Scientists create new overwintering sites for monarch butterflies on a warming planet

Using assisted migration to establish new sacred fir forests on colder mountainside could offer monarch butterflies a much-needed refuge

Frontiers

 

image: 

Planting Abies religiosa (Sacred fir) seedlings under the shade of pre-existing shrubs (Senecio cinerarioides, narrow green-greyish foliage) as protective “nurse plants”. Large trees on background are adult Pinus hartwegii, the pine that reaches the timberline. Abies religiosa is completely absent in this site at 3800 m of elevation, northeaster slope of Nevado de Toluca volcano, central Mexico, because it is too high in elevation. Planters personnel are locals of Native Indian origin.

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Credit: Cuauhtémoc Sáenz-Romero, UMSNH

The migration of the monarch butterfly is one of the wonders of the natural world. Each autumn, a new generation of monarch butterflies is born in the northern United States and southern Canada. Hundreds of millions of these butterflies then fly to the mountains of Central Mexico, between 4,000km and 4,800km away. There, they overwinter in forests of the sacred fir Abies religiosa at high altitudes. Without these sacred firs, the monarchs couldn’t survive their grueling migration.

But under global warming, these forests are predicted to slowly move up the slopes. By approximately 2090 they will run out of mountain. It will thus be necessary to create new forests outside their current geographic range: for example on mountains further east, which are higher.

“Here we show the feasibility of planting new sacred fir forests on a nearby volcano, Nevado de Toluca, at altitudes between 3,400 and 4,000 meters,” said Dr Cuauhtémoc Sáenz-Romero, a professor at the Universidad Michoacana de San Nicolás de Hidalgo in Mexico, and the lead author of a new study in a new study in Frontiers in Forests and Global Change.

“We call this ‘assisted migration’: planting seedlings grown from seeds from existing sacred fir populations to new sites whose climate by 2060 is predicted to become similar to that at today’s overwintering sites due to global warming.”

Making a stand

In 2017, Sáenz-Romero and colleagues gathered seeds from cones from eight stands of sacred fir in the Monarch Butterfly Biosphere Reserve (MBBR) in Mexico, at altitudes between 3,100 and 3,500 meters. They grew seedlings from these, at first for two years in a shade-house at 1,900 meters altitude, and then for another year in a nursery at 3,000 meters. In July 2021, they transplanted the seedlings to four sites along an elevational gradient on the northeast slope of Nevado de Toluca.

The researchers chose this mountain because it is the closest to the MBBR and has a summit 1,130 meters higher than the highest occurrence – at 3550 meters – of sacred firs there. It is also a Protected Natural Area.

They planted 960 seedlings at four altitudes: 3,400, 3,600, 3,800, and 4,000 meters. The latter is the timberline of Nevado de Toluca, and was included to find the highest elevation at which sacred firs can survive in the present climate. Seedlings were distributed over 30 spatial blocks per altitude, taking care to include equal numbers from each original stand in the MBBR.

Seedlings were always planted under ‘nurse plants’ to protect them against excess insolation and extreme cold. These were Senecio cinerarioides shrubs up to 3,800 meters, and Lupinus montanus shrubs and Pinus hartwegii trees at 4,000 meters.

Every two months between September 2021 and December 2023, Sáenz-Romero and colleagues (including graduate students and local foresters of the Matlatzincas Native Indian people) measured each seedling’s performance, that is, its survival, height, and diameter. Because the goal of the experiment was the conservation of sacred firs, not timber production, survival was considered the most important measure.

Colder and higher

The results showed that the performance of the transplanted seedlings decreased as the ‘ecological distance’ – the weighted difference across a range of climate variables such as temperature, precipitation, and dryness  – between the original and the planting site increased. Overall, survival and growth worsened when seedlings were transplanted to sites colder and higher than the original stand in the MBBR. At 4,000 meters, growth was approximately nil, while many seedlings showed frost damage.

Between 3,600 and 3,800 meters, seedlings had 54% less vertical growth, 27% less biomass, and 27% less survival than at the baseline of 3,400 meters. The authors judged this survival rate to be ‘very acceptable’.

“These planted stands could ultimately serve as overwintering sites for the Monarch butterfly under warmer climates,” concluded Sáenz-Romero.

