Thinking with your stomach? The brain may have evolved to regulate digestion

Researchers from the University of Tsukuba find that sea urchin larvae use light to control digestion

UNIVERSITY OF TSUKUBA

Research News

 

IMAGE: PHOTOIRRADIATION DRIVES THE PYLORIC OPENING. IMAGES OF FIVE SECONDS (SEC) AND 1 MIN 30 SEC view more 

CREDIT: UNIVERSITY OF TSUKUBA

Tsukuba, Japan - Many life forms use light as an important biological signal, including animals with visual and non-visual systems. But now, researchers from Japan have found that neuronal cells may have initially evolved to regulate digestion according to light information.

In a study published this month in BMC Biology, researchers from the University of Tsukuba have revealed that sea urchins use light to regulate the opening and closing of the pylorus, which is an important component of the digestive tract.

Light-dependent systems often rely on the activity of proteins in the Opsin family, and these are found across the animal kingdom, including in organisms with visual and non-visual systems. Understanding the function of Opsins in animals from different taxonomic groups may provide important clues regarding how visual/non-visual systems evolved in different creatures to use light as an external signal. The function of Opsins in the Ambulacraria groups of animals, which include sea urchins, has not been characterized, something the researchers aimed to address.

"The functions of eyes and visual systems have been well-characterized," says senior author of the study Professor Shunsuke Yaguchi. "However, the way in which light dependent systems were acquired and diversified throughout evolution is unclear especially in deuterostomes because of the lack of data regarding the signaling pathway in the Ambulacraria group."

To address this, the researchers tested whether light exposure caused changes in digestive tract activity in sea urchins. They then conducted micro-surgical and genetic knockdown experiments to test whether Opsin cells in the sea urchin digestive system mediated the effect of light.

"The results provided new information about the role of Opsins in sea urchins," explains Professor Yaguchi. "Specifically, we found that stimulation of sea urchin larvae via light caused changes in digestive system function, even in the absence of food stimuli."

Furthermore, the researchers identified brain serotonergic neurons near the Opsin-expressing cells that were essential for mediating the light-stimulated release of nitric oxide, which acts as a neurotransmitter.

"Our results have important implications for understanding the process of evolution, specifically, that of light-dependent systems controlled via neurotransmitters," says Professor Yaguchi.

The data indicate that an early function of brain neurons may have been the regulation of the digestive tract in our evolutionary ancestors. Because food consumption and nutrient absorption are critical to survival, the development of a sophisticated brain-gut regulatory system may have been a major step in animal evolution.

The article, "Sea urchin larvae utilize light for regulating the pyloric opening" was published in BMC Biology at DOI:10.1186/s12915-021-00999-1

CAPTION

A schematic diagram the light ? pylorus signaling pathway in sea urchin larvae.

CREDIT

University of Tsukuba

 

Simple fetal heartbeat monitoring still best to reduce unnecessary cesarean sections

CANADIAN MEDICAL ASSOCIATION JOURNAL

Research News

 

Newer is not always better; a study in CMAJ (Canadian Medical Association Journal) led by researchers at the University of Warwick shows that simple fetal heartbeat monitoring is still the best method for determining whether a baby is in distress during delivery and whether cesarean delivery is needed http://www.cmaj.ca/lookup/doi/10.1503/cmaj.202538.

Cesarean delivery is the most common surgical procedure worldwide, performed to expedite birth and avoid neonatal complications.

Listening to the fetal heart rate using a stethoscope -- intermittent auscultation -- has been used for years to assess the fetal state and whether the baby is experiencing distress that might require a cesarean delivery. Other monitoring techniques have become common in recent years, including echocardiograms and blood tests.

"Despite extensive investment in clinical research, the overall effectiveness of such methods in improving maternal and neonatal outcomes remains debatable as stillbirth rates have plateaued worldwide, while cesarean delivery rates continue to rise," writes Dr. Bassel Al Wattar, Warwick Medical School, University of Warwick, Coventry, United Kingdom, with coauthors.

Researchers from the United Kingdom and Spain reviewed 33 studies that included more than 118,000 women, mainly from high-income countries as well as India and Tanzania, to evaluate the effectiveness of different monitoring methods in improving outcomes for mothers and babies and reducing the number of cesarean deliveries.

They found that all methods had similar outcomes for babies, but only intermittent auscultation reduced the risk of cesarean deliveries without increased risk to babies' health. The researchers estimate that intermittent auscultation led to an average 30% reduction in emergency cesareans compared to other methods.

