Asian monsoon lofts ozone-depleting substances to stratosphere

Powerful monsoon winds, strengthened by a warming climate, are lofting unexpectedly large quantities of ozone-depleting substances high into the atmosphere over East Asia, new research shows.

The study, led by the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR) and NASA, found that the East Asian Monsoon delivers more than twice the concentration of very short-lived ozone-depleting substances into the upper troposphere and lower stratosphere than previously reported.

The research team drew on airborne observations taken during a major 2022 Asian field campaign: the Asian Summer Monsoon Chemistry and Climate Impact Project (ACCLIP). The findings raise questions about the pace of the recovery of the ozone layer, which shields Earth from the Sun's harmful ultraviolet radiation.

"It was a real surprise to fly through a plume with all those very short-lived ozone-depleting substances," said NSF NCAR scientist Laura Pan, the lead author of the study. "These chemicals may have a significant impact on what will happen with the ozone layer, and it's critical to quantify them."

The study was published in the Proceedings of the National Academy of Sciences. It was funded by NSF, NASA, and NOAA, and co-authored by a large team of international scientists.

The role of monsoons

For thousands of years, people have viewed the Asian summer monsoon as important because of its impacts on local communities. Recently, however, scientists analyzing satellite observations have begun discovering that monsoon storms and winds play an additional role: carrying pollutants high in the atmosphere, where they can influence the world's climate system.

ACCLIP investigated the chemical content of air that was borne by the two primary monsoons in the region -- the South and the East Asian Monsoon -- from Earth's surface to as high up as the stratosphere. Once at that altitude, the chemicals can have far-reaching climate impacts because air in the stratosphere spreads out globally and remains for months to years, unlike the lower atmosphere where air masses turn over weekly.

The ACCLIP observations revealed that the East Asian Monsoon delivered higher levels of pollutants to the upper atmosphere than the South Asian Monsoon during 2022. The scientists measured carbon monoxide levels of up to 320 parts per billion -- a remarkably high level to be found at an altitude of 15 kilometers (about 9 miles). Carbon monoxide is often a sign of industrial pollution, and the measurements indicated that the East Asian Monsoon was closely aligned with emissions of pollutants at the surface.

Pan, Elliot Atlas of the University of Miami, and their co-authors looked into a class of chemicals known as very short-lived organic chlorine compounds, which can destroy ozone but persist only for a relatively short time in the atmosphere (months to years). In contrast, ozone-depleting chlorofluorocarbons (CFCs) remain in the atmosphere for decades to centuries or more and are therefore viewed as a far more significant threat to the ozone layer.

For that reason, the landmark 1987 Montreal Protocol on Substances that Deplete the Ozone Layer focused on phasing out CFCs and other long-lived substances. The international treaty and subsequent revisions have enabled stratospheric ozone to begin recovering. A 2022 United Nations assessment concluded that the ozone layer, including an ozone hole over the Antarctic, will be largely restored over the next several decades.

The Montreal Protocol, however, did not limit the continued manufacture and use of very short-lived ozone-depleting substances. Emissions of these chemicals have soared in South and East Asia, including highly industrialized regions of East China.

In an unfortunate coincidence, those regions lie directly under the East Asian Monsoon, which, of the world's eight regional monsoons, is the one that is predicted to strengthen the most with global warming.

The combination of the monsoon's powerful updrafts occurring in the same region as the increasing emissions of short-lived chlorine compounds has resulted in the unexpectedly high quantity of the chemicals being swept into the stratosphere.

The analysis of the aircraft measurements by Pan and her co-authors revealed high levels of five short-lived chlorine compounds: dichloromethane (CH2Cl2), chloroform (CHCl3), 1,2-dichloroethane (C2H4Cl2), tetrachloroethene (C2Cl4), and 1,2-dichloropropane (C3H6Cl2).

Pan said more research is needed to analyze the potential implications for ozone recovery. The paper also notes that scientists will need to incorporate the new findings into climate models, as stratospheric ozone has complex effects on Earth's temperature.

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Conservation in Indonesia is at risk, a team of researchers who study the region argues

Indonesia, home to the largest tropical rainforest in Southeast Asia and over 17,500 islands, is a country packed with biodiversity and endangered species. However, scientists studying the region's species and ecosystems are getting banned from Indonesia and conservation plans are being blocked. In a letter publishing in the journal Current Biology on July 10, a team of conservation researchers with long-term experience in Indonesia discuss scientific suppression and other research challenges they have witnessed while working in the region. They offer suggestions for how to promote nature conservation, protect data transparency, and share research with the public in this and other regions of the world.