“In fact, monarch butterflies have over recent year established new and large colonies at colder places within the Nevado de Toluca, which suggests that they already are searching for new places to overwinter, as their historic sites inside the MBBR are now too warm. Once our seedlings are fully grown, they will hopefully discover our planting site, too.”

“We stress that creating new areas for monarch butterflies is not mutually exclusive with continuing efforts to conserve their current habitat in the Monarch Butterfly Biosphere Reserve. Both approaches should be complementary, with equal priority.”

Local foresters, graduate students and faculties from the state University of Michoacán, México, who established the experiments at Nevado de Toluca. This is a site at 3600 m of elevation, shortly above the maximum natural limit distribution of Abies religiosa (about 3550 m).

Planting at 4,000 meters 

F

Planting Abies religiosa (Sacred fir) seedlings at the timberline (4000 m of elevation) of Nevado de Toluca volcano, under the shade of preexisting Lupinus elegans  as protective “nurse plants”. This site is about 450 higher in elevation than the maximum natural distribution of Abies religiosa.

Abies religiosa (Sacred fir) seedlings produced in a communal nursery of Ejido La Mesa, at 3000 m of elevation (to induce hardening of the seedlings), at the border of the MBBR. Seeds originated from the MBBR, and seedlings were planted later at Nevado de Toluca. On the photo, Francisco “Don Pancho” Ramirez-Cruz, former chief of Ejido La Mesa, was in charge of the seedling production.

Abies religiosa (Sacred fir) seedlings (foreground) were planted in groups of 8 seedlings under the shade of pre-existing shrubs as “nurse plants” (Senecio cinerarioides), to have the benefit of a protective shade against extreme temperatures (either warm or cold extremes), something critical under the ongoing climatic change. Each seedling planted was originated from seed collected at the MBBR, from lower elevations than the planting site.

Monarch colony 

a (Sacred fir) covered by Monarch butterflies at Ejido La Mesa, 3340 m of elevation, core zone of MBBR. Seeds of Abies religiosa were collected at this site, to produce seedlings in a nursery that later were planted at Nevado de Toluca, at elevations of 3400 m, 3600 m, 3800 m and 4000 m.

Credit

Cuauhtémoc Sáenz-Romero, UMSNH

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Journal

Frontiers in Forests and Global Change

DOI

10.3389/ffgc.2024.1440517 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Establishing monarch butterfly overwintering sites for future climates: Abies religiosa upper altitudinal limit expansion by assisted migration

Article Publication Date

18-Oct-2024

COI Statement

 

Smaller, more specific academic journals have more sway over policy

Federal species protection orders more often cite the smaller, more obscure publications

Duke University

DURHAM, N.C. – Scientists don't just want their results to be published; they want them to be published in the most influential journal they can find. This focus on a high 'impact factor' is driven by their concerns about promotion and tenure, but it may be overlooking the important role that smaller publications can play in the advancement of their science.

A new paper, “Role of low-impact-factor journals in conservation implementation,” appearing Oct. 17 in the journal Conservation Biology, upends some assumptions about the importance of a journal's readership and impact factor.

The new study, by lead author and doctoral candidate, Jonathan J. Choi and other researchers at Duke University’s Nicholas School of the Environment, compares scientific journals of higher and lower visibility and describes their influence on conservation. Specifically, Choi and his colleagues focused on the Endangered Species Act (ESA) and demonstrated the crucial value of smaller, specialized science publications.

They found that often the journals specific to a region or a particular kind of organism play an outsized role in establishing legal protections for an endangered species. Journals focused on ferns, clams, or coral reefs had proportionally more of their articles cited by the federal government when protecting species than more prominent, higher-impact journals.

“The Endangered Species Act represents one of the most potent tools in the U.S. toolbox,” said Choi. “An endangered species can stop major construction projects and shut down industries, which can be a big political problem. So, in the 70s, Congress required that an agency use the ‘best available science’ before it listed a species for protection. My question was, where that science came from, and how it compared to what we value in academia.”

Scientific journals are often measured by “impact factor” (IF), which loosely tells researchers how often an article is cited by other research in the first two years of its publication. Though it was originally intended as a tool for librarians to understand which journals were the most widely read, it has since been used as a proxy for the influence of the underlying research.

