EV

Making self-driving cars safer, less accident prone

New AI model could enhance self-driving car safety

University of Georgia

Self-driving cars rely on artificial intelligence to predict where nearby cars will go. But when those predictions don’t match reality, that discrepancy can potentially lead to crashes and less safe roadways.

That’s why a recent study from the University of Georgia developed a new AI model to make self-driving cars safer.

This study introduces an AI model for self-driving cars, designed to predict the movement of nearby traffic and incorporate innovative features for planning safe vehicle movements.

"The planned trajectory of the self-driving car may turn out to collide with the actual trajectory of another vehicle.” —Qianwen Li, College of Engineering

The study used data from the I-75 freeway in Florida to predict other cars’ paths and determine the motion of the self-driving car when following another vehicle.

Previous research mostly predicts surrounding traffic movements and then plans a self-driving car’s motion. This separate approach, however, makes crashes and near-misses more likely.

“That’s why we wanted to consolidate those two steps — to make the autonomous vehicle operation safer,” said Qianwen Li, lead author of the study and an assistant professor in UGA’s College of Engineering. “And as illustrated by our experiments, that approach does help with safety performance.”

AI needs to do more than predict traffic

To keep drivers safe, self-driving cars have to be able to accurately anticipate the movements of surrounding traffic. However, it’s difficult to know what other drivers will do on the road.

“There are always differences between your prediction and the reality,” said Li. “The planned trajectory of the self-driving car may turn out to collide with the actual trajectory of another vehicle.”

The new model was designed to take prediction errors into account, as eliminating them isn’t possible.

Li’s group is also working on developing more complex AI models for self-driving car operations, such as large learning models like ChatGPT. Traffic scenarios could be fed to these models, and they would determine the best course of action.

However, large language models have limits. While they’re effective at making high-level decisions related to how to respond to different situations, planning the movements of a car isn’t what they’re built for.

“How do we make a perfect lane change that is safe and also efficient?” said Li. “How do we come to a smooth stop for pedestrians without inducing any riding discomfort? Basically, how do we design the specific trajectories? That part we do not ask ChatGPT or large language models to do because they do not have the capability to do so. Traditional trajectory optimization models can do a much better job based on our experiments so far.” 

Balancing safety and mobility in vehicle artificial intelligence

Designing AI for self-driving cars is a balancing act. Maximizing safety often comes at the cost of mobility.

If a self-driving car is taught to drive as safely as possible, for example, it will stay far behind the car in front of it. While a safer option, that distance would likely reduce the number of cars that could fit on the roadway at a given time.

Similarly, focusing too much on mobility could result in cars driving too aggressively, increasing the risk of crashes.

“We’re still working on how we train the model in a way that can balance the safety and mobility performance,” said Li.

The study was published in Transportation Research Part E. Co-authors include Handong Yao of UGA’s College of Engineering, Xiaopeng Li of University of Wisconsin-Madison’s Department of Civil and Environmental Engineering, and Chenyang Yu of McGill University’s Mathematics and Computer Science Department.

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Journal

Transportation Research

DOI

10.1016/j.tre.2024.103780 

Article Title

Safety aware neural network for connected and automated vehicle operations

Article Publication Date

10-Dec-2024

Nationwide study looks at when and where EV owners use public charging stations

Initial results show that demand during working hours is high in California

Society for Risk Analysis

AUSTIN, TX, Dec 10, 2024 – Electric Vehicles (EVs) represent a promising mode of transportation that can help the United States reduce its carbon emissions. But barriers such as the high cost of installing and using EV Charging Stations (EVCS), their limitations in supplying emerging demand, and their uneven distribution throughout the country limit access for many Americans.  

Researchers at the University of Maryland are using supercomputers and machine learning methods to analyze a full year of real-time data collected from individual EV charging ports at more than 50,000 publicly available stations throughout the country. The primary focus of the study is to estimate demand and peak times at EV charging stations.  

