Montreal protocol is delaying first ice-free Arctic summer

When scientists discovered a hole over Antarctica in 1985, countries across the globe got together and wrote a treaty designed to protect the ozone layer, which shields the Earth -- and us -- from harmful levels of ultraviolet radiation. The resulting Montreal Protocol, the only United Nations treaty ratified by every country in the world, was signed in 1987 and entered into effect in 1989, when little was known about its impact on the global climate. Its purpose was to reduce atmospheric concentrations of ozone-depleting substances (ODSs), materials commonly used in products such as refrigerators, air conditioners, fire extinguishers, and aerosols. For more than 50 years, it has been an important mitigation treaty, affecting many aspects of the global climate.

New study shows that the treaty's impact goes as far as the Arctic

A new study led by climate researchers at Columbia Engineering and the University of Exeter demonstrates that the treaty's impact reaches all the way into the Arctic: its implementation is delaying the occurrence of the first ice-free Arctic by as much as 15 years, depending on the details of future emissions. The study was published today by PNAS.

"The first ice-free Arctic summer-with the Arctic Ocean practically free of sea ice-will be a major milestone in the process of climate change, and our findings were a surprise to us," said the study's co-author Lorenzo Polvani, Maurice Ewing and J. Lamar Worzel Professor of Geophysics in the Department of Applied Physics and Applied Mathematics and professor of earth and environmental sciences. "Our results show that the climate benefits from the Montreal Protocol are not in some faraway future: the Protocol is delaying the melting of Arctic sea ice at this very moment. That's what a successful climate treaty does: it yields measurable results within a few decades of its implementation."

Impact of ODSs

Polvani noted that the rapid melting of Arctic sea ice is the largest and clearest signal of anthropogenic climate change. Current projections indicate that the first ice-free Arctic summer will likely occur by 2050, owing largely to increasing carbon dioxide concentrations in the atmosphere. However, other powerful greenhouse gases have also contributed to Arctic sea ice loss, notably ODSs. When ODSs became strictly regulated by the Montreal Protocol In the late 1980s, their atmospheric concentrations began to decline in the mid-1990s.

Polvani and his co-author Mark England, Royal Commission for the Exhibition of 1851 Senior Research Fellow at the University of Exeter and a former PhD student with Polvani, were particularly interested in exploring the impact of ODSs because their molecules, while a lot less common in the atmosphere, are tens of thousands of times more powerful at warming the planet than carbon dioxide.

Analysis of new climate model simulations

The researchers analyzed new climate model simulations and found that the Montreal Protocol is delaying the first appearance of an ice-free Arctic summer by up to 15 years, depending on future CO2 emissions. They compared the estimated warming from ODS with and without the Montreal Protocol under two scenarios of future CO2 emissions from 1985-2050. Their results show that if the Montreal Protocol had not been enacted, the estimated global mean surface temperature would be around 0.5 °C warmer and the Arctic polar cap would be almost 1 °C warmer in 2050.

"This important climate mitigation stems entirely from the reduced greenhouse gas warming from the regulated ODSs, with the avoided stratospheric ozone losses playing no role," said England. "While ODSs aren't as abundant as other greenhouse gasses such as carbon dioxide, they can have a real impact on global warming. ODSs have particularly powerful effects in the Arctic, and they were an important driver of Arctic climate change in the second half of the 20th Century. While stopping these effects was not the primary goal of the Montreal Protocol, it has been a fantastic by-product."

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Exercise seems to protect against major brain hemorrhage

Regular physical activity and exercise may reduce bleeding in individuals with intracerebral hemorrhage, a University of Gothenburg study shows. The researchers emphasize the importance of physical activity to protect the brain.

The study, published in the journal Stroke and Vascular Neurology, analyzed data on 686 people treated for intracerebral hemorrhage at Sahlgrenska University Hospital in Gothenburg during the years 2014 to 2019.

The results are based on a retrospective analysis. Causal connections cannot be identified, but the findings are nonetheless clear: Those who reported regular physical activity had smaller hemorrhages than those who reported being inactive.

Physically active was defined as engaging in at least light physical activity, such as walking, cycling, swimming, gardening, or dancing, for at least four hours weekly.

