Explore the latest insights from top science journals in the Muser Press daily roundup, featuring impactful research on climate change challenges.
In brief:
How changing L.A.’s tree rules could cool more neighborhoods
Expansive tree canopies are crucial for healthy ecosystems and livable cities. Yet, Los Angeles’ strict tree planting rules, originally meant to protect infrastructure and public safety, are now widening shade disparities, particularly in lower-income neighborhoods.
A new study1 published in Landscape and Urban Planning, led by the Spatial Sciences Institute and Public Exchange, both based at the USC Dornsife College of Letters, Arts and Sciences, suggests that easing these decades-old restrictions could significantly grow the city’s urban tree canopy — without compromising safety.
This research builds on an earlier USC study2 comparing L.A.’s municipal codes, engineering standards and urban forestry guidelines to those of 25 other cities — 17 outside California and eight within the state. That study found L.A.’s tree placement rules are among the nation’s strictest, often limiting new planting. The team concluded that substantial changes could be made to existing tree-spacing guidelines without re-writing laws, but better coordination between city departments is essential.
“Fixing L.A.’s rules is a step toward addressing inequities and bringing the health and ecological benefits of green infrastructure to underserved communities,” said Laura Messier, PhD candidate in the population, health and place program at the Spatial Sciences Institute.
Testing looser tree spacing rules
To test how relaxing planting guidelines might increase tree coverage, Messier and her team compared two L.A. neighborhoods: Boyle Heights, a historically lower-income area east of downtown; and Studio City, a wealthier community in the San Fernando Valley.
Both areas studied were similar in size, topography and parcel layout. But Studio City had about 3,020 trees per square mile, compared to 2,183 in Boyle Heights — a gap researchers linked to the neighborhood’s denser street grid, higher concentration of multi-family housing and smaller parcels, all of which limit where trees can be planted.
Using mapping software, the team identified obstacles like utility poles, gas lines and bus stops, then modeled potential new planting sites. They compared L.A.’s current planting restrictions with more flexible guidelines in other California cities — including San Francisco, Fremont, Oakland and Anaheim — and identified infrastructure changes that could further expand tree coverage.
The results were striking. Under L.A.’s current rules, Studio City could support up to 140 trees per square mile, while Boyle Heights maxed out at 121. But with looser guidelines, the gap nearly vanished — Studio City’s capacity rose to 158, while Boyle Heights jumped to 153, a 26% increase in the historically Latino neighborhood.
Still, Boyle Heights faces challenges beyond planting guidelines. Narrow sidewalks limit the ability to plant large shade trees. Even with the same number of trees, only 34.5% in Boyle Heights could be large-canopy species, compared to 61% in Studio City.
Small tweaks to tree spacing make big impact
Even modest policy changes could open up more space for tree planting in crowded areas.
The study found that easing restrictions near intersections could increase the number of trees in Boyle Heights by 7.6%, while relaxing rules around utility poles could add another 5.5%. Adjusting guidelines for gas lines (2.6%), streetlights (2.2%), driveways (1.4%) and other infrastructure could push the total canopy gain to 26%, helping expand shade in other dense, lower-income neighborhoods.
While planting trees at bus stops would add less than 1% to overall canopy coverage, it could make a big difference for transit riders exposed to extreme summer heat.
A major obstacle to planting more trees is L.A.’s 45-foot visibility rule at intersections, last updated in 1988. Studies show high-canopy trees don’t block drivers’ views, making this restriction ripe for revision.
Easier to change tree spacing rules than laws
Many of the restrictions are internal guidelines rather than laws, meaning changes could be implemented more easily. The city’s Urban Forestry Division would need to update its Tree Spacing Guidelines memo, but getting agreement from other departments — such as transportation and street lighting — could still be a challenge, Messier explained.
Ironically, the study found that half the street trees in Boyle Heights and nearly 40% in Studio City don’t comply with city guidelines. Yet, there’s little evidence that these violations create safety or liability issues.
