Prof. Piers Forster, Director of the Priestley Centre for Climate Futures at the University of Leeds and lead author of the study, said: “Our third annual edition of Indicators of Global Climate Change shows that both warming levels and rates of warming are unprecedented. Continued record-high emissions of greenhouse gases mean more of us are experiencing unsafe levels of climate impacts. Temperatures have risen year-on-year since the last IPCC report in 2021, highlighting how climate policies and pace of climate action are not keeping up with what’s needed to address the ever-growing impacts.”

This year’s update of key climate system indicators carried out by a team of over 60 international scientists included two additional indicators, sea-level rise and global land precipitation, to give a total of 10 indicators1. This information is crucial for decision-makers seeking a current, comprehensive picture of the state of the global climate system.

In 2024, the best estimate of observed global surface temperature rise was 1.52°C, of which 1.36°C can be attributed to human activity2. The high level of human-induced warming and its high warming rate are due to global greenhouse gas emissions remaining at an all-time high in recent years.

According to the study, 2024’s high temperatures are “alarmingly unexceptional,” given the level of human-caused climate change. This human influence is at an all-time high and, combined with natural variability in the climate system (which causes temperatures to vary naturally year-to-year), has pushed global average temperature rise to record levels.

While reaching 1.5°C of global temperature rise in a single year does not mean there has been any breach of the landmark Paris Agreement – for that, average global temperatures would need to exceed 1.5°C over multiple decades – these results do reaffirm how far and fast emissions are heading in the wrong direction. And the impacts will only stop worsening when CO2 emissions from fossil fuels and deforestation reach net zero.

When analysing longer-term temperature change, best estimates show that between 2015-2024 average global temperatures were 1.24°C higher than in pre-industrial times, with 1.22°C caused by human activities, meaning that, essentially, our best estimate is that all of the warming we have seen over the last decade has been human-induced.

Human activities have resulted in the equivalent of around 53 billion tonnes of CO2 (Gt CO2e) being released into the atmosphere each year over the last decade, primarily due to increasing emissions from burning fossil fuels and deforestation. In 2024, emissions from international aviation – the sector with the steepest drop in emissions during the pandemic – also returned to pre-pandemic levels.

GHG emissions have also led to higher levels of greenhouse gases accumulating in the atmosphere. Combined with declines in emissions of sulphur dioxide (SO2) leading to planet-cooling aerosols, the outcome is that the planet is continuing to heat up. The damage caused by aerosols to human health far outweighs any minimal cooling ‘gains’, and there are other short-lived GHGs that can and should be tackled alongside CO2, such as methane (CH4), that could provide a short-term cooling compensating for the aerosol decline.

Human activities have also been affecting the Earth’s energy balance. Surplus heat accumulating in the Earth’s system at an accelerating rate is driving changes in every component of the climate system. The rate of global heating seen between 2012 and 2024 has about doubled from the levels seen in the 1970s and 1980s, leading to detrimental changes of vital components, including sea level rise, ocean warming, ice loss, and permafrost thawing.

Dr. Karina Von Schuckmann, Senior Advisor, Ocean Science for Policy at Mercator Ocean International said: “The ocean is storing about 91% of this excess heat driven by greenhouse gas emissions, which leads to ocean warming. Warmer waters lead to rising sea levels and intensified weather extremes, and can have devastating impacts on marine ecosystems and the communities that rely on them. In 2024, the ocean reached record values globally.”

Between 2019 and 2024, global mean sea level has also increased by around 26 mm, more than doubling the long-term rate of 1.8 mm per year seen since the turn of the twentieth century.

Dr. Aimée Slangen, Research Leader at the NIOZ Royal Netherlands Institute for Sea Research said: “Since 1900, the global mean sea level has risen by around 228 mm. This seemingly small number is having an outsized impact on low-lying coastal areas, making storm surges more damaging and causing more coastal erosion, posing a threat to humans and coastal ecosystems. The concerning part is that we know that sea-level rise in response to climate change is relatively slow, which means that we have already locked in further increases in the coming years and decades.”

IPCC’s last assessment of the climate system, published in 2021, highlighted how climate change was leading to widespread adverse impacts on nature and people, with rapid and deep reductions in GHGs emissions needed to limit warming to 1.5°C.