50 percent less bleeding volume

The main author of the study is Adam Viktorisson, a PhD student in clinical neuroscience at Sahlgrenska Academy, University of Gothenburg, and doctor in general practice at Sahlgrenska University Hospital.

"We found that individuals who engage in regular physical activity had, on average, bleeding volumes that were 50 percent smaller upon arriving to the hospital. A similar connection has previously been seen in animal studies, but no prior study has demonstrated this in humans."

Everyone who comes to the hospital with a suspected intracerebral hemorrhage undergoes a computerized tomography (CT) scan of the brain. Depending on the severity of the hemorrhage, neurosurgery may be required. However, in most cases, non-surgical methods and medications are used to manage symptoms and promote patient recovery.

Intracerebral hemorrhage is the most dangerous type of stroke and can lead to life-threatening conditions. The risk of severe consequences from the hemorrhage increases with the extent of the bleeding.

"In cases of major intracerebral hemorrhages, there is a risk of increased pressure within the skull that can potentially lead to fatal outcomes" says Thomas Skoglund, associate professor of neurosurgery at the University of Gothenburg, neurosurgeon at the University Hospital, and one of the study's co-authors.

Better understanding of intracerebral hemorrhages

The findings were significant regardless of the location within the cerebrum. Physically active individuals exhibited reduced bleeding in both the deep regions of the brain, which are often associated with high blood pressure, and the surface regions, which are linked to age-related conditions like dementia.

The study creates scope for further research on intracerebral hemorrhages and physical activity. Katharina Stibrant Sunnerhagen, professor of rehabilitation medicine at the University of Gothenburg and senior consultant physician at Sahlgrenska University Hospital, oversees the study.

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Oldest architectural plans detail mysterious desert mega structures

An international team of researchers including the University of Freiburg identifies engravings in Jordan and Saudi Arabia as the oldest known scaled building plans in human history.

Although human constructions have modified natural spaces for millennia, few plans or maps predate the period of the literate civilizations of Mesopotamia and Ancient Egypt. Researchers from the French research organisation "Centre national de la recherche scientifique" (CNRS), together with Prof. Dr. Frank Preusser from the University of Freiburg, have now been able to identify engravings in Jordan and Saudi Arabia as the oldest known true-to-scale construction plans in human history. The 8,000 to 9,000-year-old engravings depict so-called desert dragons -- kilometre long prehistoric megastructures used to trap animals. "Conclusions can be drawn from the findings about the people of the time. The ability to transfer a large space to a small, two-dimensional plan represents a milestone in intelligent behaviour," explains Preusser. The results, which were published in mid-May in the scientific journal PLOS ONE, should help to understand how desert dragons were conceived and built.

Scale plans of desert dragons discovered in Jordan and Saudi Arabia

Both finds are representations of nearby desert dragons engraved with stone tools. First sighted from aircrafts in the 1920s, desert dragons, up to five kilometres long, consist of stone walls that converge in a complex bounded by pits. As archaeologists have been able to determine in recent years, they were used for large-scale trapping of wild animals. In Jordan, there are eight desert dragons in the area of Jibal al-Khasabiyeh. There, the researchers found a depiction engraved in stone that measures 80 by 32 cm, its age is about 9,000 years. At Jebel az-Zilliyat in Saudi Arabia, two visible pairs of dragons are found three and a half kilometres apart. Here, too, a scaled engraving dating back about 8,000 years was discovered with a total length of 382 cm and a width of 235 cm.

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An X-ray look at the heart of powerful quasars

Researchers have observed the X-ray emission of the most luminous quasar seen in the last 9 billion years of cosmic history, known as SMSS J114447.77-430859.3, or J1144 for short. The new perspective sheds light on the inner workings of quasars and how they interact with their environment. The research is published in Monthly Notices of the Royal Astronomical Society.

Hosted by a galaxy 9.6 billion light years away from the Earth, between the constellations of Centaurus and Hydra, J1144 is extremely powerful, shining 100,000 billion times brighter than the Sun. J1144 is much closer to Earth than other sources of the same luminosity, allowing astronomers to gain insight into the black hole powering the quasar and its surrounding environment. The study was led by Dr Elias Kammoun, a postdoctoral researcher at the Research Institute in Astrophysics and Planetology (IRAP), and Zsofi Igo, a PhD candidate at the Max Planck Institute for Extraterrestrial Physics (MPE).