Messier suggests that updating the guidelines is more practical than enforcing rules that are often ignored and seem to have little impact on safety.
While modernizing L.A.’s rules is an important step, closing the shade gap will require broader infrastructure changes. Messier and her team point to strategies like reducing street widths — known as “road diets” — to create more space for trees.
“To truly close the shade gap and ensure more equitable access to cooling and green spaces, the city must invest in infrastructure that makes room for more trees in underserved areas,” Messier said.
Journal Reference:
1. Laura Messier, Beau MacDonald, John P. Wilson, ‘Equity impacts of street tree spacing guidelines: A case study in two Los Angeles neighborhoods’, Landscape and Urban Planning 259, 105345 (2025). DOI: 10.1016/j.landurbplan.2025.105345
2. Laura Messier, Esther Margulies, John P. Wilson, ‘Elevating street trees to infrastructure status: A comparison of street tree spacing guidelines in Los Angeles with U.S. peer cities’, Urban Forestry & Urban Greening 103, 128584 (2025). DOI: 10.1016/j.ufug.2024.128584
Article Source:
Press Release/Material by Ileana Wachtel | USC Dornsife
Renting clothes for sustainable fashion – niche markets work best
Renting clothes can reduce the fashion industry’s enormous environmental impact, but so far, the business models have not worked very well. The best chance of success is for a rental company to provide clothing within a niche market, such as specific sportswear, and to work closely with the suppliers and clothing manufacturers. This is shown by a study led by researchers at Chalmers University of Technology, Sweden, which highlights the measures that can make clothing rental a success.
The fashion industry is one of the most polluting industries and can account for up to ten percent of global greenhouse gas emissions, worldwide. In Sweden, over 90 percent of the clothes’ climate impact is linked to the purchase of newly produced goods. Therefore, researchers at Chalmers University of Technology, the University of Borås and the research institute Rise have examined alternative, more sustainable business models for the clothing industry.
“Many people have clothes hanging in the closet that are rarely or never used. Renting clothes can extend the use of each garment and thus contribute to more sustainable consumption,” says Frida Lind, Professor at Chalmers and one of the researchers behind the study.
In the study, the researchers analysed nine Swedish companies that have either tried and failed, or are ongoing in the process of creating a sustainable and desirable clothes rental company. From this analysis, the researchers identified three main business models for renting out clothes:
- Membership model: customers become members and can then borrow clothes for a certain period of time, similar to a library. This model often had an enthusiast as its founder, with a focus on sustainable consumption.
- Subscription model: customers pay a monthly fee to rent a certain number of garments. These startups worked on scaling up operations and attracting venture capital.
- Individual rental model: the company would provide specific types of clothing to rent out, often in combination with other equipment, such as outdoor clothing paired with ski equipment.
Difficult to achieve profitability
By interviewing founders, managers and other key people from the nine Swedish companies, the researchers gained an understanding of each company’s situation.
“What struck us was that it seemed so difficult for them to make their business profitable. Several had had to end their investments for various reasons,” Frida Lind says.
The researchers noted that although there was a willing customer base for renting clothing in this way, they observed several other challenges that made it difficult for companies to achieve profitability.
“Renting out clothes involves many steps where each item of clothing needs to be handled and inspected before it can be rented out again, which takes time. Companies also struggled with high costs for warehousing, logistics and laundry, for example. Especially for the subscription models, there were also difficulties in obtaining venture capital to be able to survive financially through the first phase of building the company. All this shows that these business models need time to establish themselves in the market,” she says.
Specific markets performed best
At the same time, some of the business models worked better than others. Companies that focused on a specific market, such as outdoor clothing, were more successful and sustainable. Especially if they also had a local connection to an outdoor recreational area.
“They seem to have found their niche and seen that there is a specific need that the customer is willing to pay for each time they need to use that type of clothing,” states Frida Lind.