“Understanding EV users’ charging behaviors will provide valuable insights into their needs, enabling us to efficiently deploy EV charging infrastructure to meet the emerging demand,” says civil engineering Ph.D. candidate Safoura Safari. She will present the team’s preliminary findings in December at the annual meeting of the Society for Risk Analysis in Austin, Texas. 

Led by scientists in UMD’s Center for Global Sustainability and Center for Disaster Resilience, the study utilizes individual charging port statuses recorded every 10 minutes at 54,000 charging stations located in three power grid zones: California, Texas, and the Northeast. It is the first study of its kind to use real-time charging port data to understand charging behaviors across different time intervals. 

Machine learning is used to extract “clusters” or groups of behavior from the data. In their analysis, the researchers look for variations of charging patterns on daily, monthly, and seasonal scales — accounting for temperature impacts on battery range (which impacts charging decisions).  

The first round of analysis based on data for the month of August 2023, revealed working-hour patterns in all three zones, with differences in charging behavior and power demand: 

• In the California zone, about 45 percent of stations showed a working-hours charging pattern (6 am – 6 pm), with peak utilization reaching 80 percent of total stations’ charging capacity during those hours. This suggests that charging stations in this zone may be especially vulnerable in the event of a disaster or disruption of power — with the potential for lines of vehicles to form at public charging stations. 

• In the Texas zone, about 30 percent of stations showed a similar workday pattern (between 9 am and 4 pm), with peak utilization averaging 60 percent of total capacity during those hours. 

• In the Northeast zone (comprising six states), 28 percent of stations demonstrated a working-hour pattern (8 am – 6 pm), with peak utilization of 55 percent during those hours. 

Safari points out that the variation in charging behavior variation between zones may be due to several factors: differences in the price of electricity, the availability of public charging stations to EV owners, and incentive programs that may encourage owners to charge their vehicles during off-peak hours.  

As they continue to crunch a year’s worth of data on supercomputers, the team expects to find other “clustered” patterns in EV charging station usage — for example, during overnight hours, holidays, local and national events, and weather-related disasters. They hope that power grid operators can use the results of their analysis to efficiently price electricity, invest in developing new charging stations or expand existing ones, and balance supply and demand — ensuring charging port availability and reducing wait times.  

A secondary focus of the research is to explore potential inequities in access and use of EV charging stations on a national scale. “Our findings can set the foundation for future research on the equitable accessibility, availability, and utilization of EV charging facilities across diverse communities with varied socio-economic status,” says UMD assistant professor Jiehong Lou, assistant research director of the Center for Global Sustainability.  

In a previously published study, Lou and colleagues found that lower-income households face less accessibility to public EV infrastructure in both urban and rural geographies. 

According to a Pew Research Center report, there were over 61,000 publicly accessible charging stations in the U.S. as of February 2024. Experts have found that many more are needed to accommodate future EV ownership. EV charging stations are mostly accessible to residents in urban areas, with only 17 percent located in rural areas, according to the report.  

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Safoura Safari, Deb Niemeier, Jiehong Lou are presenting this research on Tuesday, December 10, from 1:30 pm, at the JW Marriot Austin, Texas. 

Spatial and Temporal Patterns of EV Charging Usage: A Nationwide Analysis Using Machine Learning Techniques – Tuesday, December 10, 1:30 p.m. 

About SRA   

The Society for Risk Analysis is a multidisciplinary, interdisciplinary, scholarly, international society that provides an open forum for all those interested in risk analysis. SRA was established in 1980. Since 1982, it has continuously published Risk Analysis: An International Journal, the leading scholarly journal in the field. For more information, visit www.sra.org. 

SwRI showcases capabilities, evaluates novel fire-safety method with customized test

Customized lab test advances understanding of EV fire dynamics

Southwest Research Institute

 

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Southwest Research Institute successfully customized and conducted a full-scale evaluation of a novel enclosure for damaged electric vehicles at risk of catching fire. The custom test highlights SwRI’s expertise and ability to help advance emerging fire technology where no standardized testing exists.

