Saturday, May 17, 2025

 

PolyU research reveals sharp depletion in soil moisture, driving land water to flow into the oceans and contributing to a rise in sea levels




The Hong Kong Polytechnic University

PolyU research reveals sharp depletion in soil moisture, driving land water to flow into the oceans and contributing to a rise in sea levels 

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PolyU research reveals sharp depletion in soil moisture, driving land water to flow into the oceans and contributing to a rise in sea levels

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Credit: © 2025 Research and Innovation Office, The Hong Kong Polytechnic University. All Rights Reserved.







The increasing frequency of once-in-a-decade agricultural and ecological drought has underscored the urgency of studying hydrological changes. A research team from the Department of Land Surveying and Geo-informatics of The Hong Kong Polytechnic University (PolyU) has collaborated with international experts to analyse the estimated changes in land water storage over the past 40 years by utilising space geodetic observation technology and global hydrological change data. This innovative method has revealed a rapid depletion in global soil moisture, resulting in a significant amount of water flowing into the oceans, leading to a rise in sea levels. The research provides new insights into the driving factors behind the alarming reduction in terrestrial water storage and rise in sea levels. The findings have been published in the international journal Science.

Since polar motion reflects mass redistribution within the Earth system, integrating models and observations across the atmosphere, hydrosphere and lithosphere is crucial. However, previous challenges in measuring terrestrial water storage, particularly groundwater and root zone soil moisture, limited understanding of hydrological depletion at continental scales. Prof. Jianli CHEN, Professor of the PolyU Department of Land Surveying and Geo-informatics and core member of the Research Institute for Land and Space and the international team employed satellite altimetry and gravity missions, including the Gravity Recovery and Satellite Experiment (GRACE), and GRACE Follow-On, to enable continental-scale observations of terrestrial water storage variations. By integrating this with global mean sea levels and polar motion data, the team has explored terrestrial water storage depletion patterns. Notably, this study introduced novel methods for estimating global soil moisture, which improves the accuracy of continental and global scale modeling to enable a more effective understanding of soil moisture variations under climate change.

The melting of Greenland’s ice sheet is recognised as the largest single contributor to the rise in global sea levels, adding approximately 0.8mm annually. This study reveals that between 2000 and 2002, the global terrestrial water storage significantly declined, with a total of 1,614 billion tons of water lost to the oceans, which is twice as much as resulting from the current melting of Greenland ice, and equivalent to a 4.5mm rise in sea levels. Since then, the rapid loss of terrestrial water storage has been followed by a more gradual but continuous depletion, with no signs of recovery.

In addition, compared to the period from 1979 to 1999, a notable decline in global average soil moisture was observed from 2003 to 2021. Between 2003 and 2011, the Earth’s pole shifted 58cm toward 93° East Longitude, demonstrating that the continued decline in soil moisture is leading to a reduction in terrestrial water storage.

The team also pointed out that precipitation deficits and stable evapotranspiration caused by global warming, changing rainfall patterns and increasing ocean temperatures are likely the key factors for the abrupt decline in terrestrial water storage. The ERA5-Land soil moisture data of the European Centre for Medium-Range Weather Forecasts’ corroborates these findings, showing substantial terrestrial water storage losses in Africa, Asia, Europe, and South America. In Asia and Europe, the affected areas expanded from northeastern Asia and eastern Europe to broader regions across East and Central Asia, as well as Central Europe, following the sharp water storage depletion observed between 2000 and 2002.

With increasing agricultural irrigation in regions such as northeast China and the western United States, and global greening, soil moisture may further diminish in semi-arid areas with intensive agriculture and high levels of greening. The team suggests the need for improved land surface models which consider these factors for a more comprehensive understanding of long- term changes in terrestrial water storage.

Prof. Jianli Chen said, “Sea level change and Earth rotation serve as indicators of large-scale mass changes in the Earth system. Accurately measured sea level change and variation in Earth rotation provide a unique tool for monitoring large-scale mass changes in the global water cycle. By integrating multiple modern space geodetic observations, it enables comprehensive analysis of the driving factors behind changes in terrestrial water storage and sea level rise. This, in turn, provides reliable data for climate and Earth system science experts to further investigate drought issues, aiding authorities in formulating water resource management and climate change mitigation strategies to address new challenges posed by climate change.”