The researchers also examined how the companies created value in collaboration with different stakeholders and concluded that certain collaborations were particularly valuable.
“Rental companies that worked closely with clothing manufacturers and suppliers, such as designers with a sustainability profile, benefited greatly from this as they were able to quickly get feedback on which types of clothing were most popular. They also gained valuable information about the quality of the garments, for example if there was something that often broke,” Lind explains.
Initiatives for change important
In the current study, the researchers have not investigated the environmental and climate impact of the business models specifically, but in general, the environmental effects of our clothes have already been well mapped. For example, previous research from Chalmers has shown that the actual production of garments accounts for 70 percent of the climate impact of Swedes’ clothes throughout their life cycle, and 22 percent of the climate impact is caused by customers’ shopping trips.
In the European Union, five million tonnes of clothing are discarded each year – around 12 kilos per person, and in the USA, the average American generates 37 kilos of textile waste each year.
Frida Lind believes that there is a great deal of room for environmental benefits through reduced clothing purchases and extended use of existing garments – especially if it can be done without extra car journeys for consumers.
She emphasises that even if some of the companies and services in the study have not survived, all initiatives that can contribute to the sustainability transition are important. Not least because they help to change attitudes about clothing consumption and increase knowledge about what can and cannot work.
“Our study can be an important contribution to the fashion industry’s sustainability transition, as it shows the possibilities of new business models in this industry. We hope that it can have an impact on decision-makers who need a basis for establishing incentives and financial motivation for a more sustainable fashion industry. Because we see that new and more sustainable business models require time and a long-term perspective to be able to establish themselves,” she says.
Recommendations for the industry
Based on the study’s results, the researchers give a number of recommendations to those who intend to try renting clothes as a business model:
- Focus on niche markets based on target group and product type where the need is clear
- Develop partnerships with suppliers to improve products based on rental experiences.
- Think about logistics and transport in the rental model right from the start to be able to get the model scalable.
More about the research
The scientific article ‘Exploring renting models for clothing items – resource interaction for value creation’ was published in the Journal of Business & Industrial Marketing. The authors are Frida Lind, Chalmers University of Technology, Agnes Andersson Wänström and Daniel Hjelmgren, University of Borås, and Maria Landqvist, Rise. The study has been financed with funds from the Swedish Energy Agency.
Facts and advice about textile consumption
- In the European Union, five million tonnes of clothing are discarded each year – around 12 kilos per person, and in the USA, the average American generates 37 kilos of textile waste each year.
- Over 90 percent of the total climate impact from Swedish clothing consumption is linked to the purchase of newly produced clothes, and 80 percent of our clothes’ climate impact occurs during the production phase.
- It also plays a big role how customers get to the stores. If they walk or cycle instead of driving, they reduce their climate impact by over 10 percent.
- The most important thing that consumers can do is to extend the use of the garments that have already been produced. A t-shirt, for example, is used an average of 30 times. If it is instead used 60 times before it is replaced by a newly produced t-shirt, the climate impact can be halved.
- Extended use can mean that one owner uses the garment for longer, or that several users share ownership. In addition to renting or borrowing clothes, this can be done, for example, by shopping and selling second-hand, arranging clothes swap days or giving away clothes to someone who continues to use them.
- A previous Chalmers study has shown that the actual production of garments accounts for 70 percent of the climate impact of Swedes’ clothes throughout their life cycle. 22 per cent of the climate impact is caused by customers’ shopping trips, 4 per cent by distribution to customers and 3 per cent by washing and drying clothes.
Journal Reference:
Andersson Wänström, A., Hjelmgren, D., Landqvist, M. and Lind, F., ‘Exploring renting models for clothing items – resource interaction for value creation’, Journal of Business & Industrial Marketing (2025). DOI: 10.1108/JBIM-04-2024-0281
Article Source:
Press Release/Material by Daniel Karlsson and Ulrika Ernström | Chalmers University of Technology
Ocean Eddies – the Food Trucks of the Sea
How is organic matter transported from productive coastal areas to the open ocean?