 

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Credit: Southwest Research Institute

SAN ANTONIO — December 10, 2024 — Southwest Research Institute successfully customized and conducted a full-scale evaluation of a novel fire mitigation method designed to safely store damaged electric vehicles and batteries. SwRI engineers demonstrate customized research and development support for government and industry clients with novel projects and challenges related to emerging technologies where no standardized testing exists.

“SwRI established the nation’s first fire-focused research program 75 years ago, so our extensive capabilities allow us to develop novel tests to evaluate emerging technologies,” said Senior Research Engineer Kyle Fernandez, who led the experiment. “For this project, we created a customized test because no standardized test exists for EV containment enclosures yet.”

As the popularity of electric vehicles rises, the likelihood of accidents involving EVs also increases. Different makes and models of lithium-Ion batteries, which power electric and hybrid vehicles and can be hazardous when compromised, also proliferate.

“With a lot of emerging industries, the test standards haven't caught up with the new technologies,” said Karen Carpenter, director of Fire Technology at Southwest Research Institute. “SwRI specializes in creating customized test programs to evaluate scenarios that don't necessarily have a standardized method associated with them.”

Transporting or storing damaged EVs for repairs comes with inherent fire risks due to a phenomenon called thermal runaway, which can cause an electric battery to heat up so quickly it sparks a chain reaction that can lead to an out-of-control fire.

“Once an EV gets into an accident, the vehicle is potentially compromised and can catch fire at any point,” said Fernandez.

If a fire occurs in a repair facility, it can spread to nearby vehicles. Due to this risk, the National Highway Traffic Safety Administration recommends storing damaged EVs 50 feet away from other vehicles and structures, which can be challenging in urban settings with limited space.

“With our technical know-how and extensive lab space, we developed the capability to replicate thermal runaway to evaluate a vehicle enclosure to mitigate fire. Using thermocouples, we measured the temperature on the interior and exterior of the enclosure as fire fully engulfed the vehicle,” said Fernandez.

Using cameras, engineers monitored the fire from a safe location while collecting corresponding temperature and air quality data. While the interior wall reached nearly 2,000 degrees F at the height of the flames, the exterior wall remained cooler at just over 350 degrees F at the peak when the team flooded the container with an extinguishing agent to test the watertight seal. The customized experiment provided valuable data about the enclosure’s effectiveness.

SwRI’s Fire Technology Department is celebrating 75 years of fire technology research and development. Our engineers and researchers offer standard, nonstandard and custom fire testing services along with fire protection engineering, fire services technology and smoke toxicity evaluations. SwRI operates one of the largest environmentally friendly fire research facilities in the world, with more than 40,000 square feet of lab space, equipped with pollution abatement and wastewater collection systems.

For more information visit, https://www.swri.org/industries/fire-research-engineering.

Storing damaged EVs poses a fire hazard due to thermal runaway, a phenomenon that can cause a battery to ignite due to a chemical chain reaction.  Southwest Research Institute replicated thermal runaway to test the novel fire mitigation method.

Credit

Southwest Research Institute

GREEN CAPITALI$M

Better environmental performance boosts profits and cuts costs

Through a study of 8,547 companies across 34 countries, Kyushu University researchers revealed that disclosing and addressing environmental concerns leads to stronger financial performance

Kyushu University

 

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Kyushu University researchers have developed a new approach to analyze how companies' sustainability efforts influence their financial performance, finding that environmental transparency and actions lead to better economic outcomes.

view more 

Credit: Kyushu University

Fukuoka, Japan—Sustainable practices in business are more than just an ethical responsibility; they make sound financial sense. Researchers from Kyushu University, in a study published on December 10, 2024, in Corporate Social Responsibility and Environmental Management, reveal that companies with better environmental performance and transparent disclosures can lower costs and boost profits.

