Extreme rainfall is one of the most damaging natural disasters costing human lives and causing billions in damage. Their frequency has been increasing over the last years due to the warming climate. For several decades, scientists have been using computer models of the Earth’s climate to better understand the mechanisms behind these events and to predict future trends. In a new study, now published in the journal Science Advances, a team of researchers from the Institute of Science and Technology Austria (ISTA) and the Max-Planck-Institute for Meteorology (MPI-M) led by ISTA postdoc Jiawei Bao used a new state-of-the-art climate model to study how cloud and storm clustering impacts extreme rainfall events — specifically in the tropics — in more detail than has been possible before.

“This new type of model with a much finer resolution showed that, with a warmer climate, extreme rainfall events in the tropics increase in severity more than was expected from theory due to clouds being more clustered,” Bao, who originally started this project during his previous postdoc position at the MPI-M, explains. “We can see that when clouds are more clustered, it rains for a longer time, so the total amount of rainfall increases. We also found that more extreme rain over high-precipitation areas happens at the cost of expansion of dry areas — a further shift to extreme weather patterns. This is due to how clouds and storms cluster together, which we could now simulate with this new climate model.” This new model, first proposed in 2019, simulates the climate with a much higher resolution than previous ones. Previous models could not factor in clouds and storms in as much detail, therefore missing much of the complex dynamics of air movement that create clouds and make them congregate to form more intense storms.

While the model simulates the whole world at once, the scientists focused their analysis on the area of the tropics around the equator. They did this because cloud and storm formation there works differently than in other latitudes. Caroline Muller, Assistant Professor at ISTA, adds, “Previous models have hinted at the influence of clouds clustering on precipitation extremes but could not provide the necessary data. In collaboration with our colleagues Bjorn Stevens and Lukas Kluft from the Max Planck Institute for Meteorology, our findings add to the growing body of evidence showing that cloud formation on a smaller scale has a crucial impact on the outcomes of climate change.”

Collaborative Models

Researchers all over the world are collaborating on creating more detailed and realistic models of the world’s climate to understand the effects of climate change. Climate models divide the Earth’s atmosphere into three-dimensional chunks, each with its own data about temperature, pressure, humidity, and many more physical properties. They then employ physical equations to simulate how these chunks interact and change over time to create a representation of the real world. As computing power and storage are not unlimited, these models have to introduce simplifications and scientist continuously work to making them more accurate.

Older generations of climate models use chunks of around 100 kilometers in horizontal length, which still result in tens to hundreds of thousands of them covering the whole globe. Advances in algorithms and supercomputers enabled scientists to increase the resolution of the models more and more. “We used a climate model developed at MPI-M and analyzed the data hosted at the German Climate Computing Centre in Hamburg with a resolution of just five kilometers which was very computationally expensive,” Bao adds. “All climate research is an immense collaborative effort by hundreds of people who want to contribute to our understanding of the world and our impact on it.”

Bao, who first got interested in climate research during his PhD at the University of New South Wales, Australia, and who now works as an IST-BRIDGE postdoctoral fellow at ISTA, wants to continue his work on extreme precipitation events to find more evidence for their causes and impacts using additional models.

Caroline Muller, who first studied mathematics and then found her passion for research questions with more real-world impact, and her research group use climate models to study air convection and the formation of clouds and storms at different scales — up to tropical cyclones — to better understand their causes and the impacts of climate change on society and nature.

More than a third of these frozen moorings, known as pinning points, have decreased in size since the turn of the century, experts say.

Further deterioration of pinning points, which hold in place the floating ice sheets that fortify Antarctica’s land ice, would accelerate the continent’s contribution to rising sea levels, scientists warn.

Floating ice sheets fringe 75 per cent of Antarctica’s coastline and cover an area equivalent to the size of Greenland.

The findings are part of the first ever study of changes in the thickness of Antarctic ice shelves — extensions of land ice that float on the ocean — stretching back to 1973. Previous observations only date from 1992.

Researchers from the University of Edinburgh used satellite imagery from the NASA/United States Geological Survey (USGS) Landsat program’s fifty-year-old archive to track variations in the appearances pinning points on the ice’s surface.

Pinning points form when part of a floating ice sheet anchors itself to an elevation on the ocean floor, creating a visible bump on the otherwise smooth ice shelf surface.

Using changes in pinning points as a reliable proxy for variations in the thickness of ice shelves, the team measured changes in these features during three periods: from 1973 to 1989, 1990 to 2000 and from 2000 to 2022.

The scientists found that only 15 per cent of pinning points reduced in size from 1973 to 1989, leading to small localised pockets of thinning ice shelves.

However, a widespread acceleration and unanchoring of ice shelves from pinning points began in the 1990s in the western Antarctic Peninsula and the Amundsen Sea.

The number of pinning points that shrank increased to 25 per cent from 1990 to 2000 and 37 per cent from 2000 to 2022.

