Study reveals the benefits and downside of fasting

Fasting helps intestinal stem cells to regenerate and heal injuries but also leads to a higher risk of cancer in mice, MIT researchers report.

Massachusetts Institute of Technology

Low-calorie diets and intermittent fasting have been shown to have numerous health benefits: They can delay the onset of some age-related diseases and lengthen lifespan, not only in humans but many other organisms.

Many complex mechanisms underlie this phenomenon. Previous work from MIT has shown that one way fasting exerts its beneficial effects is by boosting the regenerative abilities of intestinal stem cells, which helps the intestine recover from injuries or inflammation. 

In a study of mice, MIT researchers have now identified the pathway that enables this enhanced regeneration, which is activated once the mice begin “refeeding” after the fast. They also found a downside to this regeneration: When cancerous mutations occurred during the regenerative period, the mice were more likely to develop early-stage intestinal tumors.

“Having more stem cell activity is good for regeneration, but too much of a good thing over time can have less favorable consequences,” says Omer Yilmaz, an MIT associate professor of biology, a member of MIT’s Koch Institute for Integrative Cancer Research, and the senior author of the new study. 

Yilmaz adds that further studies are needed before forming any conclusion as to whether fasting has a similar effect in humans.

“We still have a lot to learn, but it is interesting that being in either the state of fasting or refeeding when exposure to mutagen occurs can have a profound impact on the likelihood of developing a cancer in these well-defined mouse models,” he says.

MIT postdocs Shinya Imada and Saleh Khawaled are the lead authors of the paper, which will appear in Nature.

Driving regeneration

For several years, Yilmaz’s lab has been investigating how fasting and low-calorie diets affect intestinal health. In a 2018 study, his team reported that during a fast, intestinal stem cells begin to use lipids as an energy source, instead of carbohydrates. They also showed that fasting led to a significant boost in stem cells’ regenerative ability.

However, unanswered questions remained: How does fasting trigger this boost in regenerative ability, and when does the regeneration begin? 

“Since that paper, we've really been focused on understanding what is it about fasting that drives regeneration,” Yilmaz says. “Is it fasting itself that's driving regeneration, or eating after the fast?”

In their new study, the researchers found that stem cell regeneration is suppressed during fasting but then surges during the refeeding period. The researchers followed three groups of mice — one that fasted for 24 hours, another one that fasted for 24 hours and then was allowed to eat whatever they wanted during a 24-hour refeeding period, and a control group that ate whatever they wanted throughout the experiment.

The researchers analyzed intestinal stem cells’ ability to proliferate at different time points and found that the stem cells showed the highest levels of proliferation at the end of the 24-hour refeeding period. These cells were also more proliferative than intestinal stem cells from mice that had not fasted at all.

“We think that fasting and refeeding represent two distinct states,” Imada says. “In the fasted state, the ability of cells to use lipids and fatty acids as an energy source enables them to survive when nutrients are low. And then it's the postfast refeeding state that really drives the regeneration. When nutrients become available, these stem cells and progenitor cells activate programs that enable them to build cellular mass and repopulate the intestinal lining.”

Further studies revealed that these cells activate a cellular signaling pathway known as mTOR, which is involved in cell growth and metabolism. One of mTOR’s roles is to regulate the translation of messenger RNA into protein, so when it’s activated, cells produce more protein. This protein synthesis is essential for stem cells to proliferate. 

The researchers showed that mTOR activation in these stem cells also led to production of large quantities of polyamines — small molecules that help cells to grow and divide.

“In the refed state, you've got more proliferation, and you need to build cellular mass. That requires more protein, to build new cells, and those stem cells go on to build more differentiated cells or specialized intestinal cell types that line the intestine,” Khawaled says. 

Too much of a good thing

The researchers also found that when stem cells are in this highly regenerative state, they are more prone to become cancerous. Intestinal stem cells are among the most actively dividing cells in the body, as they help the lining of the intestine completely turn over every five to 10 days. Because they divide so frequently, these stem cells are the most common source of precancerous cells in the intestine. 

In this study, the researchers discovered that if they turned on a cancer-causing gene in the mice during the refeeding stage, they were much more likely to develop precancerous polyps than if the gene was turned on during the fasting state. Cancer-linked mutations that occurred during the refeeding state were also much more likely to produce polyps than mutations that occurred in mice that did not undergo the cycle of fasting and refeeding.

