Thursday, November 09, 2023

Health: Lack of friend or family visits is associated with increased risk of dying

BMC (BIOMED CENTRAL)

Never being visited by friends or family is associated with an increased risk of dying, according to a study published in BMC Medicine. The authors suggest that their findings could be used to help identify patients at a higher risk of dying due to social factors, and to develop more effective interventions to combat the increased risk of death associated with social isolation.

Although previous research has identified associations between deaths due to any causes and both a ‘sense of loneliness’ and living alone, the combined impacts of different types of social interaction on mortality has been unclear.

Hamish Foster and colleagues used data from 458,146 adults recruited to UK Biobank to investigate the association between mortality and five types of social interaction. Participants were recruited between 2006 and 2010 and had a mean age of 56.5 years. The participants completed a questionnaire on recruitment during which they answered questions about five types of social interaction: how often they were able to confide in someone close to them and how often they felt lonely (subjective measures); and how often they were visited by friends and family, how often they participated in a weekly group activity, and whether they lived alone (objective measures). After a median 12.6 years follow-up, 33,135 of the participants had died based on linked death certificates.

The authors found that all five types of social interaction were independently associated with mortality from any cause. Overall, increased mortality was more strongly associated with low levels of the objective measures of social interaction compared to low levels of the subjective measures. The strongest association was for individuals who were never visited by friends or family, who were at a 39% associated increased risk of death. Furthermore, the benefit of participating in weekly group activities was not observed in participants who never had friends or family visit — participants who never received visits but did join group activities had a comparable associated increased risk of death to those who had no visits and joined no activities (50% and 49% respectively). However, participants who received friend or family visits on at least a monthly basis had a significantly lower associated increased mortality risk, suggesting that there was potentially a protective effect from this social interaction.

The authors caution that although the overall strength of association is likely to be generalisable, the sample data from UK Biobank is not fully representative of the general UK population, and that the social interaction measures they assessed were self-reported and relatively simple. The authors suggest that further research could investigate the effects of other types of social interaction on mortality, or explore how much change in a type of interaction is needed to best benefit socially isolated people.

JOURNAL

BMC Medicine

DOI

10.1186/s12916-023-03055-7

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Social connection and mortality in UK Biobank: a prospective cohort analysis

ARTICLE PUBLICATION DATE

10-Nov-2023

Any activity is better for your heart than sitting – even sleeping

Peer-Reviewed Publication

UNIVERSITY COLLEGE LONDON

The study, supported by the British Heart Foundation (BHF) and published in the European Heart Journal, is the first to assess how different movement patterns throughout the 24-hour day are linked to heart health. It is the first evidence to emerge from the international Prospective Physical Activity, Sitting and Sleep (ProPASS) consortium.

Cardiovascular disease, which refers to all diseases of the heart and circulation, is the number one cause of mortality globally. In 2021, it was responsible for one in three deaths (20.5m), with coronary heart disease alone the single biggest killer. Since 1997, the number of people living with cardiovascular disease across the world has doubled and is projected to rise further1.

In this study, researchers at UCL analysed data from six studies, encompassing 15,246 people from five countries, to see how movement behaviour across the day is associated with heart health, as measured by six common indicators2. Each participant used a wearable device on their thigh to measure their activity throughout the 24-hour day and had their heart health measured.

The researchers identified a hierarchy of behaviours that make up a typical 24-hour day, with time spent doing moderate-vigorous activity providing the most benefit to heart health, followed by light activity, standing and sleeping compared with the adverse impact of sedentary behaviour3.

The team modelled what would happen if an individual changed various amounts of one behaviour for another each day for a week, in order to estimate the effect on heart health for each scenario. When replacing sedentary behaviour, as little as five minutes of moderate-vigorous activity had a noticeable effect on heart health.

For a 54-year-old woman with an average BMI of 26.5, for example, a 30-minute change translated into a 0.64 decrease in BMI, which is a difference of 2.4%. Replacing 30 minutes of daily sitting or lying time with moderate or vigorous exercise could also translate into a 2.5 cm (2.7%) decrease in waist circumference or a 1.33 mmol/mol (3.6%) decrease in glycated haemoglobin4.