Quasars are among the brightest and most distant objects in the known universe, powered by the fall of gas into a supermassive black hole. They can be described as active galactic nuclei (AGN) of very high luminosity that emit vast amounts of electromagnetic radiation observable in radio, infrared, visible, ultraviolet and X-ray wavelengths. J1144 was initially observed in visible wavelengths in 2022 by the SkyMapper Southern Survey (SMSS).

For this study, researchers combined observations from several space-based observatories: the eROSITA instrument on board the Spectrum-Roentgen-Gamma (SRG) observatory, the ESA XMM-Newton observatory, NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), and NASA's Neil Gehrels Swift observatory.

The team used the data from the four observatories to measure the temperature of the X-rays being emitted from the quasar. They found this temperature to be around 350 million Kelvin, more than 60,000 times the temperature at the surface of the Sun. The team also found that the mass of the black hole at the quasar's centre is around 10 billion times the mass of the Sun, and the rate at which it is growing to be of the order of 100 solar masses per year.

The X-ray light from this source varied on a time scale of a few days, which is not usually seen in quasars with black holes as large as the one residing in J1144. The typical timescale of variability for a black hole of this size would be on the order of months or even years. The observations also showed that while a portion of the gas is swallowed by the black hole, some gas is ejected in the form of extremely powerful winds, injecting large amounts of energy into the host galaxy.

Dr. Kammoun, lead author of the paper, says "We were very surprised that no prior X-ray observatory has ever observed this source despite its extreme power."

He adds, "Similar quasars are usually found at much larger distances, so they appear much fainter, and we see them as they were when the Universe was only 2-3 billion years old. J1144 is a very rare source as it is so luminous and much closer to Earth (although still at a huge distance!), giving us a unique glimpse of what such powerful quasars look like."

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Fossils of a saber-toothed top predator reveal a scramble for dominance leading up to 'the Great Dying'

A tiger-sized saber-toothed creature called Inostrancevia has previously only been found in Russia. But scientists have discovered its fossils in South Africa, suggesting that it migrated 7,000 miles across the supercontinent Pangaea during the world's worst mass extinction 252 million years ago. Heading to South Africa allowed it to fill a gap in a faraway ecosystem that had lost its top predators.

Two hundred and fifty-two million years ago, Earth experienced a mass extinction so devastating that it's become known as "the Great Dying." Massive volcanic eruptions triggered catastrophic climate change, killing off nine out of every ten species and eventually setting the stage for the dinosaurs. But the Great Dying was a long goodbye -- the extinction event took place over the course of up to a million years at the end of the Permian period. During that time, the fossil record shows drama and upheaval as species fought to get a foothold in their changing environments. One animal that exemplifies this instability was a tiger-sized, saber-toothed creature called Inostrancevia: a new fossil discovery suggests that Inostrancevia migrated 7,000 miles across the supercontinent Pangaea, filling a gap in a faraway ecosystem that had lost its top predators, before going extinct itself.

"All the big top predators in the late Permian in South Africa went extinct well before the end-Permian mass extinction. We learned that this vacancy in the niche was occupied, for a brief period, by Inostrancevia," says Pia Viglietti, a research scientist at the Field Museum in Chicago and a co-author of the new study in Current Biology.

The prehistoric creature looked the part of "top predator." "Inostrancevia was a gorgonopsian, a group of proto-mammals that included the first saber-toothed predators on the planet," says Viglietti. It was about the size of a tiger and likely had skin like an elephant or a rhino; while vaguely reptilian in appearance, it was part of the group of animals that includes modern mammals.

Prior to this new paper, Inostrancevia had only ever been found in Russia. But while examining the fossil record of South Africa's Karoo Basin, Viglietti's colleague Christian Kammerer identified the fossils of two large predatory animals that were different from those normally found in the region. "The fossils themselves were quite unexpected," says Viglietti. It's not clear how they made it from what's now Russia, or how long it took them to cross Pangaea and arrive in what's now South Africa. But being far from home was just one element of what made the fossils special.

