An earthquake changed the course of the Ganges. Could it happen again?

A densely populated region could see cascading effects of shaking

Peer-Reviewed Publication

COLUMBIA CLIMATE SCHOOL

 

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THE LOWLANDS OF BANGLADESH ARE IN MANY PLACES AN ELABORATE MIXTURE OF LAND AND WATER THAT SOMETIMES CHANGE PLACES. 

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CREDIT: PHOTO BY STEVE GOODBRED

A major earthquake 2,500 years ago caused one of the largest rivers on Earth to abruptly change course, according to a new study. The previously undocumented quake rerouted the main channel of the Ganges River in what is now densely populated Bangladesh, which remains vulnerable to big quakes. The study was just published in the journal Nature Communications.

Scientists have documented many river-course changes, called avulsions, including some in response to earthquakes. However, “I don’t think we have ever seen such a big one anywhere,” said study coauthor Michael Steckler, a geophysicist at Lamont-Doherty Earth Observatory, which is part of the Columbia Climate School. It could have easily inundated anyone and anything in the wrong place at the wrong time, he said.

Lead author Liz Chamberlain, an assistant professor at the Netherlands’ Wageningen University, said, “It was not previously confirmed that earthquakes could drive avulsion in deltas, especially for an immense river like the Ganges.”

The Ganges rises in the Himalayas and flows for some 1,600 miles, eventually combining with other major rivers including the Brahmaputra and the Meghna to form a labyrinth of waterways that empty into a wide stretch of the Bay of Bengal spanning Bangladesh and India. Together, they form the world’s second-largest river system as measured by discharge. (The Amazon is first.)

Like other rivers that run through major deltas, the Ganges periodically undergoes minor or major course changes without any help from earthquakes. Sediments washed from upstream settle and build up in the channel, until eventually the river bed grows subtly higher than the surrounding flood plain. At some point, the water breaks through and begins constructing a new path for itself. But this does not generally happen all at once—it may take successive floods over years or decades. An earthquake-related avulsion, on the other hand, can occur more or less instantaneously, said Steckler.

In satellite imagery, the authors of the new study spotted what they say was probably the former main channel of the river, some 100 kilometers south of the Bangladeshi capital of Dhaka. This is a low-lying area about 1.5 kilometers wide that can be found intermittently for some 100 kilometers more or less parallel to the current river course. Filled with mud, it frequently floods, and is used mainly for rice cultivation.

Chamberlain and other researchers were exploring this area in 2018 when they came across a freshly dug excavation for a pond that had not yet been filled with water. On one flank, they spotted distinct vertical dikes of light-colored sand cutting up through horizontal layers of mud. This is a well-known feature created by earthquakes: In such watery areas, sustained shaking can pressurize buried layers of sand and inject them upward through overlying mud. The result: literal sand volcanoes, which can erupt at the surface. Called seismites, here, they were 30 or 40 centimeters wide, cutting up through 3 or 4 meters of mud.

Further investigation showed the seismites were oriented in a systematic pattern, suggesting they were all created at the same time. Chemical analyses of sand grains and particles of mud showed that the eruptions and the abandonment and infilling of the channel both took place about 2,500 years ago. Furthermore, there was a similar site some 85 kilometers downstream in the old channel that had filled in with mud at the same time. The authors’ conclusion: This was a big, sudden avulsion triggered by an earthquake, estimated to be magnitude 7 or 8.

The quake could have had one of two possible sources, they say. One is a subduction zone to the south and east, where a huge plate of oceanic crust is shoving itself under Bangladesh, Myanmar and northeastern India. Or it could have come from giant splay faults at the foot of the Himalayas to the north, which are slowly rising because the Indian subcontinent is slowly colliding with the rest of Asia. A 2016 study led by Steckler shows that these zones are now building stress, and could produce earthquakes comparable to the one 2,500 years ago. The last one of this size occurred in 1762, producing a deadly tsunami that traveled up the river to Dhaka. Another may have occurred around 1140 CE.

The 2016 study estimates that a modern recurrence of such a quake could affect 140 million people. “Large earthquakes impact large areas and can have long-lasting economic, social and political effects,” said Syed Humayun Akhter, vice-chancellor of Bangladesh Open University and a coauthor on both studies.