The paper, published in Nature, was funded by the Leverhulme Trust.

Lead author, Dr Bertie Miles, Leverhulme Early Career Fellow, School of GeoSciences, University of Edinburgh, said: “The switch over the past 50 years from relatively limited and regionally concentrated ice shelf melt, to much more widespread unanchoring, is striking. The ongoing concern is how many more of these vitally important pinning points will begin to melt away in the coming 50 years.”

Co-lead author, Professor Robert Bingham, Professor of Glaciology and Geophysics, School of GeoSciences, University of Edinburgh, said: “What we are seeing around Antarctica is a sustained attack by climate warming to the buttresses, that slow the conversion of ice melting, into global sea-level rise. This reinforces the need for us to take action where we can to reduce global carbon emissions.”

The study analysed how green spaces and waterways cool down cities and towns.

Professor Prashant Kumar, Director of Surrey’s Global Centre for Clean Air Research (GCARE), said:

“We have known for some time that green spaces and water can cool cities down. However, this study provides us the most comprehensive picture yet. What’s more — we can explain why. From trees providing shade, to evaporating water cooling the air.”

They found that while success depends heavily on local factors — there were some general patterns. Among the key findings, the following green spaces and waterways cooled the air considerably:

• Botanical gardens: -5°C avg (variation: -2.2°C to -10°C)

• Wetlands: -4.7°C avg (variation: -1.2°C to -12°C)

• Rain garden: -4.5°C avg (variation: -1.3°C to -7°C)

• Green walls: -4.1°C avg (variation: -0.1°C to -18°C)

• Street trees: -3.8°C avg (variation: -0.5°C to -12°C)

• City farm: -3.5°C avg (variation -3°C to -3.9°C)

• Parks: -3.2°C avg (variation -0.8°C to -10°C)

• Reservoirs -2.9°C avg (variation -1.8°C to 5°C)

• Playgrounds: -2.9°C avg (variation: -2.8°C to -3°C)

Up to a point, the bigger the park — the bigger the cooling effect. Cities can unlock greater benefits by connecting green spaces into ‘green corridors’.

Greening projects can also remove carbon emissions and even help prevent flooding.

Professor Kumar said:

“This will help town planners around the world confront the challenges of global heating. By implementing just some of the measures we describe, cities can become more resilient, and their citizens can be healthier and happier too.”

However — the team also found areas of the globe which were vulnerable to heat — but had not researched the best way to use green spaces to cool down.

Maria de Fatima Andrade, Professor at the Atmospheric Sciences Department at the University of Sao Paulo, Brazil, said:

“Our paper confirms just how many ways there are to keep cool. But it also reveals how much work is left to do. Institutions around the world need to invest in the right research — because what’s very clear from our study is that there is no one-size-fits-all solution. It depends on what works for your community.”

The study is published in the journal, The Innovation.

The study demonstrates the University of Surrey’s contribution towards the United Nations’ Sustainable Development Goals, especially Goal 11 (Sustainable Cities and Communities) and Goal 13 (Climate Action).

The forerunners of mammals ruled the Earth for about 60 million years, long before the origin of the first dinosaurs. They diversified as the top predators on land between 315-251 million years ago.

Researchers studied the jaw anatomy and body size of carnivorous synapsids, using these traits to reconstruct the likely feeding habits of these ancient predators and chart their ecological evolution through time. They found a major shift in synapsid jaw function roughly 270 million years ago linked to a significant shift in predatory behaviour that has important implications for the evolution of our earliest ancestors.

As herbivores grew larger and faster, carnivores adapted to become bigger and better predators to survive.

“Earlier synapsid predators such as the famous sail backed Dimetrodon, had fairly long jaws with lots of teeth to ensure that once they ensnared their prey, it wouldn’t escape,” explained lead author Dr Suresh Singh based in Bristol’s School of Earth Sciences. “However, we saw a shift in jaw function toward shorter jaws with greater muscle efficiency and fewer teeth that were concentrated at the front of the jaw — these were jaws adapted to deliver deep, powerful bites.

“The change shows that later synapsid carnivores placed more emphasis on heavily injuring and so more quickly killing their prey. Among these later synapsids were the very first sabertoothed carnivores! This change highlights that predators were facing new selective pressures from their prey.”

This finding provides important context for a key step in synapsid evolution. “The reorganisation of synapsid jaws through this time has long been known as a big step towards the evolution of mammals,” added Dr Armin Elsler, a collaborator on the study. “These changes don’t just make the jaw more efficient; they also mark the very earliest redevelopment of the jaw that also created the complex ear found in mammals. What drove this first step? Our study suggests that it was partly driven by ecological pressures from their prey.”

Co-author Dr Tom Stubbs said: “The timing of the shift in jaw function corresponds with the evolution of new larger, faster herbivores that would have posed a greater challenge for predators to tackle.