"When we reviewed the ranges and ages of the other top predators normally found in the area, the rubidgeine gorgonopsians, with these Inostrancevia fossils, we found something quite exciting," she says. "The local carnivores actually went extinct quite a bit before even the main extinction that we see in the Karoo -- by the time the extinction begins in other animals, they're gone."

The arrival of Inostrancevia from 7,000 miles away and its subsequent extinction indicates that these top predators were "canaries in the coal mine" for the larger extinction event to come.

"This shows that the South African Karoo Basin continues to produce critical data for understanding the most catastrophic mass extinction in Earth's history," says co-author Jennifer Botha, director of GENUS Centre of Excellence in Palaeosciences and professor at the Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg.

"We have shown that the shift in which groups of animals occupied apex predator roles occurred four times over less than two million years around the Permian-Triassic mass extinction, which is unprecedented in the history of life on land. This underlines how extreme this crisis was, with even fundamental roles in ecosystems in extreme flux," said Christian Kammerer, the study's first author and a research curator of paleontology at the North Carolina Museum of Natural Sciences and research associate at the Field Museum.

The vulnerability of these top predators matches what we see today. "Apex predators in modern environments tend to show high extinction risk, and tend to be among the first species that are locally extirpated due to human-mediated activities such as hunting or habitat destruction," says Kammerer. "Think about wolves in Europe or tigers in Asia, species which tend to be slow to reproduce and grow and require large geographic areas to roam and hunt prey, and which are now absent from most of their historic ranges. We should expect that ancient apex predators would have had similar vulnerabilities, and would be among the species that first go extinct during mass extinction events."

In addition to shedding new light on the extinction event that helped lead to the rise of the dinosaurs, Viglietti says that the study is important for what it can teach us about the ecological disasters the planet is currently experiencing.

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Dinosaurs were the first to take the perspectives of others

When someone near you turns their head towards something in the environment, you likely can't help to follow their gaze direction. This reaction is observed in mammals, birds and even reptiles alike. It's an effective way to gather information about what caught the attention of your fellow, which you might otherwise have missed. However, a far more advanced behavior is to follow someone's gaze to a location that is initially obstructed from your view. By repositioning yourself to see what the other person is looking at, you demonstrate an understanding that the other has a different perspective. This ability, known as visual perspective taking develops in children between the ages of one-and-a-half to two years and serves as the foundation for later comprehending referential communication and that others have minds that differ from your own.

Visual perspective taking has, to date, only been found in very few species. Mainly in apes and some monkeys, but also in dogs and crow birds. However, there is limited knowledge regarding the evolutionary origins of this crucial social skill. A team of researchers from Lund University aimed to investigate a potential early emergence of visual perspective taking in dinosaurs. Through a comparison of alligators with the most primitive existing birds, known as palaeognaths, they discovered that visual perspective taking originated in the dinosaur lineage likely 60 million years, or more, prior to its appearance in mammals.

Crocodilians are the closest living relatives to birds. Their neuroanatomy has remained largely unchanged for hundreds of millions of years, and is similar to that of the common ancestor of dinosaurs and crocodilians. Palaeognath birds comprise the ostrich birds, such as emus and rheas, but also the flighted tinamous. Their brains are in large parts comparable to their forebearers, the non- avian paravian dinosaurs, which feature such celebrities as the velociraptors. Comparing these two groups of animals creates a bracket around the extinct lineage of dinosaurs leading up to modern birds.

The study revealed that alligators do not demonstrate visual perspective taking, although they do follow gaze to a visible location. In contrast, all tested bird species exhibited visual perspective taking. Additionally, the birds engaged in a behaviour called "checking back," where the observer looks back into the eyes of the gazer, and re-tracks the gaze, when unable to find anything in the direction of their gaze the first time. This behaviour indicates an expectation that the gaze is referring to a target in the environment. Previously, this has only been observed in humans, apes and monkeys, and ravens.

Palaeognath birds emerged 110 million years ago, predating the two mammal groups endowed with visual perspective taking -- primates and dogs -- with 60 million years. Considering the neuroanatomical similarities between these birds and their non-avian forebearers, it is plausible that the skill originated even earlier in the dinosaur lineage. However, it is less likely to have been present among the earliest dinosaurs, which had more alligator-like brains. Maybe future research will show the ability to be more widespread among mammals than currently known, but even if that would be the case it will most probably still be predated by the dinosaur origin. Nevertheless, it is not surprising that visual perspective taking emerged earlier in the dinosaurs, which include the birds, given their superior vision compared to most mammals, that historically relied on nocturnal adaptations. It was only with the emergence of the primates and certain carnivores that our visual capabilities improved.