Dr Jo Blodgett, first author of the study from UCL Surgery & Interventional Science and the Institute of Sport, Exercise & Health, said: “The big takeaway from our research is that while small changes to how you move can have a positive effect on heart health, intensity of movement matters. The most beneficial change we observed was replacing sitting with moderate to vigorous activity – which could be a run, a brisk walk, or stair climbing – basically any activity that raises your heart rate and makes you breathe faster, even for a minute or two.”

The researchers pointed out that although time spent doing vigorous activity was the quickest way to improve heart health, there are ways to benefit for people of all abilities – it’s just that the lower the intensity of the activity, the longer the time is required to start having a tangible benefit. Using a standing desk for a few hours a day instead of a sitting desk, for example, is a change over a relatively large amount of time but is also one that could be integrated into a working routine fairly easily as it does not require any time commitment.

Those who are least active were also found to gain the greatest benefit from changing from sedentary behaviours to more active ones.

Professor Emmanuel Stamatakis, joint senior author of the study from the Charles Perkins Centre and Faculty of Medicine and Health at the University of Sydney, said: “A key novelty of the ProPASS consortium is the use of wearable devices that better differentiate between types of physical activity and posture, allowing us to estimate the health effects of even subtle variations with greater precision.”

Though the findings cannot infer causality between movement behaviours and cardiovascular outcomes, they contribute to a growing body of evidence linking moderate to vigorous physical activity over 24 hours with improved body fat metrics. Further long-term studies will be crucial to better understanding the associations between movement and cardiovascular outcomes.

Professor Mark Hamer, joint senior author of the study from UCL Surgery & Interventional Science and the Institute of Sport, Exercise & Health, said: “Though it may come as no surprise that becoming more active is beneficial for heart health, what’s new in this study is considering a range of behaviours across the whole 24-hour day. This approach will allow us to ultimately provide personalised recommendations to get people more active in ways that are appropriate for them.”

James Leiper, Associate Medical Director at the British Heart Foundation, said: “We already know that exercise can have real benefits for your cardiovascular health and this encouraging research shows that small adjustments to your daily routine could lower your chances of having a heart attack or stroke. This study shows that replacing even a few minutes of sitting with a few minutes of moderate activity can improve your BMI, cholesterol, waist size, and have many more physical benefits.

“Getting active isn’t always easy, and it’s important to make changes that you can stick to in the long-term and that you enjoy – anything that gets your heart rate up can help. Incorporating ‘activity snacks’ such as walking while taking phone calls, or setting an alarm to get up and do some star jumps every hour is a great way to start building activity into your day, to get you in the habit of living a healthy, active lifestyle.”

This research was funded by the British Heart Foundation.

1 More information on cardiovascular disease is available from the British Heart Foundation website.

2 The studies were part of the Prospective Physical Activity, Sitting and Sleep (ProPASS) consortium. Heart health was measured using six outcomes: body-mass index (BMI), waist circumference, HDL cholesterol, HDL-to-total cholesterol ratio, triglycerides and HbA1c.

3 The NHS website has guidance on the different levels of physical activity.

4 Glycated haemoglobin is a measure of average blood sugar levels over the last two-to-three months and is a key indicator in the management of diabetes.

Publication:

Blodgett JM and Ahmadi MH et al. ‘Device-measured physical activity and cardiometabolic health: the Prospective Physical Activity, Sitting, and Sleep (ProPASS) consortium’ is published in European Heart Journal and is strictly embargoed until Friday 10 November 2023 00:05 GMT.

DOI: https://doi.org/10.1093/eurheartj/ehad717

About UCL – London’s Global University

UCL is a diverse global community of world-class academics, students, industry links, external partners, and alumni. Our powerful collective of individuals and institutions work together to explore new possibilities.

Since 1826, we have championed independent thought by attracting and nurturing the world's best minds. Our community of more than 50,000 students from 150 countries and over 16,000 staff pursues academic excellence, breaks boundaries and makes a positive impact on real world problems.

The Times and Sunday Times University of the Year 2024, we are consistently ranked among the top 10 universities in the world and are one of only a handful of institutions rated as having the strongest academic reputation and the broadest research impact.

We have a progressive and integrated approach to our teaching and research – championing innovation, creativity and cross-disciplinary working. We teach our students how to think, not what to think, and see them as partners, collaborators and contributors.

For almost 200 years, we are proud to have opened higher education to students from a wide range of backgrounds and to change the way we create and share knowledge.