Investors are increasingly recognizing companies' contributions toward carbon neutrality, driving the growth of environmental, social, and governance (ESG) investing. To support this trend, the Sustainability Accounting Standards Board (SASB) has provided an industry-specific framework to help companies effectively communicate their sustainability risks and opportunities to investors. Many companies now disclose their environmental information using this framework, and in many countries around the world, such transparency is becoming mandatory.

Despite the advancements, the impact of corporate environmental strategies and performance on costs and profits remains unclear. To address this, Professor Hidemichi Fujii from Kyushu University’s Faculty of Economics and his team analyzed financial and environmental data from 8,547 companies across 34 countries spanning 2015 to 2022. 

The team developed two quantitative indicators to assess corporate environmental information: materiality-based scores and overall environmental scores. 

“Financial materiality is a relatively new concept. Environmental priorities vary across industries, as different companies face different key environmental challenges. Financial materiality helps investors assess whether disclosed information is relevant, and supports informed decision-making,” explained Siyu Shen, a graduate student at Kyushu University’s Graduate School of Economics and the paper's first author.

According to the SASB framework, environmental issues can be categorized into six areas, including greenhouse gas emissions, and water & wastewater management. For instance, water management is highly relevant to industries like mining but less critical for sectors such as finance. Materiality-based scores quantify only the relevant issues to see how efficiently a company addresses environmental challenges, while overall environmental scores evaluate all disclosed information to assess a company’s general environmental efforts.

The researchers applied these two scores to assess companies’ environmental disclosures and performance. They found that companies with stronger environmental engagement can achieve better financial outcomes, including enhanced short- and long-term profits, and reduced costs. Notably, firms with superior environmental performance—rather than those focusing merely on disclosure—demonstrate better financial results and attract greater interest from investors.

“Investors value what companies do for the environment more than what they say,” says Fujii. “By taking concrete action on environmental issues, companies signal sustainability and reliability to consumers and investors, lowering perceived risks, and strengthening their appeal as stable and ethical investments.”

While overall environmental scores have a clear positive link to financial performance, materiality-based scores show only a limited correlation. This contradicted the team’s hypothesis, leading them to explore differences in how environmental efficiency is valued across countries.

A closer look at the global data reveals that environmental efficiency is more strongly tied to financial performance in developed countries, such as America and Japan. In contrast, it remains less significant in developing countries like Chile and Indonesia. 

“This difference likely reflects variations in environmental regulations and public awareness across countries,” Shen explains. “In more economically developed countries, where companies have long been engaged in sustainability efforts, improving environmental efficiency can enhance profitability and market valuation. Meanwhile, in developing regions, as the overall regulatory frameworks are still developing, the priority is placed on environmental performance and transparency rather than efficiency.”

The team is further investigating how macroeconomic factors, such as regulatory and social environments,influence corporate sustainability practices and financial outcomes across countries. Through a series of studies, they aim to provide scientific evidence of the impact of corporate environmental information disclosure and conservation efforts on economic performance. “We expect our international comparative studies to offer useful information for promoting effective policy planning to promote proactive responses to environmental issues,” Fujii adds.

 

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For more information about this research, see “Does environmental materiality matter to corporate financial performance: Evidence from 34 countries,” Siyu Shen, Jun Xie, Hidemichi Fujii, Alexander Ryota Keeley, Shunsuke Managi, Corporate Social Responsibility and Environmental Management, https://doi.org/10.1002/csr.3062

About Kyushu University 
Founded in 1911, Kyushu University is one of Japan's leading research-oriented institutes of higher education, consistently ranking as one of the top ten Japanese universities in the Times Higher Education World University Rankings and the QS World Rankings. The university is one of the seven national universities in Japan, located in Fukuoka, on the island of Kyushu—the most southwestern of Japan’s four main islands with a population and land size slightly larger than Belgium. Kyushu U’s multiple campuses—home to around 19,000 students and 8000 faculty and staff—are located around Fukuoka City, a coastal metropolis that is frequently ranked among the world's most livable cities and historically known as Japan's gateway to Asia. Through its VISION 2030, Kyushu U will “drive social change with integrative knowledge.” By fusing the spectrum of knowledge, from the humanities and arts to engineering and medical sciences, Kyushu U will strengthen its research in the key areas of decarbonization, medicine and health, and environment and food, to tackle society’s most pressing issues.

