other pipeline in the United States, according to data from the Pipeline and Hazardous Materials Safety Administration.”A pipeline company that’s more aggressive in follow-up, would have identified it sooner,” said Robert Hall, who spent decades regulating pipeline safety for the federal government. “They are not one of the best pipeline companies with regard to their management of their pipeline.”
In a statement, Sunoco’s partner company Energy Transfer said it has installed “advanced water filtration systems at no cost” and is “committed to the cleanup and restoration of the…neighborhood,” but did not address why it took so long to find the leak.
As for Wojnovich, she is suing Sunoco Pipeline. With the pipeline back in operation, she doesn’t plan to stick around the neighborhood.
“Would you stay if there was 12 feet of jet fuel found on your well?” Wojnovich said. “We feel unsafe.”
Analysis used machine learning to estimate erosion for 180,000 glaciers around the globe.
Summary:Scientists used machine learning to reveal how glaciers erode the land at varying speeds, shaped by climate, geology, and heat. The findings help guide global planning from environmental management to nuclear waste storage.
A glacier in the Canadian Arctic. Credit: John Gosse, Dalhousie University
Glaciers carved the deep valleys of Banff, eroded Ontario to deposit the fertile soils of the Prairies and continue to change the Earth’s surface. But how fast do glaciers sculpt the landscape?
Published on August 7 in Nature Geoscience, University of Victoria (UVic) geographer Sophie Norris and her international team provide the most comprehensive view of how fast glaciers erode, and how they change the landscape. Most importantly, their research also provides an estimate of the rate of contemporary future erosion for more than 180,000 glaciers worldwide. Using a machine learning-based global analysis, Norris and her research team have worked to predict glacial erosion for 85 per cent of modern glaciers. Their regression equations estimate that 99 per cent of glaciers erode between 0.02 and 2.68 millimeters per year — roughly the width of a credit card.
“The conditions that lead to erosion at the base of glaciers are more complicated than we previously understood,” says Norris. “Our analysis found that many variables strongly influence erosion rates: temperature, amount of water under the glacier, what kind of rocks are in the area, and how much heat comes from inside the Earth.”
“Given the extreme difficulty in measuring glacial erosion in active glacial settings, this study provides us with estimates of this process for remote locations worldwide,” says John Gosse, Dalhousie University.
Understanding the complex factors that cause erosion underneath glaciers is vital information for landscape management, long-term nuclear waste storage and monitoring the movement of sediment and nutrients around the world.
Norris started this work while a post-doctoral fellow at Dalhousie and concluded it at UVic. The team of collaborators included the University of Grenoble Alpes (France), Dartmouth College (US), Pennsylvania State University (US) and the University of California Irvine (US). The work was carried out in partnership with and financially supported by the Canadian Nuclear Waste Management Organization.
Summary:Between 2003 and 2021, Earth saw a net boost in photosynthesis, mainly thanks to land plants thriving in warming, wetter conditions—especially in temperate and high-latitude regions. Meanwhile, ocean algae struggled in increasingly stratified and nutrient-poor tropical waters. Scientists tracked this global energy shift using satellite data, revealing that land ecosystems not only added more biomass but also helped stabilize climate by capturing more carbon.
This image illustrates the annual trend in global net primary production (NPP) — or net carbon gain by photosynthetic organisms on Earth — from 2003 to 2021. Credit: Yulong Zhang, et al, 2025
Terrestrial plants drove an increase in global photosynthesis between 2003 and 2021, a trend partially offset by a weak decline in photosynthesis — the process of using sunlight to make food — among marine algae, according to a new study published in Nature Climate Change on August 1. The findings could inform planetary health assessments, enhance ecosystem management, and guide climate change projections and mitigation strategies.
Photosynthetic organisms — also known as primary producers — form the base of the food chain, making most life on Earth possible. Using energy from the sun, primary producers fix, or convert, carbon from the air into organic, or carbon-based, matter. But primary producers also release carbon through a process called autotrophic respiration, which is somewhat akin to breathing. The rate of carbon gain after accounting for loss through respiration is called net primary production.
“Net primary production measures the amount of energy photosynthetic organisms capture and make available to support nearly all other life in an ecosystem,” said first author Yulong Zhang, a research scientist in the lab of Wenhong Li at Duke University’s Nicholas School of the Environment. “As the foundation of food webs, net primary production determines ecosystem health, provides food and fibers for humans, mitigates anthropogenic carbon emissions and helps to stabilize Earth’s climate.”
Previous research on net primary production has typically focused on either land or ocean ecosystems, leaving gaps in our understanding of net primary production across Earth and the potential implications for climate mitigation.
For this study, the team explored annual trends and variability in global net primary production, with a focus on the interplay between land and ocean ecosystems.