Prof. Joeri Rogelj, Research Director at the Grantham Institute and Climate Science & Policy Professor at the Centre for Environmental Policy at Imperial College London said: “The window to stay within 1.5°C is rapidly closing. Global warming is already affecting the lives of billions of people around the world. Every small increase in warming matters, leading to more frequent, more intense weather extremes. Emissions over the next decade will determine how soon and how fast 1.5°C of warming is reached. They need to be swiftly reduced to meet the climate goals of the Paris Agreement.”

Other key findings:

• Human-caused warming has increased at a rate of around 0.27°C/decade (2015-2024).
• The most recent decade (2015-2024) was 0.31°C warmer than the previous decade (2005-2014). These changes, although amplified somewhat by the exceptionally warm years in 2023 and 2024, are broadly consistent with warming rates over the last few decades.
• The rapid warming over the last few decades has resulted in record extreme temperatures over land, with average maximum temperatures reaching 1.9°C over the decade 2015-2024 and rising at a substantially faster rate than global mean surface temperature.

1) Full list of indicators:

• Greenhouse gas emissions
• Greenhouse gas concentrations and emissions of short-lived climate forcers
• Effective radiative forcing
• Earth energy imbalance
• Observations of global surface temperature change
• Human-induced temperature change
• Remaining carbon budget for policy-relevant temperature thresholds
• Maximum land surface temperatures
• Global land precipitation
• Global mean sea-level rise

2) The study calculated 1.52°C as the best estimate of observed global surface temperature in 2024. This number differs from the 1.55°C given by the World Meteorological Organisation (WMO) State of the Global Climate 2024 report. This is owed to slightly distinct selections from the available datasets included. The number has varied by similar amounts in past years. Future work will aim to harmonise the approaches.

The new study led by the Department of Anatomy and published on Proceedings of the Royal Society B, examines the New Zealand spotty, or paketi, a fish that can change from female to male during adulthood in response to a change in social hierarchy.

It found that the sex change process begins almost immediately when a dominant spotty is removed from a group.

Lead author Haylee Quertermous, a PhD Candidate in the Department of Anatomy, says although the full sex change process takes weeks, it only takes minutes for a second-ranked fish to take advantage of the power vacuum and assert dominant behaviors.

“The aggressive behaviors (called ‘rushes’) involved the dominant fish swimming rapidly towards subordinate individuals,” she says.

“Sometimes the dominant fish will make physical contact with the subordinates, including taking bites at them, usually around their tail and fins. These aggressive behaviors are usually accompanied by the subordinate quickly swimming away (‘escaping’) from the dominant fish.”

While she expected to be able to see behavior changes within an hour of removing the dominant fish, she was surprised by just how rapid the change could be.

“In many of the tanks, second-ranked fish increased their aggression within just a few minutes after removal of the dominant fish.”

She cautions the dominant behavior that accompanies a female to male sex change in spotties does not indicate a change from typically ‘female’ to ‘male’ behavior, as other sex-changing fish species such as clownfish for example, change from male to more dominant female fish.

The researchers observed that spotties form linear dominance hierarchies based on size, with larger individuals dominating smaller ones.

They sought to determine which fish in the hierarchy were more likely to change sex when the opportunity arose.

Results show dominant, larger fish are more likely to change sex, and when social hierarchies are disrupted, less dominant fish can quickly change their behavior to seize new opportunities.

The study also delved into the neural mechanisms underlying spotties’ social interactions, finding that the social decision-making network in the fish brain is highly involved in establishing dominance.

Fish that attained dominant positions showed significant differences in this network compared to fish of all other ranks.

Dr Kaj Kamstra, who led the neurobiological aspects of the research, says the findings provide valuable insights into the complex interplay between social behavior and neural processes in these fish.

“They also highlight the importance of social context in shaping individual behavior, shedding light on the evolution of social behavior and the flexibility of brain mechanisms in adapting to changing social environments.

“The research has broader implications for understanding social dynamics in other species, even humans.”

The findings can be applied to other species of sex-changing fish where social dominance appears to be the most common trigger for sex change, and could prove beneficial for aquaculture and open water fisheries, with many commercial valuable fisheries dependent on fishes that change sex, for example, New Zealand’s blue cod.

This is a main conclusion of a new study that analyses the body profiles of organisms — symmetry, segmented bodies, exoskeletons, etc. — from around 545 million years ago by analyzing trace fossils, which are the fossilized marks in rocks and sediments left by the activity of organisms in the past.