"Our analysis suggests that all additional methods introduced to improve the accuracy of electronic fetal heart monitoring have failed to reduce the risk of adverse neonatal or maternal outcomes beyond what intermittent auscultation achieved 50 years ago, and this may have contributed to the increased incidence of unnecessary emergency cesarean deliveries," write the authors.

The authors urge investment in developing novel techniques to monitor fetuses to make delivery safer for mothers and their babies.

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"Effectiveness of intrapartum fetal surveillance to improve maternal and neonatal outcomes: a systematic review and network meta-analysis" is published April 6, 2021.

Cannabis legalization and link to increase in fatal collisions

CANADIAN MEDICAL ASSOCIATION JOURNAL

Research News

 

Legalization of recreational cannabis may be associated with an increase in fatal motor vehicle collisions based on data from the United States, and authors discuss the implications for Canada in an analysis in CMAJ (Canadian Medical Association Journal).

"Analyses of data suggest that legalization of recreational cannabis in United States jurisdictions may be associated with a small but significant increase in fatal motor vehicle collisions and fatalities, which, if extrapolated to the Canadian context, could result in as many as 308 additional driving fatalities annually," says Ms. Sarah Windle, Lady Davis Institute/McGill University, Montreal, Quebec, with coauthors.

In Canada, the number of people reporting cannabis consumption increased from 14% in 2018 (before legalization) to 17% in 2019 (after legalization). Among cannabis users with a driver's licence, 13% reported driving within 2 hours of cannabis consumption, with the number of individuals who reported driving after recent cannabis use increasing from 573,000 to 622,000. An analysis of 2012 data estimated the cost of cannabis-related collisions in Canada to be $1.1 billion annually in societal and economic costs, with drivers aged 34 years and younger responsible for the bulk of the costs.

Health care providers can play a role in educating patients, and the authors suggest resources to help.

"Health care professionals have an opportunity to educate patients about the safer use of cannabis products, including advising against cannabis use and driving (especially in combination with alcohol), with a suggested wait time of at least 6 hours before driving," the authors say.

Government regulation and public awareness could also help reduce the risk of injuries and deaths from driving after cannabis use.

"Implementation of impaired driving regulations and educational campaigns, including federal THC driving limits and public awareness of these limits, may contribute to the prevention of potential increases in cannabis-impaired driving in Canada," the authors conclude.

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"Impaired driving and legalization of recreational cannabis" is published April 6, 

 

Canada-wide ban on menthol cigarettes leads to significant increases in quitting among smokers

UNIVERSITY OF WATERLOO

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Bans on menthol cigarettes across Canada from 2016 to 2017 led to a significant increase in the number of smokers who attempted to quit, smokers who quit successfully, and lower rates of relapse among former smokers, according to a new research study from the International Tobacco Control Policy Evaluation Project (the ITC Project) at the University of Waterloo.

Menthol is the most common flavoring for cigarettes in many countries. Menthol creates a cooling sensation, which reduces the harshness of cigarette smoke. Because of this, menthol leads to increased experimentation and progression to regular smoking among new smokers, especially among youth.

"Our study demonstrates the substantial benefits of banning menthol cigarettes," said Geoffrey T. Fong, Professor of Psychology and Public Health and Health Systems at Waterloo, and principal investigator of the ITC Project. "The enormous success of the Canadian menthol ban makes it even clearer now that the U.S. should finally ban menthol, which the tobacco industry has used for decades to attract new smokers and to keep many of them as customers, especially among the African-American community.

"The positive effects of the Canada menthol ban suggest that a U.S. menthol ban would lead to greater benefits since menthol cigarettes are much more popular in the U.S. From our findings, we estimate that banning menthol cigarettes in the U.S. would lead an additional 923,000 smokers to quit, including 230,000 African-American smokers."

The study conducted by Fong and his team examined the impact of menthol bans across seven Canadian provinces, covering 83 per cent of the Canadian population, which saw menthol cigarettes banned between August 2016 and October 2017. Canada was the one of the first countries to implement a ban on menthol cigarettes, and the first country where a menthol ban has been evaluated.

"The Canadian menthol ban did not lead to a high level of illicit menthol cigarette purchasing, which has been a concern by regulators considering a menthol ban," said Fong. "Fewer than 10 per cent of menthol smokers reported still smoking a menthol brand after the ban."

Scientific reviews conducted by the Tobacco Products Scientific Advisory Committee to the U.S. Food and Drug Administration (FDA), the FDA itself, and the World Health Organization have also concluded that banning menthol would have significant public health benefits. 