Researchers from the GEOMAR Helmholtz Centre for Ocean Research Kiel and MARUM – Centre for Marine Environmental Sciences at the University of Bremen have now shown that eddies play a crucial role in this process. The swirling currents contain large amounts of energy-rich and essential fat molecules (essential lipids), which play a key role in marine food webs and the carbon cycle.
The study has now been published in the journal Communications Earth and Environment.
Mesoscale eddies, oceanic swirling currents with typical horizontal scales of 10-100 kilometres in diameter, are ubiquitous features of the global ocean and play a vital role in marine ecosystems. Eddies, which form in biologically productive coastal upwelling regions, are important vehicles for the transport of carbon and nutrients. These eddies trap water masses and migrate into the open ocean, where productivity is comparatively low. As such, they have a significant influence on the nutrient and carbon cycles within the ocean.
For decades, marine scientists have sought to understand in detail how coastal waters are transported offshore and how this process affects productivity in the open ocean, especially as eddy activity is expected to change significantly due to climate change.
While it was previously known that ocean eddies transport large quantities of organic carbon and nutrients, the exact composition and nutritional quality of this material for zooplankton and fish has remained largely unexplored. Using high-resolution mass spectrometry, a team of researchers from GEOMAR and MARUM has now analysed the lipidome – the entire spectrum of lipid molecules including essential fats – in and around an ocean eddy.
Cutting-edge analysis reveals lipid diversity in eddies
“These eddies are basically the food trucks of the ocean,” explains Dr Kevin Becker, geochemist at GEOMAR and lead author of the study. “They transport nutrients from the highly productive coastal upwelling regions to the open ocean, where these nutrients are released and are likely to influence biological productivity.”
For their study, the researchers analysed samples collected during the GEOMAR-coordinated REEBUS project (Role of Eddies in the Carbon Pump of Eastern Boundary Upwelling Systems) on the METEOR M156 Expedition off the coast of Mauritania (West Africa). Almost 1,000 different lipids were identified. Lipids can make up to 20 percent of the carbon content of phytoplankton and are essential building blocks of cells, performing critical biological functions as energy stores, membrane components, signalling molecules, and electron transporters.
“Lipids also contain chemotaxonomic information that allows us to determine the composition of microbial communities,” adds Dr Becker. “Based on their chemical signatures, we can, for example, distinguish between lipids from phytoplankton, bacteria, and archaea species.”
The results of the study showed that the lipid signature within the mesoscale eddy was significantly different from that of the surrounding waters, indicating a distinct microbial community. In particular, energy-rich storage lipids and essential fatty acids were enriched – nutrients that higher marine organisms such as zooplankton and fish cannot synthesise on their own and must ingest through food.
Calculations show that coastal eddies in the upwelling region off Mauritania transport up to 9.7 ± 2.0 gigagrams (about 10,000 tonnes) of labile organic carbon to the open ocean each year. “Our study highlights the central role of mesoscale eddies in the local carbon cycle and provides a basis for future investigations of their importance on a global scale,” concludes Prof. Dr Anja Engel, lead scientist of the study and head of the Marine Biogeochemistry Research Division at GEOMAR.
Journal Reference:
Becker, K.W., Devresse, Q., Prieto-Mollar, X. et al., ‘Mixed-layer lipidomes suggest offshore transport of energy-rich and essential lipids by cyclonic eddies’, Communications Earth & Environment 6, 179 (2025). DOI: 10.1038/s43247-025-02152-0
Article Source:
Press Release/Material by Helmholtz Centre for Ocean Research Kiel (GEOMAR)
Losing forest carbon stocks could put climate goals out of reach
In the past, intact forests absorbed 7.8 billion tonnes of CO2 annually – about a fifth of all human emissions – but their carbon storage is increasingly at risk from climate change and human activities such as deforestation.