"If you look at a heat map of the Earth, and where endangered species are located, Indonesia and that general region are just off the charts," says tropical environmental scientist William F. Laurance of James Cook University, who has been doing research on the environmental impacts of development in Southeast Asia for over a decade.

Laurance and his co-authors say they felt drawn to raise awareness about the issues facing conservation in Indonesia because during their time working in the region, they witnessed many instances when governments and corporations impeded research -- including their own.

For example, they write in the letter, in 2022, five leading conservation researchers were banned from working in Indonesia on the premise that they had "negative intentions" to "discredit the government." The researchers reference papers about forest conservation and wildlife management in Sumatra, for which the teams had multiple colleagues from Indonesia decline co-authorship "out of concerns that it might adversely impact their funding, research permits, or opportunities for commercial contracts in Indonesia."

"The researchers said, 'Well, no, you can't tell that story, even though it's true, and you can't identify me or include all the relevant details.' And this just kept happening over and over again. It's a climate of fear," says Laurance.

To protect environmental research in Indonesia and the contributors who work on it, Laurance and his team suggest that organizations funding research in the region require data transparency for studies that they support. They also recommend the implementation and usage of online "safe houses" (whistleblower websites designed to protect anonymity and information leakage) and anonymized journals (publications in which contributors are not named). They say these interventions could help researchers get information out to the public without worrying about the consequences of being personally tied to their findings.

The authors do note that several organizations are advocating for change, especially in Indonesia. Some examples of these groups include the Indonesian Caucus for Academic Freedom and the Jakarta Legal Aid Foundation, which are organizing to support conservation and thwart efforts to silence researchers. They also note that "scientific suppression is by no means unique to Indonesia."

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Why there are no kangaroos in Bali (and no tigers in Australia)

If you travel to Bali, you won't see a cockatoo, but if you go to the neighbouring island of Lombok, you will. The situation is similar with marsupials: Australia is home to numerous marsupial species, such as the kangaroo and the koala. The further west you go, the sparser they become. While you will find just two representatives of these typically Australian mammals on the Indonesian island of Sulawesi, you will search in vain for them on neighbouring Borneo. Australia, on the other hand, is not home to mammals that you will typically find in Asia, such as bears, tigers or rhinos.

This abrupt change in the composition of the animal world already caught the eye of the British naturalist and co-discoverer of evolutionary theory Alfred Russell Wallace, who travelled through the Indo-Australian Archipelago from 1854 to 1862 to collect animals and plants. He described an (invisible) biogeographical line running between Bali and Lombok and Borneo and Sulawesi that marked the westernmost distribution of Australian fauna.

Fascinating change of wildlife

Biodiversity researchers have long been fascinated by this abrupt change of creatures along the Wallace Line. How these distribution patterns came about, however, has not yet been clarified in detail.

One explanation is plate tectonics. Forty-five million years ago, the Australian Plate began to drift northwards and slid under the mighty Eurasian Plate. This brought two land masses closer together that had previously been far apart. It became easier for land creatures to colonise one continent from the other. Tectonic movements also gave rise to the creation of countless (volcanic) islands between the two continents, which animals and plants used as stepping stones to migrate westwards or eastwards.

More Asian animals in Australia than vice versa

But why more species found their way from Asia to Australia -- countless poisonous snakes, thorny lizards (Moloch horridus), hopping mice (Notomys sp.) or flying foxes bear witness to this -- than the other way round has been a mystery until now.

In order to better understand this asymmetrical vertebrate distribution along the Wallace Line, researchers led by Loïc Pellissier, Professor of Ecosystems and Landscape Evolution at ETH Zurich, have created a new model. It combines reconstructions of the climate, plate displacements between 30 million years ago and the present day and a comprehensive data set for around 20,000 birds, mammals, reptiles and amphibians that are recorded in the region today.

Climates in areas of origin decisive

In the latest issue of Science, the researchers now show that adaptations to the climates in the areas of origin are partly responsible for the uneven distribution of Asian and Australian faunal representatives on both sides of the Wallace Line.

In addition to plate tectonics, the environmental conditions that prevailed millions of years ago were decisive for the exchange between the two continents. Based on simulations, the researchers found that animals originating from Asia were more likely to "hop" across the Indonesian islands to reach New Guinea and northern Australia.