“I want to emphasize that this was all done in mice, using very well-defined cancer mutations. In humans it's going to be a much more complex state,” Yilmaz says. “But it does lead us to the following notion: Fasting is very healthy, but if you're unlucky and you're refeeding after a fasting, and you get exposed to a mutagen, like a charred steak or something, you might actually be increasing your chances of developing a lesion that can go on to give rise to cancer.”

Yilmaz also noted that the regenerative benefits of fasting could be significant for people who undergo radiation treatment, which can damage the intestinal lining, or other types of intestinal injury. His lab is now studying whether polyamine supplements could help to stimulate this kind of regeneration, without the need to fast. 

The research was funded in part by a Pew-Stewart Trust Scholar award, the Marble Center for Cancer Nanomedicine, the Koch Institute-Dana Farber/Harvard Cancer Center Bridge Project, and the MIT Stem Cell Initiative.

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Written by Anne Trafton, MIT News

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Journal

Nature

DOI

10.1038/s41586-024-07840-z 

Article Title

“Short-term post-fast refeeding enhances intestinal stemness via polyamines”

 

Nearly 90 percent of NYC transit workers have been harassed or assaulted

Study of pandemic-era transit issues reveals attacks against public-facing workforce, with women experiencing higher rates of assault and intimidation

Peer-Reviewed Publication

New York University

The COVID-19 pandemic brought an increase in crime to New York City’s subways and buses. The transit system’s employees—especially female workers—have frequently been on the receiving end of attacks, according to a new study published in the Journal of Urban Health.

The study, led by researchers at the NYU School of Global Public Health, found that 89 percent of public-facing transit workers in New York City experienced harassment or violence on the job during the pandemic (2020-2023).

“Transit workers are our city’s unsung heroes—they kept New York City functioning during the COVID-19 pandemic, but it came at a cost to these frontline workers,” said Robyn Gershon, clinical professor of epidemiology at the NYU School of Global Public Health and the study’s senior author. “They not only experienced high rates of COVID-19 infections, hospitalizations, and even death, but throughout the pandemic they have experienced very high rates of victimization. We hope that providing evidence of the harassment and violence that workers face can lead to better data on transit worker safety and improved policies protecting this vital workforce.”

Since the start of the pandemic, frequent news reports have shed light on the violence against New York’s subway and bus workers, but there is little data on the rates at which these incidents occur. Moreover, while crime on the subways has substantially decreased this year—due to efforts by the state, city, and Metropolitan Transportation Authority (MTA)—attacks against bus drivers and subway workers persist.

Since 2020, Gershon and her research team have been collaborating with the Transport Workers Union (TWU) Local 100 to study the impact of COVID-19 among New York City’s transit workers. As part of this research, Gershon and her colleagues surveyed 1,297 public-facing New York City bus and subway workers in late 2023 and early 2024 about their work experiences during the pandemic.

Given the spike in crime on mass transit during this period, they asked workers whether they had dealt with harassment or violence on the job. Specifically, workers were surveyed about their experiences with verbal harassment or intimidation (e.g., offensive language, insults, threats), physical assault (e.g., punching, hitting, spitting, pushing), sexual assault (e.g., groping), sexual harassment (e.g., catcalling), or having something stolen from them.

Nearly nine in 10 transit workers—89 percent—reported experiencing some form of victimization on the job. Almost half of all workers surveyed reported verbal harassment or intimidation (48.7 percent) or physical assault (48.6 percent). One in five (20.6 percent) had experienced theft, while 6.3 percent reported sexual assault or harassment.

“The proportion of public-facing transit workers who have experienced violence or harassment is remarkably high, and far exceeds the rates of attacks against other workers. For example, health care workers are often subject to similar threats of violence, but by comparison, 58 percent of this workforce reports experiencing it,” said Gershon.

Notably, female transit workers experienced a higher prevalence of physical assault, intimidation, and sexual assault or harassment than did their male counterparts. Physical assault was more frequently reported by female bus workers, while sexual assault or harassment was more often reported by female subway workers.

