Hailstone library to improve extreme weather forecasting

A University of Queensland library -- full of hailstones instead of books -- is helping researchers to better understand and predict damaging storms.

Dr Joshua Soderholm, an Honorary Senior Research Fellow from UQ's School of the Environment, and lead researcher PhD candidate Yuzhu Lin from Penn State in the US, have found storm modelling outcomes change significantly when using real hailstones.

Key points:

• Researchers are measuring and scanning samples for a global 'hailstone library'
• Storm simulations using 3-D modelling of real hailstones show it behaves differently than spherical hail shapes
• Data from the hail library could lead to more accurate storm forecasts

"People tend to think of a hailstone as a perfect sphere, like a golf ball or cricket ball," Dr Soderholm said.

"But hail can be all sorts of weird shapes, from oblong to a flat disc or have spikes coming out -- no two pieces of hail are the same.

"Conventional scientific modelling of hail assumes spherical hailstones, and we wanted to know if that changed when non-spherical, natural hail shapes are used."

Ms Lin said they found the differences were dramatic.

"Modelling of the more naturally shaped hail showed it took different pathways through the storm, experienced different growth and landed in different places," Ms Lin said.

"It also affected the speed and impact the hail had on the ground.

"This way of modelling had never been done before, so it's exciting science."

Dr Soderholm said building a 'hailstone library' was critical to further fine-tuning hailstorm simulations.

"This is effectively a dataset to represent the many and varied shapes of hailstones, to make weather modelling more accurate," he said.

"Our study used data from 217 hail samples, which were 3-D scanned and the sliced in half, to tell us more about how the hailstone formed.

"This data is now part of a global library, as we try and get a really clear picture of hailstone shape and structure."

Dr Soderholm said the research has significant potential.

"At the moment, the modelling is specifically for scientists studying storms, but the end game is to be able to predict in real-time how big hail will be, and where it will fall," he said.

"More accurate forecasts would of course warn the public so they can stay safe during hailstorms and mitigate damage.

"But it could also significantly benefit industries such as insurance, agriculture and solar farming which are all sensitive to hail."

Read more at Science Daily

Detecting climate change using aerosols

Researchers analyzed long-term aerosol satellite observation big data focusing on the Pacific Ocean downwind of China. Using a newly developed metric that considered aerosols as tracers, they detected altered atmospheric transport patterns associated with climate change. They observed that the distance of transboundary air pollution moving east from China had shortened. Thus, long-term satellite-based Earth observations are crucial for early climate change detection and accurate evaluation of this trend.

Climate change is one of the most significant environmental challenges of present times, leading to extreme weather events, including droughts, forest fires, and floods. The primary driver for climate change is the release of greenhouse gases into the atmosphere due to human activities, which trap heat and raise Earth's temperature. Aerosols (such as particulate matter, PM2.5) not only affect public health but also influence the Earth's climate by absorbing and scattering sunlight and altering cloud properties. Although future climate change predictions are being reported, it is possible that the impacts of climate change could be more severe than predicted. Therefore, it is necessary to detect climate change accurately and as early as possible.

Building on these insights, a research team from Japan, led by Professor Hitoshi Irie from the Center for Environmental Remote Sensing at Chiba University, utilized long-term observational data to study the effect of climate change on transboundary air pollution in the downwind area of China by using aerosols. They utilized a completely unique perspective on how aerosols impact climate and developed a new metric to detect climate change by considering aerosols as tracers.

"The significance of this study lies in the fact that most of its results are derived from observational data. In natural sciences focused on Earth studies, the ultimate goal is to piece together highly accurate data obtained from observations to quantitatively understand the processes occurring on Earth and to pursue immutable truths. Therefore, the more observational data we have, the better. With the continued Earth observations by Japan's major Earth observation satellites (such as the GCOM series, GOSAT series, Himawari series, and ALOS series), we aim to complement these efforts with numerical simulations and data science methodologies to achieve a safe and secure global environment that mitigates the impacts of the climate crisis." explains Prof. Irie.

The research team included Ms. Ying Cai from the Graduate School of Science and Engineering, Chiba University, Dr. Alessandro Damiani from the Center for Climate Change Adaptation, National Institute for Environmental Studies, Dr. Syuichi Itahashi and Professor Toshihiko Takemura from the Research Institute for Applied Mechanics, Kyushu University, and Dr. Pradeep Khatri from Faculty of Science and Engineering, Soka University. Their study was made available online on May 23, 2024, and published in Science of The Total Environment on August 20, 2024.

China is a major contributor to air pollution in East Asia. The downwind area of China analyzed in this study is a unique open ocean area with minimal human interference yet an important zone of transboundary air pollution pathways, making it an ideal location for studying meteorological variations due to climate change.

In their study, the researchers analyzed aerosol optical depth (AOD) datasets derived from satellites, reanalysis datasets, and numerical simulations focused on the Pacific Ocean in the downwind area of China, over 19 years from 2003 to 2021. AOD, a measure of the amount of sunlight blocked by aerosols, is a key factor is analyzing aerosols and their impact on climate change.

The researchers developed a new metric called RAOD which utilized the potential of aerosols as tracers to evaluate the impact of climate change on transboundary air pollution pathways. Using RAOD the researchers were able to quantify significant temporal variations in aerosol transport. They discovered that long-term changes in RAOD due to climate change were outweighed by larger year-to-year variations in the meteorological field. Moreover, seasonal trends showed that aerosols moved west to east during spring and winter, and northward in summer. They concluded that the probability of aerosols from China to be transported far eastward was low, highlighting a shift in transboundary pollution pathways due to global warming. In this study the authors successfully detected climate change using long-term satellite observational data, in contrast to most existing studies that tracked transboundary air pollution using model simulations.

"These results suggest that RAOD is a valuable metric for quantifying the long-term changes in transboundary air pollution pathways due to climate change. These results are particularly significant because most of them are derived from observational data," says Prof. Irie, highlighting the importance of the study. Sharing the future implications of their study he concludes, "The effects of climate change could be more severe than currently predicted. This study will help verify climate change predictions from an unconventional perspective of 'aerosol observation,' enabling a more accurate understanding of climate change progression and implementation of rational countermeasures."

Read more at Science Daily

Experiencing extreme weather predicts support for policies to mitigate effects of climate change

Most Americans report having personally experienced the effects of extreme weather, according to new survey data from the Annenberg Public Policy Center that finds support for pro-environmental government policies meant to lessen the effects of climate change.

More than 6 in 10 people favor increased investment in energy-efficient public transit and an equal number support providing tax credits to families who install rooftop solar or battery storage, according to the nationally representative panel survey, fielded in November 2023 with over 1,500 U.S. adults.

Two-thirds of U.S. adults say that in the past year their typical daily activities were affected either sometimes, often, or frequently by extreme outdoor heat, and half say that their typical daily activities were affected sometimes, often, or frequently by poor air quality resulting from wildfire smoke.

Importantly, an analysis finds a connection between these reported experiences and policy support: exposure to extreme weather is associated with support for a half-dozen policies intended to mitigate the effects of climate change, policies that are contained in the Inflation Reduction Act of 2022.

Annenberg opens new Climate Communication division

The findings were released at an opening session of the Society of Environmental Journalists' (SEJ) 33rd annual conference, #SEJ2024, which was held at the University of Pennsylvania. Penn's Annenberg Public Policy Center (APPC) hosted the group in celebration of the Penn Center for Science, Sustainability, and the Media. APPC director Kathleen Hall Jamieson released the findings at the SEJ conference on April 3, 2024.

"We've traditionally assumed that experiencing a threat will affect policy preferences," Jamieson said. "In this polarized time, on this polarized topic, that assumption holds true. People who report exposure to extreme weather are more supportive of measures to help address climate change."

Jamieson also announced that APPC, now celebrating its 30th anniversary, is marking the occasion with the creation of a Climate Communication division, led by Annenberg School for Communication vice dean and professor Emily Falk, who heads a communication neuroscience lab at Penn. The new climate division joins APPC's Communication Science and Institutions of Democracy divisions, which are headed, respectively, by Penn Integrates Knowledge Professor Dolores Albarracín and political science Professor Matt Levendusky.