“If you’re looking at planetary health, you want to look at both terrestrial and marine domains for an integrated view of net primary production. The pioneering studies that first combined terrestrial and marine primary production have not been substantially updated in over two decades,” said co-author Nicolas Cassar, Lee Hill Snowdon Bass Chair at the Nicholas School who jointly oversaw the research with Zhang.
Satellite Insights
Observations from satellites offer continuous perspective on photosynthesis by plants and marine algae called phytoplankton. Specifically, specialized satellite instruments measure surface greenness, which represents the abundance of a green pigment called chlorophyll produced by photosynthetic life. Computer models then estimate net primary production by combining greenness data with other environmental data, such as temperature, light and nutrient variability.
The authors of the new study used six different satellite-based datasets on net primary production — three for land and three for oceans — for the years from 2003 to 2021. Using statistical methods, they analyzed annual changes in net primary production for land and, separately, for the ocean.
They found a significant increase in terrestrial net primary production, at a rate of 0.2 billion metric tons of carbon per year between 2003 and 2021. The trend was widespread from temperate to boreal, or high-latitude, areas, with a notable exception in the tropics of South America.
By contrast, the team identified an overall decline in marine net primary production, of about 0.1 billion metric tons of carbon per year for the same time period. Strong declines mainly occurred in tropical and subtropical oceans, particularly in the Pacific Ocean.
All told, trends on land dominated those of oceans: Global net primary production increased significantly between 2003 and 2021, at a rate of 0.1 billion metric tons of carbon per year.
Environmental Drivers
To understand the potential environmental factors at play, the team analyzed variables such as light availability, air and sea-surface temperature, precipitation and mixed layer depth — a measure that reflects the extent of mixing in the ocean’s top layer by wind, waves and surface currents.
“The shift toward greater primary production on land mainly stemmed from plants in higher latitudes, where warming has extended growing seasons and created more favorable temperatures, and in temperate regions that experienced local wetting in some areas, forest expansion and cropland intensification,” said Wenhong Li, a professor of earth and climate sciences at the Nicholas School and a co-author on the study.
Warming temperatures appeared to have an opposite effect in some ocean areas.
“Rising sea surface temperatures likely reduced primary production by phytoplankton in tropical and subtropical regions,” Cassar added. “Warmer waters can layer atop cooler waters and interfere with the mixing of nutrients essential to algal survival.”
Although land drove the overall increase in global primary production, the ocean primarily influenced year-to-year variability, especially during strong climate events such as El Niño and La Niña, the authors found.
“We observed that ocean primary production responds much more strongly to El Niño and La Niña than land primary production,” said co-author Shineng Hu, an assistant professor of climate dynamics at the Nicholas School. “A series of La Niña events was partly responsible for a trend reversal in ocean primary production that we identified after 2015. This finding highlights the ocean’s greater sensitivity to future climate variability.”
Broad Implications
The study points to the important role of terrestrial ecosystems in offsetting declines in net primary production among marine phytoplankton, according to the authors.
But they added that declines in net primary production in tropical and subtropical oceans, coupled with stagnation on land in the tropics, can weaken the foundation of tropical food webs, with cascading effects on biodiversity, fisheries and local economies. Over time, these disruptions could also compromise the ability of tropical regions to function as effective carbon sinks, potentially intensifying the impacts of climate warming.
“Whether the decline in ocean primary production will continue — and how long and to what extent increases on land can make up for those losses — remains a key unanswered question with major implications for gauging the health of all living things, and for guiding climate change mitigation,” Zhang said. “Long-term, coordinated monitoring of both land and ocean ecosystems as integrated components of Earth is essential.”
Funding: Y.Z., W.L., and G.S. were partially supported by the Duke University-USDA Forest Service collaboration (23-JV-11330180-119). N.C. was supported by the National Science Foundation (OCE-2123198). J.M. was supported by the Oak Ridge National Laboratory. J.X. is supported by the National Science Foundation (Macrosystem Biology) and NEON-Enabled Science Program (DEB-2017870).
Summary:Researchers are exploring AI-powered digital twins as a game-changing tool to accelerate the clean energy transition. These digital models simulate and optimize real-world energy systems like wind, solar, geothermal, hydro, and biomass. But while they hold immense promise for improving efficiency and sustainability, the technology is still riddled with challenges—from environmental variability and degraded equipment modeling to data scarcity and complex biological processes.
As the world grapples with the urgent need to reduce carbon emissions and combat climate change, researchers at the University of Sharjah are turning to a cutting-edge technology that could reshape the future of energy: AI-powered digital twins.
According to the researchers, these digital replicas of the physical world have the potential to transform the generation, management, and optimization of energy across diverse clean energy platforms, accelerating the transition away from fossil fuels, which environmental scientists associate with global warming.