“The risks to carnivores of getting injured or killed went up, so some synapsid carnivores became bigger, better killers to overcome these risks.”

This shift reflects a new dynamism in predator-prey interactions that shows that life on land was moving more quickly.

“The late Palaeozoic was the time when animals first began to live, eat and reproduce entirely on land,” said Professor Mike Benton, a co-supervisor on the study

“They became fully terrestrial, colonising new habitats and exploiting new resources further inland from the aquatic environments they’d previously relied on.

“Our findings show how the selective pressures on these early land animals changed as they became better adapted for life on land — catching another animal that can move fast and grow to larger sizes is much more difficult than catching a slippery little fish or amphibian.”

Professor Emily Rayfield also co-supervised the study. She added: “Predator-prey interactions are an important driver of animal behaviour today so it’s quite something to see that influence through anatomical evolution over millions of years, and find that they are potentially responsible for driving some big leaps in our own evolutionary history.

“It highlights how palaeontologists can use the relationship between form and function to explore how different prehistoric animals may have lived, which can tell us so much about the evolution of life on Earth.”

The researchers also found that synapsid carnivore morphological diversity increased following the shift, with the addition of new functional groups adapted for either faster biting speeds or even more powerful bites through the mid-late Permian — around 265-251 million years ago. By assessing how the sizes of these new carnivore species compared within different communities through time, they realised these communities may have begun to closely resemble those of modern carnivorous mammals.

According to a representative survey of 38,616 high school students from 22 public school districts in 14 U.S. states, the quarter of those adolescents who had experienced the highest number of days in a climate disaster within the past two years and the past five years — such as hurricanes, floods, tornadoes, droughts, and wildfire — had 20% higher odds of developing mental distress than their peers who experienced few or no disaster events.

The paper is the first large scale research looking at mental health of adolescents following multiple disaster events — including the timing, frequency, and duration of the events — spanning 83 federally declared climate disasters occurring within 10 years before the survey was completed. The findings, using May 2019 data on sadness/hopelessness and short sleep from the U.S. Youth Risk Behavior Survey and disaster data from the Federal Emergency Management Agency, were published this month in the journal Preventive Medicine Reports.

“We know that climate change has and will have catastrophic impacts across the globe,” said lead author Amy Auchincloss, PhD, an associate professor of epidemiology in the Dornsife School of Public Health. “But we were alarmed to find that climate related disasters already were affecting so many teens in the U.S. For example, within the past 2 years, many school districts in our study were subject to climate disasters for over 20 days.”

Respondents reported mental health distress by responding affirmatively to persistent feelings of sadness or hopelessness and short sleep duration, two factors that previous studies strongly link to mental health disorders among adolescents. The group controlled for other factors that may influence mental health, such as age, race, gender, experience of bullying, concerns about school safety and household income.

A positive, but not statistically significant, link between experiencing climate disasters and mental distress was also found when spanning ten years before the U.S. Youth Risk Survey.

“We found the strongest effects on mental distress in the 2 years immediately following a climate disaster — with the effect gradually weakening 5 to 10 years after the disaster,” said co-author Josiah Kephart, PhD, an assistant professor in the Dornsife School of Public Health.

As the results cannot prove causation, the authors say they would like to see more studies into the range of effects of climate change on youth and methods to improve preparing for potential worsening mental health among this population.

Already, roughly half of adolescents have experienced a mental health disorder in their childhood or teen years, according to the U.S. Department of Health and Human Services.

“Resources for the youth mental health crisis already have difficulty meeting demand and demand will increase as disasters increase,” said co-author Esther Chernak, MD, a clinical professor and director of the Center for Public Health Readiness and Communication at Dornsife School of Public Health. “The current study is evidence that clinicians, policymakers, parents, and many others with a stake in youth mental health can point to when advocating for increasing adolescent-specific mental health resources — particularly in lower-income communities who will be hit hardest by disasters.”

Drexel’s Dornsife School of Public Health is home to significant ongoing work addressing health and climate change. Among other projects, the school’s Urban Health Collaborative recently received National Institutes of Health funding to support establishment of the Drexel Climate Change and Urban Health Research Center (CCUH), which with foster research on the effects of climate change on health across the Americas. The Urban Health in Latin America Project (SALURBAL-Climate), of which Dornsife School of Public Health is an institutional partner, funds research on climate change’s links to health and health inequity impacts across Latin America using data on as any as 400 cities in 11 countries. Additional work at the school, in collaboration with the World Resources Institute (WRI), WRI Brasil, SALURBAL, and WRI Mexico, seeks to deepen our understanding of the relationship between neighborhood-scale heat mortality and neighborhood social characteristics in two Brazilian cities; the findings of which aim to inform public policy.

In addition to Auchincloss, additional authors on the study includes Dominic A. Ruggiero, and Meghan T. Donnelly, who were graduate students at Drexel at the time of this work.