The authors of the article are the experts Olmo Miguez Salas, from the Faculty of Earth Sciences at the University of Barcelona, and Zekun Wang, from the Natural History Museum in London (United Kingdom).

Fossil traces of extinct animals

The Cambrian explosion is a unique period in the history of life that poses many unanswered questions. To delve into the biodiversity of this period, most studies in paleontology tend to focus on the study of organisms that had hard parts. However, the study of trace fossils (or ichnofossils) opens up the possibility of discovering what the activity of hard-bodied, soft-bodied or skeletally deficient organisms preserved in the stratigraphic record was like.

“The trace fossil record provides valuable information about evolutionary periods when soft-bodied fauna were dominant,” says Olmo Miguez Salas, a Beatriu de Pinós postdoctoral researcher at the UB’s Department of Earth and Ocean Dynamics. “Fossil traces reflect the behavior of the organism that generates them, which is determined by habitat and responses to environmental stimuli. Therefore, they are an indicator of the paleoecological conditions in which the organisms that generated them lived.”

The authors have focused on the study of trace fossils in the Ediacaran-Cambrian transition, “a period of recognized paleoevolutionary interest that was a turning point in the evolution of complex life on Earth,” says Miguez Salas.

In this transition, there was a radical change in biodiversity and in the structure of organisms and ecosystems. “The Ediacaran fauna was dominated by complex, multicellular soft-bodied organisms. The transition to the Cambrian involved the extinction of much of the Ediacara fauna, and a rapid diversification of complex multicellular life forms with hard parts (e.g. exoskeletons). This is the evolutionary core from which most modern animal phyla emerged: what is known as the Cambrian explosion,” notes the researcher.

The Cambrian explosion may have happened much earlier

The study published in Geology quantitatively indicates that organisms with slender body profiles thrived around 545 million years ago. “These organisms probably possessed coelomic hydrostatic bodies, with an anteroposterior axis, muscles and possibly segmentation,” the expert says.

“Furthermore, these organisms could move in a specific direction (directional locomotion) and probably possessed sensory capabilities to move and feed on heterogeneous substrates in a habitat dominated by microbial mats. Therefore, the so-called Cambrian explosion and its evolutionary implications may have occurred much earlier than estimated.”

These adaptations in body profile and mobility allowed these early animals to thrive in increasingly dynamic and complex environments, an ecological engineering that could promote evolutionary innovations. The methodology of the study was based on the analysis of the linear proportionality exhibited by the trace trajectories of modern and fossilized animals. Subsequently, this scaling law has been applied to locomotor traces of Ediacaran-Cambrian fossils (e.g. Archaeonassa, Gordia, Helminthopsis and Parapsammichnites).

Although some previous studies had described trace fossils associated with mobile benthic bilateral organisms in the Ediacara fauna, detailed quantitative approaches were lacking and there were still many unknowns about the body shape of these organisms (length, width, cephalization, etc.). The findings of the new study establish an innovative quantitative approach to analysing the fossil locomotion traces from ancient times, early animal anatomy and paleoecological dynamics.

“This new discovery opens the door to quantitatively study future Ediacara trace fossils discovered in the coming years and to corroborate that the Cambrian explosion did not happen in the Cambrian, but many millions of years earlier. Moreover, the scaling laws obtained in this study enable the study of the morphological evolution of different faunal phyla generating fossil locomotion traces, not only during this evolutionary period, but also during other evolutionary periods of similar importance, such as the great diversification event of the Ordovician,” concludes Olmo Miguez Salas. ​​​​​​​

Led by an international team of researchers, and published in Limnology and Oceanography, the study quantifies for the first time how these tiny creatures collectively enhance carbon sequestration through their seasonal, vertical migrations.

The Southern Ocean is a key region for carbon storage. Traditional thinking is that the carbon storage in the Southern Ocean is dominated by gravitational sinking of detritus produced by large zooplankton grazers, such as krill.

This new research concerns another more recently described process called the ‘seasonal migrant pump’. This process sees zooplankton migrate each year from surface waters to depths below 500m, storing carbon via their respiration and mortality during this deep overwintering phase.

This figure shows the traditional view of how zooplankton transport carbon to depth (left panel) by eating phytoplankton in surface waters in summer, whereby their waste material (Particulate Organic Carbon, POC) sinks passively to great depth, thereby storing the carbon for thousands of years. This new study shows that a winter process known as the ‘seasonal migrant pump’ also leads to a substantial deep carbon storage (right panel). The zooplankton migrate downwards in autumn to overwinter below 500m where their respiration and death directly inject around 65 million tonnes of carbon annually into the deep ocean.