The Ganges is not the only river facing such hazards. Others cradled in tectonically active deltas include China’s Yellow River; Myanmar’s Irrawaddy; the Klamath, San Joaquin and Santa Clara rivers, which flow off the U.S. West Coast; and the Jordan, spanning the borders of Syria, Jordan, the Palestinian West Bank and Israel.

Other coauthors of the new study are at the University of Cologne, Germany; the University of Dhaka; Bangladesh University of Professionals; Noakhali Science and Technology University, Bangladesh; and the University of Salzburg, Austria. The research was funded by the U.S. National Science Foundation.

A classic sign of a landscape disrupted by an earthquake: a vein of sand that has been pushed up through darker-colored sediments. 

CREDIT

Photo by Liz Chamberlain

More information: Columbia Climate School senior editor, science news kevin Krajick  kkrajick@climate.columbia.edu   +1 917-361-7766

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JOURNAL

Nature Communications

DOI

10.1038/s41467-024-47786-4 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Cascading hazards of a major Bengal basin earthquake and abrupt avulsion of the Ganges River

ARTICLE PUBLICATION DATE

17-Jun-2024

 

Estimating the energy of past earthquakes from brecciation in a fault zone

TOHOKU UNIVERSITY

 

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THE ICHINOKAWA MINE. AN OUTCROP ALONG THE RIVER RECORDS BRECCIATION BY EARTHQUAKES.

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CREDIT: NORIYOSHI TSUCHIYA

During a 2017 research field trip to the Ichinokawa Mine (Ehime prefecture), which is famous for beautiful, sword-shaped stibnite crystals, Noriyoshi Tsuchiya found something unexpected. Although most would be entranced by the glittering crystals, it was a sedimentary rock bundle called breccia that caught his eye.

"I could not stop thinking about the breccia," Tsuchiya (professor at the Graduate School of Environmental Studies, and the Hachinohe National College of Technology) explains, "We visited the mine several times and discovered that the breccia records the traces of earthquakes and provides valuable evidence to estimate the energy of past earthquakes."

In the same way that the number of rings in a tree can tell us its age, the characteristics of rocks such as breccia can tell us about the history of a region. The Ichinokawa breccia are unique in that they can retain a record of the frequent seismic activity that occurs along the Median Tectonic Line (MTL). The MTL is a fault line that extends approximately 1000 kilometres along the southwest region of Japan. This makes the breccia formed in this area to be of particular interest to researchers.

In this study, Tsuchiya and their team assessed fragmented rocks both in the field and in the lab by extracting sections (slices so thin that they allow light to penetrate) from the collected rocks to observe under a microscope. The energy dissipated by the past earthquake was successfully estimated on the basis of statistical and fractal analyses of angular deformation and the powdery texture of rocks from a micro to macro scale.

It was found that the surface energy required to explain the naturally occurring distribution of fractured rocks was considerably greater (about 100 times greater) than the surface energy required from a single impact fracture experiment on a rock performed in the laboratory.

Many factors were assessed in order to calculate the energy and nature of the earthquake. For example, close observation of breccia revealed the formation of carbonates such as CaMg(CO3)2. Since the host rock that broke off did not contain any carbonates, it was deduced that this mineral must have formed after the formation of breccia. They concluded that the earthquake did not occur just once, but repeatedly, and that caused the fine particles to be crushed into even finer particles. Their findings suggest the Ichinokawa breccia were formed by 10-100 earthquakes with a moment magnitude (an index of seismic energy) estimated to be 5.8-8.3 Mw.

Further analysis revealed that the breccia had a very unique pattern of fragmentation (or pulverization). "Previous models designed to explain the earthquake history use a different theory, based primarily on hydrofracturing. However, we adopted a multi-disciplinary approach, so our analysis can be used to propose a new model that takes more factors into account" Tsuchiya adds.

This study, which was a collaboration with the National Institute of Technology and Hachinohe College, may redefine our understanding of the coseismic energy budget in this region.

These findings were published in Scientific Reports on May 27, 2024.

Photo of breccia with wide particle size distribution and in situ fragmentation.

sion of particle size distribution. 

The matrix component and dolomite composition (f) Relative abundance of the matrix. (a-c) The dolomite profile within the matrix shows the variation of Mg and Fe corresponding to five oscillatory zoning under backscattered image (BSE). A thin-section scan with a red-dashed square indicates the areas analyzed for a couple of analyses in this study. 