"This moves the policy center into an important new area in which communication plays a crucial role," Jamieson said.

Experiencing extreme weather

APPC's survey, the 17th wave of a nationally representative panel of 1,538 U.S. adults, finds that millions of Americans report that extreme weather has affected their daily lives over the past year (subtotals may not add due to rounding):

•     Temperature: Over 4 in 10 (45%) say temperatures in their local area were warmer than usual last summer.
•     Heat: Two-thirds (68%) say extreme outdoor heat either sometimes (34%), often (19%), or frequently (16%) affected their typical daily activities.
•     Smoke: Half (50%) say poor air quality resulting from wildfire smoke either sometimes (31%), often (12%), or frequently (7%) affected their typical daily activities.
•     Flooding: 29% say flooding produced by unusual levels of rain either sometimes (20%), often (6%), or frequently (3%) affected their typical daily activities.
•     Tornado/hurricane: 19% said a tornado or hurricane either sometimes (13%), often (4%), or frequently (1%), affected their typical daily activities.

Support for pro-environment measures

More than half of Americans strongly or somewhat favor a series of government steps designed to mitigate the effects of climate change. Although these steps were not identified as such in the survey, these measures are contained in the Inflation Reduction Act of 2022, which was passed by the 117th Congress and signed into law by President Joe Biden on Aug. 16, 2022.

Support for these government initiatives varied widely by party affiliation and was driven by Democrats, who expressed strong support for all. Support by Republicans was much weaker.

In these findings, "favor" includes strongly favor and somewhat favor. The survey found that:

•     62% favor increased investment in energy-efficient public transit.
•         86% Democrats, 44% independents, 42% Republicans
•     62% favor tax credits for rooftop solar or battery storage.
•         80% Democrats, 52% independents, 46% Republicans
•     60% favor community grants to protect against impacts of climate change.
•         85% Democrats, 50% independents, 36% Republicans
•     57% favor forgivable loans for rural communities improving energy efficiency.
•         78% Democrats, 43% independents, 38% Republicans
•     56% favor taxing corporations based on carbon emissions to reduce climate change.
•         81% Democrats, 41% independents, 33% Republicans
•     46% favor tax credits for electric cars.
•         71% Democrats, 29% independents, 26% Republicans

The initiative that garnered the most support ("strongly favor") was community grants to protect against impacts of climate change (27%). The initiative that had the greatest opposition ("strongly oppose") was tax credits for electric cars (18%). The policy with the strongest Democratic support was energy-efficient public transit (86%), while the one with the strongest Republican support was tax credits for rooftop solar or battery storage (46%).

Extreme weather exposure associated with policy support

A regression analysis of the survey data by APPC research analyst Shawn Patterson Jr. finds that reported exposure to extreme weather is associated with greater support for policies that address the effects of climate change. This support extends to both parties -- Republicans who report experiencing extreme weather are more supportive of these policies than those who do not, and the same holds true for Democrats.

Read more at Science Daily

Paper provides a clearer picture of severe hydro hazards

Over the last two decades an estimated three billion people have been affected by water-related natural disasters such as droughts and floods. Climate change is expected to increase the frequency of these hydro hazards, with some prognosticators estimating there will be upwards of $3.7 trillion in water-related damage over the next 30 years in the U.S. alone. Beyond damaging homes and infrastructure, severe wet and dry spells will also devastate crops and deplete water reservoirs.

An increasing area of interest to researchers is the frequency of compound drought and pluvial flooding (caused by quick, heavy rainfall or sustained rainfall beyond the norm), which is when both occur in succession in the same area within a year of each other.

Historically, this level of coincidence has been under-examined.

Of similar interest is when the reverse happens: extreme rainfall followed by a meteorological drought.

Meteorological drought is when dry weather patterns prevail, which can eventually trigger hydrological drought, leading to dry streams and plunging reservoir levels, such as what happened at Lake Mead in 2022.

A new study co-authored by researchers in the University of Arkansas Department of Geosciences, as well as colleagues in China, now provides a global examination of drought-pluvial volatility -- or the tendency to shift from one extreme to another (from dry to wet or wet to dry) in a short period of time.

Yichan Li, a Ph.D. candidate at the U of A, was the first of four authors on the paper, "Observational Uncertainty for Global Drought-Pluvial Volatility," published in Water Resources Research, while Linyin Cheng, an assistant professor of geosciences, was second author.

The study looks at extreme dry-to-wet and wet-to-dry transitions over the past seven decades through event coincidence analysis, a method of quantifying the number of consecutive extreme events that also considers instantaneous or lagged responses within an uncertain period between them.

The study used three widely used climate data sets to provide evidence of increased drought-pluvial volatility on time scales of less than a year.

The team also evaluated the accuracy of these data sets, finding varying strengths and weaknesses of each due to observational uncertainties in data collection.

For instance, the remoteness of a region may play a role in collecting accurate data.

Averaged out at the global scale, the team found that 15.46% of all meteorological droughts were succeeded by a pluvial the following season.

The wet-to-dry transition percentage proved remarkably similar: 15.49%. However, prominent differences exist when looking at particular regions.

Toward that end, the study provides a map demonstrating how incidents of these two phenomena are distributed globally.

Overall, the spatial pattern of extreme dry-to-wet and wet-to-dry events' coincidence rates is largely in agreement among the three data sets, though there is prominent regional variability.

For instance, in Eurasia since the mid-20th century, there is a relatively low probability for meteorological droughts transitioning to pluvials, but a higher chance for the opposite scenario, rapid shifts from wet to dry events.

A similar pattern also exists over western North America, which sees severe wet to dry transitions at a frequency greater than 17% on average.

Conversely, South Asia and Australia are more prone to immediate transitions from meteorological droughts to pluvials.

The authors noted: "Our findings indicate that differences associated with drought-pluvial volatility among the considered observations are in many regions larger than that of their single events [droughts or pluvials alone], highlighting a need of to use multiple independent observation-based data sets for more robust examinations when studying such compound extreme events."

Ultimately, the authors stress the need to use multiple independent observation-based data sets when analyzing extreme, compound dry-to-wet events.

This will provide clearer guidelines for climate-related decision making, especially water resources planning, as well as ensure better accuracy when modeling future weather events.

Read more at Science Daily

'Biodiversity time machine' provides insights into a century of loss

Scientists have run the first proof of concept of their DNA 'time machine' to shed light on a century of environmental change in a freshwater lake -- including warming temperatures and pollution, leading to the potentially irreversible loss of biodiversity.

Their approach, which uses AI applied to DNA-based biodiversity, climate variables and pollution, could help regulators to protect the planet's existing biodiversity levels, or even improve them.

Researchers from the University of Birmingham, in collaboration with Goethe University in Frankfurt, used sediment from the bottom of a lake in Denmark to reconstruct a 100-year-old library of biodiversity, chemical pollution, and climate change levels. This lake has a history of well-documented shifts in water quality, making it a perfect natural experiment for testing the biodiversity time machine.

Publishing their findings today (7 Nov) in eLife, the experts reveal that the sediment holds a continuous record of biological and environmental signals that have changed over time -- from (semi)pristine environments at the start of the industrial revolution to the present.

The team used environmental DNA -- genetic material left behind by plants, animals, and bacteria -- to build a picture of the entire freshwater community. Assisted by AI, they analysed the information, in conjunction with climate and pollution data, to identify what could explain the historic loss of species that lived in the lake.

Principal investigator Luisa Orsini, Professor of Evolutionary Systems Biology and Environmental Omics at the University of Birmingham and Fellow of the Alan Turing Institute, explained: "We took a sediment core from the bottom of the lake and used biological data within that sediment like a time machine -- looking back in time to build a detailed picture of biodiversity over the last century at yearly resolution. By analysing biological data with climate change data and pollution levels we can identify the factors having the biggest impact on biodiversity.