“Our findings point to the need for greater attention to recording and reporting victimization against workers in both buses and subways,” said David Vlahov, professor at the Yale School of Nursing and the study’s first author. “We need to better understand the frequency and risk factors related to this violence and harassment, especially for female workers.”

The researchers note that the survey results may be influenced by volunteer bias—meaning those who have experienced harassment or assault may have been more likely to complete the survey—which could have led to a higher rate of incidents than would be found across the overall transit workforce.

In addition, the survey captured workers’ experience during the pandemic, when rates of violence on New York City’s mass transit were higher than they currently are. In response to the increased crime, the state, city, and MTA took steps to improve safety and support the workforce, including increasing the police presence, deploying the National Guard to support bag checks, tougher criminal charges for those who assault workers, and adding cameras focused on conductor cabins on subways to protect workers. In addition to advocating for safer work conditions for its members, TWU Local 100 introduced relaxation and yoga classes in an effort to support the mental health of workers.

“Despite important strides being made to protect the health and safety of this vital workforce, much more work remains to ensure the safest possible workplace for these dedicated and essential workers,” said Gershon.

In addition to Gershon and Vlahov, study authors include Daniel Hagen, Michael Cziner, and Alexis Merdjanoff of the NYU School of Global Public Health, as well as Martin Sherman of Loyola University. The research was supported by the National Institute of Nursing Research (R01NR020174).

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Journal

Journal of Urban Health

DOI

10.1007/s11524-024-00912-5 

Method of Research

Survey

Subject of Research

People

Article Title

Association of Victimization by Sex among Public Facing Bus and Subway Transit Workers, New York City

Article Publication Date

21-Aug-2024

 

New technology extracts lithium from brines inexpensively and sustainably

Stanford University

A new technology can extract lithium from brines at an estimated cost of under 40% that of today’s dominant extraction method, and at just a fourth of lithium’s current market price. The new technology would also be much more reliable and sustainable in its use of water, chemicals, and land than today’s technology, according to a study published today in Matter by Stanford University researchers.

Global demand for lithium has surged in recent years, driven by the rise of electric vehicles and renewable energy storage. The dominant source of lithium extraction today relies on evaporating brines in huge ponds under the sun for a year or more, leaving behind a lithium-rich solution, after which heavy use of potentially toxic chemicals finishes the job. Water with a high concentration of salts, including lithium, occurs naturally in some lakes, hot springs, and aquifers, and as a byproduct of oil and natural gas operations and of seawater desalination.

Many scientists are searching for less expensive and more efficient, reliable, and environmentally friendly lithium extraction methods. These are generally direct lithium extraction that bypasses big evaporation ponds. The new study reports on the results of a new method using an approach known as “redox-couple electrodialysis,” or RCE, along with cost estimates.

“The benefits to efficiency and cost innate to our approach make it a promising alternative to current extraction techniques and a potential game changer for the lithium supply chain,” said Yi Cui, the study’s senior author and a professor of materials science and engineering in the School of Engineering.

The research team estimates its approach costs $3,500 to $4,400 per ton of high-purity lithium hydroxide, which can be converted to battery-grade lithium carbonate inexpensively, compared with costs of about $9,100 per ton for the dominant technology for extracting lithium from brine. The current market price for battery-grade lithium carbonate is almost $15,000 per ton, but a shortage in late 2022 drove the volatile lithium market price to $80,000.

Meeting growing demand

Lithium, so far, has had a critical role in the global transition to sustainable energy. The demand for lithium is expected to rise from approximately half a million metric tons in 2021 to an estimated 3 million to 4 million metric tons by 2030, according to a report by McKinsey & Co. This sharp increase is driven mostly by the rapid adoption of electric vehicles and renewable energy storage systems, both of which rely heavily on batteries.

Traditionally, lithium has been extracted from mined rocks, a method that is even more expensive, energy intensive, and driven by toxic chemicals than brine extraction. As a result, the dominant method for lithium extraction today has switched to evaporating salt-lake brines, though still at high financial and environmental costs. This method is also heavily dependent on specific climatic conditions that limit the number of commercially viable salt lakes, throwing into doubt the lithium industry’s ability to meet rising demand.