A new study from the Potsdam Institute for Climate Impact Research (PIK) shows that failing to account for the potentially decreasing ability of forests to absorb CO2 could make reaching the Paris agreement targets significantly harder, if not impossible, and much more costly.
“Delaying action leads to disproportionately higher costs,” explains Michael Windisch, the study’s lead author and PIK guest scientist. “Right now, our climate strategies bet on forests not only remaining intact, but even expanding,” Windisch says. “However, with escalating wildfires like in California, and continued deforestation in the Amazon, that’s a gamble. Climate change itself puts forests’ immense carbon stores at risk.”
According to the study, postponing action to reduce emissions and to protect and monitor forests could jeopardise climate targets. “We must act immediately to safeguard the carbon stored in forests,” Windisch emphasises. “Otherwise, compensating for potential forest carbon losses through steeper emissions cuts in key emission sectors like energy, industry and transport will become increasingly expensive and possibly unattainable.”
Considering forest carbon losses in climate mitigation pathways
The study, published in Nature Communications, analysed how climate targets can be met despite forests’ reduced capacity for storing carbon. The authors used REMIND-MAgPIE – an integrated global land and water use modelling as well as an energy-economy modelling system – together with the global vegetation model LPJmL to evaluate how natural disturbances and human impacts on forests influence the feasibility of achieving climate mitigation goals. The research team compared a foresighted policy response with various delayed and myopic approaches.
Regardless of the assessed disturbance rate, the study revealed just how steep the price of inaction can be. Even a five-year delay in responding to forest carbon loss would lead to a roughly two-fold increase in both the stringency and overall cost of measures to offset that lost carbon, the authors find.
Emission cuts in the energy sector, for instance, would have to be ramped up considerably, supported by a near-doubling of negative emissions capacity – which itself demands a corresponding expansion in land use. Ultimately, these extra efforts drive up overall costs, and result in GDP setbacks that are approximately double those of immediate action.
The study also highlights that current models may be overly optimistic about future forest carbon storage because they ignore disturbances, overvalue CO2 fertilisation and underestimate deforestation.
To mitigate climate impacts, safeguard carbon stocks and prevent escalating costs, the scientists recommend immediate action. “Forests are not an infinite resource, but need careful monitoring to detect reductions in carbon sinks early on,” explains Florian Humpenöder, PIK scientist and study author. He also stresses the need for stronger forest conservation, and faster decarbonisation. Forests may absorb less CO2 than expected, making realistic forest carbon projections essential.
“Staying below critical warming thresholds requires more than just hoping forests will remain intact,” concludes Alexander Popp, head of PIK’s Land Use Transition lab and author of the study. “Alongside protecting forests, it is essential to promote sustainable land use practices– not only to preserve biodiversity but also to avoid drastic economic consequences and to secure our climate future.”
Journal Reference:
Michael G. Windisch, Florian Humpenöder, Leon Merfort, Nico Bauer, Gunnar Luderer, Jan Philipp Dietrich, Jens Heinke, Christoph Müller, Gabriel Abrahao, Hermann Lotze-Campen, Alexander Popp, ‘Hedging our bet on forest permanence for the economic viability of climate targets’, Nature Communications 16, 2460 (2025). DOI: 10.1038/s41467-025-57607-x
Article Source:
Press Release/Material by Potsdam Institute for Climate Impact Research (PIK)
By 2100, more than 80% of amphibian species in and around the Pantanal will lose suitable habitat
A study published in the Journal of Applied Ecology shows that the Upper Paraguay River Basin, which includes the Pantanal and its surroundings, could lose almost all of the areas suitable for anuran amphibians (toads, frogs and tree frogs) by the end of the century.
By cross-referencing a database on species locations in the region with climate projections for 2100, researchers from Brazil and Switzerland also concluded that more than 80% of the species in this group will lose suitable habitat.