 

What behavioral strategies motivate environmental action?



A collaborative study from researchers affiliated with the Annenberg School for Communication, Annenberg Public Policy Center, and School of Arts & Sciences tested 17 strategies in an ‘intervention tournament.’



University of Pennsylvania





Survey data show that most people believe climate change is happening, but many don’t act, and as a postdoctoral fellow in Annenberg School for Communication Professor Emily Falk’s Communication Neuroscience Lab, Alyssa (Allie) Sinclair has thought a lot about why that might be.

“People may struggle to understand how the issue is relevant to them or people they know [relevance], focus on the present instead of future consequences [future thinking], or feel like their actions don’t matter [response efficacy],” says Sinclair, also a member of Professor Michael Mann’s Penn Center for Science, Sustainability, and the Media, a joint venture of the Annenberg Public Policy Center and School of Arts & Sciences.

Building off health behavior studies and other literature in psychology, neuroscience, and communication, Sinclair led an interdisciplinary team of researchers examining how to overcome these barriers to climate action. In an “intervention tournament” with 7,624 U.S. adults, Penn researchers including Sinclair, Falk, and Mann tested 17 interventions targeting the themes of relevance, future thinking, and response efficacy to see which were most effective for motivating action.

“We find that helping them think about the future—especially when that future involves themselves and people they care about—is the most effective way to motivate action,” Sinclair says. This is true for motivating both individual actions, such as driving less or eating vegetarian meals, and collective actions, such as donating or volunteering. Interventions emphasizing relevance—why climate change should matter to you and people you care about—were the most effective in motivating people to share articles and petitions. Their findings are published in the Proceedings of the National Academy of Sciences.

“There’s been a growing number of efforts from other teams and from us to systematically look at what works and what doesn’t work, and it’s been really gratifying to see the fruits of that—to see that people are open to change when we give them the tools and resources,” Falk says. This study builds on her research on messaging to motivate positive changes in health behaviors.

This study embodies the call in Penn’s strategic framework, In Principle and Practice, for an “all-in” University effort to do more in the challenge of climate.

“This work reflects the emerging collaborations across campus in the climate space, something that I’m trying to foster in my new role as Vice Provost for Climate Science, Policy & Action,” Mann says, adding that “understanding how to communicate the science and its implications in a way that leads to useful policy and action is central” to the role.

The work is also inventive in its approach. Sinclair, the paper’s first author, explains that the traditional model of testing whether one idea works makes it difficult to compare findings across studies, so the researchers decided to test many ideas. She says intervention tournaments are not new, but they are rare, as they are ambitious efforts involving a lot of time, energy, and expertise.

Findings

The study—conducted among participants who affirm the existence and anthropogenic causes of climate change—found that two strategies targeting future thinking had the strongest impact on intentions to act: imagining oneself experiencing a negative future that could result from not addressing climate change and writing a letter for a child to read in the future. Both increased intentions to engage in both collective and individual actions.

The letter-writing approach also had the highest impact on intention to share petitions, both broadly on social media and directly with another person. Two interventions targeting relevance had the greatest impact on intention to share news articles: describing why news headlines on climate change matter to them and to people they know. They found that interventions emphasizing response efficacy increased the perceived impact of pro-environmental actions but did not consistently inspire action.

Some strategies exist at the intersection of relevance, future thinking, and response efficacy: brainstorming short-term personal benefits from engaging in pro-environmental behaviors in the next six months and developing a detailed plan to achieve an individual or collective goal. These also increased intentions to act.

Researchers also identified ineffective strategies, showing that receiving information about reducing one’s carbon footprint did not increase intentions to act. This is important because many environmental agencies promote actions focused on individual carbon footprints, but these strategies may not be effective.

“There is a huge gulf between the actions people tend to think make a difference, and the actions that *actually* make a difference when it comes to climate action,” Mann says. “Practitioners, i.e. communicators and organizations that participate in climate communication, could increase their effectiveness by incorporating the key findings of this and related work.”

Sinclair says the perspective of climate scientists has been missing from a lot of behavioral science work on climate change, and Mann advised the team on what actions matter most.