We were the first in England to welcome women to university education and that courageous attitude and disruptive spirit is still alive today. We are UCL.

JOURNAL

European Heart Journal

DOI

10.1093/eurheartj/ehad717

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Device-measured physical activity and cardiometabolic health: the Prospective Physical Activity, Sitting, and Sleep (ProPASS) consortium

ARTICLE PUBLICATION DATE

9-Nov-2023

Bullying victims who perceive they’re targeted due to social characteristics feel the effects worse, new research suggests

“Schools should do more to support children at risk of discriminatory bullying”

Peer-Reviewed Publication

TAYLOR & FRANCIS GROUP

Students who feel they have been victimized because of social characteristics such as their ethnicity or their sexuality are at additional risk of trauma, a new national US study has revealed.

Published in the peer-reviewed Journal of School Violence, the research, of more than 2,200 young victims of bullying, found students reported that their physical health; self-esteem; social relationships, and schoolwork suffered more if they felt bias was behind the perpetrators’ actions.

This was particularly acute for those who felt they had more than one characteristic which put them at risk of discrimination.

Schools’ anti-bullying and violence prevention programs should place more emphasis on these types of prejudicial victimization, the findings conclude, and staff should work to identify those whose characteristics might make them particularly vulnerable.

“This study adds to the rising tide of evidence demonstrating that adolescent victimization motivated by bias is uniquely impactful. And I find that victimization involving multiple bias types appears to be especially influential,” states author Allison Kurpiel of the Pennsylvania State University.

“Students who experienced biased victimization were also more likely than nonbiased victims to perceive negative effects on their schoolwork, implying that biased victimization might contribute to lower educational achievement for minoritized groups. This association between biased victimization and impacts on schoolwork was observed for students across the academic spectrum.

“The findings demonstrate that schools should prioritize programming that targets the reduction of biased victimization.

“Failing to do so could result in the exacerbation of existing inequalities through damage to students’ self-esteem, physical health, social relationships, and educational achievement.”

Allison, who is a PhD Candidate in the Department of Sociology and Criminology at Pennsylvania, investigated data on under-18s who filled in a School Crime Supplement to the 2017 and 2019 National Crime Victimization Survey – a nationally representative household survey conducted every two years in the United States.

Students were asked whether in the past year anyone had made fun of them, called them names, insulted them in a hurtful way, spread rumors about them or tried to make others dislike them, threatened them, pushed, shoved, tripped or spat on them, or tried to make them do things they did not want to do, such as giving away money. They were also asked if they had been excluded on purpose from activities or had their property destroyed in a non-accidental way.

Those who said they had been victimized in one or more of these ways were asked if they had ever thought this was related to their race, religion, ethnic background, disability, gender, sexual orientation or physical appearance. They were then divided into two groups: those who said they had felt their experience was the result of these types of bias, and those who said they had not.

The research then analyzed the impacts on the victims, asking whether those who felt they experienced more than one type of bias were more likely to suffer adverse effects than those who suffered just one.

The study found around a quarter of all students had been victimized in the past year, and of those, around four out of 10 felt the actions were motivated by bias. The most commonly-reported bias – around three out of 10 of those who felt bias was a factor – related to physical appearance.

The most common forms of victimization were being threatened or being subject to the spreading of rumors, and these were each experienced by around two-thirds of victims. Overall, students who reported bias against them felt they had suffered a greater range of types of victimization than those who did not.

When it came to the perceived impacts, negative effects on self-esteem were the most common and were reported by more than a quarter of victims, while effects on physical health were the least common and were experienced by fewer than one in seven.

Those who felt their victimization was linked to bias were three times more likely to suffer negative effects on their self-esteem, the research found, and also had increased odds of damage to their physical health, social relationships and schoolwork.

Those who felt they suffered more than one type of bias had higher odds of experiencing all four of the negative effects which were measured. For example, each additional type of reported bias reported raised the odds of reporting negative effects on schoolwork by 70 per cent. Girls were more likely than boys to suffer all four negative effects, as were those who had lower grades.

“Peer aggression which involves prejudice causes additional harm and can threaten schools’ abilities to create inclusive learning environments,” adds Ms Kurpiel.