These islands featured a tropically humid climate, which they were comfortable with and had already adapted to. The Australian wildlife was different, having evolved in a cooler climate that had become increasingly drier over time, and was therefore less successful in gaining a foothold on the tropical islands than the fauna migrating from Asia.

The Asian climate thus favoured creatures that reached Australia via the tropical islands of the faunal region known as Wallacea, especially those that could tolerate a wide range of climates. This made it easier for them to settle on the new continent. "The historical context is crucial for understanding the biodiversity distribution patterns observed today and was the missing piece of the puzzle explaining the enigma of Wallace's line," says first author Alexander Skeels, a postdoctoral researcher in Pellissier's group.

Competitive advantages for tropical species

Traits of species that evolved in tropical habitats include faster growth and higher competitiveness to enable them to withstand the pressure of coexistence with many other species. In harsher climates, such as the colder and drier regions of Australia, organisms usually have to evolve special adaptations to cope with drought and heat stress. These include behavioural adaptations such as nocturnal activity and physiological adaptations to minimise water loss. "Many Australian frogs bury themselves in the ground and remain dormant for long periods for this reason," Skeels points out. "Something that is rare in tropical frogs."

The findings are important for the researchers: "They make it clear that we can only understand today's distribution patterns of biodiversity if we include the geological development and climatic conditions of prehistoric times in our considerations," says Pellissier.

The heritage of long past epochs has shaped the patterns of biodiversity right up to the present. It also helps us to understand why more species are found in the tropics today than in temperate latitudes. "To fully understand the distribution of biodiversity and the processes that maintain it in the present, we need to find out how it came about," says the researcher.

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New species of stegosaur is oldest discovered in Asia, and possibly the world

Relatively small, but fearsome-looking stegosaur measured about 2.8 metres (9 feet) from nose to tail -- but scientists can't tell whether the remains are those of an adult or juvenile.

A new species of one of the most recognisable types of dinosaur is the oldest stegosaur ever found in Asia, and one of the earliest unearthed anywhere in the world, according to research published today in the peer-reviewed Journal of Vertebrate Paleontology.

Remains of the stegosaur, which included bones from the back, shoulder, thigh, feet, and ribs, as well as several armour plates, date to the Bajocian stage of the Middle Jurassic period -- much earlier than most known stegosaurs.

A team from the Chongqing Bureau of Geological and Mineral Resource Exploration and Development in China and London's Natural History Museum named it Bashanosaurus primitivus - "Bashan" in reference to the ancient name for the area of Chongqing in China where the dinosaur was found, and the Latin for 'first' -- primitivus.

The new dinosaur, which roamed the planet 168 million years ago, plays a part in uncovering how the stegosaurs evolved -- of which, to this day, little is known.

It has a smaller and less developed should blade, narrower and thicker bases to its armour plates and other features that are different from all other Middle Jurassic stegosaurs discovered so far. However, it does have similarities with some of the first armoured dinosaurs, which are over 20 million years older.

"All these features are clues to the stegosaurs' place on the dinosaur family tree," says Dr Dai Hui from Chongqing Bureau of Geological and Mineral Resource Exploration and Development who led the research. "Bashanosaurus can be distinguished fromother Middle Jurassic stegosaurs, and clearly represents a new species.

"What's more, our analysis of the family tree indicates that it is one of the earliest-diverging stegosaurs along with the Chongqing Lizard (Chungkingosaurus) and Huayangosaurus. These were all unearthed from the Middle to Late Jurassic Shaximiao Formation in China, suggesting that stegosaurs might have originated in Asia," adds Hui.

Instantly recognisable by the huge back plates, long tail spikes and tiny head, stegosaurs were four-legged, plant-eating dinosaurs that lived during the Jurassic and early Cretaceous periods. Stegosaur fossils have been found on all continents except for Antarctica and Australia, and 14 species of stegosaur have been identified so far.

Well-known members of Stegosauria include Huayangosaurus (one of the most primitive stegosaurs), Gigantspinosaurus, notable for its enormous shoulder spines, and Miragaia for its extremely long neck. However, the fragmentary fossil material has hindered attempts to understand how the stegosaurs evolved and how they relate to one another.

With the discovery of this new species the mystery has started to clear up. Bashanosaurus primitivus has several primitive features that are similar to the earliest stegosaurs like Huayangosaurus and Gigantspinosaurus and early-branching thyreophorans (armoured dinosaurs). These include longer tail vertebrae, a shoulder blade that is narrower and flares out, and features of the back vertebrae that are similar to the early armoured dinosaur Scelidosaurus, which lived during the Early Jurassic.