The road ahead

The authors note that while research shows “behavioral intentions are reliably related to actual behavior,” an important goal for future work is to test whether their top-performing interventions change real-world behavior. Such studies could measure the impact on a particular action—such as donating to environmental organizations or signing up for renewable energy programs—or take a longitudinal approach by repeatedly assessing participants’ behaviors in real time.

In the future, the team aims to adapt their findings into interactive online tools, work with museums to highlight the leading interventions through displays and interactive activities, and partner with environmental journalists.

“Overall, we recommend illustrating future scenarios and emphasizing the personal and social impact of climate change as leading strategies to promote behavior change and information sharing,” they write. Additionally, they note that their findings around behavior change, motivation, and information sharing have potential applications in domains beyond climate action, such as for motivating healthy behaviors or civic engagement.

Alyssa H. Sinclair is the Joan Bossert Post-Doctoral Research Fellow at the Penn Center for Science, Sustainability, and the Media and the Annenberg Public Policy Center and a member of the Communication Neuroscience Lab at the University of Pennsylvania.

Emily B. Falk is a professor of communication, psychology, marketing, and operations, informatics, and decisions at the University of Pennsylvania; vice dean of the Annenberg School for Communication; director of the Communication Neuroscience Lab; and director of the Climate Communication Division at the Annenberg Public Policy Center.

Michael E. Mann is Vice Provost for Climate Science, Policy, and Action at the University of Pennsylvania; Presidential Distinguished Professor in the Department of Earth and Environmental Science in the School of Arts & Sciences, with a secondary appointment in the Annenberg School for Communication; director of the Penn Center for Science, Sustainability, and the Media; and affiliate of the Annenberg Public Policy Center. 

The other co-authors are José Carreras-Tartak, Danielle Cosme, and Kirsten Lydic of the Annenberg School for Communication and Diego A. Reinero of the Department of Psychology in the School of Arts & Sciences at the University of Pennsylvania.

This research was supported by the Defense Advanced Research Projects Agency (140D0423C0048), Annenberg Public Policy Center’s Climate Communication Division, the Annenberg School for Communication, and the Penn Center for Science, Sustainability and the Media.

 

Language a barrier in biodiversity work




University of Queensland





A University of Queensland study has shown scientific knowledge on the conservation of endangered species is often overlooked when not presented in English.

PhD candidate Kelsey Hannah examined articles about the protection and management of birds, mammals, and amphibians and compared how often those in English and 16 other languages were cited in further work.

“The 500 papers in my study were published in peer-reviewed journals and available internationally to people working in conservation,” Ms Hannah said.

“Across the board, the non-English language papers had significantly fewer citations.

“The English-language articles had a median of 37 citations while the non-English articles had a median of zero.”

Ms Hannah said the number of citations was unchanged regardless of the robustness of the study design or even the conservation status of the study species.

“This suggests the reason this work isn’t being noticed is a lack of visibility or lack of search effort because of language barriers,” she said.

“One thing that did make a difference for non-English-language articles was providing an English abstract – those articles had 1.5 times as many citations.”

The analysis showed that many non-English-language studies had a high number of citations within their own language, but cross-language citations were very low.

“A Japanese study of the Oriental stork in 2011 for example only had citations in Japanese – even though the species is also endangered in China, Korea and Russia,” Ms Hannah said.

“This means timely and relevant work may not be being seen by the people who can use it to understand and address the conservation challenges of many species.”

Associate Professor Tatsuya Amano at UQ’s School of the Environment said it was crucial that language was not a barrier in addressing the ongoing global biodiversity crisis.

“A lot of the world's biodiversity is in areas where English is not the primary language,” Dr Amano said.

“If we're missing out on information from those regions, and not making decisions using that expertise, conservation efforts could have less impact.

“We encourage researchers to think about the accessibility of their work and consider providing multi-lingual abstracts.

“Importantly, English speaking scientists could remember to look beyond English language studies when conducting research to gain a broader perspective.”    

This work is a part of translatE and is supported by an Australian Research Council Future Fellowship, an Australian Research Council Discovery Project, and a University of Queensland Research Training Program Scholarship.

The research is published in Conservation Biology.

 

Clean power surge needed: China’s 2035 climate plan must aim high



As countries prepare to release long-awaited climate pledges, researchers urge China to set its sights on wind and solar ambitions



University of California - San Diego





China will need to generate more than half of its power from wind and solar by 2035 to align with global climate goals, according to new research led by  the University of California San Diego. The study offers timely recommendations to meet the country’s forthcoming climate commitments.