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Journal

Corporate Social Responsibility and Environmental Management

DOI

10.1002/csr.3062 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Does environmental materiality matter to corporate financial performance: Evidence from 34 countries

Article Publication Date

10-Dec-2024

 

A greener, cleaner way to extract cobalt from ‘junk’ materials

Penn researchers led a collaborative effort pioneering safer, more sustainable technique to extract elements critical to battery-powered technologies. Findings pave the way for getting value from materials that would otherwise be considered waste.

University of Pennsylvania

Siddarth Kara’s bestseller, “Cobalt Red: How the Blood of Congo Powers Our Lives,” focuses on problems surrounding the sourcing of cobalt, a critical component of lithium-ion batteries that power many technologies central to modern life, from mobile phones and pacemakers to electric vehicles.

“Perhaps many of us have read how lithium-ion batteries are vital for energy storage technologies,” says Eric Schelter, the Hirschmann-Makineni Professor of Chemistry at the University of Pennsylvania. “But how material that make up such batteries are sourced can be concerning and problematic, both ethically and environmentally.”

Schelter says that cobalt mining in the Democratic Republic of Congo, which supplies about 70% of the world’s cobalt, raises concerns due to environmental degradation and unsafe working conditions, and that large-scale mining disrupts ecosystems, can contaminate water supplies, leaving lasting environmental damage. In addition, he notes that a looming cobalt shortage threatens to strain global supply chains as demand for battery technologies continues to grow.

To that end, an area of research his lab has been focusing on is the separation of battery-critical metals like nickel and cobalt. In a new paper, published in the journal Chem, Schelter’s team and collaborators at Northwestern University presented an “easier, more sustainable, and cheaper way to separate both from materials that would otherwise be considered waste.”

“Our chemistry is attractive because it’s simple, works well, and efficiently separates nickel and cobalt—one of the more challenging separation problems in the field,” Schelter says. “This approach offers two key benefits: increasing the capacity to produce purified cobalt from mining operations with potentially minimal environmental harm, addressing the harshness of traditional purification chemicals, and creating value for discarded batteries by providing an efficient way to separate nickel and cobalt.”

The right ingredients for selective separation

Typically, the researchers say, cobalt is often produced as a byproduct of nickel mining by way of hydrometallurgical methods such as acid leaching and solvent extraction, which separates cobalt and nickel from ores. It’s an energy-intensive method that generates significant hazardous waste.

The process Schelter and the team developed to circumvent this is based on a chemical-separation technique that leverages the charge density and bonding differences between two molecular complexes: the cobalt (III) hexammine complex and the nickel (II) hexammine complex.

“A lot of separations chemistry is about manifesting differences between the things you want to separate,” Schelter says, “and in this case we found conditions where ammonia, which is relatively simple and inexpensive, binds differently to the nickel and cobalt hexammine complexes.”

By introducing a specific negatively charged molecule, or anion, like carbonate into the system, they created a molecular solid structure that causes the cobalt complex to precipitate out of the solution while leaving the nickel one dissolved. Their work showed that the carbonate anion selectively interacts with the cobalt complex by forming strong “hydrogen bonds” that create a stable precipitate. After precipitation, the cobalt-enriched solid is separated through filtration, washed with ammonia, and dried. The remaining solution contains nickel, which can then be processed separately.

“This process not only achieves high purities for both metals—99.4% for cobalt and more than 99% for nickel—but it also avoids the use of organic solvents and harsh acids commonly used in traditional separation methods,” says first author Boyang (Bobby) Zhang, a graduate student in Penn’s School of Arts & Sciences and a Vagelos Institute for Energy Science and Technology Graduate Fellow. “It’s an inherently simple and scalable approach that offers environmental and economic advantages.”