Her paper recommends schools should “work to raise awareness of these issues” and that prevention programs should aim, in particular, to identify students who are at risk because of multiple factors in their lives.

“One potential intervention is to increase school organizations designed to promote inclusivity, such as Gay Straight Alliance clubs, which have been demonstrated as effective for reducing multiple types of bias-based bullying among female students who identify as LGBT,” she states.

The results of the paper should be assessed while considering some limitations.

For example, all possible types of victim impacts were not measured, so “biased victimization might not be associated with greater odds of impacts than nonbiased victimization for some unmeasured outcomes (e.g., risky behavior)”, the study declares.

Factors related to the school climate that could be important for understanding the impacts of biased victimization (e.g., support groups) were not accounted for due to their lack of measurement in the data.

JOURNAL

Journal of School Violence

DOI

10.1080/15388220.2023.2272133

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Biased and Nonbiased Victimization at School: Perceived Impacts among Victimized Youth in a National Sample

ARTICLE PUBLICATION DATE

10-Nov-2023

Palaeo-CSI: Mosasaurs were picky eaters

Signs of wear on teeth betray dietary preferences

Peer-Reviewed Publication

UNIVERSITEIT UTRECHT FACULTEIT GEOWETENSCHAPPEN

Joint press release Utrecht University and Natural History Museum Maastricht

The cradle of palaeontology – the study of fossil remains of animals and plants – lies in the Maastricht limestones, where the first Mosasaurus was discovered in 1766. The Dutch-Belgian border area around the Limburg capital is one of the best-explored areas in the world where Cretaceous rocks are concerned, the era that came to an abrupt end 66 million years ago. New data can now be added to all previous knowledge: the Maastricht mosasaurs turned out to be quite picky in their choice of diet. This is the conclusion of researchers from Utrecht University and the Natural History Museum Maastricht. In collaboration with English colleagues from the University of Leicester, they were the first in the world to study the wear marks on mosasaur teeth.

"We were curious whether different species of mosasaurs around Maastricht were really getting in each other's way in their choice of food, or whether this was not so much of a problem," explains Dr Femke Holwerda, palaeontologist at the Utrecht University Faculty of Geosciences. In the absence of data on stomach contents of the Maastricht monitor lizards, the researchers therefore looked at minute scratches on the teeth of these animals from southern Limburg (the Netherlands) and in the vicinity of Eben-Emael (province of Liège, Belgium).

Seafood banquet

"It seems that the various species of mosasaur reveal differences in diet. We noted these differences mainly between the smaller species - by mosasaur standards - of about three to seven metres in overall size, and the larger ones, eight to fifteen metres in length.” But there were also some differences between the larger species. “Prognathodon in particular, with its large cone-shaped teeth, appears to have had a surprising amount of shellfish in its diet, so it apparently loved its seafood buffet. Another species, Plioplatecarpus, with narrow pointed teeth, showed a striking number of signs of wear. Perhaps this species was also fond of fish with strongly scaled bodies.”

First

The researchers first made casts of the teeth in silicone rubber and put them in the 3D scanner. "This technique had already been used in dinosaurs, but we were the first to look at the teeth of mosasaurs in the same way," explains fellow palaeontologist Anne Schulp, also affiliated with Utrecht University.

Diversity

With this research, some missing pieces of the puzzle from the long-gone latest Cretaceous world are found. "We wish to understand diversity better," says Schulp. "And that is made easier for us because the animals studied all come from the same rocks, and therefore the same period. So instead of describing just one species, we look at the ecosystem as a whole."

Soft limestone

The limestone deposits around Maastricht are a goldmine for palaeontologists. Schulp: "Nowhere else in the world is the habitat of mosasaurus as well preserved as here. You can find them in very soft limestone, so wear and tear of the teeth from other causes may be ruled out."

Attraction

Of course, such an abundance of potential finds also exerts a great attraction on amateur palaeontologists. "There's nothing wrong with that," emphasises John Jagt, curator at the Natural History Museum Maastricht. "Amateur literally means 'enthusiast' and thanks to 250 years of intensive research by these enthusiasts, we have learnt a lot about mosasaurs and other extinct life forms. A museum like ours benefits greatly from this. What also helps is that this kind of amateur science is stimulated in the Netherlands: it is simply allowed by law. That's not the case everywhere."