"Protecting every species without impacting human production is unrealistic, but using AI we can prioritise the conservation of species that deliver ecosystem services. At the same time, we can identify the top pollutants, guiding regulation of chemical compounds with the most adverse effect. These actions can help us not only to preserve the biodiversity we have today, but potentially to improve biodiversity recovery. Biodiversity sustains many ecosystem services that we all benefit from. Protecting biodiversity mean protecting these services."

The researchers found that pollutants such as insecticides and fungicides, alongside increases in minimum temperature (a 1.2-1.5-degree increase) caused the most damage to biodiversity levels.

However, the DNA present in the sediment also showed that over the last 20 years the lake had begun to recover. Water quality improved as agricultural land use declined in the area surrounding the lake. Yet, whereas the overall biodiversity increased, the communities were not the same as in the (semi)pristine phase. This is concerning as different species can deliver different ecosystem services, and therefore their inability to return to a particular site can prevent the reinstatement of specific services.

Niamh Eastwood, lead author and PhD student at the University of Birmingham said: "The biodiversity loss caused by this pollution and the warming water temperature is potentially irreversible. The species found in the lake 100 years ago that have been lost will not all be able to return. It is not possible to restore the lake to its original pristine state, even though the lake is recovering. This research shows that if we fail to protect biodiversity, much of it could be lost forever."

Dr Jiarui Zhou, co-lead author and Assistant Professor in Environmental Bioinformatics at the University of Birmingham, said: "Learning from the past, our holistic models can help us to predict the likely loss of biodiversity under a 'business as usual' and other pollution scenarios. We have demonstrated the value of AI-based approaches for understanding historic drivers of biodiversity loss. As new data becomes available, more sophisticated AI models can be used to further improve our predictions of the causes of biodiversity loss."

Read more at Science Daily

Our favorite vintages and their precarious mountainside homes are at risk due to climate change, environmental scientists warn

Tucked into the hillsides of Italy, Portugal, and Spain, some of the world's most famous -- and most difficult to maintain -- vineyards are heralded for their unique flavor profiles and centuries of tradition. But as extreme weather and changing socioeconomic conditions make this so-called "heroic viticulture" even more challenging, scientists worry these grapes and their cultural histories are at risk. In a Backstory publishing on July 14 in the journal iScience, researchers argue that farmers and scientists must work together to protect some of the world's most celebrated wines.

"The risk is not only losing an agricultural product or seeing a landscape change, negatively impacting the local economy," write the authors from the University of Padova. "The risk is losing entire communities' history and their cultural roots."

Vineyards are considered "heroic viticulture" sites if they have a slope steeper than 30 percent, are located on small islands or at an altitude higher than 500 meters above sea level, or if they incorporate vines grown on terraces. The name "heroic" originated from the inherent difficulty of cultivating and harvesting crops in these landscapes. Some of the most famous, centuries-old examples of heroic viticulture include the Prosecco Hills of Conegliano and Valdobbiadene and the traditional vineyards of Pantelleria Island, both of which are protected by UNESCO.

"The great effort required to manage these areas reinforces the specific human-environment connection," write the authors. "This is why they are recognized as cultural uniquenesses of primary historical and social importance, where traditional knowledge is still the determining element."

In the Backstory, the authors list soil degradation and drought as the biggest climate change-related risks to heroic viticulture. They also argue that the vineyards face several significant socioeconomic barriers.

"The last half past century has been characterized by rural exodus and a gradual abandonment of mountain landscapes," the authors write. "The new generation is unwilling to continue working under extreme conditions if economic benefits are insignificant."

In order to protect heroic viticulture sites, the authors suggest several forms of potential solutions, from strategic communications designed to unite scientists, farmers, and consumers to onsite solutions like small water storage systems integrated into the vineyard landscapes that prevent runoff and retain water for future usage. They also underline the importance of education, including "educating the new generation about the benefits of rural reality, the need to preserve cultural heritage, live in equilibrium with the environment, and to have a sustainable approach to agriculture."

Read more at Science Daily

Three things to know: Climate change's impact on extreme-weather events

In an article published in the Proceedings of the National Academy of Sciences, Michael Mann, professor in the Department of Earth and Environmental Science in the University of Pennsylvania's School of Arts & Sciences, and colleagues from Clemson University, the University of California Los Angeles, and Columbia University investigate the effects of climate change on exacerbating compounding heat and drought situations.

Their findings offer new insights into predicting their interplay, which will provide scientists and policymakers with a clearer and more holistic approach to preventing and preparing for extreme-weather events.

"We wanted to see how the state-of-the-art climate models used in the most recent assessment reports of the Intergovernmental Panel on Climate Change address the episodes of heat waves and droughts that have given rise to some of the worst wildfires we've witnessed in recent history," Mann says.

"We also wanted to get a better understanding of how often these events were occurring, their typical durations, and their intensity to improve not only our forecasting but approaches to mitigating further damage to human life."

Compound drought and heat wave events and their effects

The researchers document the deleterious effects of increasingly severe droughts and wildfires occurring in the past three years.

"Two standout events," Mann says, "were the 2020 California wildfires and the 2019-20 Australian bush fire season, which lasted nearly one whole year and came to be known as the Black Summer. These are known as compound drought and heat wave (CDHW) events and refer to situations wherein a region experiences both prolonged hot temperatures and a shortage of water."

These conditions can occur together and worsen each other's impacts, the researchers say, and could potentially lead to heat-related illnesses and deaths, water scarcity for drinking and agriculture, reduced crop yields, increased wildfire risk, and ecological stress. They also note that anthropogenic climate change -- climate change that is driven by human activity -- can contribute to the frequency and severity of these events.

Projected impact of a worst-case versus moderate-case scenario

The researchers compared two contrasting socioeconomic pathways: the high-end or worst-case scenario, wherein society fails to mitigate the effects of anthropogenic climate change, and a moderate scenario, wherein some conservative measures are put in place and efforts are made to abide by them.

In the worst-case scenario, they found that by the late 21st century approximately 20% of global land areas are expected to witness approximately two CDHW events per year. These events could last for around 25 days and a fourfold increase in severity.

"Comparatively, the average CDHW frequency over the recent observed reference period was approximately 1.2 events per year, lasting less than 10 days, with far less severity," Mann says.

The most vulnerable geographical regions, such as eastern North America, southeastern South America, Central Europe, East Africa, Central Asia, and northern Australia, are projected to experience the largest increases in CDHW frequency by the end of the 21st century.

"Interestingly, places like Philadelphia and some of the regions in the eastern U.S. are where we expect to see an increase in these sorts of events; urban environments in the summertime will witness the highest relative frequency of these events," Mann says.

Critical need for proactive measures

The researchers emphasize the profound threat posed by more frequent and intense CDHW events in the coming decades and the dependence the emissions pathway chosen has on the severity of these events.

As climate change continues to unfold, addressing the escalating risks associated with CDHW events becomes crucial. This study contributes to the growing understanding of the projected changes in CDHWs and highlights the need for proactive measures, including emission reductions and adaptation strategies, to build resilience and safeguard vulnerable regions from the impacts of compound drought and heat wave events.

"Our findings provide important scientific context for the record heat and wildfire that we're witnessing right now here in the United States," Mann says.

"They underscore that we need to get off fossil fuels as quickly as possible to prevent a worsening of these dangerous combinations of heat and drought."

Read more at Science Daily

Weather anomalies are keeping insects active longer

As Earth's climate continues to warm due to the emission of greenhouse gasses, extreme and anomalous weather events are becoming more common. But predicting and analyzing the effects of what is, by definition, an anomaly can be tricky.

Scientists say museum specimens can help. In the first study of its kind, researchers at the University of Florida used natural history specimens to show that unseasonably warm and cold days can prolong the active period of moths and butterflies by nearly a month.

"The results are not at all what we expected," said lead author Robert Guralnick, curator of biodiversity informatics at the Florida Museum of Natural History.

Most studies view climate change and its consequences through a periscope of average temperature increases. As temperature goes up over time, the plants and animals in a particular region become active earlier in the spring, delay dormancy until later in the fall and slowly shift their ranges to align with the climate in which they're best suited to survive.

Erratic weather adds a layer of complexity to these patterns, with unknown consequences that erect an opaque screen ahead of scientists attempting to predict the future of global ecosystems.