Digital twins’ ability to replicate and interact with complex systems has made them a cornerstone of innovation across industries, driving improvements in efficiency, cost reduction, and the development of novel solutions.
However, the scientists caution that current digital twin models still face notable limitations that restrict their full potential in harnessing energy from sources such as wind, solar, geothermal, hydroelectric, and biomass.
“Digital twins are highly effective in optimizing renewable energy systems,” the researchers write in the journal Energy Nexus. “Yet, each energy source presents unique challenges — ranging from data variability and environmental conditions to system complexity — that can limit the performance of digital twin technologies, despite their considerable promise in improving energy generation and management.”
In their study, the authors conducted an extensive review of existing literature on the application of digital twins in renewable energy systems. They examined various contexts, functions, lifecycles, and architectural frameworks to understand how digital twins are currently being utilized and where gaps remain.
To extract meaningful insights, the researchers employed advanced text mining techniques, leveraging artificial intelligence, machine learning, and natural language processing. This scientifically rigorous approach enabled them to analyze large volumes of raw data and uncover structured patterns, concepts, and emerging trends.
From this in-depth analysis, the authors drew several key conclusions. They identified research gaps, proposed new directions, and outlined the challenges that must be addressed to fully harness the potential of digital twin technology in the renewable energy sector.
Following a detailed discussion on the integration of digital twins across various renewable energy applications, the authors summarized their most significant findings across five major energy sources: wind, solar, geothermal, hydroelectric, and biomass. Each source presents unique opportunities and challenges, and the study offers a comprehensive overview of how digital twins can be tailored to optimize performance in each domain.
The study reveals that digital twins offer significant advantages across various renewable energy systems:
Wind Energy: Digital twins can predict unknown parameters and correct inaccurate measurements, enhancing system reliability and performance.
Solar Energy: They help identify key factors that influence efficiency and output power, enabling better system design and optimization.
Geothermal Energy: Digital twins can simulate the entire operational process — particularly drilling — facilitating cost analysis and reducing both time and expenses.
Hydroelectric Energy: The AI-driven models simulate system dynamics to identify influencing factors. In older hydro plants, they are used to mitigate the impact of worker fatigue on productivity.
Biomass Energy: Digital twins improve performance and management by offering deep insights into operational processes and plant configurations.
But the authors’ contribution to the field stands out in highlighting critical limitations in the application of digital twin technology across these energy sources. Their analysis underscores the need for more robust models that can address specific challenges unique to each renewable energy system.
The authors identify several limitations in the application of digital twins across different renewable energy systems:
Wind Energy: Digital twins face challenges in accurately modeling and monitoring environmental conditions. They struggle to simulate critical factors such as blade erosion, gearbox degradation, and electrical system performance — particularly in aging turbines.
Solar Energy: Despite their potential, digital twins still fall short in reliably predicting long-term performance. They have difficulty tracking panel degradation and accounting for environmental influences over time, which affects their accuracy and usefulness.
Geothermal Energy: A major obstacle is the lack of high-quality data, which hampers the ability of digital twins to simulate geological uncertainties and subsurface conditions. The technology also faces complexity in modeling the long-term behavior of geothermal systems, including heat transfer and fluid flow dynamics.
Hydroelectric energy: Applied to hydroelectric projects, digital twins face challenges in accurately modeling water flow variability and in capturing environmental and ecological constraints. These limitations reduce their effectiveness in optimizing system performance and sustainability.
biomass energy: When used with biomass energy systems, digital twins still struggle to simulate the entire production supply chain. They fall short in providing precise models for biological processes, biomass conversion, and the complex biochemical and thermochemical reactions involved.
The authors emphasize the broader implications of these shortcomings for the renewable energy sector. To address these challenges, they offer a set of guidelines and a research roadmap aimed at helping scientists enhance the reliability and precision of digital twin technologies.
Their recommendations focus on improving data collection methods, advancing modeling techniques, and expanding computational capabilities to ensure digital twins can deliver trustworthy insights for decision-making and system optimization.
A boy pushes a trolley with containers as Palestinians wait to collect water amid shortages, in Gaza City August 6, 2025. REUTERS/Mahmoud Issa
By Nidal al-Mughrabi
GAZA/CAIRO (Reuters) -Weakened by hunger, many Gazans trek across a ruined landscape each day to haul all their drinking and washing water – a painful load that is still far below the levels needed to keep people healthy.
Even as global attention has turned to starvation in Gaza, where after 22 months of a devastating Israeli military campaign a global hunger monitor says a famine scenario is unfolding, the water crisis is just as severe according to aid groups.
Though some water comes from small desalination units run by aid agencies, most is drawn from wells in a brackish aquifer that has been further polluted by sewage and chemicals seeping through the rubble, spreading diarrhoea and hepatitis.