Article

Femke M. Holwerda, Jordan Bestwick, Mark A. Purnell, John W.M. Jagt, Anne S. Schulp, ‘Three-dimensional dental microwear in type-Maastrichtian mosasaur teeth (Reptilia, Squamata)’, Scientific Reports, https://doi.org/10.1038/s41598-023-42369-7

JOURNAL

Scientific Reports

DOI

10.1038/s41598-023-42369-7

METHOD OF RESEARCH

Imaging analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Three-dimensional dental microwear in type-Maastrichtian mosasaur teeth (Reptilia, Squamata)

ARTICLE PUBLICATION DATE

9-Nov-2023

SEXISM IN SCIENCE

Women produce skin temperature data that are just as predictable as men

The finding shows that women should not be excluded from clinical studies because of variations in physiological signals due to menstrual cycles

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SAN DIEGO

Picture of the OURA ring — IMAGE:
THE RESEARCHERS USED THE ŌURA RING, A SMART WEARABLE PRODUCED BY FINLAND-BASED COMPANY OURA RING TO TRACK SKIN TEMPERATURE IN THE STUDY.
view more
CREDIT: OURA RING

Women produce physiological data that is just as predictable as men, at least when it comes to skin temperature. This might seem like common sense, but variations in body signals due to menstrual cycles, such as temperature, were used as an excuse to keep women out of clinical studies for decades.

The data for the finding was gathered from a wearable device to continuously monitor the skin temperature of 600 people, half female and half male, over six months.

The team found that there were more differences between any two individuals in the study, whether male or female, than between the sexes. The researchers found that skin temperature mostly varied as a function of time of day and whether the subject was awake or asleep, across male and female participants.

Many women do not have large menstrual cycles, and neither cycles nor sex accounted for significant differences in variability of any group. It’s the first time that a study has continuously tracked human skin temperature over such a long period of time, to the best of the researchers’ knowledge. The team published their findings in the Nov. 1, 2023 issue of the journal Biology of Sex Differences.

Despite guidelines from the National Institutes of Health that require studies to include females and minorities in clinical studies, women are still disproportionately excluded from research, particularly in drug trials. This is due in part to concerns that menstrual cycles would introduce too many variables in the data.

And despite the harm to women that results from using medicines designed for men, including higher overdose and side effect rates, no one had yet looked at continuous physiology signals across large groups of men and women to see if women’s cycles really did make the data harder to analyze–until now. The study didn’t find any statistically significant differences, showing that concern is not warranted.

The team included researchers from the San Diego Supercomputer Center, the Halicioglu Data Science Institute and the Jacobs School of Engineering at the University of California San Diego as well as the UC San Francisco Osher Center for Integrative Health.

The UC San Diego team has been working with the UC San Francisco team, led by co-senior author Dr. Ashley E. Mason, since 2020 to gather wearable data from around the world and develop tools for detecting disease outbreaks. “If the point is that we can now use wearables to track health over big groups of people, then it makes no sense to exclude whole groups of people from the research” said Mason, a sleep clinician and principal investigator of the broader TemPredict project from which this study grew.

The team chose to track skin temperature because it’s essentially a way to monitor the state of a person’s endocrine system, said Ben Smarr, the paper’s corresponding author and a professor in the Shu Chien Gene Lay Department of Bioengineering and the Halicioglu Data Science Institute at the University of California San Diego. Temperature has been tied to hormonal changes, daily rhythms and women’s health states by previous research.

“In this study, the difference between two men is bigger than the difference between the average man and the average woman,” said Lauryn Keeler Bruce, the paper’s first author and a Ph.D. student in the Biomedical Informatics and Systems Biology program at UC San Diego. “In addition, the variability between men and women is not statistically significant.”

Smarr and colleagues used the ŌURA ring, a smart wearable produced by Finland-based company Oura Ring to track skin temperature in the study. The device can also track heart rate, activity, and provides sleep tracking. The ŌURA Ring has become a go-to research tool because it’s easy to use and delivers high-quality data. It has been used in recent publications about medical device adherence, predicting pregnancy outcomes, and tracking COVID-19.

Through statistical analysis the team developed, they found, in women who cycled, a pattern of variation in nightly maximum skin temperature over a roughly 28-day period, consistent with menstrual cycles. This was not unexpected, as temperature monitoring has been used as a tool to track fertility across many cultures. If anything, the pattern made variations easier to predict for the subjects that experienced it. The data for these females was more predictable than for all the other subjects in the study.