"There had been hints in the scientific literature that weather anomalies can have cumulative effects on ecosystems, but there wasn't anything that directly addressed this question at a broad scale," Guralnick said.

This omission, he explained, was due primarily to a lack of sufficient data. While climate data has been reliably collected in many areas of the world for more than a century, records documenting the location and activity of organisms are harder to come by.

Natural history museums have been increasingly regarded as a potential solution. The oldest museums have accumulated specimens for hundreds of years, and recent efforts to digitize collections have made their contents widely available. But digital museum records come with their own unique pitfalls and drawbacks.

In 2022, study co-author Michael Belitz constructed a dataset of moths and butterflies from museum collections to chart a course for other researchers hoping to use similar data. The result was a comprehensive instruction manual for how to gather, organize and analyze information from natural history specimens.

With this robust resource at their disposal, Belitz and his colleagues wanted to see if they could detect a signal from aberrant weather patterns. Restricting their analyses to the eastern United States, the authors used records for 139 moth and butterfly species collected from the 1940s through the 2010s.

Their results were unequivocal: Unusually warm and cold weather has significantly altered insect activity to a greater extent than the average increase in global temperature for the last several decades.

The location and timing of extreme weather events influenced how insects responded. In higher latitudes, warm days in winter meant moths and butterflies became active earlier in the spring. Unusually cold days kept insects at all latitudes active longer, and the combination of exceptionally high and low temperatures had the strongest effect.

"If you have a succession of abnormally cold and warm days, it limits the ability of insects to function at peak performance," Guralnick said. "If cold doesn't kill you, it slows you down, and it might force insects into a torpor. Insects can recover from the cold snaps pretty quickly and go on to have longer lifespans as a direct result of sudden temperature declines."

Insects being active for longer periods of time might initially seem like a good thing. But rather than a counterweight to the negative repercussions of climate change, co-author Lindsay Campbell -- who studies mosquitos -- points out that longer or altered insect lifespans may also mean more opportunities for pathogen transmission.

"There's a correlation between El Niño and rift valley fever outbreaks in East Africa, and there are anecdotal observations that show unusually warm or hot and dry springs, followed by a heavy precipitation event, are also linked with increased outbreaks," said Campbell, an assistant professor at the University of Florida.

Long-term ecosystem stability is also entirely dependent on the synchronized activity of its constituent parts, and plants may not respond to extreme weather in the same way as insects. If moths and butterflies take flight too early, they risk encountering plants that haven't yet produced leaves or flowers, expending their energy in a vain search for food.

And with a constantly shifting baseline for what constitutes 'extreme,' it's unclear if insects will be able to keep pace with the changes.

Read more at Science Daily

Cities will need more resilient electricity networks to cope with extreme weather

Dense urban areas amplify the effects of higher temperatures, due to the phenomenon of heat islands in cities. This makes cities more vulnerable to extreme climate events. Large investments in the electricity network will be necessary to cool us down during heatwaves and keep us warm during cold snaps, according to a new study led by Lund University in Sweden.

"Unless we account for extreme climate events and continued urbanisation, the reliability of electricity supply will fall by up to 30%. An additional outlay of 20-60 per cent will be required during the energy transition in order to guarantee that cities can cope with different kinds of climate," says Vahid Nik, Professor of Building Physics at Lund University and one of the authors of the article in Nature Energy.

The study presents a modelling platform that ties together climate, building and energy system models in order to facilitate simulation and evaluation of cities' energy transition. The aim is to secure the cities' resilience against future climate changes at the same time as densification of urban areas is taking place. In particular, researchers have looked closely at extreme weather events (e.g. heatwaves and cold snaps) by producing simulations of urban microclimates.

"Our results show that high density areas give rise to a phenomenon called urban heat islands, which make cities more vulnerable to the effects of extreme climate events, particularly in southern Europe. For example, the outdoor temperature can rise by 17% while the wind speed falls by 61%. Urban densification -- a recommended development strategy in order to reach the UN's energy and climate goals -- could make the electricity network more vulnerable. This must be taken into consideration when designing urban energy systems, says Kavan Javanroodi, Assistant Professor in Building and Urban Physics.

"The framework we have developed connects future climate models to buildings and energy systems at city level, taking the urban microclimate into account. For the first time, we are getting to grips with several challenges around the issues of future climate uncertainty and extreme weather situations, focussing in particular on what are known as 'HILP' or High Impact Low Probability events," says Vahid Nik.

There is still a large gap between future climate modelling and building and energy analyses and their links to one another. According to Vahid Nik, the model now being developed makes a great contribution to closing that gap.

"Our results answer questions like 'how big an effect will extreme weather events have in the future, given the predicted pace of urbanisation and several different future climate scenarios?', 'how do we take them and the connections between them into account?' and 'how does the nature of urban development contribute to exacerbating or mitigating the effects of extreme events at regional and municipal level?' "

The results show that the peaks in demand in the energy system increase more than previously thought when extreme microclimates are taken into account, for example with an increase in cooling demand for 68% in Stockholm and 43% in Madrid on the hottest day of the year. Not considering this can lead to incorrect estimates of cities' energy requirements, which can turn into power shortage and even blackouts.

"There is a marked deviation between the heat and cooling requirements shown in today's urban climate models, compared to the outcomes of our calculations when urban morphology, the physical design of the city, is more complex. For example, if we fail to take into account the urban climate in Madrid, we could underestimate the need for cooling by around 28%," says Kavan Javanroodi.

Vahid Nik explains that an increasing number of countries have become interested in extreme weather events, energy issues and the impact on public health. At the same time, there are no methods of quantifying the effects of climate change and planning for adapting to them, especially when it comes to extreme weather events and climate variations across space and time.

Read more at Science Daily

Researchers correlate Arctic warming to extreme winter weather in midlatitude and its future

A warmer Arctic has been linked to extreme winter weather in the midlatitude regions. But, it is not clear how global warming affects this link. In a new study, researchers from Korea and USA show, using weather data and climate models, that while the "Warm Arctic-Cold Continent" pattern will continue as the climate continues to warm, Arctic warming will become a less reliable predictor of extreme winter weather in the future.

Pictures of melting glaciers and stranded polar bears on shrinking sea ice in the Arctic are perhaps the most striking images that have been used to highlights the effects of global warming. However, they do not convey the full extent of the consequences of warmer Arctic. In recent years, there has been growing recognition of the Arctic's role in driving extreme weather events in other parts of the world. While the Arctic has been warming at a rate twice as fast as the global average, winters in the midlatitude regions have experienced colder and more severe weather events. For instance, the winter of 2022-2023 saw record-breaking cold temperatures and snowfall in Japan, China, and Korea. Similarly, many parts of Eurasia and North America have experienced severe cold snaps, with heavy snowfall and prolonged periods of sub-zero temperatures.

While there are multiple theories for this climate phenomenon, an international team of researchers led by Professor Jin-Ho Yoon from Gwangju Institute of Science and Technology (GIST), Korea set out to examine the relationship between the severe winters in the Northern Hemisphere and the melting sea ice in the Arctic region, a phenomenon referred to as the "Warm Arctic-Cold Continent" (WACC), and how this relationship changed with the warming climate.

In their study published online on 27 March 2023 in the journal npj Climate and Atmospheric Science, the researchers looked at historic climate data and turned to climate projection models to explore the potential connection and assess how this phenomenon might be influenced by different global warming scenarios.

Based on the climate data from the European Center for Medium-Range Weather Forecasting (ECMWF) going back almost 40 years, the researchers correlated winter temperatures in East Asia and North America to the temperatures of the Barents-Kara Sea and the East Siberian-Chukchi Sea in the Arctic region. They observed that lower winter temperatures in East Asia and North America are usually accompanied by warmer Arctic Sea temperatures. However, they also found that in some winters, such as the 2017/18 winter in East Asia, this pattern did not hold, suggesting that this linkage include uncertainty likely due to factors other than Arctic Sea temperatures were at play.