This is yet another finding that calls into question the prevailing view that mammals drove the evolution of complex cognition, and that they are the cognitive yardstick to which other animals should be compared. An increasing number of studies show the remarkable neurocognition of the avian dinosaurs, the birds, which might prompt a rethinking of the natural history of cognition.

Comments from the authors:

Senior author, prof. Mathias Osvath: "Early in my career, crow birds earned the nickname "feathered apes," due to numerous research findings that showcased their remarkable cognition. However, I'm beginning to question whether it would be more fitting to consider primates as honorary birds."

First author (then PhD-student), Dr Claudia Zeiträg: "Birds are commonly being overlooked when it comes to their cognitive skills. Our findings show that they do not only have several cognitive skills on par with those of apes, but that their forebearers most likely had these skills long before they evolved in mammals."

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Humanity's earliest recorded kiss occurred in Mesopotamia 4,500 years ago

Recent research has hypothesised that the earliest evidence of human lip kissing originated in a very specific geographical location in South Asia 3,500 years ago, from where it may have spread to other regions, simultaneously accelerating the spread of the herpes simplex virus 1.

But according to Dr Troels Pank Arbøll and Dr Sophie Lund Rasmussen, who in a new article in the journal Science draw on a range of written sources from the earliest Mesopotamian societies, kissing was already a well-established practice 4,500 years ago in the Middle East. And probably much earlier, moving the earliest documentation for kissing back 1,000 years compared to what was previously acknowledged in the scientific community.

"In ancient Mesopotamia, which is the name for the early human cultures that existed between the Euphrates and Tigris rivers in present-day Iraq and Syria, people wrote in cuneiform script on clay tablets. Many thousands of these clay tablets have survived to this day, and they contain clear examples that kissing was considered a part of romantic intimacy in ancient times, just as kissing could be part of friendships and family members' relations," says Dr Troels Pank Arbøll, an expert on the history of medicine in Mesopotamia.

He continues:

"Therefore, kissing should not be regarded as a custom that originated exclusively in any single region and spread from there but rather appears to have been practiced in multiple ancient cultures over several millennia."

Dr Sophie Lund Rasmussen adds:

"In fact, research into bonobos and chimpanzees, the closest living relatives to humans, has shown that both species engage in kissing, which may suggest that the practice of kissing is a fundamental behaviour in humans, explaining why it can be found across cultures."

Kissing as potential transmitter of disease

In addition to its importance for social and sexual behaviour, the practice of kissing may have played an unintentional role in the transmission of microorganisms, potentially causing viruses to spread among humans.

However, the suggestion that the kiss may be regarded as a sudden biological trigger behind the spread of particular pathogens is more doubtful. The spread of the herpes simplex virus 1, which researchers have suggested could have been accelerated by the introduction of the kiss, is a case in point:

"There is a substantial corpus of medical texts from Mesopotamia, some of which mention a disease with symptoms reminiscent of the herpes simplex virus 1," Dr Arbøll remarks.

He adds that the ancient medical texts were influenced by a variety of cultural and religious concepts, and it therefore must be emphasized that they cannot be read at face value.

"It is nevertheless interesting to note some similarities between the disease known as bu?shanu in ancient medical texts from Mesopotamia and the symptoms caused by herpes simplex infections. The bu'shanu disease was located primarily in or around the mouth and throat, and symptoms included vesicles in or around the mouth, which is one of the dominant signs of herpes infection."

"If the practice of kissing was widespread and well-established in a range of ancient societies, the effects of kissing in terms of pathogen transmission must likely have been more or less constant," says Dr Rasmussen.

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Butterflies on the decline

Research shows that the numbers of butterflies in meadows and pastures of Europe are in a continuous decline. A new EU regulation aims to stop this trend.

