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Top 10 climate science insights unveiled

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Top 10 climate science insights unveiled


The report equips policymakers with the latest and most pivotal climate science research from the previous 18 months, synthesised to help inform negotiations at COP28 and policy implementation through 2024 and beyond. Simon Stiell, the UNFCCC Executive Secretary says: “The 10 New Insights in Climate Science report provides an essential tool for decision makers at a critical time in the climate calendar each year. Scientific findings from reports like these should inform the ambitious and evidence-based action plans needed in this critical decade of accelerated climate action.”

The 10 full list of insights:

  • Overshooting 1.5°C is fast becoming inevitable. Minimising the magnitude and duration of overshoot is essential.
  • A rapid and managed fossil fuel phase-out is required to stay within the Paris Agreement target range.
  • Robust policies are critical to attain the scale needed for effective carbon dioxide removal (CDR).
  • Over-reliance on natural carbon sinks is a risky strategy; their future contribution is uncertain.
  • Joint governance is necessary to address the interlinked climate and biodiversity emergencies.
  • Compound events amplify climate risks and increase their uncertainty.
  • Mountain glacier loss is accelerating.
  • Human immobility in areas with climate risks is increasing.
  • New tools to operationalise justice enable more effective climate adaptation.
  • Reforming food systems can contribute to just climate action.

Professor Laura Pereira from the Wits Global Change Institute, who contributed to the report and who is presenting at COP28 says: “Given the lack of mitigation action to date, inadequate climate commitments by developed countries, and a development model that remains coupled to carbon emissions, exceeding 1.5C is indeed fast becoming inevitable (Insight 1). However, now is not the time to succumb to a feeling of hopelessness in the face of powerful drivers leading the world towards the edge of a precipice that will see countless lives lost, homes and ancestral lands destroyed, and species never to be seen again. Rather, this is the time to find the transformative pathways that are needed to get onto a better trajectory for people and planet.”

The scientific insights of the report function as indispensable evidence for decision makers in business and policy, equipping them with the latest climate science to facilitate informed, effective decision-making on holistic climate and nature solutions, especially against the backdrop of the inaugural Global Stocktake at COP28, which underscores the pressing need for transformative actions to fulfil the Paris Agreement’s ambitions.

The report findings underscore the looming inevitability of overshooting the Paris Agreement’s 1.5°C global warming target, emphasising the urgency of a rapid and managed fossil fuel phase-out.

Pereira comments:”Some of the other insights offer important aspects that need to be considered as we confront this challenge head-on. Insight 5 emphasises how the climate and biodiversity crises are fundamentally interconnected and have to be addressed together. Insight 10 talks to the critical need for JUST food system transformations that can contribute to climate action, whilst insight 9 puts justice at the centre of operationalising climate adaptation, which is of critical in developing countries that sit at the forefront of climate injustices. In the African context, it’s also important to highlight that there is a lot of emphasis on carbon removal as an important mechanism for staying within 1.5 degrees (insight 3), but as insight 4 shows relying on natural carbon sinks is risky. ‘Natural’ climate solutions such as planting trees that sequester carbon needs to be done very carefully because of the potential for undermining ecosystems and livelihoods. For example, afforestation in grassy ecosystems (like our grasslands and savanna) might not sequester carbon effectively (as these systems store carbon below ground in the soil rather than aboveground) whilst impacting biodiversity and livelihoods such as pastoralism. So, some important caveats come from taking all of the insights together.”

Prof. Johan Rockström, Director of the Potsdam Institute of Climate Impact Research adds: “Science is clear. COP28 must be the global meeting when the world gets serious about phasing out fossil-fuels. Dubai is the grand mitigation moment for coal, oil and gas, which need to shift from increasing 1%/yr to decreasing globally by at least 5 %/yr, and for nature by protecting remaining carbon sinks and stocks in ecosystems, plus building resilience and new carbon sinks in agriculture. So far, we have failed on both nature and energy, taking us on a dangerous path towards losing sight of the Paris Agreement target — the 1.5°C biophysical limit.”

The report also highlights the need for robust policies to attain the scale needed for effective complementary technology solutions, such as carbon dioxide removal (CDR), especially amidst emerging concerns over the future of land and ocean carbon sinks.