Nonetheless, using climate projections from the Half degree Additional warming, Prognosis and Projected Impacts (HAPPI) experiments which were targeted to project future climate under 1.5°C to 2°C warming scenarios, the researchers found the WACC pattern to persist even when global temperatures rose. However, they found that the correlation between the Arctic Sea temperature and the East Asia temperatures became more uncertain with the intensification of global warming. "We found that the relationship between Arctic warming and cold weather events in midlatitude would become more uncertain under warmer climates, challenging the forecast of winter temperature in the future," says Mr. Yungi Hong, a Ph.D. student at GIST and a member of the research team.

"Our study shows that while one can expect the Arctic warming-triggered cold waves in the midlatitudes to persist in a warmer future, they will become more difficult to predict," adds Prof. Jin-Ho Yoon.

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Honey bee colony loss in the U.S. linked to mites, extreme weather, pesticides

About one-third of the food eaten by Americans comes from crops pollinated by honey bees, yet the insect is dying off at alarming rates. In one year alone, between April of 2019 and April of 2020, one study reported a 43% colony loss in honey bees across the United States.

A new study led by Penn State researchers provides preliminary insight on the potential effects of several variables, including some linked to climate change, on honey bees. Their findings show that honey bee colony loss in the U.S. over the last five years is primarily related to the presence of parasitic mites, extreme weather events, nearby pesticides, as well as challenges with overwintering, according to a new study led by Penn State researchers. The study took advantage of novel statistical methods and is the first to concurrently consider a variety of potential honey bee stressors at a national scale. The study, published online in the journal Scientific Reports, suggests several areas of concern to prioritize in beekeeping practices.

"Honey bees are vital pollinators for more than 100 species of crops in the United States, and the widespread loss of honey bee colonies is increasingly concerning," said Luca Insolia, first author of the study, a visiting graduate student in the Department of Statistics at Penn State at the time of the research, and currently a postdoctoral researcher at the University of Geneva in Switzerland. "Some previous studies have explored several potential stressors related to colony loss in a detailed way but are limited to narrow, regional areas. The one study that we know of at the national level in the United States explored only a single potential stressor. For this study, we integrated many large datasets at different spatial and temporal resolutions and used new, sophisticated statistical methods to assess several potential stressors associated with colony collapse across the U.S."

The research team, composed of statisticians, geographers, and entomologists, gathered publicly available data about honey bee colonies, land use, weather, and other potential stressors from the years 2015 to 2021. Because these data came from a variety of sources, they varied in resolution over both space and time. The weather data, for example, contained daily data points for areas only few square miles in size, but data on honey bee colonies was at the state level for a several-month period.

"In order to analyze the data all together, we had to come up with a technique to match the resolution of the various data sources," said Martina Calovi, corresponding author of the study, a postdoctoral researcher in the Department of Ecosystem Science and Management at Penn State at the time of the research, and currently an associate professor of geography at the Norwegian University of Science and Technology. "We could have just taken an average of all the weather measurements we had within a state, but that boils all the information we have into one number and loses a lot of information, especially about any extreme values. In addition to averaging weather data, we used an 'upscaling' technique to summarize the data in several different ways, which allowed us to retain more information, including about the frequency of extreme temperature and precipitation events."

The researchers used the resulting integrated resolution-matched dataset -- which they have made available for use by other researchers -- alongside sophisticated statistical modeling techniques that they developed to assess the large number of potential stressors at the same time.

The research team found that several stressors impacted honey bee colony loss at the national level, including the presence of nearby pesticides, frequent extreme weather events, and weather instability. Colony loss was also related to the presence of parasitic mites, Varroa destructor, which reproduce in honey bee colonies, weaken the bees, and potentially expose them to viruses. The researchers also found that losses typically occurred between January and March, likely related to challenges with overwintering, but that some states do not follow this pattern.

"Our results largely reinforce what regional studies have observed and confirm that regional patterns around these stressors are actually more widespread," said Insolia, a beekeeper himself. "These results also inform actions that beekeepers could take to help circumvent these stressors and protect their colonies, including treatments for the Varroa mite‚ especially in areas of weather instability. Beekeepers could also consider strategies to move their colonies to areas with high food availability or away from nearby pesticides or to provide supplementary food during certain seasons or months with frequent extreme weather events."

The researchers note that having data about beekeeping practices and colony loss at a finer resolution would allow validation of their results and a more nuanced look at honey bee stressors.

"It would be incredibly beneficial to explore beekeeping practices at a finer scale than the state level," said Calovi. "In many cases, beekeeping associations and other organizations collect this data, but it is not made available to researchers. We hope our study will help motivate more detailed data collection as well as efforts to share that data -- including from smaller organizations such as regional beekeeper associations."

The research team also found a strong relationship between colony loss and a broad category of beekeeping practices noted on a USDA survey as "other," which contained everything from hives being destroyed to food scarcity to queen failure. They noted that collecting this data in more detail and breaking up this catch-all type variable would improve their ability to connect particular stressors to colony collapse.

"A changing climate and high-profile extreme weather events like Hurricane Ian -- which threatened about 15% of the nation's bees that were in its path as well as their food sources -- are important reminders that we urgently need to better understand the stressors that are driving honey bee colony collapse and to develop strategies to mitigate them," said Francesca Chiaromonte, professor of statistics and the holder of the Lloyd and Dorothy Foehr Huck Chair in Statistics for the Life Sciences at Penn State and a senior member of the research team. "Our results highlight the role of parasitic mites, pesticide exposure, extreme weather events, and overwintering in bee colony collapse. We hope that they will help inform improved beekeeping practices and direct future data collection efforts that allow us to understand the problem at finer and finer resolutions."

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Entomologists issue warning about effects of climate change on insects

In a new scientific review, a team of 70 scientists from 19 countries warned that if no steps are taken to shield insects from the consequences of climate change, it will "drastically reduce our ability to build a sustainable future based on healthy, functional ecosystems."

Citing research from around the world, the team painted a bleak picture of the short- and long-term effects of climate change on insects, many of which have been in a state of decline for decades. Global warming and extreme weather events are already threatening some insects with extinction -- and it will only get worse if current trends continue, scientists say. Some insects will be forced to move to cooler climes to survive, while others will face impacts to their fertility, life cycle and interactions with other species.

Such drastic disruptions to ecosystems could ultimately come back to bite people, explained Anahí Espíndola, an assistant professor of entomology at the University of Maryland and one of the paper's co-authors.

"We need to realize, as humans, that we are one species out of millions of species, and there's no reason for us to assume that we're never going to go extinct," Espíndola said. "These changes to insects can affect our species in pretty drastic ways."

Insects play a central role in ecosystems by recycling nutrients and nourishing other organisms further up the food chain, including humans. In addition, much of the world's food supply depends on pollinators like bees and butterflies, and healthy ecosystems help keep the number of pests and disease-carrying insects in check.

These are just a few of the ecosystem services that could be compromised by climate change, the team of scientists cautioned. Unlike mammals, many insects are ectotherms, which means they are unable to regulate their own body temperature. Because they are so dependent on external conditions, they may respond to climate change more acutely than other animals.

One way that insects cope with climate change is by shifting their range, or permanently relocating to places with lower temperatures. According to one study cited by Espíndola and other scientists, the ranges of nearly half of all insect species will diminish by 50% or more if the planet heats up 3.2°C. If warming is limited to 1.5°C -- the goal of the global Paris Agreement on climate change -- the ranges of 6% of insects will be affected.

Espíndola, who studies the ways in which species respond to environmental changes over time, contributed to the sections of the paper that address range shifts. She explained that drastic changes to a species' range can jeopardize their genetic diversity, potentially hampering their ability to adapt and survive.

On the other hand, climate change may make some insects more pervasive -- to the detriment of human health and agriculture. Global warming is expected to expand the geographical range of some disease vectors (such as mosquitoes) and crop-eating pests.

"Many pests are actually pretty generalist, so that means they are able to feed on many different types of plants," Espíndola said. "And those are the insects that -- based on the data -- seem to be the least negatively affected by climate change."

The team noted that the effects of climate change are often compounded by other human-caused impacts, such as habitat loss, pollution and the introduction of invasive species. Combined, these stressors make it more difficult for insects to adapt to changes in their environment.