The harms of menthol cigarettes in the U.S. have been much greater among African-Americans. Menthol cigarettes are smoked by 85 per cent of African-American smokers, over 2.8 times the percentage of menthols among white smokers.

A national sample of 1098 non-menthol and 138 menthol smokers participating in the ITC Canada Smoking and Vaping Survey were surveyed both before the menthol ban (in 2016) and after the menthol ban (in 2018).

The survey demonstrated three benefits of the Canadian menthol ban. Menthol smokers were significantly more likely than non-menthol smokers to attempt to quit after the menthol ban (58.7 per cent vs. 49 per cent). 

Daily menthol smokers were almost twice as likely than daily non-menthol smokers to quit after the menthol ban (21 per cent vs. 11.6 per cent). 

Finally, those menthol smokers who had quit smoking before the menthol ban were significantly less likely than non-menthol smokers who had quit smoking to have relapsed back to smoking.

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The study, Evaluating the impact of menthol cigarette bans on cessation and smoking behaviours in Canada: longitudinal findings from the Canadian arm of the 2016-2018 ITC Four Country Smoking and Vaping Surveys, was published today in the journal Tobacco Con

 

Aquatic biodiversity key to sustainable, nutrient-rich diets

UNIVERSITY OF BRITISH COLUMBIA

Research News

 

IMAGE: FISH MARKET IN LIMA, PERU. NEW RESEARCH FROM THE UNIVERSITY OF BRITISH COLUMBIA HIGHLIGHTS THE CRITICAL LINK BETWEEN AQUATIC BIODIVERSITY AND NUTRIENT-RICH SEAFOOD DIETS. view more 

CREDIT: IMAGE COURTESY JULIANO PALACIOS-ABRANTES.

Seafood is a pillar of global food security--long recognized for its protein content. But research is highlighting a critical new link between the biodiversity of aquatic ecosystems and the micronutrient-rich seafood diets that help combat micronutrient deficiencies, or 'hidden hunger', in vulnerable populations.

"Getting the most nutritional value per gram of seafood is crucial in fighting hidden hunger and meeting United Nations Sustainable Development Goals," says Dr. Joey Bernhardt, an ecologist from the University of British Columbia (UBC) who led the study, published this week in the Proceedings of the National Academy of Sciences.

"We've found that aquatic species contain distinct and complementary sets of micronutrients, so the most efficient way to fulfill our nutritional requirements is to fill our diets with small amounts of a variety of species. In order to be able to do that, we need to preserve the biodiversity of our aquatic ecosystems locally and globally."

Dr. Bernhardt and UBC biodiversity researcher Dr. Mary O'Connor analyzed nutrient concentrations in the edible portions of 547 aquatic finfish and shellfish species. While different animals offered similar amounts of protein, they varied greatly in concentrations of micronutrients like iron, zinc, calcium and two fatty acids (docosahexaenoic and eicosapentaenoic acid, known as DHA and EPA). This variation is critical to the value of biodiversity to human well-being.

Most animals did not meet a single micronutrient recommended dietary allowance (RDA) in a 100g portion--fewer than half reached a target of 10% RDA for calcium, iron and EPA. Increasing biodiversity from one to 10 species in seafood diets was correlated with reaching more nutrient targets established by the US Institute of Medicine--and the nutritional value increased even when the seafood portion size remained constant.

"We know that biodiversity is a critical component of the many economic, cultural and ecological benefits humans enjoy from healthy natural ecosystems--from elevated forest production to water quality to nutrient cycling. Our analysis proves that biodiversity also enhances nutritional metrics in aquatic systems, and this benefit is at least as great as the biodiversity benefits we've seen in other sectors," says Dr. O'Connor.

"And this study further demonstrates the importance of biodiversity, measured as the number of different kinds of animals out there, for human-wellbeing in wild ecosystems--showing that protecting biodiversity in nature is as important as maintaining agro-biodiversity."

The finding is of particular importance coastal communities, including many Indigenous communities, who eat on average 15 times more seafood than other groups--and tend to rely more on locally available seafood.

"Aquatic ecosystems are under threat from human activities, and we're observing major changes in biodiversity patterns worldwide," adds Dr. Bernhardt.

"Until now, we didn't understand the consequences of these aquatic biodiversity changes for human nutrition and health. With this new work, we have bridged the gap between biodiversity science and human nutrition science, demonstrating that aquatic biodiversity change can have direct and immediate impact on human nutrition and well-being."