For this study, Choi and colleagues reframed the definition of ‘impact’ by using a different metric: which journals were cited, and how often, in supporting the federal government’s listing of a species for federal protection. The team combed through the listing decisions data from the second Obama Administration (2012-16). During this period, 260 species were added to the list, more than during other Administrations in recent history.

They found 13,000 supporting references to list species as endangered. Of those, more than 4,000 references were to academic journals. By calculating the number of times each journal was cited in the government listings the same way academic impact factor is calculated, the team was able to assess the journals’ importance to federal conservation implementation.

They were surprised to find that a disproportionate number of academic articles referenced in ESA listings came from ‘low impact-factor’ or ‘no impact-factor’ journals. For example, research was more often cited from journals like the American Fern Journal and Ichthyology & Herpetology than from Nature or Science.

Publications with a larger footprint can offer cutting-edge science that sets new theory, but it’s the small journal that provides granular detail. The naturalist stepping through old-growth forest collecting fern samples is the most likely to observe subtle species and habitat changes on the ground and find an outlet in a specialized journal willing to publish a species-specific article.

Co-author Brian R. Silliman, Rachel Carson Distinguished Professor of Marine Conservation Biology at the Nicholas School, noted the foundational work of the small journals, which are often under financial strain compared to for-profit journals. Given the higher likelihood of these smaller journals to influence conservation agencies like the U.S. Fish & Wildlife Service, Silliman called upon academic departments “to expand their criteria of important contributions to look at not only impact factor, but how many times a paper is cited by practitioners that are applying their work.”

“If young researchers feel a lot of pressure to only shoot for high impact-factor journals, what kind of research isn’t getting published?” Choi asks. “What conservation questions aren’t getting explored? The kind of research that gets published in Nature and Science is still important, novel, and cross-cutting, but what we’re saying is that small journals haven’t always received the kind of credit for the conservation-oriented science they produce. That contribution should be celebrated and recognized within the academy.”

In addition to Choi and Silliman, co-authors included Patrick N. Halpin, Professor of Marine Geospatial Ecology at Duke, and Duke alumni Leo Gaskins, Joseph Morton, Julia Bingham, Ashley Blawas, Christine Hayes, and Carmen Hoyt.

This research was funded by the Nicholas School of the Environment and a graduate research fellowship from the Rob & Bessie Welder Wildlife Foundation.

CITATION: Role of Low-Impact-Factor Journals in Conservation Implementation," Jonathan J. Choi, Leo C. Gaskins, Joseph P. Morton, Julia A. Bingham, Ashley M. Blawas, Christine Hayes, Carmen Hoyt, Patrick N. Halpin, Brian Silliman. Conservation Biology, Oct. 17, 2024. DOI: 10.1111/cobi.14391

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Journal

Conservation Biology

DOI

10.1111/cobi.14391 

 U$A

Medicaid ACOs have not yet improved care for kids with asthma

UMass Amherst/UMass Chan Medical School-Baystate study finds disparities in quality of care persist for children with Medicaid compared to those with private insurance

University of Massachusetts Amherst

In its first three years of operation, Medicaid’s primary care-focused Accountable Care Organizations (ACOs) in Massachusetts showed “no clear evidence of success” in improving asthma care for children, according to research led by the University of Massachusetts Amherst and UMass Chan Medical School-Baystate Health.

The study, published recently in JAMA Pediatrics, compared the asthma care of Medicaid-insured children affiliated with a Medicaid ACO to that of children with private insurance. Senior author Dr. Sarah Goff, a practicing pediatrician and internist and professor of health promotion and policy in the UMass Amherst School of Public Health and Health Sciences, says she was “not terribly surprised” at the findings, in part because it was so early in the post-implementation time period , though she had hypothesized there might be some improvements in the outcomes measured.

“The goal of the Accountable Care Organizations is to improve healthcare value by improving quality of care and reducing costs or holding them steady,” she says, adding that Massachusetts’ Medicaid program is a leader in the nation, expanding their value formula to include patient experience. “But healthcare systems are really big and really complex. So when you introduce a major change in policy and the way care is delivered, three years is a fairly short time to see a lot of change, but it’s still really important to take a look at those first three years.” 