Techno-economic and life cycle analyses

In evaluating the real-world applicability of their new method, the team, led by Marta Guron, conducted both techno-economic analysis and life-cycle assessment, with the former revealing an estimated production cost of $1.05 per gram of purified cobalt, substantially lower than the $2.73 per gram associated with a reported separations process.

“We focused on minimizing chemical costs while also using readily available reagents, which makes our method potentially competitive with existing technologies,” Schelter says.

The life-cycle analysis found that eliminating volatile organic chemicals and hazardous solvents allows the process to significantly reduce environmental and health risks, which was supported by metrics like Smog Formation Potential and Human Toxicity by Inhalation Potential, where the process scored at least an order of magnitude better than traditional methods.

“This means fewer greenhouse gas emissions and less hazardous waste, which is a seriously big win for both the environment and public health,” says Zhang.

Cleaner path forward

Owing to how the team accomplished their separation, Schelter says, there’s an exciting fundamental science aspect of this work that he thinks they can take in many different directions, even for other metal separation problems.

“Based on the unique set of molecular recognition principles we identified through the course of this work, I think we can extend this work in many different directions,” he says. “We could apply it to other metal separation problems, ultimately driving broader innovation in sustainable chemistry and materials recovery.”

Eric Schelter is the Hirschmann-Makineni Professor of Chemistry in the Department of Chemistry at the School of Arts & Sciences at the University of Pennsylvania.

Boyang (Bobby) Zhang is a Vagelos Institute for Energy Science and Technology Graduate Fellow in the Schelter Group at Penn Arts & Sciences.

Marta Guron is an adjunct lecturer in the Department of Chemistry and project manager in the Office of Environmental and Radiation Safety.

Other authors are Andrew J. Ahn, Michael R. Gau, and Alexander B. Weberg from Penn and Leighton O. Jones and George C. Schatz of Northwestern University.

This research was supported by the Vagelos Institute for Energy Science and Technology at Penn, Vagelos Integrated Program in Energy Research at Penn, National Science Foundation Center (Award CHE-1925708), Center for Advanced Materials for Energy Water Systems of the U.S. Department of Energy (Grant 8J-30009-0007A), and Research Corporation for Science Advancement (Award #CS-SEED-2024-022).

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Journal

Chem

DOI

10.1016/j.chempr.2024.10.028 

Article Title

A Sustainable Cobalt Separation with Validation by Techno-Economic Analysis and Life Cycle Assessment

 

These are now the smokiest cities in America, new science says

Mountain cities in Oregon win the contest over the last five years, but in 2023, Canada’s severe wildfires made cities in midwestern states such as Minnesota contenders

Reports and Proceedings

American Geophysical Union

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WASHINGTON  — Normally, America’s smokiest cities lie out west. But Canada’s unusually intense 2023 wildfire season smothered American cities in smoke farther east than is usual, according to new research to be presented on at AGU’s 2024 Annual Meeting.  

Smoke from forest fires impacts millions of people every year. It can travel thousands of miles from its origin, creating a layer of haze and worsening respiratory conditions such as asthma.  

Now, researchers have developed a new algorithm using satellite imagery and particulate matter (PM2.5) levels to quickly see which parts of the country experienced the most smoke over the last five years. Cities in Oregon, Nevada, Washington and other Western states had the highest smoke levels on average. But 2023 saw metropolitan areas as far east as Baltimore flooded with unhealthy smoke levels, and cities in Wisconsin and Minnesota bore the brunt of the incoming smoke from Canadian forest fires.  

Knowing where smoke strikes can help cities prepare for health issues and understand just how much of their PM2.5 air pollution comes down to wildfires, said Dan Jaffe, an atmospheric chemist at the University of Washington who led the research. 

Jaffe will present his research on 10 December at AGU’s 2024 Annual Meeting in Washington, D.C., where more than 26,000 scientists will gather to discuss the latest Earth and space science research. 