The fossilised remains of Bashanosaurus also reveal a host of features that make it unique from other known stegosaurs. For example, the bony point at the end of the shoulder blade is small and less well developed than in other stegosaurs; a bony projection of the thighbone (fourth trochanter) is positioned below the middle of the shaft; and the bases of the armour plates curve outwards and are thicker than the plates on the backs of its later relatives.

"The discovery of this stegosaur from the Middle Jurassic of China adds to an increasing body of evidence that the group evolved in the early Middle Jurassic, or perhaps even in the Early Jurassic, and as such represent some of the earliest known bird-hipped dinosaurs," says Dr Susannah Maidment, co-author and palaeontologist at London's Natural History Museum.

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Balkanatolia: The forgotten continent that sheds light on the evolution of mammals

A team of French, American and Turkish palaeontologists and geologists led by CNRS researchers1 has discovered the existence of a forgotten continent they have dubbed Balkanatolia, which today covers the present-day Balkans and Anatolia. Formerly inhabited by a highly specific fauna, they believe that it enabled mammals from Asia to colonise Europe 34 million years ago. Their findings are published in the March 2022 volume of Earth Science Reviews.

For millions of years during the Eocene Epoch (55 to 34 million years ago), Western Europe and Eastern Asia formed two distinct land masses with very different mammalian faunas: European forests were home to endemic fauna such as Palaeotheres (an extinct group distantly related to present-day horses, but more like today's tapirs), whereas Asia was populated by a more diverse fauna including the mammal families found today on both continents.

We know that, around 34 million years ago, Western Europe was colonised by Asian species, leading to a major renewal of vertebrate fauna and the extinction of its endemic mammals, a sudden event called the 'Grande Coupure'. Surprisingly, fossils found in the Balkans point to the presence of Asian mammals in southern Europe long before the Grande Coupure, suggesting earlier colonisation.

Now, a team led by CNRS researchers has come up with an explanation for this paradox. To do this, they reviewed earlier palaeontological discoveries, some of which date back to the 19th century, sometimes reassessing their dating in the light of current geological data. The review revealed that, for much of the Eocene, the region corresponding to the present-day Balkans and Anatolia was home to a terrestrial fauna that was homogeneous, but distinct from those of Europe and eastern Asia. This exotic fauna included, for example, marsupials of South American affinity and Embrithopoda (large herbivorous mammals resembling hippopotamuses) formerly found in Africa. The region must therefore have made up a single land mass, separated from the neighbouring continents.

The team also discovered a new fossil deposit in Turkey (Büyükteflek) dating from 38 to 35 million years ago, which yielded mammals whose affinity was clearly Asian, and are the earliest discovered in Anatolia until now. They found jaw fragments belonging to Brontotheres, animals resembling large rhinoceroses that died out at the end of the Eocene.

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Runoff, sediment flux in High Mountain Asia could limit food, energy for millions

Rivers flowing from the Tibetan Plateau and the surrounding high Asian mountains which support one-third of the world's population have experienced rapid increases in annual water and sediment runoff since the 1990s, and the volume of sediment washed downstream could more than double by 2050 under the worst-case scenario, a team of scientists has found.

The cause is "amplified warming": Since 1950, the High Mountain Asia area, or the region of Asia containing five mountain ranges including the Himalaya and Hindu Kush around the Tibetan Plateau, has warmed by about 2 degrees Celsius, twice the amount of warming worldwide. That warming is precipitating more glacier melt, permafrost thaw while annual rainfall is also increasing, the researchers note.

"These findings have far-reaching implications for the region's hydropower, food and environmental security," the researchers observe. The findings also highlight the under-appreciated importance of sediment fluxes and have implications for potential changes in the global carbon cycle, they add.

The research, published today in the journal Science, is led by the National University of Singapore and includes three researchers from the University of Colorado Boulder, including Irina Overeem, Jaia Syvitski and Albert Kettner, all researchers in the Institute of Arctic and Alpine Research. Overeem is also a CU Boulder associate professor of geological sciences, and Syvitski is professor emeritus of geological sciences.

The scientists analyzed observational data of runoff and sediment fluxes from 28 headwater basins over the past six decades.