The new method from Cui and his team uses electricity to move lithium through a solid-state electrolyte membrane from water with a low lithium concentration to a more concentrated, high-purity solution. Each of a series of cells increases the lithium concentration to a solution from which final chemical isolation is relatively easy. This approach uses less than 10% of the electricity required by current brine extraction technology and has a lithium selectivity of almost 100%, making it very efficient.

“The advantages displayed by our approach over conventional lithium extraction techniques enhance its feasibility in eco-friendly and cost-effective lithium production,” said co-lead author of the study, Rong Xu, a former postdoctoral researcher in Cui’s lab, now a faculty member at Xi'an Jiaotong University in China. “Eventually, we hope our method will significantly advance electrified transportation and the ability to store renewable energy.”

Cost and environmental benefits

The study includes a brief techno-economic analysis comparing the costs of current lithium extraction with those of the RCE approach. The new method is expected to be relatively inexpensive due mostly to lower capital costs. It eliminates the need for large-scale solar evaporation ponds, which are expensive to build and maintain. The new method’s use of significantly less electricity, water, and chemical agents – aside from the sustainability benefits – further lowers costs.

By avoiding the extensive land use and water consumption of traditional methods, the RCE approach also reduces the ecological footprint of lithium production.

The RCE method works with a variety of saline waters, including those with varying concentrations of lithium, sodium, and potassium. Study experiments showed that the new technology could extract lithium, for example, from wastewater resulting from oil production. It could potentially be used to extract lithium from seawater, which has lower lithium concentrations than brines. Lithium extraction from seawater using conventional methods is not commercially viable today.

“Direct lithium extraction techniques like ours have been in development for a while. The main contending technologies to date have significant drawbacks, like the inability to operate continuously, high energetic costs, or relatively low efficiency,” said Ge Zhang, a Stanford postdoctoral scholar and co-author of the study. “Our method seems to have none of these drawbacks. Its continuous operation could contribute to a more reliable lithium supply and calm the volatile lithium market.”

Looking ahead

The scalability of the RCE method is also promising. In experiments where the scale of the device was increased fourfold, the RCE method continued to perform well, with both energy efficiency and lithium selectivity remaining very high.

“This suggests that the method could be applied on an industrial scale, making it a viable alternative to current extraction technologies,” said Cui.

Nevertheless, the study highlights some areas for further research and development. The researchers experimented with two versions of their method. One extracted the lithium more quickly and used more electricity. The other was slower and used less electricity. The slower extraction resulted in lower costs and a more stable membrane for extracting the lithium continuously and for a long time, compared with the faster extraction. Under high current densities and faster water flow, the membranes degraded, leading to reduced efficiency over time. Even though this was not evident in the slower extracting experiment, the researchers want to optimize the design of their device for potentially faster extraction. They are already testing other promising materials for the membrane.

Also, the researchers did not demonstrate lithium extraction from seawater in this study.

“In principle, our method is applicable for seawater as well, but there could be stability problems for the membrane in seawater,” said Zhang.

Still, the team remains quite optimistic.

“As our research continues, we think our method could soon move from the laboratory to large-scale industrial applications,” said Xu.

The other co-lead author of the study, Xin Xiao, was a postdoc at Stanford when this work was done, and is now a faculty member at Zhejiang University. Other co-authors are Yusheng Ye, Pu Zhang, Yufei Yang, and Sanzeeda Baig Shuchi, all at Stanford. Yi Cui is also the Fortinet Founders Professor in the School of Engineering, faculty director of the Sustainability Accelerator in the Stanford Doerr School of Sustainability, a professor of energy science and engineering and of photon science, senior fellow and former director of the Precourt Institute for Energy, and senior fellow of the Woods Institute for the Environment. This research was funded by the StorageX Initiative, an industrial affiliates program within Stanford’s Precourt Institute for Energy.