According to the projections, in the optimistic greenhouse gas emissions scenario, in which current levels are maintained, 99.87% of the basin would experience local extinctions. In the pessimistic scenario, in which emissions increase, 99.99% of the region would suffer from species loss.
The first author of the study was Matheus Oliveira Neves, who conducted the research as part of his doctoral studies at the Federal University of Mato Grosso (UFMT) in Brazil.
According to the research, the integral conservation units, which represent only 5.85% of the territory, protect on average less than 5% of the geographical distribution of amphibians.
In 2022, the United Nations (UN) Convention on Biodiversity recommended that 30% of the Earth’s surface be covered by protected areas by 2030 as a strategy to reduce species extinction.
The current rate is 17% and includes both conservation units and indigenous lands.
Given the data on amphibian biodiversity, the authors of the study propose the creation of new conservation units in the Upper Paraguay River Basin, in places that will be more suitable in the future for this group of animals, which is highly dependent on humidity.
“Fully protected conservation units are currently doing very little to protect amphibian species in the Pantanal, the world’s largest floodplain. Protected areas need to be expanded, considering the scenario of a hotter and drier future,” says Brazilian researcher Mario Ribeiro Moura, who coordinated the study during his time as a researcher at the Institute of Biology of the State University of Campinas (IB-UNICAMP), supported by FAPESP.
Moura is currently a professor at the Federal University of Paraíba (UFPB). In the study, his group considered two climate change scenarios, following the projections of the Intergovernmental Panel on Climate Change (IPCC). In the optimistic scenario, emissions would remain at current levels, resulting in a 2 °C increase in the average global temperature by 2100. In the pessimistic scenario, with emissions rising, the increase would be 4 °C.
More than 4,000 records were used for the 74 known amphibian species from the Upper Paraguay River Basin, which in addition to the Pantanal in Brazil also includes parts of Paraguay and Bolivia.
Possible futures
The few areas that would be suitable for hosting amphibians in the future, in both the optimistic and pessimistic emissions scenarios, are currently located in the north of the Upper Paraguay River Basin, in the transition to the Cerrado (Brazilian savannah-like biome), near Cuiabá (Mato Grosso state), and in the southeast of the region, near Campo Grande (Mato Grosso do Sul state), as well as in the southwest, near the Paraguayan Chaco.
Among the current protected areas, none had higher amphibian richness than expected for the current climate scenario, although six of them (8.2%) had significantly lower richness than expected. The comparison was made with non-protected areas of the same size and shape, chosen at random.
The projections for the future also show a greater gain of species than expected in five of them (6.8%) in the optimistic scenario and in three (4.1%) in the pessimistic scenario. However, two and three (2.7% and 4.1%) in the optimistic and pessimistic scenarios, respectively, show greater loss of species than expected.
“In summary, only 13.7% of the current protected areas in the Upper Paraguay River Basin have the potential to host more or lose fewer species in at least one future scenario. Most of these areas are indigenous lands,” explains Moura.
Although the researchers advocate the creation of new integral conservation units and the expansion of existing ones, they stress the need to mitigate the impacts of inappropriate agricultural practices and promote the restoration of aquatic ecosystems.
“While the Paris Agreement aimed to limit the global temperature increase to 1.5 °C by the end of the century, we already reached that level in 2024. The change in the economic model, currently based on fossil fuel consumption, needs to be radical to mitigate the impacts of the climate catastrophe on biodiversity and society,” concludes Moura.
Journal Reference:
Neves, M. O., Broennimann, O., Mod, H. K., Bolochio, B. E., Santana, D. J., Guisan, A., & Moura, M. R., ‘Climate change threatens amphibians and species representation within protected areas in tropical wetlands’, Journal of Applied Ecology 62, 2, 290–302 (2025). DOI: 10.1111/1365-2664.14846
Article Source:
Press Release/Material by André Julião | Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Featured image credit: Gerd Altmann | Pixabay