Smoke City, USA 

Wildfires are growing in size and frequency because of climate change, and as people move from urban areas to woodlands and other more fire-prone areas, the population exposed to smoke is growing. Current methods for measuring impacts of wildfire often focus on “smoke days,” where smoke is above ‘normal’ levels. Those methods are labor intensive, and data analysis can take up to a year to complete.  

To get a faster turnaround time, Jaffe and colleagues created an algorithm that could quickly sorted through two sets of data collected between 2019 and 2023: satellite images of smoke and PM2.5 concentrations collected at ground level throughout the United States. The researchers trained an algorithm to recognize smoke days from these two data sets. They then added health data from hospitals in those cities to see whether smoke had an impact on emergency room visits during especially hazy days.  

The algorithm revealed that three cities in western Oregon — Medford, Grants Pass and Bend — were the smokiest cities on average over five years. In Medford, the smokiest city, daily levels of PM2.5 averaged 4.2 µg/m3 over one year. Smoke doesn’t impact towns every day. But averaged out over a whole year, the smokiest cities in each Western state saw daily averages of 3.4 µg/m3 in Gardenville-Rancho in Nevada; 2.7 µg/m3 in Bishop, California; Yakima, at 2.5 µg/m3 in Washington; and 2.3 µg/m3 in Fairbanks-College, Alaska. The smokiest city with more than a million people is the Sacramento metropolitan area, with an annual daily PM2.5 averaging 2.0 µg/m3.   

The EPA recommends that annual exposure to PM2.5 should not exceed 9.0 ug/m3. That means that in the smokiest parts of the country, average daily exposures are “a very significant fraction’ of the EPA’s annual cut off, Jaffe said.  

 A strange wildfire season 

States outside the West also saw a rise in emergency room visits due to smoke. The researchers estimate that around one-third of all PM2.5-related emergency room visits in Detroit during 2023 were due to smoke. Those visits were likely caused by smoke from Canadian fires pouring in over the border.  

“2023 was this strange year where the Canadian forests were just torched like crazy, and the Midwest got hit extremely hard,” Jaffe said.  

Within the study period, 2023 saw the highest increase in emergency room visits related to wildfire smoke. The entire country saw an extra 16,000 emergency room visits during “smoke days” in 2023 compared to previous years. In Bend, Oregon, a city that outside of the fire season has relatively clean air, around 60% of asthma-related visits in 2023 were related to smoke.  

Because of the Canadian fires, North Dakota, Minnesota and Wisconsin joined the list of smokiest spots. Even Baltimore’s daily PM2.5 average reached 2.0 µg/m3 in 2023, compared to an average of 0.7 µg/m3 during the other four years.  

A repeat of 2023 isn’t likely to occur immediately, Jaffe said. But wildfire patterns are changing in North America. That comes with health implications for millions of Americans, with a growing body of research suggesting that smoke exposure can have long-term impacts on human health.   

“For cities and towns, I think it’s important to be planning ahead and thinking about what’s a normal year, and what’s an extreme year,” Jaffe said. 

Bighorn sheep face death by avalanche in Sierra Nevada range

Even as snow cover becomes less reliable, climate change may make deadly avalanches in the California range more frequent

American Geophysical Union

 

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Even as snow becomes less consistent in the Sierra Nevada mountain range, climate change could be making deadly avalanches more common, threatening the recovery of bighorn sheep there.

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Credit: California Department of Fish and Wildlife/Steve Yaeger

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WASHINGTON — Snow cover in the Sierra Nevada is expected to shrink overall as the climate warms, but avalanche frequency could remain the same or even increase at high elevations. That’s bad news for bighorn sheep that live there, according to new research to be presented at AGU’s 2024 Annual Meeting. 