The study, published in Cell Reports Sustainability, comes as countries worldwide are expected to submit a new round of  Nationally Determined Contributions (NDCs)—the five-year climate plans required under the Paris Agreement. Originally due in February of this year, the release has been delayed, but is anticipated soon. China’s updated 2035 NDC, in particular, is seen as pivotal to global efforts to limit warming to well below 2°C.

The authors of the paper who looked specifically at China’s power sector, emphasize that current policy frameworks are insufficient and that the 2035 NDC is a chance to reset expectations.

“There’s no solution to climate change without China,” said Michael Davidson, the study’s corresponding author who is an assistant professor at the School of Global Policy and Strategy and the Department of Mechanical and Aerospace Engineering at the Jacobs School of Engineering. “It accounts for about 30% of global greenhouse gas emissions—more than double that of the next biggest emitter, the United States. What China does next will be a litmus test for global climate change efforts.”

Powering Half the Grid With Wind and Solar

In order to meet climate commitments, wind and solar should supply up to 56% of China’s electricity by 2035, the study finds—up from just 18% in 2024. When including hydro, nuclear, and biomass, clean energy should make up nearly 80% of the generation mix.

This would significantly reduce the role of fossil fuels in China's power system, cutting coal and gas generation to as little as 20% by 2035.

“Setting a wind and solar generation share target is a robust approach for power sector planning, given massive uncertainties related to economic activity and energy use,”  Davidson explained. “Generation share targets provide clear guidance to maintain momentum toward the country’s 2060 carbon neutrality target.”

The researchers recommend China deploy between 2,910 and 3,800 gigawatts (GW) of wind and solar power by 2035—up from around 1,200 GW today—to stay on track. That would require installing 120–220 GW of new renewables per year, a goal China has already outpaced with its record-breaking deployment of 357 GW in 2024.

“It’s feasible and we think pragmatic,” said Davidson, who collaborated with researchers from Tsinghua University in Beijing on the paper. “In fact, the growth rates we propose are below what China has already achieved historically. These targets reflect a cautious optimism, grounded in current capacity and policy momentum.”

The authors assessed what kind of power sector targets China could realistically adopt to align with its climate goals by modeling various scenarios with granular representation of where the wind and solar farms would be built. They incorporated both technical constraints and a large range of uncertainties. 

“Our findings show a pathway that is both ambitious and achievable,” the authors said. 

As nearly every country prepares to release updated climate plans, China’s decisions could shape the pace and ambition of global efforts. The researchers say this study offers a data-driven benchmark to guide policymakers—not just in Beijing but in other capitals where wind and solar are playing an increasing role.

The study was led by PhD student in Mechanical and Aerospace Engineering at the Jacobs School of Engineering, Zhenhua Zhang, with co-authors from Tsinghua University, Ziheng Zhu, Xi Lu and Da Zhang. 

Read the full paper, “Ratcheting up wind and solar targets for decarbonizing the power sector in China and beyond.

A vicious cycle: How methane emissions from warming wetlands could exacerbate climate change




University of Colorado at Boulder





Warming in the Arctic is intensifying methane emissions, contributing to a vicious feedback loop that could accelerate climate change even more, according to a new study published May 7 in Nature.

“Methane is a very potent greenhouse gas that we need to address urgently,” said co-author Xin (Lindsay) Lan, a climate scientist at CU Boulder’s Cooperative Institute for Research in Environmental Sciences (CIRES). “Our study suggests that a significant portion of the recent rise in atmospheric methane originates from natural sources driven by climate change. Our emission reduction efforts need to be more aggressive.”

Methane is the second most abundant human-produced greenhouse gas after carbon dioxide. But an equal amount of methane traps about 30 times more heat than CO₂ over a 100-year time frame. Methane has been responsible for roughly a quarter of the planet’s warming since the Industrial Revolution.

Lan has spent the past decade tracking methane concentrations in the atmosphere at Boulder’s Global Monitoring Laboratory at the National Oceanic and Atmospheric Administration (NOAA).