CREDIT

Noriyoshi Tsuchiya

JOURNAL

Scientific Reports

DOI

10.1038/s41598-024-62838-x 

ARTICLE TITLE

Multiscale off-fault brecciation records coseismic energy budget of principal fault zone

 

Public acceptance of adoption and surrogacy methods currently prohibited in UK increases if one or both parents are infertile - study

UNIVERSITY OF BIRMINGHAM

New research has found that the public is more accepting of adoption and surrogacy if one or both parents are infertile, even when applied to methods of adoption and surrogacy which are currently illegal in the UK.

The interdisciplinary research from the University of Birmingham and the University of Nottingham and published in The Journal of Bioethical Enquiry, has revealed that while the UK public is broadly supportive of all forms of adoption and surrogacy, no matter the circumstances this support increases significantly when one or both parents are infertile.

Dr Evelyn Svingen, Assistant Professor at the University of Birmingham, said: “Surrogacy and adoption are both family-making measures subject to extensive domestic and international regulation, and the UK is one country considering a legal overhaul with the Law Commission setting out its recommendations for reform surrounding surrogacy in March last year. Given the possible changes to the law, we wanted to understand the public attitudes to different forms of adoption and surrogacy.

“Our research found that both the family and fertility circumstances of a couple (that is, their fertility and whether they had children already) and the proposed form of adoption or surrogacy influenced participant attitudes.”

The study set out hypothetical scenarios where a heterosexual couple would like to have a child without going through pregnancy and childbirth. The hypothetical couple had four sets of circumstances:

1. Fertile with children.
2. Fertile without children.
3. One partner infertile.
4. Both partners infertile.

How the couple wanted to have a child was also split into four options:

1. Regular adoption.
2. Using a surrogate mother and sperm/egg from the intending father or mother.
3. Using a surrogate mother and donated sperm and egg (double donor surrogacy).
4. “Clear-cut” planned private adoption.

Currently planned private adoption and double donor surrogacy are legally prohibited in the UK.

1552 UK adults were then asked to what extent they agreed that the couple should be allowed to acquire a child in the proposed way. The researchers measured the variation in public support for different policies and the influence that family circumstances and fertility issues had on the participants' attitudes.

The results showed that in the hypothetical scenarios in which one or both partners in the couple were infertile, participants expressed overwhelming support for most types of adoption and surrogacy. This includes a planned private adoption scenario, in which the fictional couple asks another couple to conceive a child and hand it over to them to raise. In the scenarios where the couple had no fertility issues, support for any use of surrogacy decreased, as did support use of adoption, although by a smaller margin.

The lowest levels of support were shown for clear private adoption scenarios where a couple experiences no fertility issues. Still, even those scenarios received agreement from around half of the participants (47-50%), with the level of support increasing from 69-71% in case of fertility difficulties. Levels of moral agreement also increased for the double donor surrogacy scenario in the presence of infertility, 56-58% for fertile couples and 84-90% for infertile couples.

These results show that most of the public surveyed showed higher levels of support for any policy allowing a couple experiencing infertility to acquire a child, including in the case of the two policies that are prohibited by current U.K.

Dr Teresa Baron, Research Fellow at the University of Nottingham, concluded: “Our study found that the public expressed strong support for the current policy on surrogacy, with 63-65% of the public surveyed supporting the policy in cases of a fertile couple and 87-90% supporting the policy in cases of one of the parents being infertile. We also found that the level of support for any policy, including planned private adoption, currently illegal in the United Kingdom, significantly increases if at least one of the partners experiences fertility-related issues.

“These public attitudes may be something that policymakers want to consider when it comes to any changes in law; however, the law should not always and only seek to reflect public morality. Legal reform may sometimes play an important role in motivating public support for a policy.”