Grassland butterflies will soon play an even greater role in EU nature conservation legislation. Based on the occurrences and population trends of butterflies, the member states are supposed to document the progress they have made in implementing the planned "Nature Restoration Law." The Butterfly Grassland Indicator, recently calculated for the eighth time by European foundation "Butterfly Conservation Europe," is to be used for this. This analysis, which also includes data and expertise from many volunteers in Germany -- coordinated by experts from the Helmholtz Centre for Environmental Research (UFZ) in Halle -- shows an urgent need for action. This is because the situation of grassland butterflies in Europe has deteriorated considerably since the first calculations in 1990.

The diagnosis sounds worrying: More than 80% of habitats in the EU are currently considered vulnerable. This has negative consequences on their functional capability and thus the services they provide for humans. In order to counter this, the European Commission has proposed a new set of rules. This "Nature Restoration Law" is one of the key elements of the EU Biodiversity Strategy 2030 to be published this May. It defines binding targets for the entire EU for the renaturation of various ecosystems. Two years after the regulation enters into force, member states must submit plans on how they intend to meet these targets. They must also document the success of their measures.

However, the latter is not so easy. So far, there are only a few indicators that can reliably show the state of biodiversity. For most animal and plant groups, there is a lack of comparable data across Europe from which to assess the development of populations. The few exceptions include birds, bats, and butterflies.

"Butterflies in particular are ideal bioindicators," says agricultural ecologist Prof. Dr Josef Settele from the UFZ. This is because these insects occur in a wide range of habitats and react sensitively to environmental changes. With their specific requirements, they are often representative of many other insects. Finally, they are eye-catching, attractive, and popular. It is thus relatively easy to motivate volunteers to take part in scientifically oriented butterfly counts.

Such actions are becoming increasingly popular. For example, in 2005 the UFZ and the Gesellschaft für Schmetterlingsschutz (GfS) launched a citizen science project called "Tagfaltermonitoring Deutschland" (Butterfly Monitoring Germany) in which anyone interested can participate. Since then, butterfly enthusiasts from all over Germany have been walking fixed routes from spring to autumn to record the number of individuals and species they have seen. Similar monitoring programmes now exist in most other European countries. "Around 5,000 volunteers spread all over Europe are now taking part -- all following the same protocol," says Settele.

The data are collected and analysed in the central "European Butterfly Monitoring Scheme" (eBMS) database, managed by UKCEH and mirrored at UFZ and the Dutch "Vlinderstichting." In this way, the population development of individual species can then be tracked. Common trends for the inhabitants of certain habitats can also be identified.

This is precisely the idea behind the Butterfly Grassland Indicator, which is based on the population trends of 17 typical species of meadows and pastures. If the positive and negative trends in these species roughly balance each other out, the indicator remains at the same level. If more species decline than increase in the same period, the value decreases -- and vice versa. Lower values thus indicate greater problems among grassland dwellers.

The latest results of these calculations, which include data from 1990 to 2020, therefore do not bode well. The analysis, which was also co-financed by the EU project SPRING (Strengthening Pollinator Recovery through Indicators and monitoring) coordinated by the UFZ, shows only one winner: In the 27 memberstates of the EU, only the Orange Tip (Anthocharis cardamines) displayed a moderate increase. Three species are stable: the Large Skipper (Ochlodes sylvanus), the Common Copper (Lycaena phlaeas), and the Meadow Brown (Maniola jurtina). Five species -- from the Common Blue (Polyommatus icarus) to the Wall Brown (Lasiommata megera) -- are showing declining populations. "The biggest loser in recent years has been the large blue (Phengaris arion), which for example has disappeared completely in the Netherlands," says Settele. For the remaining species of the 17 grassland inhabitants studied, there is either no clear trend or too little data.

The picture becomes even less favourable if we look not only at the EU but rather at Europe as a whole. Then there are no species on the rise and only three are stable. Six show a moderate and one even a strong decline.

In view of these developments, it is not surprising that the grassland indicator is now at a considerably lower level than before. In the last 10 years alone, the calculated value for the EU has fallen by 32% -- and that for Europe as a whole by as much as 36%. The crisis of the grassland dwellers has apparently already taken hold of the entire continent. This is becoming increasingly more evident the more information is provided by the volunteer butterfly counters from different countries. "The declines are not confined to north-western Europe," says Chris van Swaay of Butterfly Conservation Europe. "However, some species in the South and East are doing much better."