More than one-third of the nearly six million children in the U.S. with asthma are insured with Medicaid, the paper notes. Asthma is poorly controlled for more than half of children with the disease. “Racial, ethnic, socioeconomic and geographic disparities in asthma quality of care and outcomes are large and persist despite interventions at the health system, state and national levels,” the paper states.

“Understanding the impacts of major changes to state Medicaid policy for children with asthma was particularly important because there are clinical treatments and strategies that we know work to improve asthma control. However, these are underused, particularly among those with Medicaid. This can result in high rates of emergency department use – which is not the ideal place for asthma care,” says Kimberley Geissler, formerly a UMass Amherst researcher and now an associate professor of healthcare delivery and population sciences at UMass Chan Medical School-Baystate.

The researchers examined Massachusetts insurance claims data between 2014 and 2020 for several asthma control markers: routine asthma visits, asthma medication ratio and emergency department/hospital care. In 2018, primary care-oriented Medicaid ACOs were launched in Massachusetts. Asthma medication ratio compares the use of controller medications, used on a regular basis, to rescue medications, used in an urgent situation when symptoms are not being controlled by the routine medication. 

The study found no significant change in the rates of routine asthma visits for Medicaid and privately insured children after the implementation of ACOs, meaning that the insurance-based disparities persisted. There was a narrowing in disparities in the appropriate asthma medication rates. However, this was because the rate for privately insured children got worse, rather than the rate for children with Medicaid improving. “So it looks better, but it’s really not,” Goff explains.

For the third marker, the team found worsening disparities in emergency department/hospital use for children with Medicaid ACOs compared to children with private insurance. 

“We don’t know why it looks like emergency visits went up,” Goff says. “One of the main foci of the Accountable Care Organizations is to improve care management and coordination,” which is in part designed to result in fewer visits to the hospital for care. 

Goff and Geissler say more research is needed as Medicaid ACOs mature to determine the effects they may have on asthma quality of care, outcomes and disparities for children.

“The Massachusetts Medicaid program is a national leader in innovation to improve care delivery,” Geissler says. “It is very important to continue studying impacts of changes to the program over time to ensure that all children receive high-quality, accessible care so that they can thrive.”  

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Journal

JAMA Pediatrics

DOI

10.1001/jamapediatrics.2024.3935 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Medicaid Accountable Care Organizations and Disparities in Pediatric Asthma Care

 

Sexual and gender-diverse individuals face more health challenges during COVID-19: Insights from a large-scale social media analysis

Health Data Science

 

image: 

The proportion of tweets concerning mental health to the total number of tweets. A 7-day moving average to smooth the curve was applied.

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Credit: [Zhiyun Zhang, Zhiyun Zhang]

A new study by researchers at Zhejiang University has highlighted the disproportionate health challenges faced by sexual and gender-diverse (SGD) individuals during the COVID-19 pandemic. By analyzing over 471 million tweets using advanced natural language processing (NLP) techniques, the study reveals that SGD individuals were more likely to discuss concerns related to social connections, mask-wearing, and experienced higher rates of COVID-19 symptoms and mental health issues than non-SGD individuals. The study has been published in the journal Health Data Science.

The COVID-19 pandemic has exposed and intensified health disparities, particularly for vulnerable populations like the sexual and gender-diverse (SGD) community. Unlike traditional health data sources, social media provides a more dynamic and real-time reflection of public concerns and experiences. Zhiyun Zhang, a Ph.D. student at Zhejiang University, and Jie Yang, Assistant Professor at the same institution, led a study that analyzed large-scale Twitter data to understand the unique challenges faced by SGD individuals during the pandemic.

To address this, the research team used NLP methods such as Latent Dirichlet Allocation (LDA) models for topic modeling and advanced sentiment analysis to evaluate the discussions and concerns of SGD Twitter users compared to non-SGD users. This approach allowed the researchers to explore three primary questions: the predominant topics discussed by SGD users, their concerns about COVID-19 precautions, and the severity of their symptoms and mental health challenges.