ENDS
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JOURNAL

Journal of Bioethical Inquiry

DOI

10.1007/s11673-024-10343-1 

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

People

 

Scope for action in the Anthropocene: Leopoldina Conference “Crossing Boundaries in Science” in cooperation with the Max Planck Institute of Geoanthropology

LEOPOLDINA

Changes to the Earth’s climate, the severe decline in biodiversity, and the intense use of land, water and natural resources show the extent of humanity’s impact on the Earth’s biological, geological and atmospheric processes. Experts are already referring to the Anthropocene, the human epoch. Understanding the complex causes and processes of the Anthropocene and identifying and implementing effective actions are crucial for mitigating the negative effects of these developments. At the Leopoldina’s “Crossing Boundaries in Science” conference, which will take place from Monday 24 June to Wednesday 26 June in Jena/Germany, international scientists will participate in interdisciplinary discussions on causes, consequences and solutions in the Anthropocene. The event is also the opening conference of the new Max Planck Institute of Geoanthropology. Symposium “Crossing Boundaries 2024: The Anthropocene – Addressing its challenges for humanity – crossing the boundaries of science” Monday 24 June to Wednesday 26 June 2024 Dorint Hotel Esplanade Jena, Carl-Zeiss-Platz 4, 07743 Jena, Germany, and online Following the opening by Leopoldina President Professor (ETHZ) Dr Gerald Haug, the President of the Max Planck Society Professor Dr Patrick Cramer, Professor Dr Jürgen Renn, Founding Director of the Max Planck Institute of Geoanthropology, and Professor Dr Thomas Lengauer, Emeritus Scientific Member of the Max Planck Institute for Informatics in Saarbrücken/Germany, the event will focus on humanity’s impact on the Earth system, as well as the question as to how limited knowledge on this subject is. Key figures in the Anthropocene and their scope of action will be introduced and discussed over the next days of the conference. Experts from the natural and social sciences and the humanities will speak about economic, political and social control mechanisms as well as the responsibility of the individual. Speakers will include marine researcher Professor Dr Antje Boetius, biologist Professor Dr Katrin Böhning-Gaese, historian Professor Dr Dipesh Chakrabarty (virtual), system ecologist Professor Dr Johan Rockström, climatologist Professor Dr Jochem Marotzke, chemist and Vice-President of the Leopoldina Professor Dr Robert Schlögl and physicist Professor Dr Ricarda Winkelmann, Founding Director of the Max Planck Institute for Geoanthropology. As part of the symposium, cultural historian Andrea Wulf will speak about the natural scientist Alexander von Humboldt in a public lecture on Monday evening. The English-language lecture “The Invention of Nature – Alexander von Humboldt’s New World” will begin at 7.30 p.m. at the Volkshaus Jena (Carl-Zeiss-Platz 15). The conference is the third event in the “Crossing Boundaries in Science” (CBiS) series by the German National Academy of Sciences Leopoldina. The objective of the series is to discuss, at an early stage, the research areas which are particularly dependent on interdisciplinary cooperation. This event is open to all interested parties and will also be livestreamed. The conference will take place in English. The complete programme and all information about the livestream can be found at: https://www.leopoldina.org/en/events/event/event/3180/ Journalists who would like to attend should register by email at presse@leopoldina.org. The Leopoldina on X: www.twitter.com/leopoldina About the German National Academy of Sciences Leopoldina As the German National Academy of Sciences, the Leopoldina provides independent science-based policy advice on matters relevant to society. To this end, the Academy develops interdisciplinary statements based on scientific findings. In these publications, options for action are outlined; making decisions, however, is the responsibility of democratically legitimized politicians. The experts who prepare the statements work in a voluntary and unbiased manner. The Leopoldina represents the German scientific community in the international academy dialogue. This includes advising the annual summits of Heads of State and Government of the G7 and G20 countries. With around 1,700 members from more than 30 countries, the Leopoldina combines expertise from almost all research areas. Founded in 1652, it was appointed the National Academy of Sciences of Germany in 2008. The Leopoldina is committed to the common good.

 

Why some plant diseases thrive in urban environments

WASHINGTON UNIVERSITY IN ST. LOUIS

 

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A TEAM LED BY BIOLOGIST RACHEL PENCZYKOWSKI IN ARTS & SCIENCES AT WASHINGTON UNIVERSITY IN ST. LOUIS FOUND MORE INFESTATIONS OF POWDERY MILDEW IN ST. LOUIS THAN IN THE CITY’S SURROUNDING SUBURBS AND COUNTRYSIDE.

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CREDIT: RACHEL PENCZYKOWSKI, WASHINGTON UNIVERSITY IN ST. LOUIS

Something about city life seems to suit powdery mildew, a fungal disease that afflicts many plants, including leaves of garden vegetables and roadside weeds.