He and his colleagues attribute the dwindling butterfly occurrences mainly to changes in agriculture. In north-western Europe, for example, the over-intensive use of meadows and pastures has a particularly unfavourable effect. The heavy use of fertilisers often also pollutes adjacent protected areas with excessive amounts of nitrogen. In the rest of Europe, the main problem is the complete abandonment of cultivation. That's because grassland butterflies also cope poorly with this.

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South Africa's desert-like interior may have been more inviting to our human ancestors

Lining the Cape of South Africa and its southern coast are long chains of caves that nearly 200,000 years ago were surrounded by a lush landscape and plentiful food.

During a glacial phase that lasted between 195,000 to 123,000 years ago, these caves served as refuge to a group of humans that some researchers think were the only people to survive this ice age, called Marine Isotope Stage Six, or MIS6. And in this coastal region, a lot of archaeological research has taken place. Of less interest to archaeologists has been the interior of South Africa, which was thought to be an uninhabited, inhospitable place during at least two waves of ice ages, MIS3 and 2.

Now, a study has shown that the region might have been more fertile and temperate during these two glacial periods than previously thought, and that the region likely played host to human populations living around a series of paleolakes. The study, led by University of Michigan archaeologist Brian Stewart, provides a more comprehensive timeline of the age and stages of these lakes, and shows human fingerprints across the region. The research, funded by the National Geographic Society, is published in the journal PNAS.

"There's this perennial assumption that human population centers were always along the coast and that the interior, especially the southern interior of the Karoo Desert, were largely depopulated for long stretches of time," Stewart said. "The funny thing is that one just has to go into the interior and walk around and notice that there's archaeology everywhere."

But to flag the region as worthy of archaeological attention, the researchers needed to show that humans could have actually lived there. The research team, an international group including researchers from South Africa, the United Kingdom and France, examined a series of super flat areas of land ringed by higher ground. They showed that these regions, called "pans" in Afrikaans, are ancient lake beds, while the areas of higher elevation that encircle them are erosional landforms and sedimentary deposits left over from their ancient shorelines.

This suggests that these time periods were not as dry in this region as previously thought: there would have needed to have been sustained rainfall and humidity to keep these lakes full. The more temperate climate required to sustain lakes also meant the landscape was also able to sustain both vegetation and animals required to support human populations.

Reconstructing the paleolakes

The researchers used a variety of technologies to date and reconstruct these ancient lakes, shorelines and lake bottom deposits, and to recreate the landscape of the region.

These include radiocarbon dating and a technique called luminescence, which measures the radioactivity of tiny crystals of quartz or feldspar that haven't seen the light of day since they were covered by sediment tens of thousands of years earlier. While buried, electrons from radioactive elements common to all sediments get trapped in these crystal matrices at a constant rate. By measuring how many electrons accumulated in the sample and comparing that to the degree of background radioactivity, the researchers can predict its age.

The researchers used these techniques to date columns of sedimentary lakeshore and lake bottom deposits, called lacustrine deposits, found surrounding and within a series of three pans dotted across a region some 100,000 square miles, about the size of Texas. They also aged the shells of freshwater mollusks found scattered throughout the region and embedded within the sedimentary lake deposits.

An aquatic gastropod, Tomichia ventricosa, found at a pan called Swartkolkvloer, was embedded in a column of lacustrine deposits. Together, the deposits and shells were radiocarbon dated to two time periods: approximately 39-55 thousand years before present, and approximately 31-34 thousand years before present.

At another pan called Grootvloer, the researchers found a freshwater mollusk called Unio caffer, which required "perennial freshwater" and the presence of fish to reproduce. These shells and lacustrine deposits in this pan were dated to between approximately 20-22 thousand years before present.

The researchers were also able to predict the area of land the lakes encompassed, as well as how deep they were, based on the height of the lacustrine deposits ringing their shorelines. For example, they determined that the paleolake at Swartkolkvloer was about 83 miles square and 59 feet deep, while the paleolake at Grootvloer was likely about 17 miles square and 62 feet deep. Another pan called Alexanderfontein, some 300 miles northeast near the town of Kimberley, held a lake about 13.5 miles square and 48 feet deep.