Though these effects are already being felt by insects, it is not too late to take action. The paper outlined steps that policymakers and the public can take to protect insects and their habitats. Scientists recommended "transformative action" in six areas: phasing out fossil fuels, curbing air pollutants, restoring and permanently protecting ecosystems, promoting mostly plant-based diets, moving towards a circular economy and stabilizing the global human population.

The paper's lead author, Jeffrey Harvey of the Netherlands Institute of Ecology (NIOO-KNAW) and Vrije Universiteit Amsterdam, said in a statement that urgent action is needed to protect insects and the ecosystems they support.

"Insects are tough little critters, and we should be relieved that there is still room to correct our mistakes," Harvey said. "We really need to enact policies to stabilize the global climate. In the meantime, at both government and individual levels, we can all pitch in and make urban and rural landscapes more insect-friendly."

The paper suggested ways that individuals can help, including managing public, private or urban gardens and other green spaces in a more ecologically-friendly way -- for instance, incorporating native plants into the mix and avoiding pesticides and significant changes in land usage when possible.

Read more at Science Daily

Learning about the first animals on Earth from life at the poles

The amazing survival strategies of polar marine creatures might help to explain how the first animals on Earth could have evolved earlier than the oldest fossils suggest according to new research. These first, simple and now extinct, animals might have lived through some of the most extreme, cold and icy periods the world has ever seen. The study is published in the journal Global Change Biology, published this week (12 October 2022).

The fossil record places the earliest animal life on Earth at 572-602 million years ago, just as the world came out of a huge ice age, whilst molecular studies suggest an earlier origin, up to 850 million years ago. If correct, this means that animals must have survived during a time influenced by multiple global ice ages, when the whole or large parts of the planet were encased in ice (snowball and slushball Earths), far bigger than any seen since. If animal life did arise before, or during, these extreme glacial periods it would have faced conditions like modern marine habitats found in Antarctica and the Arctic today, and required similar survival strategies.

Over millions of years, the expansion and contraction of the ice sheets during cold and warm periods has driven the evolution of Antarctica's thousands of unique animals and plant species. The same could be true for the evolution of animal life on Earth. Whilst to humans the polar regions seem like the most hostile environments to life, they are the perfect place to study the past and the potential for life in the universe beyond our planet, such as on icy moons like Europa.

Marine biologist and lead author, Dr Huw Griffiths of British Antarctic Survey (BAS), says:

"This work highlights how some animals in the polar regions are incredibly adapted to life in and around the ice, and how much they can teach us about the evolution and survival of life in the past or even on other planets.

"Whether it is animals living upside down on the underside of ice instead of the seafloor, sponges living hundreds of kilometres under thick floating ice shelves, organisms that are adapted to live in seawater colder than ?2°C, or whole communities existing in the darkness on food sources that don't require sunlight, Antarctic and Arctic life thrives in conditions that would kill humans and most other animals. But these cold and icy conditions help to drive ocean circulation, carry oxygen into the ocean depths and make these places more suitable for life."

Floating ice covers more than 19 million km2 of the seas around Antarctica and 15 million km2 of the Arctic Ocean during winter. Under possibly the most extreme snowball Earth, lasting 50 to 60 million years during the Cryogenian period (720 to 635?million years ago), the whole world (510 million km²) is believed to have been entombed in ice around a kilometre thick, but there is some evidence that this ice was thin enough at the equator to allow marine algae to survive.

"The fact that there is this huge difference in the timing of the dawn of animal life between the known fossil record and molecular clocks means that there are huge uncertainties about how and where animals evolved" says co-author Dr Emily Mitchell, palaeontologist and ecologist at the University of Cambridge. "But if animals did evolve before or during these global ice ages, they would have to contend with extreme environmental pressures, but ones that may have helped to force life to become more complex to survive."

"Just like in Antarctica during the Last Glacial Maximum (33-14 thousand years ago), the huge amounts of advancing ice would have bulldozed the shallows, making them inhospitable to life, destroying fossil evidence and forcing creatures into the deep sea. This makes the chances of finding fossils from these times less likely and sheltered areas and the deep sea the safest places for life to evolve."

Read more at Science Daily

Potential threat to heart health from extreme weather

An analysis in nearly 2.3 million Europeans has found detrimental associations between cold weather and deaths from heart disease, particularly in poor neighbourhoods. The late-breaking research is presented at ESC Congress 2022.1 Hot weather was linked with excess deaths from heart disease and stroke in patients with heart conditions.

Study author Professor Stefan Agewall of the University of Oslo, Norway said: "Climate change is leading to a rise in the average global temperature but also extreme cold in some regions. More than 70,000 excess deaths occurred across Europe during the summer of 2003 due to intense heatwaves.2 Cold weather also accounts for excess deaths and hospital admissions.3,4 Previously studies on the cardiovascular effects of heat and cold mainly used aggregated data, such as daily deaths in a city. The EXHAUSTION project used individual data, enabling us to identify vulnerable subgroups for protective interventions, thereby increasing resilience for future weather events."

The analysis included 2.28 million adults from five cohort studies conducted in Italy, Germany, the UK, Norway, and Sweden between 1994 and 2010. The average age ranged from 49.7 years to 71.7 years and the proportion of women ranged from 36.0% to 54.5%. Participants with and without cardiovascular disease at baseline were included. Data on mortality and new-onset disease were collected through death and disease registries and follow up surveys. Daily average air temperatures at participants' home addresses were collected from local weather stations or estimated using modelling of temperature data from weather stations

The relationships between temperature and cardiovascular conditions and death were analysed for all participants and in subgroups with particular characteristics. A time-stratified case-crossover study design was used where for each participant, the researchers compared the temperature on the day of the week an adverse event occurred (e.g. Monday) with the temperature on the same day of the week without an adverse event (e.g. all remaining Mondays) within the same month. Using within-participant comparisons between days in the same month eliminated the potential confounding effects of participant characteristics and time trends.

The analysis found increased risks of death from cardiovascular disease overall and ischaemic heart disease in particular, as well as an elevated risk of new-onset ischaemic heart disease, associated with cold weather. With an approximately 10°C temperature drop, from 5°C to -5°C, there was a 19% greater risk of death from cardiovascular disease (relative risk [RR] 1.19; 95% confidence interval [CI] 1.04-1.36) and a 22% elevated likelihood of death from ischaemic heart disease (RR 1.22; 95% CI 1.07-1.38). There was a 4% higher risk of new-onset ischaemic heart disease associated with an approximately 11°C temperature drop, from 2°C to -9°C (RR 1.04; 95% CI: 1.01-1.08).

Professor Agewall said: "The relationships between cold temperatures and deaths were more pronounced in men and people living in neighbourhoods with a low socioeconomic status. The links between cold and new-onset ischaemic heart disease were stronger among women and people older than 65 years."

Heat was not related to detrimental effects in the overall study population. However, temperature rises from 15°C to 24°C were associated with 25% (RR 1.25; 95% CI 1.12-1.39) and 30% (RR 1.30; 95% CI 1.10-1.53) elevated risks of death from cardiovascular disease and stroke, respectively, in people with heart disease at baseline.

Professor Agewall said: "Clinicians can use this information to provide tailored advice to those most at risk of adverse health outcomes during hot and cold days. Patients with heart conditions should stay hydrated in hot weather and adhere to advice from their cardiologist on medication use. We can all check the news for extreme heat and cold alerts and follow safety tips from local authorities."

Read more at Science Daily

Which animals can best withstand climate change?

Extreme weather such as prolonged drought and heavy rainfall is becoming more and more common as the global average temperature rises -- and it will only get worse in the coming decades. How will the planet's ecosystems respond?

"That is the big question and the background for our study," said biologist John Jackson, who, together with his biologist colleagues Christie Le Coeur from the University of Oslo and Owen Jones from University of Southern Denmark, authored a new study, published in eLife.

John Jackson is now at Oxford University but was at the University of Southern Denmark when the study was made. Owen Jones is associate professor at the Department of Biology, University of Southern Denmark.