Dr Oliver Geden, Senior Fellow at the German Institute for International and Security Affairs and IPCC WG III Vice-Chair says: “While not a replacement for rapid and deep emissions reductions, Carbon Dioxide Removal (CDR) will be necessary to deal with hard-to-eliminate emissions and eventually to reduce the global temperature. Current CDR is predominantly forest-based, but rapid acceleration and deployment at scale of other CDR methods with permanent CO2 removal is required, supported by stronger governance and better monitoring.”

The report spotlights the urgent need for enhanced just climate adaptation strategies that proactively address simultaneous interconnected extreme events and ensure resilience for the most vulnerable. It also accentuates the critical role of food systems in climate action, which are currently responsible for approximately one third of global greenhouse gas emissions. It advocates for the rectification of existing inequalities and emphasises that policies must be adapted to regional and sociocultural contexts, to enable the establishment of just, low-carbon food systems.

As Dr Aditi Mukherji, Director, Climate Change Adaptation and Mitigation Impact Area Platform CGIAR, explains: “The intimate links between climate change mitigation and adaptation, biodiversity conservation, and broader societal needs, including food security, requires transformative change in how we jointly govern socio-ecological systems at all scales. Most importantly, due to the growing risks of food insecurity, policies and solutions must be designed and implemented with those who suffer the most.”

The 10 New Insights in Climate Science series, launched with the UNFCCC at the COPs since 2017, is a collaborative initiative of Future Earth, the Earth League and the World Climate Research Programme, synthesising the latest developments in climate change research. This year’s report represents the collective efforts of 67 leading researchers from 24 countries.

Dr Wendy Broadgate, Global Hub Director, Future Earth, concludes: “Science shows that we are heading for overshooting 1.5°C degrees. Minimising this overshoot is critical if we want to reduce risks to societies all over the world. COP28 must be the inflection point where collective action to phase out fossil fuels gathers pace.”



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Inherited predisposition for higher muscle strength may protect against common morbidities

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Inherited predisposition for higher muscle strength may protect against common morbidities


A study conducted at the Faculty of Sport and Health Sciences at the University of Jyväskylä showed that a genetic predisposition for higher muscle strength predicts a longer lifespan and a lower risk for developing common diseases. This is the most comprehensive international study to date on hereditary muscle strength and its relationship to morbidity. The genome and health data of more than 340,000 Finns was used in the research.

Muscle strength, especially hand grip strength, can indicate an individual’s physiological resources to protect against age-related diseases and disabilities, as well as their ability to cope with them. Age-related loss of muscle strength is individual and influenced not only by lifestyle but also by genetics.

The study revealed that individuals with a genetic predisposition for higher muscle strength have a slightly lower risk for common noncommunicable diseases and premature mortality. However, it did not predict better survival after acute adverse health events compared to the time before illness onset.

“It seems that a genetic predisposition for higher muscle strength reflects more on an individual’s intrinsic ability to resist and protect oneself against pathological changes that occur during aging than the ability to recover or completely bounce back after severe adversity,” says doctoral researcher Päivi Herranen from the Faculty of Sport and Health Sciences.

The research utilized a unique study population

Muscle strength is a multifactorial trait influenced by lifestyle and environmental factors but also by numerous genetic variants, each with a very small effect on muscle strength. In this study, the genetic predisposition for muscle strength was defined by constructing a polygenic score for muscle strength, which summarizes the effects of hundreds of thousands of genetic variants into a single score. The polygenic score makes it possible to compare participants with an exceptionally high or low genetic predisposition for muscle strength, and to investigate associations with inherited muscle strength and other phenotypes, in this case, common diseases.

“In this study, we were able to utilize both genetic information and health outcomes from over 340,000 Finnish men and women,” Herranen explains.

“To our knowledge, this is the first study to investigate the association between a genetic predisposition for muscle strength and various diseases on this scale.”

Further research on the effects of lifestyles is still needed

Information about the genetic predisposition for muscle strength could be used alongside traditional risk assessment in identifying individuals who are at particularly high risk of common diseases and health adversities. However, further research on the topic is still needed.

“Based on these results, we cannot say how lifestyle factors, such as physical activity, modify an individual’s intrinsic ability to resist diseases and whether their impact on health differs among individuals due to genetics,” Herranen notes.

The study utilized the internationally unique FinnGen dataset, compiled through the collaboration of Finnish biobanks. The dataset consisted of 342,443 Finns who had given their consent and provided a biobank sample. The participants were aged 40 to 108 years, and 53% of them were women. The diagnoses selected for the study were based on the leading causes of death and the most significant noncommunicable diseases in Finland. Selected diagnoses included the most common cardiometabolic and pulmonary diseases, musculoskeletal and connective tissue diseases, falls and fractures, mental health and cognitive disorders, cancers, as well as overall mortality and mortality from cardiovascular diseases.