Sediment flux is the mass of sediment that passes through a specific point in a river basin over a given time period, "like truckloads of sand being transported, in this case by water," Overeem said. Although river runoff, the amount of water entering a river system, and sediment flux are both increasing, they are rising at different rates.

In the river basins the scientists studied, runoff increased by about 5% per decade, while sediment flux increased about 12% per decade.

Overeem explained the variability is affected in two ways: "With glacial melt and permafrost thaw there are new sources of sediment, that previously had been frozen in place in the landscape now can slump into the river. In addition, if more rainfall triggers bigger floods, you suddenly have exceeded a threshold and you can pick up so much more sediment" compared to average conditions. "If you increase the source and the proportion of a couple of these extreme events, you'll get disproportionally much more sediment. So that is maybe what's going on in this system."

River-borne sediment can benefit highly populated areas like Bangladesh, where sediment helps maintain the coastal zone. But in other areas such as Tibet or Nepal, which have hydro-electric power plants, rising levels of sediment can wear out the dams' turbines and fill reservoirs with sand and silt.

By harming existing or planned hydropower projects and reducing irrigation capacity, rising sediment fluxes can thus "threaten the region's food and energy security," the authors write. Additionally, the rising levels of sediment, which can carry nutrients, pollutants and organic carbon, can have implications for water quality and flooding, potentially affecting millions of people.

Research on the High Mountain Asia watershed was facilitated by the area's unusually good, long-term records of streamflow and sediment flux, Overeem said, adding that datasets of similar quality do not exist for Greenland or the whole Arctic.

In the Arctic, scientists have also recorded increases in water discharge from melting ice and increasing rainfall but have few measurements of sediment flux.

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Early modern human from Southeast Asia adapted to a rainforest environment

Traditional assumptions have often seen tropical rainforests as a barrier to early Homo sapiens. However, growing proof shows that humans adapted to and lived in tropical rainforest habitats of Southeast Asia. Some researchers also suggest that, in the past, other human species, like Homo erectus and Homo floresiensis, became extinct because they could not adapt to this environment as our species did. However, we know very little about the ecological adaptation of fossil humans, including what they were eating.

Zinc isotopes reveal what kind of food was primarily eaten

In this study, researchers analysed the zinc stable isotope ratios from animal and human teeth from two sites in the Huà Pan Province of Laos: Tam Pà Ling and the nearby site of Nam Lot. "The site of Tam Pà Ling is particularly important for palaeoanthropology and archaeology of Southeast Asia because it holds the oldest and most abundant fossil record of our species in this region," explains Fabrice Demeter, researcher at the University of Copenhagen. However, there is little archaeological evidence, like stone tools, hearth features, plant remains, cut marks on bones, in Tam Pà Ling: only teeth and bones. This makes isotopic approaches the only way to gain insight into past dietary reliance.

Nitrogen isotope analysis, in particular, can help scientists learn if past humans were eating animals or plants. However, the collagen in bones and teeth needed to do these analyses is not easily conservable. In tropical regions like the one at Tam Pà Ling this problem is even more acute. "New methods -- such as zinc isotope analysis of enamel -- can now overcome these limitations and allow us to investigate teeth from regions and periods we could not study before," says study leader Thomas Tütken, professor at the Johannes Gutenberg University's Institute of Geosciences. "With zinc stable isotope ratios, we can now study Tam Pà Ling and learn what kind of food our earliest ancestors in this region were eating."

First study that reveals the whole diet of fossil humans from Southeast Asia

The fossil human studied in this research dates from the Late Pleistocene, more precisely from 46,000 to 63,000 years ago. With it, various mammals from both sites, including water buffaloes, rhinos, wild boars, deer, bears, orangutans, macaques, and leopards, were also analysed. All these different animals show various eating behaviours, making for an ideal background to determine what exactly humans were eating at the time. The more diverse the animal remains found at a particular site are, the more information the researchers can use to understand the diet of prehistoric humans.

When we compare the zinc isotope values from the fossil Homo sapiens of Tam Pà Ling to that of the animals, it strongly suggests that its diet contained both plants and animals. This omnivorous diet also differs from most nitrogen isotope data of humans in other regions of the world for that time period, where a meat-rich diet is almost consistently discerned. "Another kind of analysis performed in this study -- stable carbon isotopes analysis -- indicates that the food consumed came strictly from forested environments," says Élise Dufour, researcher at the National Natural History Museum of Paris. "The results are the oldest direct evidence for subsistence strategies for Late Pleistocene humans in tropical rainforests."

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