“This analysis confirms that ovarian rhythms do affect temperature,” the researchers write. “This analysis does not suggest that these rhythms make any given measurement more prone to error.”

Researchers also pointed out that none of their female subjects constantly had a 28-day cycle. “No one was a textbook example,” Keeler Bruce said.

Researchers hope that other teams will adopt their methodology. Being able to continuously monitor physiological signals, such as temperature, is crucial in capturing a more accurate picture of a person’s health, Smarr said. “In order to know what disturbs a pattern, you need to know what the pattern is in the first place,” he said.

The team plans to examine data from pregnant people throughout pregnancy next. They also plan to examine the differences in activity patterns between male and female subjects.

Funders include the Medical Technology Enterprise Consortium (MTEC), the Start Small foundation, and Oura Health.

Variability of temperature measurements recorded by a wearable device by biological sex

https://doi.org/10.1186/s13293-023-00558-z

UC San Diego

Department of Biomedical Informatics: Lauryn Keeler Bruce

Shu Chien-Gene Lay Department of Bioengineering: Patrick Kasl and Benjamin L. Smarr

Bioinformatics and Systems Biology: Severine Soltani

Department of Electrical and Computer Engineering: Varun K. Viswanath

Halicioglu Data Science Institute: Iklay Altintas, Amaranath Gupta and Benjamin L. Smarr

San Diego Supercomputer Center: Saubhasis Dasgupta, Iklay Altintas and Amaranath Gupta

UC San Francisco Osher Center for Integrative Health: Wendy Hartogensis, Frederick M. Hecht, Anoushka Chowdhary, Claudine Anglo, Keena Pandya and Ashley Mason

City University New York, Baruch College: Stephan Dilchert

JOURNAL

Biology of Sex Differences

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Variability of temperature measurements recorded by a wearable device by biological sex

New research: Fivefold increase in the melting of Greenland's glaciers over the last 20 years

In the largest survey of its kind ever conducted researchers from the University of Copenhagen firmly establish that Greenland’s glaciers are melting at an unprecedented pace.

Peer-Reviewed Publication

UNIVERSITY OF COPENHAGEN - FACULTY OF SCIENCE

The Ujaraannaq valley 1936 — IMAGE:
GLACIER IN THE UJARAANNAQ VALLEY IN WEST GREENLAND TAKEN FROM A SEAPLANE IN 1936
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CREDIT: (CREDIT: THE AGENCY FOR DATA SUPPLY AND INFRASTRUCTURE)

New research: Fivefold increase in the melting of Greenland's glaciers over the last 20 years

In the largest survey of its kind ever conducted, using both satellite imagery and old aerial photos from the Danish National Archives, researchers from the University of Copenhagen firmly establish that Greenland’s glaciers are melting at an unprecedented pace. Melting has increased fivefold in the past 20 years. The study eliminates any lingering doubts about the impact of climate change on Greenland's more than 20,000 glaciers.

Based on the most comprehensive monitoring of Greenland’s glaciers to date, Danish researchers have been able to cast aside any doubt regarding the impact of climate change on the planet.

Their new results document that, compared to the 80s and 90s, when glaciers shrank by an average of about five meters a year, melting has increased fivefold during the past 20 years, so that today, 25 meters per year are lost.

The new study shows the response of Greenland’s glaciers to climate change over a 130-year period. The past two decades stand out in particular, as melting during this period increased even more dramatically.

The study has been published today in the scientific journal Nature Climate Change. [link] https://www.nature.com/articles/s41558-023-01855-6

A number of studies in recent years have shown that Greenland's largest glaciers are under massive pressure due to climatic changes and rising temperatures. However, doubts remained about the extent of the melting glaciers, of which there are approx. 22,000 in Greenland, partly due to inadequate measurement methods. But any doubts that may have existed before have now been dispelled by the Danish researchers.

"In this article, we make it clear that Greenland's glaciers are all melting, and that things have moved exceptionally fast over the past 20 years. There is no doubt about the extent anymore and actually no reason to investigate the claim further," says Assistant Professor Anders Bjørk from the Department of Geosciences and Natural Resource Management.