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Journal

Matter

DOI

10.1016/j.matt.2024.07.014 

Article Title

Continuous Lithium Extraction from Brine by Efficient Redox-Couple Electrodialysis

Article Publication Date

21-Aug-2024

Greenhouse gas HFC-23: Abatement of emissions is achievable

Novel measuring method for gas emissions Greenhouse gas HFC-23: Abatement of emissions is achievable Researchers from Empa, the University of Bristol and the Netherlands Organization for Applied Scientific Research (TNO) have investigated 

Peer-Reviewed Publication

Swiss Federal Laboratories for Materials Science and Technology (EMPA)

Hydrofluorocarbons (HFCs) are potent greenhouse gases (GHGs). The most potent of these compounds is trifluoromethane, also known as HFC-23. One kilogram of HFC-23 in the atmosphere contributes as much to the greenhouse effect as 12,000 kilograms of CO₂. It takes around 200 years for the gas to break down in the atmosphere. For this reason, more than 150 countries have committed to significantly reducing their emissions of HFC-23 as part of the Kigali Amendment to the Montreal Protocol.

The main source of HFC-23 is the industrial production of certain coolants and of polytetrafluoroethylene (PTFE), better known as Teflon. HFC-23 is a by-product of the synthesis of a precursor to Teflon. Since 2020, all Teflon manufacturers are obligated to destroy the climate-damaging gas. According to the reports of the individual countries, this is happening: On paper, global emissions of HFC-23 for the year 2020 were only 2,000 tons. The actual global emissions, which have been determined in numerous studies, show a different picture: In 2020 alone, around 16,000 tons of the GHG were released into the atmosphere.

Accurate measurements thanks to tracer gas

Why this discrepancy? To answer this question, researchers from Empa, the University of Bristol and the Netherlands Organization for Applied Scientific Research (TNO) took a close look at HFC-23 emissions from a Teflon factory in the Netherlands. They have just published their latest findings in the journal Nature.

In order to record the factory's emissions as comprehensively and accurately as possible, the researchers used a novel method. They released a tracer gas right next to the factory: a non-toxic gas that does not occur in the atmosphere and decomposes within just a few weeks. At a distance of around 25 kilometers, they measured the concentrations of HFC-23 and other by-products of Teflon manufacture – and also the concentration of the tracer. "Since we knew exactly how much tracer we had released and how much of it arrived at the measuring point, we were able to calculate the emissions of HFC-23 and other gases," says first author Dominique Rust, who worked on the project as part of her doctorate at Empa.

The factory utilizes abatement measures to curb its HFC-23 emissions; the gas is burned off before it can escape. But the new study shows: "The emissions we measured were higher than the ones the factory reported", explains Empa researcher Martin Vollmer. "However, the amount emitted is still low, showing that the abatement measures work well." Co-author Kieran Stanley from the University of Bristol agrees: "These results are really encouraging. They show that abatement measures for plants producing fluoropolymers like Teflon can significantly reduce emissions of this highly potent GHG." And Empa researcher Stefan Reimann adds: "If all factories had emissions similar to the one we measured, we could prevent global HFC-23 emissions corresponding to almost 20% of CO₂ emissions from global air traffic."

Verification and compliance

So if the abatement measures are effective, how can the high readings in the atmosphere be explained? "We must assume that the measures reported by the countries do not correspond to reality everywhere," says Martin Vollmer. The authors of the study call on countries to have their Teflon factories independently audited. "Such independent verification of GHG emissions from the production of fluoropolymers and coolants are needed to help close the gaps in our understanding of emission sources and check that countries are fully compliant under different international climate and environment agreements," adds Stanley. "The collaboration with the Teflon manufacturer and the Dutch authorities was key to the success of our study," says Rust, who is now a research associate at the University of Bristol.

The tracer method developed by the researchers would be suitable for independent audits of factories and industrial areas – also for other gases, the scientists are convinced. Empa researchers are already planning another study in South Korea in October, in which they want to use the tracer method to determine the emissions of halogenated substances in the South Korean capital Seoul. "At the Cabauw measuring station, TNO will extend the monitoring of the GHG’s in the context of the European ICOS infrastructure with continuous monitoring of halogenated substances. This allows us to track the location and determine the emission of the sources of halogenated substances that were found to pass by the station during this experiment," adds TNO researcher Arnoud Frumau.