The findings reveal significant differences between the two groups. SGD users were more frequently involved in discussions about "friends and family" (20.5% vs. 13.1%) and "wearing masks" (10.1% vs. 8.3%). They also expressed higher levels of positive sentiment toward vaccines such as Pfizer, Moderna, AstraZeneca, and Johnson & Johnson. The study found that SGD individuals reported significantly higher frequencies of both physical and mental health symptoms compared to non-SGD users, underscoring their heightened vulnerability during the pandemic.

"Our large-scale social media analysis highlights the concerns and health challenges of SGD users. The topic analysis showed that SGD users were more frequently involved in discussions about ‘friends and family’ and ‘wearing masks’ than non-SGD users. SGD users also expressed a higher level of positive sentiment in tweets about vaccines," said Zhiyun Zhang, the lead researcher. "These insights emphasize the importance of targeted public health interventions for SGD communities."

The study demonstrates the potential of using social media data to monitor and understand public health concerns, especially for marginalized communities like SGD individuals. The results suggest the need for more tailored public health strategies to address the unique challenges faced by SGD communities during pandemics.

Moving forward, the research team aims to develop an automated pipeline to continuously monitor the health of targeted populations, offering data-driven insights to support more comprehensive public health services.

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Journal

Health Data Science

DOI

10.34133/hds.0127 

Article Title

Sexual and Gender-Diverse Individuals Face More Health Challenges during COVID-19: A Large-Scale Social Media Analysis with Natural Language Processing

 

Study finds legalization didn’t increase recreational cannabis use among young adults in country of Georgia

Boston University School of Medicine

(Boston)—Cannabis is one of the most widely used drugs, with an estimated 219 million users globally in 2021, with the highest number of users in the Americas. It is also the most used drug among young people. In the U.S., cannabis use among young adults (age 19 to 22) reached a historically high level in 2021, with 42.6% reporting use in the past year.

 

Effects and impact of recreational cannabis legalization and decriminalization on societies is a topic of global relevance and increasing scientific interest. Despite a rapidly growing body of published evidence, findings remain mostly mixed with little attention given to young adults.

 

A new study from researchers at Boston University Chobanian & Avedisian School of Medicine and Boston Medical Center (BMC) has found that cannabis use among young adults in the country of Georgia, did not increase following recreational use legalization, despite having easier access.

 

“We saw that a country can carefully legalize cannabis use, without a surge in use in the mid-term. It would be reasonable to additionally actively regulate and control production and distribution, to restrict black market, control the quality of products while keeping populations, particularly young people, safe. We need more studies, preferably longitudinal, from different populations and socio-political contexts, to inform societies and policy makers how to balance between liberty and health.” said corresponding author Ilia Nadareishvili, MD, PhD, a National Institute on Drug Abuse (NIDA) International Visiting Scientists and Technical Exchange Program (INVEST)  fellow working in general internal medicine at the school and BMC.

 

Georgia legalized cannabis consumption and decriminalized cannabis possession in 2018, becoming one of the first countries in the world and the first in the region to do so. Restrictions on use by persons younger than 21, including the sale and distribution, were retained. The researchers conducted a national, wide-scale survey in 2015 and again in 2022, comparing the data to see how cannabis use changed among young adults following legalization. While usage did not increase following the legalization, they did find age of first use increased significantly. Additionally they found the use of cannabis was associated with gambling, tobacco smoking, alcohol use and with having a higher income.
 

According to the researchers, recreational cannabis use legalization, as implemented in Georgia, could be a useful example of balancing public liberty and public health interests. “This research provides crucial scientific evidence to inform the ongoing discussions surrounding the impact of cannabis legalization, particularly its limited effect on usage rates among emerging adults. The findings offer a critical contribution to both local and international discourse on drug policy and public health.” added Irma Kirtadze, MD, PhD, from Ilia State University (Georgia).

 

Mentored by BU/BMC’s Karsten Lunze MD, MPH, DrPH and Jeffrey Samet, MD, MA, MPH, Nadareishvili is the sixth NIDA INVEST fellow to join the BU/BMC team. Other researchers involved in this study include: Sowmya R Rao, MA, PhD from BU School of Public Health; Natalia Gnatienko from BMC, and David Otiashvili, MD, PhD from Ilia State University (Georgia). 

 

These findings appear online in the journal Addiction.