Rachel Penczykowski, an assistant professor of biology in Arts & Sciences at Washington University in St. Louis, and five WashU graduate and undergraduate students tracked infestations of powdery mildew on common broadleaf weeds. Their study, published in the journal Ecology, covered 22 sites in the St. Louis area ranging from the rural environment of Shaw Nature Reserve near Gray Summit to Forest Park in the heart of the city.

Penczykowski and her team found a strong and surprising pattern: Weeds in the city had significantly more mildew than the weeds in the suburbs or countryside. “Now we need to figure out what’s driving those patterns,” she said.

While the particular fungus the team studied is harmless to other plants or animals, different species of powdery mildew can be a major threat to vegetable gardens, flowers and vineyards, said Quinn Fox, a 2023 PhD graduate and the study’s lead author. “It’s a big concern in different agricultural industries,” Fox said.

At any given location, mildew did best in places where trees or buildings provided a bit of shade. This observation was backed up by experiments that made use of solar array panels at Tyson Research Center, Washington University’s environmental field station. Potted plants placed in the shade of the panels had more mildew than those exposed to full sun.

But that finding raised a bigger question: If mildew does well in shade, why is it so common in the city, which is generally sunnier than the suburbs and countryside? “That’s the paradox,” Penczykowski said.

The heat of city life may be a double-edged sword for the mildew, Penczykowski said. As with other cities, St. Louis tends to be warmer in urban areas because pavement, buildings and other human-made structures absorb heat, creating a phenomenon known as “urban heat islands.” While too much summer heat can be lethal to powdery mildew, the extra warmth could help spores grow faster in spring. It’s also possible that people and vehicles help encourage the spread of spores along busier city roads and between city parks, she said.

In follow-up studies, Penczykowski’s team sowed seeds from city, suburban and countryside locations in a greenhouse before transplanting them into gardens across the St. Louis region to study the factors that encourage or discourage mildew growth. Each garden was split into a full sun and shade treatment, and plants and temperatures were monitored over an entire year. The team’s unpublished preliminary results suggest extra heat is generally bad for mildew growth, but small patches of shade are sufficient to promote infestations of mildew — even in hot city environments and regardless of the plants’ locations of origin. “We’re starting to understand how heat and other aspects of human activity can change the dynamics of disease in plants,” Penczykowski said.

“St. Louis has a thriving urban agriculture scene,” she added. “There are a lot of backyard gardens and community gardens. But very little work has been done on understanding the particular risks of plant diseases to agriculture in cities.”

Penczykowski’s research into plant pathogens is funded by the National Science Foundation (NSF). In 2023, she won a NSF CAREER grant to support her ongoing research and mentoring.

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Originally published on The Ampersand website

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JOURNAL

Ecology

DOI

10.1002/ecy.4313 

ARTICLE TITLE

Effects of microclimate on disease prevalence across an urbanization gradient

 

Ancient ocean slowdown warns of future climate chaos

Ocean circulation enables tolerable climate

UNIVERSITY OF CALIFORNIA - RIVERSIDE

 

IMAGE: 

FORAMINIFERA SHELLS HELPED SCIENTISTS PIECE TOGETHER A PICTURE OF OCEAN MOVEMENT DURING THE EOCENE PERIOD, WHERE HIGH ATMOSPHERIC CARBON LEVELS CAUSED THE EXCHANGE OF OCEAN WATERS TO SLOW DOWN. 

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CREDIT: MARCI ROBINSON, USGS

When it comes to the ocean’s response to global warming, we’re not in entirely uncharted waters. A UC Riverside study shows that episodes of extreme heat in Earth’s past caused the exchange of waters from the surface to the deep ocean to decline.

This system has been described as the "global conveyer belt," because it redistributes heat around the globe through the movement of the ocean waters, making large portions of the planet habitable. 

Using tiny, fossilized shells recovered from ancient deep-sea sediments, the study in the Proceedings of the National Academy of Sciences demonstrates how the conveyor belt responded around 50 million years ago. At that time, Earth’s climate resembled conditions predicted by the end of this century, if significant action is not taken to reduce carbon emissions.

Oceans play a crucial role in regulating Earth’s climate. They move warm water from the equator toward the north and south poles, balancing the planet’s temperatures. Without this circulation system, the tropics would be much hotter and the poles much colder. Changes in this system are linked to significant and abrupt climate change.  