COGAT, the Israeli military agency responsible for coordinating aid in the Israeli-occupied Palestinian territories, says it operates two water pipelines into the Gaza Strip providing millions of litres of water a day.
Palestinian water officials say these have not been working recently.
Israel stopped all water and electricity supply to Gaza early in the war but resumed some supply later though the pipeline network in the territory has been badly damaged.
Most water and sanitation infrastructure has been destroyed and pumps from the aquifer often rely on electricity from small generators – for which fuel is rarely available.
COGAT said the Israeli military has allowed coordination with aid organisations to bring in equipment to maintain water infrastructure throughout the conflict.
Moaz Mukhaimar, aged 23 and a university student before the war, said he has to walk about a kilometre, queuing for two hours, to fetch water. He often goes three times a day, dragging it back to the family tent over bumpy ground on a small metal handcart.
“How long will we have to stay like this?” he asked, pulling two larger canisters of very brackish water to use for cleaning and two smaller ones of cleaner water to drink.
His mother, Umm Moaz, 53, said the water he collects is needed for the extended family of 20 people living in their small group of tents in Deir al-Balah in the central Gaza Strip.
“The children keep coming and going and it is hot. They keep wanting to drink. Who knows if tomorrow we will be able to fill up again,” she said.
Their struggle for water is replicated across the tiny, crowded territory where nearly everybody is living in temporary shelters or tents without sewage or hygiene facilities and not enough water to drink, cook and wash as disease spreads.
The United Nations says the minimum emergency level of water consumption per person is 15 litres a day for drinking, cooking, cleaning and washing. Average daily consumption in Israel is around 247 litres a day according to Israeli rights group B’Tselem.
Bushra Khalidi, humanitarian policy lead for aid agency Oxfam in the Israeli-occupied Palestinian territories said the average consumption in Gaza now was 3-5 litres a day.
Oxfam said last week that preventable and treatable water-borne diseases were “ripping through Gaza”, with reported rates increasing by almost 150% over the past three months.
Israel blames Hamas for the suffering in Gaza and says it provides adequate aid for the territory’s 2.3 million inhabitants.
QUEUES FOR WATER
“Water scarcity is definitely increasing very much each day and people are basically rationing between either they want to use water for drinking or they want to use a lot for hygiene,” said Danish Malik, a global water and sanitation official for the Norwegian Refugee Council.
Merely queuing for water and carrying it now accounts for hours each day for many Gazans, often involving jostling with others for a place in the queue. Scuffles have sometimes broken out, Gazans say.
Collecting water is often the job of children as their parents seek out food or other necessities.
“The children have lost their childhood and become carriers of plastic containers, running behind water vehicles or going far into remote areas to fill them for their families,” said Munther Salem, water resources head at the Gaza Water and Environment Quality Authority.
With water so hard to get, many people living near the beach wash in the sea.
A new water pipeline funded by the United Arab Emirates is planned, to serve 600,000 people in southern Gaza from a desalination plant in Egypt. But it could take several more weeks to be connected.
Much more is needed, aid agencies say. UNICEF spokesperson James Elder said the long-term deprivations were becoming deadly. “Starvation and dehydration are no longer side effects of this conflict. They are very much frontline effects.”
Oxfam’s Khalidi said a ceasefire and unfettered access for aid agencies was needed to resolve the crisis.
“Otherwise we will see people dying from the most preventable diseases in Gaza – which is already happening before our eyes.”
(Reporting by Ramadan Abed in Deir al-Balah, Gaza, Nidal al-Mughrabi in Cairo and Olivia Le Poidevin in Geneva; writing by Angus McDowall; Editing by Alexandra Hudson)
More “plant destroyer” water mold species discovered in Minnesota
Scientists at the University of Minnesota say they’ve discovered more than a dozen different types of a mold known as “plant destroyers.”
At first, this rhodadendron plant just looks like it needs a little extra love. But through the microscope, you’ll see something more destructive.
“It’ll cause a wilting, or it’ll kill the tree or plant outright,” said Nick Rajtar, a researcher with the U’s plant pathology program. “It’s really species-specific, but basically mortality is the end goal for the pathogen, and it’s really good at what it does.”
It goes by the name Phytophthora, a water mold that can kill trees, plants, and crops.
Rajtar and his team found 22 different species in the state, 14 of which were previously undetected.
“Minnesota’s nurseries ship a lot of material in from a lot of other places around the country, be it Missouri, Oregon, Washington, where these phytophthora are a little more prominent,” he said. “And that’s a potential avenue for them to be introduced to Minnesota’s landscapes.”
Rajtar says phytophthora loves Minnesota’s recent wet weather, potentially helping them spread even faster.
If you suspect a plant or tree around your home is infected, you can get it tested at the university’s lab. If infected, the plant will need to be destroyed.