 

Funding for this study was provided through the National Institutes of Health, National Institute on Drug Abuse, 2023 and 2024 NIDA INVEST Drug Use and Addiction Research Fellowship

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Journal

Addiction

DOI

10.1111/add.16688 

Method of Research

Survey

Subject of Research

People

Article Title

Post-legalization shifts in cannabis use among young adults in Georgia—A nationally representative study

Article Publication Date

17-Oct-2024

 

Global study reveals people, including those most affected by climate change, do not understand climate justice

University of Nottingham

An international study involving people from 11 countries has shown most people, including those in areas most affected by climate change, don’t understand the term ‘Climate Justice’. However they do recognise the social, historical, and economic injustices that characterise the climate crisis. The findings could help shape more effective communications and advocacy.

Researchers from the Univeristy of Nottingham’s School of Psychology led a study that surveyed 5,627 adults in 11 countries (Australia, Brazil, Germany, India, Japan, Netherlands, Nigeria, Philippines, United Arab Emirates, United Kingdom, and United States) to assess familiarity with the concept of climate justice. This is the first study to examine public understanding of climate change outside of Europe and North America. The research has been published in Nature Climate Change.

The findings demonstrate that basic recognition of the social, historical, and economic injustices that characterise the climate crisis is common around the world, even if people do not consciously connect this understanding with the concept of climate justice.

The researchers found that two-thirds of people in these countries had never heard of climate justice. The majority of people surveyed were supportive of climate justice-related beliefs including the notions that poorer people suffer worse impacts from climate change (78% agreement), people from worst-affected communities should have more of a say in decisions concerning climate change (78%), and that capitalism and colonialism are underpinning elements of the climate crisis (70%). Endorsement of these climate justice-related beliefs was also positively associated with engagement in climate actions and support for just climate policies.

Climate justice broadly encompasses recognition that (1) climate change impacts are unequally felt across society; (2) the worst affected groups often have the least say in the selection and implementation of societal responses to climate change, and (3) climate change-related policymaking processes often fail to recognise the legitimate interests of politically voiceless communities, consequently contributing to further disenfranchisement of marginalised groups. It is a framework that enables those involved in policymaking to identify and tackle the multiple different ways in which the climate crisis intersects with longstanding patterns of social injustice.

Dr Charles Ogunbode, Assistant Professor in Applied Psychology at the University of Nottingham led the research, he said: “Taking account of climate justice as we respond to a changing climate is key to orientating our societies towards solutions that are fair and equitable. It is ironic that research tends to be limited to what people in more affluent regions believe about climate change and climate justice. Citizens of frontline i.e. climate-vulnerable countries, are largely confined to being the subjects of climate discourse, as opposed to active participants.  The unbalanced discourse matches the inequalities that characterise climate change itself.”

“By revealing the wide endorsement of climate justice principles around the world, we hope that climate advocates will leverage our research to further pressurise policymakers and leaders to enact just responses to the climate crisis.”

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Journal

Nature Climate Change

DOI

10.1038/s41558-024-02168-y 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Climate justice beliefs related to climate action and policy support around the world

Article Publication Date

18-Oct-2024

Understanding the relationship between food waste, climate change, and aging population

Researchers pry into the intricacies of household food waste in Japan, paving the way to effective strategies for mitigating it

Ritsumeikan University

 

image: 

Researchers investigated how household food waste relates to various demographic and economic factors, revealing the intricate role of age.

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Credit: Dr. Yosuke Shigetomi from Ritsumeikan University, Japan

Food production is one of the pillars of human civilization and underlies many of the changes caused by humans on planet’s landscapes. Producing food and getting it to people’s plates entails a significant expenditure of energy and resources. Unfortunately, approximately one third of all food produced globally is not consumed and discarded. Hence, to build sustainable societies, it is essential to minimize food waste.

In Japan, based on estimates reported by governmental institutions, an astonishing 2.47 megatons of food waste was generated in households in 2021, much of which was likely still edible. Thus, Japan has quite some room for improvement in terms of minimizing household food waste. The problem, however, is that not much is known about what types of food contribute the most to food waste, their associated greenhouse gas emissions, and whether specific sectors of the population are more prone to wasting food. 