The team first built a big database of zooplankton collected in thousands of net hauls from around the Southern Ocean, dating from the 1920s to the present day. From these they quantified the extent of the zooplankton’s annual descent to overwinter at great depths, where they respire CO2 — directly and efficiently injecting carbon into the deep ocean.

Key Findings:

• 65 Million Tonnes of Carbon Stored Annually: The seasonal, vertical migration of zooplankton transports roughly 65 million tonnes of carbon to depths below 500 meters.
• Copepods Dominate the ‘Seasonal Migrant Pump’: Mesozooplankton (mainly small crustaceans called copepods) account for 80% of this carbon flux, while krill and salps contribute 14% and 6%, respectively.
• Climate Implications: The Southern Ocean is a critical carbon sink, but current Earth System Models overlook this zooplankton-driven process. As warming shifts species distributions (e.g., declining krill, increasing copepods, changing food sources), the carbon storage dynamics may change dramatically.

Why does the ‘Seasonal Migrant Pump’ matter:

The Southern Ocean absorbs approximately 40% of all human-made CO2 taken up by oceans, yet the role of zooplankton has been underestimated. Unlike sinking detritus, which removes both carbon and essential nutrients like iron, migrating zooplankton efficiently inject carbon into the deep ocean while recycling nutrients near the surface. This ‘Seasonal Migrant Pump’ could become even more important as marine ecosystems respond to climate change.

Dr Guang Yang, first author and Marine Ecologist from Institute of Oceanology, Chinese Academy of Sciences, said: “Our work shows that zooplankton are unsung heroes of carbon sequestration. Their seasonal migrations create a massive, previously unquantified carbon flux — one that models must now incorporate.”

Prof. Angus Atkinson MBE, co-author and Senior Marine Ecologist at Plymouth Marine Laboratory, added: “This study is the first to estimate the total magnitude of this carbon storage mechanism. It shows the value of large data compilations to unlock new insights and to get an overview of the relative importance of carbon storage mechanisms.”

Dr Katrin Schmidt, co-author and Marine Ecologist at the University of Plymouth, said: “The study shows the ‘seasonal migrant pump’ as an important pathway of natural carbon sequestration in polar regions. Protecting these migrants and their habitats will help to mitigate climate change.”

Dr Jen Freer, co-author and Ecological Modeller at the British Antarctic Survey (BAS), added: “Krill are famous for their role in the Antarctic food web, but we find that copepods significantly dominate carbon storage overwinter. This has big implications as the ocean warms and their habitats may shift.”

This research stresses the urgent need for updates to climate models to include zooplankton-driven carbon fluxes. It also highlights the necessity to manage and protect Southern Ocean ecosystems, where industrial fishing and warming threaten krill populations — a key species that supports both carbon export and Antarctica’s unique biodiversity.

This international study was a collaboration among scientists from China, UK, and Canada, and leverages a century’s worth of data on zooplankton biomass, distribution, respiration and mortality across the Southern Ocean.

For people with autoimmune disease, T cell reactivity is a big problem. Haywire T cell responses lead to autoimmune diseases such as type 1 diabetes, rheumatoid arthritis, and inflammatory bowel disease.

In recent years, scientists at La Jolla Institute for Immunology (LJI) have discovered that T cells may also contribute to the development of Parkinson’s disease. Researchers in the laboratory of LJI Professor Alessandro Sette, Dr.Biol.Sci., have found that many people with Parkinson’s disease have T cells that target key proteins, called alpha-synuclein and PINK1, on vulnerable brain cells.

Earlier this year, Sette and his colleagues published a study in npj Parkinson’s Disease that sheds light on exactly which subtypes of T cells target alpha-synuclein. Their findings offered further clues that T cell reactivity plays a role in Parkinson’s disease. Still, the scientists didn’t have a timeline to show when T cells might contribute to disease development.

“We can see these reactive T cells in people after they develop Parkinson’s, but what happens before that?” says LJI Visiting Scientist Emil Johansson, Ph.D., a researcher in the Sette Lab and co-author of the study.

Now we have answers. In a new npj Parkinson’s Disease paper, Sette and his colleagues show that potentially harmful T cell reactivity is highest during the “prodromal” period in Parkinson’s — the years before patients receive a diagnosis.