Llama, moose and elephant

In the study, the authors analyzed data on population fluctuations from 157 mammal species from around the world and compared them with weather and climate data from the time the animal data were collected. For each species there are 10 or more years of data.

Their analysis has given them an insight into how populations of animal species have coped at times of extreme weather: Did they become more, or less, numerous? Did they have more or fewer offspring?

"We can see a clear pattern: Animals that live a long time and have few offspring are less vulnerable when extreme weather hits than animals that live for a short time and have many offspring. Examples are llamas, long-lived bats and elephants versus mice, possums and rare marsupials such as the woylie," said Owen Jones.

Less affected by extreme weather:

African elephant, Siberian tiger, chimpanzee, greater horseshoe bat, llama, vicuña, white rhinoceros, grizzly bear, American bison, klipspringer, Schreibers's bat.

More affected by extreme weather:

Azara's grass mouse, olive grass mouse, elegant fat-tailed mouse opossum, Canadian lemming, Tundra vole, Arctic fox, stoat, common shrew, woylie, arctic ground squirrel.

Quick drop -- but also quick boom

Large, long-lived animals are better able to cope with conditions like prolonged drought; their ability to survive, to reproduce and to raise their offspring is not affected to the same extent as small, short lived animals. They can, for example, invest their energy into one offspring, or simply wait for better times when conditions become challenging.

On the other hand, small short-lived rodents have more extreme population changes in the short term. In the event of a prolonged drought, for example, large parts of their food base may disappear more rapidly: insects, flowers, fruits, and they are left to starve because they have limited fat reserves.

The populations of these small mammals may also boom to take advantage when conditions improve because, in contrast to large mammals, they can produce many offspring.

Not the same as risk of extinction

"These small mammals react quickly to extreme weather, and it goes both ways. Their vulnerability to extreme weather should therefore not be equated with a risk of extinction," said John Jackson.

He also reminds us that the ability of an animal species to withstand climate change must not stand alone when assessing the species' vulnerability to extinction:

"Habitat destruction, poaching, pollution and invasive species are factors that threaten many animal species -- in many cases even more than climate change," he emphasized.

The animals we don't know much about

The researchers' study not only gives an insight into how these specific 157 mammal species react to climate changes here and now. The study can also contribute to a better general understanding of how the planet's animals will respond to ongoing climate change.

"We expect climate change to bring more extreme weather in the future. Animals will need to cope with this extreme weather as they always have. So, our analysis helps predict how different animal species might respond to future climate change based on their general characteristics -- even if we have limited data on their populations," said Owen Jones.

An example is the woylie, a rare Australian marsupial. Biologists do not know very much about this species, but because it shares a similar life style with mice -- that is, it is small, lives for a short time and reproduces quickly -- it can be predicted that it will respond to extreme weather in a similar way to mice.

Entire ecosystems will change

"In the same way, there are lots of animal species that we don't know very much about, but whose reaction we can now predict," explained John Jackson.

In this way, the researchers expect that the ability of different animal species to adapt to climate change is related to their life strategy, and this can help us predict ecological changes:

As habitat suitability changes due to climate change, species may be forced to move to new areas as old areas become inhospitable. These shifts depend on species' life strategies and can have big impacts on ecosystem function.

Read more at Science Daily

Today's heat waves feel a lot hotter than heat index implies

If you looked at the heat index during this summer's sticky heat waves and thought, "It sure feels hotter!," you may be right.

An analysis by climate scientists at the University of California, Berkeley, finds that the apparent temperature, or heat index, calculated by meteorologists and the National Weather Service (NWS) to indicate how hot it feels -- taking into account the humidity -- underestimates the perceived temperature for the most sweltering days we're now experiencing, sometimes by more than 20 degrees Fahrenheit.

The finding has implications for those who suffer through these heat waves, since the heat index is a measure of how the body deals with heat when the humidity is high, and sweating becomes less effective at cooling us down. Sweating and flushing, where blood is diverted to capillaries close to the skin to dissipate heat, plus shedding clothes, are the main ways humans adapt to hot temperatures.

A higher heat index means that the human body is more stressed during these heat waves than public health officials may realize, the researchers say. The NWS currently considers a heat index above 103 to be dangerous, and above 125 to be extremely dangerous.

"Most of the time, the heat index that the National Weather Service is giving you is just the right value. It's only in these extreme cases where they're getting the wrong number," said David Romps, UC Berkeley professor of earth and planetary science. "Where it matters is when you start to map the heat index back onto physiological states and you realize, oh, these people are being stressed to a condition of very elevated skin blood flow where the body is coming close to running out of tricks for compensating for this kind of heat and humidity. So, we're closer to that edge than we thought we were before."

Romps and graduate student Yi-Chuan Lu detailed their analysis in a paper accepted by the journal Environmental Research Letters and posted online Aug. 12.

The heat index was devised in 1979 by a textile physicist, Robert Steadman, who created simple equations to calculate what he called the relative "sultriness" of warm and humid, as well as hot and arid, conditions during the summer. He saw it as a complement to the wind chill factor commonly used in the winter to estimate how cold it feels.

His model took into account how humans regulate their internal temperature to achieve thermal comfort under different external conditions of temperature and humidity -- by consciously changing the thickness of clothing or unconsciously adjusting respiration, perspiration and blood flow from the body's core to the skin.

In his model, the apparent temperature under ideal conditions -- an average-sized person in the shade with unlimited water -- is how hot someone would feel if the relative humidity were at a comfortable level, which Steadman took to be a vapor pressure of 1,600 pascals.

For example, at 70% relative humidity and 68 F -- which is often taken as average humidity and temperature -- a person would feel like it's 68 F. But at the same humidity and 86 F, it would feel like 94 F.

The heat index has since been adopted widely in the United States, including by the NWS, as a useful indicator of people's comfort. But Steadman left the index undefined for many conditions that are now becoming increasingly common. For example, for a relative humidity of 80%, the heat index is not defined for temperatures above 88 F or below 59 F. Today, temperatures routinely rise above 90 F for weeks at a time in some areas, including the Midwest and Southeast.

To account for these gaps in Steadman's chart, meteorologists extrapolated into these areas to get numbers that, Romps said, are correct most of the time, but not based on any understanding of human physiology.

"There's no scientific basis for these numbers," Romps said.

He and Lu set out to extend Steadman's work so that the heat index is accurate at all temperatures and all humidities between zero and 100%.

"The original table had a very short range of temperature and humidity and then a blank region where Steadman said the human model failed," Lu said. "Steadman had the right physics. Our aim was to extend it to all temperatures so that we have a more accurate formula."

One condition under which Steadman's model breaks down is when people perspire so much that sweat pools on the skin. At that point, his model incorrectly had the relative humidity at the skin surface exceeding 100%, which is physically impossible.

"It was at that point where this model seems to break, but it's just the model telling him, hey, let sweat drip off the skin. That's all it was," Romps said. "Just let the sweat drop off the skin."

That and a few other tweaks to Steadman's equations yielded an extended heat index that agrees with the old heat index 99.99% of the time, Romps said, but also accurately represents the apparent temperature for regimes outside those Steadman originally calculated. When he originally published his apparent temperature scale, he considered these regimes too rare to worry about, but high temperatures and humidities are becoming increasingly common because of climate change.

Romps and Lu published the revised heat index equation earlier this year. In the most recent paper, they apply the extended heat index to the top 100 heat waves that occurred between 1984 and 2020. The researchers find mostly minor disagreements with what the NWS reported at the time, but also some extreme situations where the NWS heat index was way off.

One surprise was that seven of the 10 most physiologically stressful heat waves over that time period were in the Midwest -- mostly in Illinois, Iowa and Missouri -- not the Southeast, as meteorologists assumed. The largest discrepancies between the NWS heat index and the extended heat index were seen in a wide swath, from the Great Lakes south to Louisiana.

During the July 1995 heat wave in Chicago, for example, which killed at least 465 people, the maximum heat index reported by the NWS was 135 F, when it actually felt like 154 F. The revised heat index at Midway Airport, 141 F, implies that people in the shade would have experienced blood flow to the skin that was 170% above normal. The heat index reported at the time, 124 F, implied only a 90% increase in skin blood flow. At some places during the heat wave, the extended heat index implies that people would have experienced an increase of 820% above normal skin blood flow.