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Journal

Nature

DOI

10.1038/s41586-024-07833-y 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Effective realization of abatement measures can reduce HFC-23 emissions

Article Publication Date

21-Aug-2024

Pioneering study shows effective regulation and monitoring is key to tackling emissions of a super-greenhouse gas

University of Bristol

 

image: 

The measurements of HFC-23 and other by-products of Teflon manufacture, and of the emitted tracer gas were carried out at the Cabauw tall tower in the Netherlands. The 213-meter mast, as pictured, is operated by the Royal Netherlands Meteorological Institute (KNMI).

view more 

Credit: ICOS RI

New research has revealed factories globally are not properly destroying one of the most potent greenhouse gases emitted from the production of fluoropolymers like Teflon, and refrigerants.

The study investigated a known disparity between real and reported emissions of this gas, prompting calls for more countries to sign up to official agreements to limit emissions and for their Teflon factories to be independently audited to ensure compliance.

The study, published today in the journal Nature, scrutinised emissions of one of the most potent hydrofluorocarbon (HFC) greenhouse gases called trifluoromethane, also known as HFC-23. Its main source is as a by-product in the industrial production of certain refrigerants and Teflon, which is used in products such as nonstick cookware. More than 150 countries have pledged to significantly reduce their HFC-23 emissions as part of the Kigali Amendment to the Montreal Protocol.

Since 2020, all Teflon manufacturers are obligated to destroy the strong greenhouse gas. According to the reports of the individual countries producing these products, this is happening. On paper the global annual emissions of HFC-23 were only 2,000 tons in 2020 but the actual global emissions, shown in numerous studies, uncover a different picture. In 2020 alone, around 16,000 tons of the greenhouse gas were found to be released into the atmosphere.

To unravel this discrepancy, researchers from the University of Bristol in the UK, Empa in Switzerland, and the Netherlands Organisation for Applied Scientific Research compared HFC-23 levels reported by individual countries with actual levels emitted from a Teflon factory in the Netherlands. To record the emissions as comprehensively and accurately as possible, a novel technique was used. This involved releasing a tracer directly next to the factory: a non-toxic gas that does not occur in the atmosphere and decomposes within a few weeks. At a distance of around 25 kilometres, they then measured the concentrations of HFC-23 and other by-products of Teflon manufacture – and also the concentration of the tracer.

First author Dr Dominique Rust, a Research Associate at the University of Bristol, said: “Since we knew exactly how much tracer we had released and how much of it arrived at the measuring point, we were able to calculate the emissions of HFC-23 and other gases.”

Results showed that even though estimated emissions are higher than those reported by the factory, measures to curb HFC-23 levels are largely effective.

Dr Rust, who worked on the study as part of her doctorate at Empa, the Swiss Federal Laboratories for Materials Science and Technology, added: “The collaboration with the Teflon manufacturer and the Dutch authorities was key to understanding the real picture.”

Co-author Dr Martin Vollmer, Researcher at Empa, said: “We suspect higher actual readings in the global atmosphere are explained by some countries underreporting emissions, resulting in this disconnect. One explanation is that abatement technologies aren’t as effectively implemented globally as at the factory we investigated."

The researchers are calling for factories to be independently audited. This independent verification of greenhouse gas emissions from the production of fluoropolymers and refrigerants would help close gaps in understanding the emission sources and check that countries are fully compliant under different international climate and environment agreements.

Co-author Dr Kieran Stanley, Senior Research Fellow at the University of Bristol, said: "Studies like this can help us to independently verify reported declines in emissions from fluorochemical plants and ensure that countries are reaching their obligations under the Kigali Amendment to the Montreal Protocol.

"These results are therefore really encouraging and show that abatement of emissions from fluorochemical plants producing fluoropolymers like Teflon can significantly reduce emissions of a highly potent greenhouse gas.”

The researchers are now planning another study in South Korea in October which will involve using the tracer method to determine the emissions of other halogenated substances in the capital city Seoul.

The measurements of HFC-23 and other by-products of Teflon manufacture, and of the emitted tracer gas were carried out at the Cabauw tall tower in the Netherlands. The 213-meter mast, as pictured, is operated by the Royal Netherlands Meteorological Institute (KNMI).

Credit

ICOS RI

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Journal

Nature

Subject of Research

People

Article Title

'Effective realization of abatement measures can reduce HFC-23 emissions'

Article Publication Date

21-Aug-2024

 

Hydropower generation projected to rise, but climate change brings uncertain future

A new analysis combines hydrology data with climate change models to help water managers prepare for hydropower’s future

DOE/Pacific Northwest National Laboratory

 

image: 

McNary Lock & Dam on the Columbia River.