“This T cell immunity could be a marker for early Parkinson’s treatment, even before people show symptoms,” says Sette, who was senior author on the new paper. “And there’s reason to think that treating Parkinson’s in the very early stages can lead to a better outcome.”

How the study worked

The prodromal period in Parkinson’s disease can last for decades before a person develops noticeable symptoms such as tremors and cognitive impairments.

Because prodromal Parkinson’s disease is very difficult to detect, the LJI team studied T cell reactivity in research volunteers at high risk of developing Parkinson’s disease. These volunteers had genetic risk factors for Parkinson’s and some had symptoms such as disrupted REM sleep cycles and loss of sense of smell, which can be early signs of Parkinson’s disease development.

The researchers used a technique called Fluorospot to learn more about T cells found in blood samples from these study volunteers. This technique revealed which volunteers had high levels of T cells that reacted to alpha-synuclein or PINK1 — and when those T cell numbers were highest.

Sette and his colleagues found that potentially harmful T cells show up early on, well before the onset of noticeable motor symptoms, such as tremors. “You can see that T cell reactivity before diagnosis,” says Sette.

In fact, T cell reactivity to PINK1 was at an all-time high before diagnosis.

Sette warns against jumping to conclusions. Parkinson’s is a complex disease, and the new research doesn’t prove that T cells are actually driving the inflammation associated with Parkinson’s disease.

“Parkinson’s disease is associated with the destruction of nervous system cells. Does that destruction cause autoimmunity — or is the autoimmunity the cause of the disease? That’s the chicken-and-the-egg of inflammation in Parkinson’s disease,” says Sette.

“Certainly, the fact that this T cell reactivity is highest when patients are closest to a diagnosis is intriguing,” Sette adds. “The finding suggests T cells could have something to do with it.”

Next steps for helping patients

The new research may guide the development of early diagnostic tools. In the meantime, LJI scientists are looking for ways to block inflammation and protect brain cells.

As Johansson explains, some T cells actually help dial back inflammation to protect our tissues. “We want to see if there are specific T cells that are protective,” says Johansson. “Could they interfere in inflammation and maybe reduce the number of autoimmune T cells?”

Sette and his colleagues are also working to understand the role of T cells in other neurodegenerative diseases.

“We are very interested in diseases such as Alzheimer’s, for example, where a lot of progress has been made toward identifying people in very early stages of the disease progression,” says Sette.

Additional authors of the study, “T cell responses towards PINK1 and α-synuclein are elevated in prodromal Parkinson’s disease,” included first author Antoine Freuchet, Gregory P. Williams, Tanner Michealis, April Frazier, Irene Litvan, Jennifer G. Goldman, Roy N. Alcalay, David G. Standaert, Amy W. Amara, Natividad Stover, Edward A. Fon, Ronald B. Postuma, John Sidney, David Sulzer, and Cecilia S. Lindestam Arlehamn.

This study was supported by LJI & Kyowa Kirin, Inc. (KKNA- Kyowa Kirin North America), the Swedish Research Council (grant references 2024-00175), Aligning Science Across Parkinson’s (ASAP-000375), and the Michael J. Fox Foundation.

Currently, standard tests for diagnosing fatty liver disease include ultrasounds, CTs, and MRIs, which require costly specialized equipment and facilities. In contrast, chest X-rays are performed more frequently, are relatively inexpensive, and involve low radiation exposure. Although this test is primarily used to examine the condition of the lungs and heart, it also captures part of the liver, making it possible to detect signs of fatty liver disease. However, the relationship between chest X-rays and fatty liver disease has rarely been a subject of in-depth study.

Therefore, a research group led by Associate Professor Sawako Uchida-Kobayashi and Associate Professor Daiju Ueda at Osaka Metropolitan University’s Graduate School of Medicine developed an AI model that can detect the presence of fatty liver disease from chest X-ray images.

In this retrospective study, a total of 6,599 chest X-ray images containing data from 4,414 patients were used to develop an AI model utilizing controlled attenuation parameter (CAP) scores. The AI model was verified to be highly accurate, with the area under the receiver operating characteristic curve (AUC) ranging from 0.82 to 0.83.

“The development of diagnostic methods using easily obtainable and inexpensive chest X-rays has the potential to improve fatty liver detection. We hope it can be put into practical use in the future,” stated Professor Uchida-Kobayashi.