"I'm no physiologist, but a lot of things happen to the body when it gets really hot," Romps said. "Diverting blood to the skin stresses the system because you're pulling blood that would otherwise be sent to internal organs and sending it to the skin to try to bring up the skin's temperature. The approximate calculation used by the NWS, and widely adopted, inadvertently downplays the health risks of severe heat waves."

Physiologically, the body starts going haywire when the skin temperature rises to equal the body's core temperature, typically taken as 98.6 F. After that, the core temperature begins to increase. The maximum sustainable core temperature is thought to be 107 F -- the threshold for heat death. For the healthiest of individuals, that threshold is reached at a heat index of 200 F.

Luckily, humidity tends to decrease as temperature increases, so Earth is unlikely to reach those conditions in the next few decades. Less extreme, though still deadly, conditions are nevertheless becoming common around the globe.

"A 200 F heat index is an upper bound of what is survivable," Romps said. "But now that we've got this model of human thermoregulation that works out at these conditions, what does it actually mean for the future habitability of the United States and the planet as a whole? There are some frightening things we are looking at."

Read more at Science Daily

Urban greening 'not a panacea' for dealing with extreme weather

Urban greening is unlikely to provide a single fix for tackling extreme weather events brought on by climate change, scientists have suggested.

A team led by researchers from Cardiff University has shown that the majority of cities around the world will not be able to reduce instances of heatwaves and flooding at the same time through the introduction of strategies such as green roofs, living walls, vegetated urban spaces and parks.

Publishing their findings today in the journal Nature Communications, the team show that the cooling or flood-reducing potential of green urban spaces depends strongly on the prevailing climate of the city in question, with flood protection likely to be more successful in arid environments, whilst a cooling effect more likely in more humid climates.

Urban areas each have unique climates that pose significant risks, even more so as climate change increases the likelihood and severity of extreme weather events in the future.

Heatwaves within our cities can be attributed to the urban heat island effect (UHI), caused by the predominance of concrete and steel that absorb and retain heat, and the lack of cooling by water evaporating from plants. Flooding is part of the urban stream syndrome (USS), whereby city structures and systems negatively affect the natural runoff of rainwater back into the environment.

To tackle these problems, a commonly proposed strategy is to implement urban greening in our cities in the form of green roofs, living walls, vegetated urban spaces or parks.

Not only can these measures reduce the UHI and USS effects in our cities, they can also support local wildlife, reduce pollution and improve the general wellbeing of local populations.

In their study, the team used global climate model outputs and weather information from 175 cities around the world spanning 15 years of daily observations, from 2000 to 2015.

This data was used in conjunction with theories taken from soil science to calculate water infiltration into soils, which act like a sponge to reduce rainwater runoff, and the evaporation of water from plants, which can induce the desired cooling effect.

"Our research found that the ability of urban greening to mitigate local flooding and excess heat is not automatic nor, in some areas, even possible," said lead author of study Dr Mark Cuthbert, from Cardiff University's School of Earth and Environmental Sciences.

"Local and regional climatic conditions significantly impact the capacity of urban soils and plant growth to simultaneously defend against flooding and extreme heating. In fact, our findings indicate that in many, possibly the majority, of global cities, urban greening will not be able to mitigate cooling and flooding at the same time."

The team also found that increasing variability in rainfall patterns due to climate change may reduce the performance of thinner green structures, such as green roofs, more quickly compared to larger greened areas with thicker soils and root systems.

They say these things must be considered by urban planners in order to find the best solution for each individual city, with a balance needed between performance, cost and viability.

"While urban greening may not be a panacea, our results show what's possible in designing the cities of the future," Dr Cuthbert concluded.

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Climate change is intensifying extremes also in the oceans

Anthropogenic climate change is becoming increasingly noticeable, in Switzerland most recently during the summer of 2021, which was marked by heavy rains and flooding. It has long been known that global warming is causing not only longer and more intense heatwaves, but also, depending on the region, more severe droughts, rains and storms. Moreover, these kinds of extreme weather events increasingly occur in combination, compounding each other.

However, there has been little research into how extreme events develop in the world's oceans. Beginning in the early 2000s, first scientific studies pointed out the significance of marine heatwaves and their impact on ecosystems. A wake-up call came in 2011 in the form of a persistent marine heatwave off the west coast of Australia that destroyed the species-rich kelp forests there. Probably the most prominent example of a marine heatwave is the "Blob," as it is known -- a giant bubble of warm water that spread in the northeast Pacific Ocean and along the US West Coast from Alaska to the equator from 2013 to 2015. It killed millions of marine birds, fish and other creatures.

Researchers at ETH Zurich, the University of Bern and the University of Tasmania used a high-resolution ocean model to analyse this extreme weather event from a new perspective. Led by Nicolas Gruber, Professor of Environmental Physics at ETH Zurich, the international team concluded that it was not solely the high water temperatures that caused the mass die-off, but probably a combination of extreme events that occurred simultaneously.

A combination of extreme events is particularly dangerous

The researchers used their model to reconstruct the Blob's development over time, and in doing so, they analysed for the first time the combination of temperature, acidity and oxygen concentration of the ocean water. Their simulations show that, at the peak of the heatwave in July 2015, extremes in acidity and low oxygen had also spread extensively throughout the affected region in the northeast Pacific.

From this, the ETH researchers concluded that what occurred off the coasts of Oregon, Washington and British Columbia was not merely a heatwave but a compound extreme event. "When marine life is confronted with multiple stressors at once, it has difficulty acclimatising," Gruber says. "For a fish species that's already living at the upper end of its optimal temperature range, an added oxygen deficiency can mean death."

That's why, in their study -- which was just published in the journal Nature -- the researchers called on the scientific community to pay greater attention to compound extreme events in the ocean. "To assess the risks of these kinds of events, we urgently need to study the chain of different environmental factors leading to such extremes more closely -- and not only in individual regions, but also at the global level," Gruber says.

Global distribution analysed for the first time

The authors of this study have already taken a first step in this direction. In addition to the Blob, they used a global climate model to investigate where and how often extreme events -- separated into heatwaves and situations involving anomalously high acidity and low oxygen -- occur and how severe they are.

To demonstrate the impact of climate change, the researchers simulated the extreme events for the period from 1861 to 2020 and compared the current situation with pre-industrial times. The results speak for themselves: globally, the number of hot days on the ocean surface each year has increased tenfold, from around 4 days to 40. The number of days on which the ocean depths are characterized by anomalously low oxygen has increased fivefold.

With regard to acidity extremes, the situation is even graver. Compared with pre-industrial times, what has now established itself is almost a permanent extreme situation. "This shows how far climate change has already advanced in the ocean," says Thomas Frölicher, Professor at the University of Bern and co-author of the study.

The researchers also show on a world map which ocean regions see the most intense extreme events -- both at the ocean surface and 200 metres below it. The spatial resolution of these events within the water column is important because this further limits the possibilities for the affected marine life to escape, as the study's authors highlight.

Huge knowledge gaps

The researchers cannot assess the ecological consequences of extreme events in detail, but one thing is clear: compared with climate change, which progresses slowly, the effect of extremes on ocean life is generally stronger. The sudden occurrence of environmental changes makes many kinds of adaptation strategies impossible.

Current model simulations can replicate the response of these ecosystems to extremes only to a limited extent -- they cannot yet do justice to the complexity of biological and ecological processes. "For example, our models are still extremely limited in their ability to distinguish between different groups of algae and zooplankton," says Meike Vogt, a senior researcher in Gruber's group. But this differentiation is important, as different species differ greatly in their ability to withstand extremes.

"We know from Swiss forests that beech trees are less drought-tolerant than, for instance, pines," Gruber says. By contrast, far too little is known at present about the marine ecosystems. "We lack broad understanding of the ecosystem structure and function in the various ocean regions. Only when we have this foundation will we be able determine the impact of climate change and extremes," Vogt says.

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