Now, a research team led by Associate Professor Yosuke Shigetomi from College of Science and Engineering, Ritsumeikan University, Japan, along with Ms. Asuka Ishigami from Nagasaki University, Associate Professor Andrew Chapman from Kyushu University, and Associate Professor Yin Long from The University of Tokyo, Japan set out to tackle this knowledge gap. Through a detailed analysis of food waste in Japanese households incorporating demographics and dietary trends, they established important links between the amount and type of food waste and their associated emissions and age. Their findings were published in Nature Communications on 21 October, 2024.

To conduct their analysis, the researchers gathered food consumption and waste statistics from previously released surveys. The information enabled the team to determine the ratios between edible/inedible parts of over 2,000 food products, as well as the physical amount of household food waste for various food categories. By combining these data with food-related socioeconomic statistics, they explored how age and other factors affect the amount and type of about 200 foods wasted.

Worth noting, Dr. Shigetomi highlights the important contributions by Ms. Asuka Ishigami in this study. “Ms. Asuka Ishigami was my supervised student at my former affiliation, Nagasaki University. Although she graduated as a bachelor in 2022, she worked hard to collect all the fundamental data and conduct the initial analysis for this study through her dissertation,” says Dr. Shigetomi.

One of the most notable findings was that household food waste per person appears to increase significantly with the age of the household’s head. The difference was quite stunning, as elderly households potentially produced nearly twice as much food waste compared to households in which the head was in their 30s. Vegetables were also the most often wasted food type. Similarly, greenhouse gas emissions associated with food waste also increased with the age of the household head. In this case, however, vegetables, ready meals, and fish and seafood were the biggest contributors.

Taken together, the results highlight how age might be directly linked to food waste and associated greenhouse gas emissions. “An aging population would be one of the hidden but key factors for consideration when proposing strategies to reduce food waste directly generated by households,” remarks Dr. Shigetomi. Moreover, identifying vegetables and meats as an either major or minor source of food waste but both major sources of greenhouse gases also emphasize the importance of understanding which food categories contribute most to these issues, which in turn allows for developing more targeted interventions and policies. “It will be essential to pay closer attention to the dietary preferences and lifestyles among different generations, particularly under the desire of dietary shifts towards vegetarianism for combating climate change,” adds Dr. Shigetomi.

The findings of this study will help in the development of effective strategies for reducing food waste and raising awareness of the environmental threat it poses. Educational campaigns could go a long way in helping people be more mindful about the food they consume, how they cook and store it, and how much of it ends up being thrown away.

 

***

 

Reference

 

DOI: https://doi.org/10.1038/s41467-024-51553-w

 

About Ritsumeikan University, Japan
Ritsumeikan University is one of the most prestigious private universities in Japan. Its main campus is in Kyoto, where inspiring settings await researchers. With an unwavering objective to generate social symbiotic values and emergent talents, it aims to emerge as a next-generation research university. It will enhance researcher potential by providing support best suited to the needs of young and leading researchers, according to their career stage. Ritsumeikan University also endeavors to build a global research network as a “knowledge node” and disseminate achievements internationally, thereby contributing to the resolution of social/humanistic issues through interdisciplinary research and social implementation.

Website: http://en.ritsumei.ac.jp/

Ritsumeikan University Research Report: https://www.ritsumei.ac.jp/research/radiant/eng/

 

About Associate Professor Yosuke Shigetomi from Ritsumeikan University, Japan
Dr. Yosuke Shigetomi is an Associate Professor at the Department of Civil and Environmental Engineering, College of Science and Engineering, Ritsumeikan University, Japan. He is also appointed as a Co-Researcher at the Research Institute of Humanity and Nature. He received his PhD (Energy Science) from Kyoto University in 2016. His current research focuses on carbon neutrality, aging society, and social equity. He has published over 39 peer-reviewed papers on these and related topics. He is a member of the Institute of Japan Life Cycle Assessment and the International Society for Industrial Ecology.

 

Funding information
This study was supported by JSPS KAKENHI (grant numbers JP21H03673 and JP24K03149) and Research Institute for Humanity and Nature (RIHN: a constituent member of NIHU) Project No. RIHN14210156.

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Journal

Nature Communications

DOI

10.1038/s41467-024-51553-w 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Curbing household food waste and associated climate change impacts in an ageing society

Article Publication Date

21-Oct-2024

COI Statement

The authors declare no competing interests.