The study is the second publication of Päivi Herranen’s doctoral thesis, which investigates how genetics and environmental factors affect biological aging, particularly the weakening of muscle strength and functional capacity with age. The research is part of the GenActive project, funded by the Research Council of Finland and the Juho Vainio and Päivikki and Sakari Sohlberg foundations. The project is led by Assistant Professor and Academy Research Fellow Elina Sillanpää. The research was conducted in collaboration with the Gerontology Research Center (GEREC), the Institute for Molecular Medicine Finland (FIMM), and the FinnGen research project.



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Brightest gamma-ray burst of all time came from the collapse of a massive star

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Brightest gamma-ray burst of all time came from the collapse of a massive star


In October 2022, an international team of researchers, including Northwestern University astrophysicists, observed the brightest gamma-ray burst (GRB) ever recorded, GRB 221009A.

Now, a Northwestern-led team has confirmed that the phenomenon responsible for the historic burst — dubbed the B.O.A.T. (“brightest of all time”) — is the collapse and subsequent explosion of a massive star. The team discovered the explosion, or supernova, using NASA’s James Webb Space Telescope (JWST).

While this discovery solves one mystery, another mystery deepens.

The researchers speculated that evidence of heavy elements, such as platinum and gold, might reside within the newly uncovered supernova. The extensive search, however, did not find the signature that accompanies such elements. The origin of heavy elements in the universe continues to remain as one of astronomy’s biggest open questions.

The research will be published on Friday (April 12) in the journal Nature Astronomy.

“When we confirmed that the GRB was generated by the collapse of a massive star, that gave us the opportunity to test a hypothesis for how some of the heaviest elements in the universe are formed,” said Northwestern’s Peter Blanchard, who led the study. “We did not see signatures of these heavy elements, suggesting that extremely energetic GRBs like the B.O.A.T. do not produce these elements. That doesn’t mean that all GRBs do not produce them, but it’s a key piece of information as we continue to understand where these heavy elements come from. Future observations with JWST will determine if the B.O.A.T.’s ‘normal’ cousins produce these elements.”

Blanchard is a postdoctoral fellow at Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), where he studies superluminous supernovae and GRBs. The study includes co-authors from the Center for Astrophysics | Harvard & Smithsonian; University of Utah; Penn State; University of California, Berkeley; Radbound University in the Netherlands; Space Telescope Science Institute; University of Arizona/Steward Observatory; University of California, Santa Barbara; Columbia University; Flatiron Institute; University of Greifswald and the University of Guelph.

Birth of the B.O.A.T.

When its light washed over Earth on Oct. 9, 2022, the B.O.A.T. was so bright that it saturated most of the world’s gamma-ray detectors. The powerful explosion occurred approximately 2.4 billion light-years away from Earth, in the direction of the constellation Sagitta and lasted a few hundred seconds in duration. As astronomers scrambled to observe the origin of this incredibly bright phenomenon, they were immediately hit with a sense of awe.

“As long as we have been able to detect GRBs, there is no question that this GRB is the brightest we have ever witnessed by a factor of 10 or more,” Wen-fai Fong, an associate professor of physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences and member of CIERA, said at the time.

“The event produced some of the highest-energy photons ever recorded by satellites designed to detect gamma rays,” Blanchard said. “This was an event that Earth sees only once every 10,000 years. We are fortunate to live in a time when we have the technology to detect these bursts happening across the universe. It’s so exciting to observe such a rare astronomical phenomenon as the B.O.A.T. and work to understand the physics behind this exceptional event.”

A ‘normal’ supernova

Rather than observe the event immediately, Blanchard, his close collaborator Ashley Villar of Harvard University and their team wanted to view the GRB during its later phases. About six months after the GRB was initially detected, Blanchard used the JWST to examine its aftermath.

“The GRB was so bright that it obscured any potential supernova signature in the first weeks and months after the burst,” Blanchard said. “At these times, the so-called afterglow of the GRB was like the headlights of a car coming straight at you, preventing you from seeing the car itself. So, we had to wait for it to fade significantly to give us a chance of seeing the supernova.”