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Credit: Andrea Starr | Pacific Northwest National Laboratory

RICHLAND, Wash.—In a new study assessing how climate change might alter hydropower generation across the continental United States, researchers show that except for some parts of the Southwest, hydropower generation is expected to rise in the future.

The analysis also shows that in the Pacific Northwest in the future, less water will be stored in the mountains as snowpack in the winter as warmer temperatures bring more rain. This seasonal shift will challenge water managers and grid operators to rebalance how and when to use dams to produce electricity.

“We know the climate is changing and we know that’ll affect how much water will be available to produce hydropower,” said Daniel Broman, a hydro-climatologist at the Department of Energy’s Pacific Northwest National Laboratory and lead author on the new paper. “Our research provides a consistent look across the country, so even if water and energy planners are only looking ahead regionally, our data can provide a broader outlook.”

The new study published on August 8 in Environmental Research Letters.

How climate change affects hydropower

Water flows through 2,250 hydropower facilities across the United States, contributing 6% of the country’s electricity. Hydropower dominates in the Pacific Northwest, providing 60% of energy in the region. Dam operations don't just consider power, they also consider flood control, transportation routes and water for irrigation and support fisheries and natural ecosystems. So, understanding how water availability will change in the future is important for water managers when planning for their various resource needs.

To support this planning, DOE periodically releases a report known as the 9505 Assessment (referring to Section 9505 of the SECURE Water Act). The report provides a detailed assessment of climate change’s effects on hydropower facilities. The third of these reports was delivered to Congress in December of 2023.

But that report only includes 132 facilities, all federally owned. The power they generate makes up 46% of the nation’s hydropower capacity, said study coauthor Nathalie Voisin, chief scientist for water-energy dynamics at PNNL and a lead researcher on the project. To better understand how climate change may affect hydropower generation across the entire continental United States, the researchers added streamflow and hydropower generation data from an additional 1,412 non-federal facilities. 

The researchers teamed up with colleagues at DOE’s Oak Ridge National Laboratory, who have developed models that show how climate change might alter the timing and volume of water flow in streams and rivers over the next few decades. The PNNL team then ran that water flow data through models that captured the multiple uses of water and calculated hydropower generation for two time periods: a near-term period spanning 2020–2039 and a midterm period spanning 2040–2059.

The team found that hydropower production generally increases about 5% in the near term and 10% in the midterm across the continental United States. This could be because climate models generally show an increase in precipitation as Earth warms. 

Only one part of the country saw an average decrease in hydropower generation: in some parts of the Southwest, which is already facing drought, the models project a slight decrease in hydropower production between 3­­–6% in the near term. 

Broman stressed that because the future of climate change is uncertain, the range of possible outcomes for hydropower generation is large. For example, between 2020­­–2039, hydropower generation could change between –5­­–21% while in later years it could change –4­­–28%. 

Seasonal changes could also have big implications for how water is managed across the country, Broman said.

Hydropower changes by season

In the winter, the team found that hydropower generation may rise 12% in the near term and 18% in the midterm across the United States. Similarly, increased rainfall during the fall may lead to a near-term 5–20% rise in hydropower production in the Southeast, as well as smaller increases in the Northeast and Midwest. 

But some of the biggest hydropower generation changes may occur in the summer, especially in the West. In the summer, hydropower generation may decrease 1–5% in the western region of the country, while higher precipitation may increase hydropower generation in the eastern areas by 1–5%, both in the near-term.

Historically, mountain snowpack in the West has stored water until the late spring and summer. When the snow melts, that water generates more electricity. Now, due to increased temperatures, less snow accumulates on mountains and melts earlier in the year. The early snowmelt and shift toward rain in the winter means hydropower generates more electricity during the winter and less in the following spring and summer. 

“Snow is storage. If the snow melts earlier, it changes the timing and volume of water availability,” Voisin said. “And because temperatures are rising overall, the hydropower availability and energy demand might not be in sync.”

The future of hydropower

Voisin stressed that even if hydropower generation declines in certain seasons, it still offers a reliable source of energy for the power grid. Like a coal or gas plant, hydropower can be dispatched as needed and provide stability to the grid as a whole—highlighting its flexibility as a renewable energy source. 