CAPTION

Fish market in Lima, Peru. New research from the University of British Columbia highlights the critical link between aquatic biodiversity and nutrient-rich seafood diets. Image courtesy Renato Molina.

CREDIT

Image courtesy Renato 

Ammonia decomposition for hydrogen economy, improvement in hydrogen extraction efficiency

Development of a zeolite-based nanocatalyst for extraction of hydrogen stored in ammonia; development of a platform for commercializing ammonia as a means of large-capacity hydrogen transport

NATIONAL RESEARCH COUNCIL OF SCIENCE & TECHNOLOGY

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IMAGE: A SCHEMATIC DIAGRAM OF THE CATALYTIC STRUCTURE FOR AMMONIA DECOMPOSITION DEVELOPED BY KIST RESEARCHERS view more 

CREDIT: KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY(KIST)

For the implementation of the effective hydrogen economy in the forthcoming years, hydrogen produced from sources like coal and petroleum must be transported from its production sites to the end user often over long distances and to achieve successful hydrogen trade between countries. Drs. Hyuntae Sohn and Changwon Yoon and their team at the Center for Hydrogen-fuel Cell Research of the Korea Institute of Science and Technology (KIST) have announced a novel nanometal catalyst, constituting 60% less *ruthenium (Ru), an expensive precious metal used to extract hydrogen via ammonia decomposition.

*Ruthenium is a metal with the atomic number 44, and is a hard, expensive, silvery-white member of the platinum group of elements.

Ammonia has recently emerged as a liquid storage and transport medium that has shown promising stability for long-distance hydrogen transport. At 108 kg H2/m3, liquefied ammonia (NH3) can store 50% more hydrogen than liquid hydrogen. When ammonia is decomposed at high temperatures, only hydrogen and nitrogen gases are produced, with minimal carbon dioxide emissions. Because over 200 million tons of ammonia is currently produced annually for industrial use around the globe, the infrastructure for its mass storage and long-distance transport already exists and can simply be re-purposed for hydrogen transport.

The need for a lot of heat has been a pressing issue thwarting the widespread adoption of ammonia for use in hydrogen transport and storage, however. The decomposition reaction through which hydrogen is extracted from ammonia can only proceed at high temperaturewhich requires high energy input. A catalyst in the form of a solid powder can be added during the decomposition reaction to lower the reaction temperature; however, the existing ruthenium-metal-based catalysts are very expensive and have low stability, thus requiring regular replacement.

The KIST research team has developed a catalyst for hydrogen production from ammonia decomposition in which ruthenium metal particles and **zeolite are strongly bound by calcination under vacuum, which results in the containment of sub-nanometer and nanometer (one billionth of a meter) ruthenium metal particles in each pore of the zeolite support. This novel catalyst exhibits 2.5-times higher ammonia decomposition performance than conventional commercial catalysts and achieves this efficiency while using only 40% of ruthenium metal. Because nanometer-sized (or smaller) ruthenium metal particles are present and maintain their stability during the ammonia decomposition process even at high reaction temperatures, the use of the proposed catalyst can overcome the problem of low stability, which has been significantly limiting the commercialization of existing catalysts.

** Zeolite is a mixed oxide of silicon and aluminum, which is a type of crystalline mineral connected by nanometer-level pores. It is often used as a catalyst support and exists in a structure in which pores having the size on the order of several nanometers to tens of nanometers are connected, depending on the type.

"The developed catalyst has an advantageous structure in that the nanometer-sized ruthenium metal particles are uniformly spread over zeolite, a crystalline mineral. Thus, this catalyst has shown higher performance and stability than previously reported catalysts and is expected to facilitate the commercialization of the process for high-purity hydrogen production from ammonia," said Dr. Hyuntae Sohn, KIST. "The importance of large-capacity hydrogen transport based on ammonia is rapidly increasing, with fierce competition among advanced countries over the development and acquisition of related technologies. The application of the proposed catalyst for large-capacity hydrogen production via ammonia decomposition, which is currently under research and development, will ultimately help the commercialization of ammonia-derived hydrogen and the large-capacity hydrogen transportation between countries," said Dr. Changwon Yoon.

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This research was supported by the New & Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning(KETEP), granted financial resources by the Ministry of Trade, Industry & Energy (MOTIE). The results of this study were published in the latest issue of "Applied Catalysis B: Environmental", an international journal in the field of energy and the environment.