Blanchard used the JWST’s Near Infrared Spectrograph to observe the object’s light at infrared wavelengths. That’s when he saw the characteristic signature of elements like calcium and oxygen typically found within a supernova. Surprisingly, it wasn’t exceptionally bright — like the incredibly bright GRB that it accompanied.

“It’s not any brighter than previous supernovae,” Blanchard said. “It looks fairly normal in the context of other supernovae associated with less energetic GRBs. You might expect that the same collapsing star producing a very energetic and bright GRB would also produce a very energetic and bright supernova. But it turns out that’s not the case. We have this extremely luminous GRB, but a normal supernova.”

Missing: Heavy elements

After confirming — for the first time — the presence of the supernova, Blanchard and his collaborators then searched for evidence of heavy elements within it. Currently, astrophysicists have an incomplete picture of all the mechanisms in the universe that can produce elements heavier than iron.

The primary mechanism for producing heavy elements, the rapid neutron capture process, requires a high concentration of neutrons. So far, astrophysicists have only confirmed the production of heavy elements via this process in the merger of two neutron stars, a collision detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2017. But scientists say there must be other ways to produce these elusive materials. There are simply too many heavy elements in the universe and too few neutron-star mergers.

“There is likely another source,” Blanchard said. “It takes a very long time for binary neutron stars to merge. Two stars in a binary system first have to explode to leave behind neutron stars. Then, it can take billions and billions of years for the two neutron stars to slowly get closer and closer and finally merge. But observations of very old stars indicate that parts of the universe were enriched with heavy metals before most binary neutron stars would have had time to merge. That’s pointing us to an alternative channel.”

Astrophysicists have hypothesized that heavy elements also might be produced by the collapse of a rapidly spinning, massive star — the exact type of star that generated the B.O.A.T. Using the infrared spectrum obtained by the JWST, Blanchard studied the inner layers of the supernova, where the heavy elements should be formed.

“The exploded material of the star is opaque at early times, so you can only see the outer layers,” Blanchard said. “But once it expands and cools, it becomes transparent. Then you can see the photons coming from the inner layer of the supernova.”

“Moreover, different elements absorb and emit photons at different wavelengths, depending on their atomic structure, giving each element a unique spectral signature,” Blanchard explained. “Therefore, looking at an object’s spectrum can tell us what elements are present. Upon examining the B.O.A.T.’s spectrum, we did not see any signature of heavy elements, suggesting extreme events like GRB 221009A are not primary sources. This is crucial information as we continue to try to pin down where the heaviest elements are formed.”

Why so bright?

To tease apart the light of the supernova from that of the bright afterglow that came before it, the researchers paired the JWST data with observations from the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile.

“Even several months after the burst was discovered, the afterglow was bright enough to contribute a lot of light in the JWST spectra,” said Tanmoy Laskar, an assistant professor of physics and astronomy at the University of Utah and a co-author on the study. “Combining data from the two telescopes helped us measure exactly how bright the afterglow was at the time of our JWST observations and allow us to carefully extract the spectrum of the supernova.”

Although astrophysicists have yet to uncover how a “normal” supernova and a record-breaking GRB were produced by the same collapsed star, Laskar said it might be related to the shape and structure of the relativistic jets. When rapidly spinning, massive stars collapse into black holes, they produce jets of material that launch at rates close to the speed of light. If these jets are narrow, they produce a more focused — and brighter — beam of light.

“It’s like focusing a flashlight’s beam into a narrow column, as opposed to a broad beam that washes across a whole wall,” Laskar said. “In fact, this was one of the narrowest jets seen for a gamma-ray burst so far, which gives us a hint as to why the afterglow appeared as bright as it did. There may be other factors responsible as well, a question that researchers will be studying for years to come.”

Additional clues also may come from future studies of the galaxy in which the B.O.A.T. occurred. “In addition to a spectrum of the B.O.A.T. itself, we also obtained a spectrum of its ‘host’ galaxy,” Blanchard said. “The spectrum shows signs of intense star formation, hinting that the birth environment of the original star may be different than previous events.”

Team member Yijia Li, a graduate student at Penn State, modeled the spectrum of the galaxy, finding that the B.O.A.T.’s host galaxy has the lowest metallicity, a measure of the abundance of elements heavier than hydrogen and helium, of all previous GRB host galaxies. “This is another unique aspect of the B.O.A.T. that may help explain its properties,” Li said.