200,000 aerial photos from the Danish National Archives

According to the researcher, previous doubts were warranted to a certain extent. Indeed, the possibilities of investigating and documenting the extent to which glaciers melted away over extended periods of time were limited prior to the era of satellite imagery.

For example, only one of Greenland’s approximately 22,000 glaciers was continuously monitored using so-called mass balance measurements, which began in the mid-1990s. At the same time, there were areas of Greenland covered by glacier that seemed unaffected by rising temperatures just a few years back.

"Previously, we saw areas in northern Greenland, for example, that were lagging behind and melting less compared to the hardest hit glaciers. This generated a bit of doubt about how serious things were in these areas. At the same time, no one before us had ever shed light on such a long period of time, which precipitated doubts as well. But now, the picture is conclusive: The melting of all glaciers is in full swing, there is no longer any doubt," says Anders Bjørk.

To gain a full overview, the researchers closely studied 1,000 of Greenland's glaciers, a representative amount for the entire country. They tracked the melting of glaciers over the past 130 years using satellite images and 200,000 old aerial photos from the Danish National Archives, which had previously been used to make maps.

"Slightly more than 1,000 glaciers is an enormous number to study, but we did so because we simply wanted to be absolutely certain to get a comprehensive picture of developments over the last 130 years," says Anders Bjørk.

Sea level rise and lack of water

While Anders Bjørk says that there is no longer much reason to look into whether glaciers are melting or not, the development still needs to be closely monitored. Over the past twenty years, melting glaciers have contributed to about 21% of observed sea level rise.

"Of course, we’ll be keeping a close eye on developments. We’re in a new era where glaciers are generally in retreat, with major consequences for sea levels that will rise faster and faster," he says.

Paradoxically, the melting of glaciers in Greenland will lead to a lack of water. Glaciers will reach a point at which they become so small that meltwater rivers will be diminished or disappear altogether. Among other things, this means that Greenland’s ecosystems will change and that renewable energy will face unforeseen hurdles:

"Today, there is already a very real problem in Greenland that the sites where hydroelectric power plants were built 15-20 years ago, based upon the melt from smaller glaciers, do not get enough water because the ice is gone and not being formed again," says the researcher.

As a researcher and private person, what do you think about the extent of the melt that your study presents?

"I think it's quite disturbing. Because we’re well aware of where this is headed in the future. Temperatures will continue to rise and glaciers will melt faster than they do now," says Anders Bjørk, adding:

"But our study also shows that glaciers respond to climate change very quickly, which is in itself positive because it tells us that it’s not too late to minimise warming. Everything that we can do to reduce CO2 emissions now will result in slower sea level rise in the future."

About the study

In combination with satellite observations, the researchers used an untapped archive of aerial photos to document the development of more than 1,000 land-terminating glaciers in Greenland.
The researchers' observations cover all of Greenland's major regions over a 130-year period and, for the first time ever, make it possible to document the extent of glacial retreat during the 21’ century, throughout Greenland, within the 130-year time scale.
Over thirteen decades of observation, scientists have observed a significant and widespread retreat among Greenland's glaciers.
The pace at which glaciers have retreated over the past two decades has accelerated dramatically.
Furthermore, despite the wide range of climate zones and glacier characteristics across Greenland, scientists find that this latest acceleration in retreat is ubiquitous and includes Earth's northernmost glaciers.
Together, these findings indicate that the rate of retreat observed in the twenty-first century is exceptional for Greenland when viewed in a century-long context.
The study was conducted by a group of researchers from the University of Copenhagen and GEUS together with American colleagues.
The study has been published in the scientific journal Nature Climate Change.

The Ujaraanaq valley in 2013, the fjord is now bare of ice and the glaciers have melted onto land.
CREDIT
(Credit: Hans Henrik Tholstrup / University of Copenhagen)

The open Heinkel seaplane made for the mapping expeditions.

CAPTION

The open Heinkel seaplane over the Stauning Alps in East Greenland, 1933.

CREDIT

P20 – (Credit: The Agency for Data Supply and Infrastructure)

JOURNAL

Nature Climate Change

DOI

10.1038/s41558-023-01855-6

ARTICLE TITLE

'Greenland-wide accelerated retreat of peripheral glaciers in the twenty-first century

ARTICLE PUBLICATION DATE

9-Nov-2023