Transportation noise pollution and cardio- and cerebrovascular disease

DPT OF CARDIOLOGY - UNIVERSITY MEDICAL CENTER MAINZ

Research News

 

Epidemiological studies have found that transportation noise increases the risk of cardiovascular morbidity and mortality, with high-quality evidence for ischaemic heart disease. According to the WHO, ?1.6 million healthy life-years are lost annually from traffic-related noise in Western Europe. Traffic noise at night causes fragmentation and shortening of sleep, elevation of stress hormone levels, and increased oxidative stress in the vasculature and the brain. These factors can promote vascular dysfunction, inflammation and hypertension, thereby elevating the risk of cardiovascular disease. In this Review, the authors such as Mette Sørensen from the Danish Cancer Society, Copenhagen, Denmark and the Department of Natural Science and Environment, Roskilde University, Denmark as well as Thomas Münzel MD and Andreas Daiber PhD from the University Medical Center Mainz at the Johannes Gutenberg University, Mainz Germany focus on the indirect, non-auditory cardiovascular health effects of transportation noise. They provide an updated overview of epidemiological research on the effects of transportation noise on cardiovascular risk factors and disease, discuss the mechanistic insights from the latest clinical and experimental studies, and propose new risk markers to address noise-induced cardiovascular effects in the general population. The authors also explain, in detail, the potential effects of noise on alterations of gene networks, epigenetic pathways, gut microbiota, circadian rhythm, signal transduction along the neuronal-cardiovascular axis, oxidative stress, inflammation and metabolism. Lastly, they describe current and future noise-mitigation strategies and evaluate the status of the existing evidence on noise as a cardiovascular risk factor.

Thomas Münzel, MD, lead author of the review and director of Cardiology at University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany, said, "as the percentage of the population exposed to detrimental levels of transportation noise will rise again when the COVID pandemic is over, noise mitigation efforts and legislation to reduce noise are highly important for future public health." (DOI: 10.1038/s41569-021-00532-5)

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Distinctive MJO activity during 2015/2016 super El Niño

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

Research News

 

IMAGE: WARM SST COULD INCREASE WATER VAPOR IN THE TROPOSPHERE, STIMULATING CONVECTION. view more 

CREDIT: WENJUN ZHANG

El Niño-Southern Oscillation (ENSO) is one of the most prominent ocean-atmosphere interactions that varies year-to-year. This process exerts significant impacts on global weather and climate. El Niño is the warm phase of ENSO, which can be strong, moderate, or even weak. Within the past four decades, climatologists observed three super El Niño events (1982/83, 1997/98 and 2015/16). These extreme phases impacted global climate far more than moderate or weak events.

El Niño has a profound effect on the Madden-Julian Oscillation (MJO), which is the most significant sub-seasonal variability element of the tropic atmosphere. The MJO is a major force that drives monsoon sub-seasonal variability, bringing sustained wet or dry weather to Asia. Extreme El Niño events have similar severity and evolution processes. However, scientists have sought to understand whether El Niño altered the behavior of the MJO in the same way during each of these three super El Niño winters.

A research group, led by Dr. Wenjun Zhang from the Nanjing University of Information Science and Technology analyzed MJO activity of the super El Niño event during the Northern Hemisphere winter of 2015/16. Observations show that the western Pacific MJO activity was strongly suppressed during the peak phase of the 1982/83 and 1997/98 super El Niño events. However, during the crest of the 2015/16 super El Niño event, western Pacific MJO-related convection was enhanced.

"It is apparent that the enhanced western Pacific MJO is mainly related to its sea surface temperature (SST) anomaly distribution and the associated background thermodynamic conditions." said Dr. Zhang. His team's complete research and data are published in Advances in Atmospheric Sciences.

When compared to the previous super El Niño events, the warm SST anomaly, or change from average, of the 2015/16 El Niño was located more westward than during the other two extreme seasons. Additionally, no significant cold SST anomaly was detected in the western Pacific. Accordingly, the moisture and air temperature tended to increase in the central-western Pacific during the winter of 2015/16 unlike the previous super El Niño events.

This research highlights that climatologists should consider the SST anomaly distribution of super El Niño events for future MJO activity studies.

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How do lakes affect energy, heat, and carbon exchange processes in mountainous areas?