The study, “JWST detection of a supernova associated with GRB 221009A without an r-process signature,” was supported by NASA (award number JWST-GO-2784) and the National Science Foundation (award numbers AST-2108676 and AST-2002577). This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope.



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Stellar winds of three sun-like stars detected for the first time

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Stellar winds of three sun-like stars detected for the first time


An international research team led by a researcher from the University of Vienna has for the first time directly detected stellar winds from three Sun-like stars by recording the X-ray emission from their astrospheres, and placed constraints on the mass loss rate of the stars via their stellar winds. The study is currently published in Nature Astronomy.

Astrospheres, stellar analogues of the heliosphere that surrounds our solar system, are very hot plasma bubbles blown by stellar winds into the interstellar medium, a space filled with gas and dust. The study of the stellar winds of low-mass stars similar to the Sun allows us to understand stellar and planetary evolution, and ultimately the history and future of our own star and solar system. Stellar winds drive many processes that evaporate planetary atmospheres into space and therefore lead to atmospheric mass loss.

Although escape rates of planets over an hour or even a year are tiny, they operate over long geological periods. The losses accumulate and can be a decisive factor for a planet evolving into a habitable world or an airless rock. Despite their importance for the evolution of both stars and planets, winds of Sun-like stars are notoriously difficult to constrain. Mainly composed of protons and electrons, they also contain a small quantity of heavier highly charged ions (e.g. oxygen, carbon). It is these ions which, by capturing electrons from the neutrals of the interstellar medium around the star, emit X-rays.

X-ray emission from astropheres detected

An international research team led by Kristina Kislyakova, Senior Scientist at the Department of Astrophysics of the University of Vienna, has detected for the first time the X-ray emission from the astrospheres around three sun-like stars, so called main sequence stars which are stars in the prime of their life, and has thus recorded such winds for the first time directly, allowing them to place constraints on the mass loss rate of the stars via their stellar winds.

These results, based on observations with the XMM-Newton space telescope, are currently published in Nature Astronomy. The researchers observed the spectral fingerprints (so-called spectral lines) of the oxygen ions with XMM-Newton and were able to determine the quantity of oxygen and ultimately the total mass of stellar wind emitted by the stars. For the three stars with detected astrospheres, named 70 Ophiuchi, epsilon Eridani, and 61 Cygni, the researchers estimated their mass loss rates to be 66.5±11.1, 15.6±4.4, and 9.6±4.1 times the solar mass loss rate, respectively. This means that the winds from these stars are much stronger than the solar wind, which might be explained by stronger magnetic activity of these stars.

“In the solar system, solar wind charge exchange emission has been observed from planets, comets, and the heliosphere and provides a natural laboratory to study the solar wind’s composition,” explains the lead author of the study, Kristina Kislyakova. “Observing this emission from distant stars is much more tricky due to the faintness of the signal. In addition to that, the distance to the stars makes it very difficult to disentangle the signal emitted by the astrosphere from the actual X-ray emission of the star itself, part of which is “spread” over the field-of-view of the telescope due to instrumental effects. We have developed a new algorithm to disentangle the stellar and the astrospheric contributions to the emission and detected charge exchange signals originating from stellar wind oxygen ions and the surrounding neutral interstellar medium of three main-sequence stars. This has been the first time X-ray charge exchange emission from astrospheres of such stars has been detected. Our estimated mass loss rates can be used as a benchmark for stellar wind models and expand our limited observational evidence for the winds of Sun-like stars.”

Co-author Manuel Güdel, also of the University of Vienna, adds, “there have been world-wide efforts over three decades to substantiate the presence of winds around Sun-like stars and measure their strengths, but so far only indirect evidence based on their secondary effects on the star or its environment alluded to the existence of such winds; our group previously tried to detect radio emission from the winds but could only place upper limits to the wind strengths while not detecting the winds themselves. Our new X-ray based results pave the way to finding and even imaging these winds directly and studying their interactions with surrounding planets.”

“In the future, this method of direct detection of stellar winds in X-rays will be facilitated thanks to future high resolution instruments, like the X-IFU spectrometer of the European Athena mission. The high spectral resolution of X-IFU will resolve the finer structure and emission ratio of the oxygen lines (as well as other fainter lines), that are hard to distinguish with XMM’s CCD resolution, and provide additional constraints on the emission mechanism; thermal emission from the stars, or non-thermal charge exchange from the astrospheres.” — explains CNRS researcher Dimitra Koutroumpa, a co-author of the study.



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