Lan and her colleagues at NOAA have observed a rapid increase in atmospheric methane levels in recent years. While previous studies have shown fossil fuel production accounts for 30% of global methane emissions, Lan and colleagues have noticed a steady increase in emissions from microbial sources since 2007.

These microbes, specifically a group known as archaea, produce methane as a byproduct of their metabolism in environments like wetlands, landfills and livestock’s digestive systems.

Together, microbial emissions contribute to nearly half of global methane emissions, but it remains unclear which specific sources are driving this increase.  

“While long-term methane trends are important to investigate, we also need to look at seasonal variations to understand how individual sources are changing and how the natural mechanisms that remove methane from the atmosphere are evolving,” Lan said.

A vicious cycle

To get a clearer picture, Lan and her team analyzed seasonal fluctuations in atmospheric methane levels over the past four decades.

They found that methane’s seasonal amplitude — the difference between peak and lowest methane levels within a year— has been decreasing in northern high-latitude regions, including the Arctic.

Using computer models, the team showed that this trend since the 1980s is largely a result of increased methane emissions from wetlands. Increased precipitation in the Arctic has expanded the region’s wetlands by 25% during the warmer months. Rising temperatures have also been melting some of the perpetually frozen soil layer deep underground, known as permafrost, in summer.

The melted, waterlogged soils have provided ideal conditions for archaea to thrive, leading to higher methane emissions which in turn could accelerate warming further.

Scientists have long warned about such climate feedback loops, but the precise scale and speed of these effects remain uncertain. Lan said this new study added another piece of evidence that natural methane emissions have already been responding to a warming climate.

“This study, along with a few previous studies, has provided indirect evidence on potential climate feedback on methane emissions, which would be beyond our ability to control directly,” Lan said.

The sharp increase in atmospheric methane and its climate feedback effects since 2007 resemble the planet’s most dramatic warming events that brought past ice ages to an end, according to Lan’s previous research.

“Our hope is that by rapidly reducing emissions, we can avoid triggering more severe and abrupt climate feedback that could lead to catastrophic events,” she said.

Methane sponges

The team’s simulations also found a 10% increase in the levels of hydroxyl (OH) radical since 1984. These radicals are highly reactive molecules that can soak up and remove methane and other air pollutants.

Because these molecules stay in the air for less than a second before they react with other compounds, scientists cannot directly measure them globally. In the past, researchers had assumed the OH levels remained constant over the years when calculating atmospheric methane emissions, but this study suggested that assumption might be wrong.

“Our result showed that we’ve been underestimating how much methane the atmosphere has been removing, which means that there’s actually more methane being emitted than we previously estimated,” Lan said.

Understanding the specific source of emission is vital in designing climate mitigation policies. While microbial emissions are responsible for most of the methane growth, human-produced methane from burning fossil fuels remains an important contributor.

“We need to aggressively cut all greenhouse gas emissions from the sources we can control,” Lan said. She added that the world’s permafrost currently holds at least twice as much carbon as is currently in the atmosphere. If future warming causes widespread permafrost thaw and releases that carbon, it could trigger irreversible changes to the planet’s climate. “We need to address the feedback loop before reaching that tipping point.”


 

Empowering cities to act: The Climate Action Navigator highlights where climate action is most needed



Heidelberg Institute for Geoinformation Technology





What does a climate-neutral, livable city look like – and what concrete actions can help us get there? The new Climate Action Navigator (CAN) from HeiGIT (Heidelberg Institute for Geoinformation Technology) offers data-driven answers. This interactive online tool supports cities, NGOs, and community initiatives in identifying and addressing key areas for climate action – scientifically sound, locally adaptable and practical. The tool is funded by the Klaus Tschira Foundation with the aim of harnessing open geodata – such as OpenStreetMap – for effective climate protection.

Identifying challenges, taking action

By 2050, an estimated 70% of the world’s population will live in cities — in Europe, that number is already 75%. This makes it clear that urban areas play a key role in driving the transition toward greater climate protection. But how can we turn that knowledge into action?

The Climate Action Navigator (CAN) provides answers — offering insights much like an energy efficiency rating, but for whole neighborhoods, and across multiple dimensions of urban climate action. The dashboard highlights where walking and cycling infrastructure needs improvement, which districts have high heating emissions, and where land consumption is becoming a concern.