In John Muir’s 1894 book “The Mountains of California,” he praised the “perfect strength and beauty” of the wild Sierra Nevada bighorn sheep, “leaping unscathed from crag to crag.” Those bighorn sheep are now an endangered species. After surmounting its first threats — diseases from and overgrazing by domestic sheep settlers introduced to the Sierra Nevada — the species made a slow comeback, crawling from 100 individuals in 1995 to 600 in 2015. But much of that conservation work is being undone by a new threat: avalanches. Together with mountain lion predation, the Sierra bighorn sheep population has halved since 2023. 

Ned Bair, a researcher at the University of California, Santa Barbara, and colleagues ran simulations for the current (1990-2020) and future (2050-2080) climate to find out how avalanches might continue to affect bighorn sheep. They found that while snow cover may decrease in the Sierra Nevada as the climate warms, avalanches that kill bighorn sheep might not. 

“There’s certainly going to be less snow in the future, and it’s going to impact the sheep, which are very fragile as is,” Bair said. “In dry winters, they don’t have enough forage. And in the big winters, they die of starvation and avalanches.”  

Bair will present his work on Tuesday, 10 December 2024 at AGU’s Annual Meeting in Washington, D.C., where more than 26,000 scientists gather to discuss the latest Earth and space science research. 

A perilous environment for bighorn sheep 

While bighorn sheep exist in other western mountain ranges, the Sierra Nevada subgroup is genetically distinct — the remaining 350 sheep are all that remain of the species. The few remaining herds of the sheep live at rocky, high elevations, and forage on grasses, herbs and shrubs. 

“They like to live in very challenging environments, hence the avalanche problem,” Bair said. 

Snow is an essential water source for bighorn sheep, but it can also be dangerous. The 2022-2023 winter in California set precipitation records and dumped approximately 18 meters (60 feet) of snow onto the Sierra Nevada. That winter, avalanches killed at least 73 bighorn sheep, with 12 deaths from just one avalanche, according to the California Department of Fish and Wildlife. 

The researchers projected how much snow would fall throughout the Sierra Nevada under future climate change, using precipitation data from past dry years (2013 and 2018) and a wet year (2019) to run their simulations.  

While snow cover will generally decrease in the Sierra Nevada in the future, that decrease will mostly be at lower elevations, where snowfall may become rain. The high elevations where bighorn sheep live will have fewer changes to snow cover. Those high elevations may even see an increase in snow accumulation as climate change increases the number and strength of California’s atmospheric rivers, which were responsible for the Sierra Nevada’s deep snowpack in 2023. More snow could mean more avalanches at high elevations, leading to more bighorn sheep deaths. 

It is not yet clear how the California Department of Fish and Wildlife’s Bighorn Sheep Recovery Program, founded after 2023’s devastating winter, will adapt to increased avalanches. The wild sheep could also see increased threats from recovering wolf and mountain lion populations. 

“It’s a hard population to sustain,” Bair said. “I think there are some real challenges with being assured of at least my children being able to see a bighorn sheep in the wild when they're my age.”  

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Abstract information: 
A complex relationship: Sierra Nevada bighorn sheep and snow 
Tuesday, 10 December, 8:30 – 12:20 EST 
Hall B-C (Poster Hall, Convention Center) 

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AGU’s Annual Meeting (#AGU24) will bring more than 26,000 Earth and space scientists to the Walter E. Washington Convention Center in Washington, D.C. from 9-13 December. Members of the press and public information officers can request complimentary press registration for the meeting now through the end of the conference. Learn more about the press AGU24 experience in our online Press Center. 

AGU (www.agu.org) is a global community supporting more than half a million advocates and professionals in Earth and space sciences. Through broad and inclusive partnerships, AGU aims to advance discovery and solution science that accelerate knowledge and create solutions that are ethical, unbiased and respectful of communities and their values. Our programs include serving as a scholarly publisher, convening virtual and in-person events and providing career support. We live our values in everything we do, such as our net zero energy renovated building in Washington, D.C. and our Ethics and Equity Center, which fosters a diverse and inclusive geoscience community to ensure responsible conduct.