Based on these parameters, the researchers knew the lakes would have required a climate drastically different from the one that exists in South Africa's interior today. Using a hydrological model, they determined that evaporation rates within the region were between 20% and 25% lower than what they are today, while precipitation would have been more than 200% higher at Swartkolkvloer and 88% higher at Alexanderfontein.

"In various parts of the interior, between about 60 to about 12,000 years ago, we can see that there were enduring phases of pretty large bodies of water kicking around what used to be thought of as an arid and inhospitable environment," Stewart said. "This was a period that used to be thought of as notoriously dry and freezing cold in the winter. But we've got this evidence for these large lakes existing during this time period."

The researchers say current day regions that have similar climates and rates of precipitation and evaporation are likely northern Botswana, Zambia and Zimbabwe. Based on this estimation and data found from a contemporaneous site called Equus Cave, the researchers think large grazing and browsing mammals would have thrived in this region.

A complex, prehistoric people

Scattered alongside the lakes are human artifacts such as triangular points, bladelets, weathered ostrich shells and other assemblages. Much of these are from the Middle Stone Age, which ranged from about 280,000 years ago to about 25,000 years ago, and the Later Stone Age, which lasted from 25,000 years ago right up to European contact in the 15th century.

"There's Middle Stone Age archaeology just everywhere," Stewart said. "You can't drive anywhere and open the car door and not step on it. It's astounding how much there is."

Stewart says their findings could also expand the region where archaeologists think humans became more behaviorally complex. Over the past decades, researchers have found evidence that humans living in coastal South Africa started making the leap into complex thought, showing some of the earliest signs of behavioral complexity. It was thought that both climate and nutrient stability -- including the rich omega fatty acids gleaned from seafood -- allowed humans here to become behaviorally modern.

The group's work may challenge this idea by suggesting that favorable conditions for hunter-gatherers were not confined to the coastline but probably characterized many regions as climates changed, including the interior, current-day desert.

"Ours is a basin-wide study with much more macro scale implications. It also involves some of these areas that are just inland of this coastal and mountain belt that's dominated the archaeological narratives for so long," Stewart said. "Just inland of this area is a region that has been, for a long time, portrayed as hostile, and it just simply appears not to have been the case for big chunks of time -- with the caveat that we need information on temperature depressions to understand how humans dealt with that."

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Losing sleep over losing sleep: how watching the clock impacts insomnia, use of sleep aids

Watching the clock while trying to fall asleep exacerbates insomnia and the use of sleep aids, according to research from an Indiana University professor -- and a small change could help people sleep better.

The research, led by Spencer Dawson, clinical assistant professor and associate director of clinical training in the College of Arts and Sciences' Department of Psychological and Brain Sciences, focuses on a sample of nearly 5,000 patients presenting for care at a sleep clinic.

Insomnia affects between 4 and 22% of adults and is associated with long-term health problems including cardiovascular disease, diabetes and depression.

Participants completed questionnaires about the severity of their insomnia, their use of sleep medication and the time they spent monitoring their own behavior while trying to fall asleep. They were also asked to report any psychiatric diagnoses. Researchers conducted mediation analyses to determine how the factors influenced each other.

"We found time monitoring behavior mainly has an effect on sleep medication use because it exacerbates insomnia symptoms," Dawson said. "People are concerned that they're not getting enough sleep, then they start estimating how long it will take them to fall back asleep and when they have to be up. That is not the sort of activity that's helpful in facilitating the ability to fall asleep -- the more stressed out you are, the harder time you're going to have falling asleep."

As the frustration over sleeplessness grows, people are more likely to use sleep aids in an attempt to gain control over their sleep.

The results are published in The Primary Care Companion for CNS Disorders. Additional co-authors are Dr. Barry Krakow, professor of psychiatry and behavioral health in the Mercer University School of Medicine; Patricia Haynes, associate professor in the Mel and Enid Zuckerman School of Public Health at the University of Arizona and Darlynn Rojo-Wissar, a postdoctoral fellow at Alpert Medical School of Brown University.

Dawson said the research indicates a simple behavioral intervention could provide help for those struggling with insomnia. He gives the same advice to every new patient the first time they meet.

"One thing that people could do would be to turn around or cover up their clock, ditch the smart watch, get the phone away so they're simply not checking the time," Dawson said. "There's not any place where watching the clock is particularly helpful."

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