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

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IMAGE: THE EDDY COVARIANCE OBSERVATION SITE AT THE ERHAI LAKE IN THE DALI BASIN. view more 

CREDIT: LUJUN XU

Lakes act as an important part of the earth system. They have special functions in regulating regional climate and maintaining regional ecological balance. More than 39.2% of the lakes in China are distributed in the plateau. The topography around the plateau lake area is complex and diverse. It leads to a complex and unique local circulation characterized by the superposition of lake-land breeze circulation and mountain-valley breeze circulation, which has a significant impact on the local energy and material circulation, according to Prof. Huizhi Liu, researcher at the Institute of Atmospheric Physics, Chinese Academy of Sciences.

"Due to the difficulty and high cost of continuous observation in lakes, the understanding of lake- air interactions are still very limited. The mechanism of the impact of lakes on regional hydrothermal cycle and carbon exchange needs to be further analyzed." says Prof. Liu

Since 2011, Prof. Huizhi Liu and his team - a research group from the State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, had established an eddy covariance observation site at the Erhai Lake in the Dali Basin, southwest China.

Based on meteorological and turbulent fluxes data from the observation site, characteristics of local circulations and their impacts on water, heat and carbon exchange in the Erhai Lake are investigated by his team.

"Compared with other land surfaces, lakes promote latent heat mixing but suppress carbon dioxide exchange." states Prof. Liu.

"The lake breeze promotes latent heat flux exchange and reduces sensible heat flux and carbon dioxide flux exchange during daytime. At night, mountain breeze increases the exchange of carbon dioxide flux and decreases the exchange of sensible and latent heat flux. The southeast wind from lake surface at night has the opposite effects." he explains.

The findings were published in Advances in Atmospheric Sciences. "Future field experiments in the horizontal and vertical direction are needed to further investigate energy and carbon dioxide exchange at different temporal and spatial scales." Liu adds.

Tibetan Plateau will warm faster than expected

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

Research News

 

IMAGE: PROJECTED FUTURE WARMING OF THE TIBETAN PLATEAU IN THE CMIP5 ENSEMBLE. THE THICK CURVES INDICATE THE MULTI-MODEL ENSEMBLE MEANS AND THE SHADINGS DENOTE THE 90% MODEL INTERVALS, DERIVED FROM THE... view more 

CREDIT: WENXIA ZHANG

The Tibetan Plateau, known as "the roof of the world", has warmed more rapidly than global average in the past decades. The observed warming of the Tibetan Plateau since 1960s can be attributed to human activities, particularly greenhouse gas emissions. Moreover, the Plateau may warm faster in the future than climate models projected, according to a study recently published in Environmental Research Letters.

The Tibetan Plateau contains the largest volumes of ice outside the Arctic and Antarctic, feeding water to dozens of major Asian rivers. However, the rapid warming of the "Water Tower of Asia" has significantly affected regional hydrological cycle and ecosystem services, leading to remarkable glacier retreat and geohazard disasters such as landslides, debris flows and glacial lake outbursts.

"A clear understanding of the past warming of the Tibetan Plateau, particularly the underlying human influence, can help better anticipating and interpreting future changes," said Tianjun Zhou, the lead and corresponding author on the paper. Zhou is a senior scientist at the Institute of Atmospheric Physics (IAP) and CAS Center for Excellence in Tibetan Plateau Earth Sciences in the Chinese Academy of Sciences. He is also a professor at the University of Chinese Academy of Sciences.

To disentangle and quantify the relative contributions of different external forcings in the observed warming, Zhou and his team used CMIP5, an archive of comprehensive climate models, in which historical simulations are driven by individual external forcings. Using an optimal fingerprinting detection and attribution analysis, the researchers demonstrate that human influence is the dominant driver for the observed warming of the Tibetan Plateau (1.23°C over 1961-2005) with the greenhouse gases in particular contributing approximately 1.37°C, which was slightly offset by anthropogenic aerosols. Moreover, by quantitatively comparing observations and modeled responses, the attribution analysis indicates that the CMIP5 ensemble tends to underestimate the anthropogenic warming trend on the Tibetan Plateau.

Considering the underestimated anthropogenic warming on the Tibetan Plateau by current global climate models, the team went further to correct future projections using the attribution result as an observational constraint, and found the Tibetan Plateau will likely warm faster than previously expected in the future.

"For example, under a medium carbon emission scenario (RCP4.5), the Tibetan Plateau is expected to warm by 2.25°C and 2.99°C in the mid-term (2041-2060) and end of 21st century (2081-2100), which are 0.24°C and 0.32°C warmer than the uncorrected projections, respectively," introduced Wenxia Zhang, the second author of the study. "This implies a greater loss of glacier mass and further increased geohazard risks in the Asian water tower."

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