Broman and Voisin hope that power system operators and water managers can use the new consistent multiscale assessment and the accompanying data to inform water-energy tradeoffs discussions, such as hydropower flexibility needs amid other societal benefits of water uses. 

With climate change bringing an uncertain future, historical records don’t necessarily reflect what the next few decades may bring, Broman said. What’s more, “utilities may be thinking about hydropower generation under climate change for their own region, but the electricity grid is bigger than that.” 

This work was supported by the DOE Office of Energy Efficiency & Renewable Energy’s Water Power Technologies Office as a part of the SECURE Water Act Section 9505 Assessment.

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Journal

Environmental Research Letters

DOI

10.1088/1748-9326/ad6ceb 

Article Title

Multi-scale impacts of climate change on hydropower for long-term water-energy planning in the contiguous United States

 

WPI researchers awarded $2 Million grant to use science to combat wildlife trafficking

Team will develop ways to identify vulnerable species, get ahead of trends in illegal animal trade

Worcester Polytechnic Institute

 

image: 

Renata Konrad

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Credit: Matt Burgos/WPI

Worcester, Mass. (Aug. 21, 2024) – Focusing on certain species of sharks, rays, and sea turtles, Worcester Polytechnic Institute (WPI) is leading a potentially groundbreaking project aimed at disrupting the illegal wildlife trade. The interdisciplinary effort combines expertise in computer science, biology, and social science to develop innovative tools for researchers and law enforcement.  

WPI will partner with researchers from Florida International University and the University of Maryland on the four-year, $2 million grant. It is one of 10 projects funded by the Partnership to Advance Conservation Science and Practice (PACSP) program, a first-of-its-kind collaboration between the National Science Foundation and the Paul G. Allen Family Foundation, a philanthropic organization founded by the late Paul G. Allen (co-founder of Microsoft) that, among other endeavors, supports the use of science and technology to protect wildlife. Now in its second year, the program is designed to promote deep collaboration between researchers advancing basic science and conservation partners engaging in on-the-ground conservation.  

For Kyumin Lee, professor of computer science, and Renata Konrad, a professor in The Business School at WPI, the new grant represents an evolution of work they started in 2020 to use a mix of artificial intelligence, physical tools, and supply chain, financial, and social media data to deter illegal wildlife trade.  

Driven by demand for exotic pets, traditional medicines, and luxury goods, the multi-billion-dollar illegal wildlife trade poses a severe threat to biodiversity and the survival of numerous species. Law enforcement agencies around the world face significant challenges in identifying and intercepting illegal wildlife products, particularly when only fragments of animals, such as fins or shells, are involved, Lee said.  

“Without the right tools, it’s nearly impossible to determine if a species is protected or not,” Lee said. “This project hopes to change that.” 

Using a method called high-resolution melting, the team is developing an inexpensive test kit, similar to commercially available COVID-19 tests, that can quickly and accurately feed unique molecular markers into an artificial intelligence-powered database of 20,000 samples from 185 protected species.  

The kit is projected to cost just under $1, and it will produce results in under three hours, making it an effective tool that could be used in ports and airports around the globe, Lee said. Officials could determine on the spot if they were dealing with illegally trafficked wildlife.  

Beyond the physical identification of wildlife products, the project will set up an online infrastructure to analyze social networks where illegal wildlife trade is often discussed. By tracking keywords, using machine learning to detect when illegal wildlife trade is being discussed, and employing data analytics and rapidly evolving large-language artificial intelligence models, end users will get a look at both real-time results and long-term trends.  

Lee said the datasets the team creates will be integrated into one open-source repository available to researchers and law enforcement. Right now, information is scattered. Lee said the team’s work will identify the most critical nodes in trafficking networks—such as key buyers, sellers, or transport routes—that should be targeted to disrupt the trade most effectively. 

Both Lee and Konrad have previously focused their research on malicious human activity. Lee has used machine learning and predictive modeling to build algorithms to detect fake product reviews and disinformation online. Konrad, an expert on supply chains, has explored how data analytical tools could be used to disrupt the supply chains that sustain human trafficking.