The CAN brings together a range of assessment tools focused on topics such as active mobility, heating emissions, and land use. It is based on open data sources such as OpenStreetMap, remote sensing data and census data. These data serve as the foundation for spatial analyses that enable cities, planners, NGOs, and local initiatives to develop targeted and effective climate strategies.

“To build climate-resilient cities, we need shared perspectives, reliable data, and real-world experience. With the Climate Action Navigator, we want to bring together technical expertise and local knowledge to help cities rethink infrastructure and make it fit for the future,” - says Kirsten von Elverfeldt, Community engagement manager.

Three tools for one goal: targeted climate action

The first version of the dashboard includes three assessment tools:

hiWalk and hiBike assess how walkable and bike-friendly a city is. hiWalk analyzes factors such as the type of pathways (e.g., pedestrian zones or shared traffic), surface quality, and elevation changes. This helps determine how safe, comfortable, and accessible the infrastructure is for pedestrians. hiBike focuses on cycling infrastructure and also takes into account potential risk areas — including the risk of “dooring,” i.e. the danger of suddenly opening car doors alongside parked cars. Both tools highlight where existing infrastructure is already safe and user-friendly — and where there is room for improvement.

In Berlin, for example, hiWalk data shows that districts with more designated pedestrian routes, such as Friedrichshain-Kreuzberg, have significantly higher levels of foot traffic compared to districts like Spandau.

Heating Emissions analyzes CO₂ emissions from residential heating using data from the 2022 German national census. It incorporates factors such as building age, energy source, and living space per person. This allows not only for visualizing emission hotspots, but also for identifying potential savings through renovations or a switch to renewable heating systems.

More tools — focusing on traffic emissions, land consumption, or local CO₂ budgets — are currently in development.

Shaping cities together: co-creation as a guiding principle

The development of CAN is rooted in close collaboration with local partners — because sustainable urban transformation requires practical knowledge just as much as a solid data foundation. Our indicators are not defined “from above”, but developed together with municipal experts, civil society organizations or transport initiatives. For example, the hiBike tool was developed together with Radlobby Austria (cycling advocacy group) to systematically record real danger spots in the cycling network. Each indicator is geared towards specific local challenges and can be flexibly adapted.

Comment from our partners:

“As a cycling advocacy group, we need reliable data and clear assessments to develop and back up targeted demands — it’s the only way the mobility transition can succeed. hiBike opens up many new possibilities for us.”

– Roland Romano, a spokesperson from Radlobby Austria.

„In Lagos, there are neighborhoods that hardly see any cars - the context is different. Thanks to co-creation, HeiGIT, LUDI, and other partners have been able to work together to develop indicators that provide a more realistic view of local mobility needs in West African cities, like Lagos.”
– Olamide Udoma-Ejorh, Direktor von LUDI, Lagos Urban Development Initiative.

“The added value for PLANUM lies in the interdisciplinary design of the decision-making tool: Our many years of experience in transport planning and in research projects in the field of active mobility flow directly into the development - this makes HiWalk particularly sound.”

– Marie-Therese Fallast, PLANUM Fallast & Partner, Graz.“

Online Event: Discover CAN & Join the Conversation

Join us on June 5 at 2:00 PM (CEST) to to learn more about the full potential of the Climate Action Navigator, concrete application examples and opportunities for cooperation.

Register now at: Climate Action Navigator Launch

Climate Action Navigator: Climate Action

Video: Bikeability

Contact at HeiGIT (Heidelberg Institute for Geoinformation Technology)

Assoc. Prof. Dr. Kirsten Von Elverfeldt

kirsten.vonelverfeldt@heigit.org

About HeiGIT gGmbH: 

HeiGIT (Heidelberg Institute for Geoinformation Technology) performs applied research relating to geographic information. Results and data are made freely available for the benefit of the environment and society through stakeholders such as researchers and aid organizations & associations.

The core foci of HeiGIT range from supporting humanitarian missions with customized geodata, to developing intelligent routing solutions for disasters or heatwaves. HeiGIT also implements innovative methods from the fields of spatial data processing and machine learning to analyze, enrich, and visualize geodata (e.g. OpenStreetMap data), as well as offering practical data analysis for climate protection initiatives.

HeiGIT gGmbH was founded in 2019 as an affiliated institute of Heidelberg University, with core funding from the Klaus Tschira Foundation.