Furthermore, the oceans serve a critical role in removing anthropogenic carbon dioxide from the atmosphere. “The oceans are by far the largest standing pool of carbon on Earth’s surface today,” said Sandra Kirtland Turner, vice-chair of UCR’s Department of Earth and Planetary Sciences and first author of the study.

“Today, the oceans contain nearly 40,000 billion tons of carbon — more than 40 times the amount of carbon in the atmosphere. Oceans also take up about a quarter of anthropogenic CO2 emissions,” Kirtland Turner said. “If ocean circulation slows, absorption of carbon into the ocean may also slow, amplifying the amount of CO2 that stays in the atmosphere.”

Previous studies have measured changes in ocean circulation in Earth’s more recent geologic past, such as coming out of the last ice age; however, those do not approximate the levels of atmospheric CO2 or warming happening to the planet today. Other studies provide the first evidence that deep ocean circulation, particularly in the North Atlantic, is already starting to slow. 

To better predict how ocean circulation responds to greenhouse gas-driven global warming, the research team looked to the early Eocene epoch, between roughly 49 and 53 million years ago. Earth then was much warmer than today, and that high-heat baseline was punctuated by spikes in CO2 and temperature called hyperthermals. 

During that period, the deep ocean was up to 12 degrees Celsius warmer than it is today. During the hyperthermals, the oceans warmed an additional 3 degrees Celsius. 

“Though the exact cause of the hyperthermal events is debated, and they occurred long before the existence of humans, these hyperthermals are the best analogs we have for future climate change,” Kirtland Turner said. 

By analyzing tiny fossil shells from different sea floor locations around the globe, the researchers reconstructed patterns of deep ocean circulation during these hyperthermal events. The shells are from microorganisms called foraminifera, which can be found living throughout the world’s oceans, both on the surface and on the sea floor. They are about the size of a period at the end of a sentence. 

“As the creatures are building their shells, they incorporate elements from the oceans, and we can measure the differences in the chemistry of these shells to broadly reconstruct information about ancient ocean temperatures and circulation patterns,” Kirtland Turner said. 

The shells themselves are made of calcium carbonate. Oxygen isotopes in the calcium carbonate are indicators of temperatures in the water the organisms grew in, and the amount of ice on the planet at the time. 

The researchers also examined carbon isotopes in the shells, which reflect the age of the water where the shells were collected, or how long water has been isolated from the ocean surface. In this way, they can reconstruct patterns of deep ocean water movement. 

Foraminifera can’t photosynthesize, but their shells indicate the impact of photosynthesis of other organisms nearby, like phytoplankton. “Photosynthesis occurs in the surface ocean only, so water that has recently been at the surface has a carbon-13 rich signal that is reflected in the shells when that water sinks to the deep ocean,” Kirtland Turner said. 

“Conversely, water that has been isolated from the surface for a long time has built up relatively more carbon-12 as the remains of photosynthetic organisms sink and decay. So, older water has relatively more carbon-12 compared to ‘young’ water.”

Scientists often make predictions about ocean circulation today using computer climate models. They use these models to answer the question: ‘how is the ocean going to change as the planet keeps warming?’ This team similarly used models to simulate the ancient ocean’s response to warming. They then used the foraminifera shell analysis to help test results from their climate models. 

During the Eocene, there were about 1,000 parts per million (ppm) of carbon dioxide in the atmosphere, which contributed to that era’s high temperatures. Today, the atmosphere holds about 425 ppm. 

However, humans emit nearly 37 billion tons of CO2 into the atmosphere each year; if these emission levels continue, similar conditions to the Early Eocene could occur by the end of this century. 

Therefore, Kirtland Turner argues it is imperative to make every effort to reduce emissions. 

“It’s not an all-or-nothing situation,” she said. “Every incremental bit of change is important when it comes to carbon emissions. Even small reductions of CO2 correlate to less impacts, less loss of life, and less change to the natural world.”

Sandra Kirtland Turner, of UC Riverside, and an ocean core sediment sample.

CREDIT

Integrated Ocean Drilling Program

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JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2311980121 

ARTICLE TITLE

Sensitivity of ocean circulation to warming during the Early Eocene greenhouse