The Atlantic Meridional Overturning Circulation, or AMOC, is a vast system of ocean currents that acts like a planetary conveyor belt. It carries warm tropical water northward, helping keep regions such as Europe relatively mild. After the water cools and becomes denser, it sinks and flows southward along the ocean floor.

“It is well known that the AMOC is a big player in the world’s climate system, and that it is slowing down. What we didn’t know is exactly how the AMOC might impact atmospheric moisture and storms outside the Atlantic region,” said Mohima Mimi, a UCR doctoral student in climate dynamics and the paper’s lead author.

“It turns out a weakening AMOC will strengthen storms across parts of North America by the end of the century, along the California coast in particular, while reducing them over Greenland and the Arctic.”

Stronger Atmospheric Rivers for California

The study, published in Nature Communications, found that a weaker AMOC could alter ocean temperatures in ways that change how much moisture the atmosphere can carry. It could also strengthen winds high in the atmosphere that guide storms across the Northern Hemisphere.

Those stronger winds would help storms move more moisture toward the West Coast, increasing the intensity of atmospheric rivers.

Atmospheric rivers are long, narrow bands of water vapor that transport moisture from tropical regions toward higher latitudes. They provide California with a significant share of its water, but they can also produce severe flooding and widespread damage.

“In California, atmospheric rivers are a double-edged sword,” Mimi said. “They supply much of the state’s water supply, but as they become stronger, they’re likely to also bring widespread destruction.”

Storm Patterns Could Shift Worldwide

The climate modeling also points to more atmospheric rivers along the eastern coast of South America and around Antarctica. At the same time, Greenland would experience fewer storms, leading to less snowfall and slower ice accumulation.

These projected changes appear in a high greenhouse gas emissions scenario in which the AMOC continues weakening throughout the century.

Scientists have already observed signs that the AMOC is slowing as human-caused climate change raises global temperatures. Climate models indicate that the decline is likely to continue if greenhouse gas emissions remain high.

Cutting Emissions Could Reduce the Impact

Greenhouse gases mainly come from burning fossil fuels such as coal, oil, and natural gas. Other major sources include methane from livestock such as cattle, deforestation, industrial activity, and waste from sources including landfills.

Wei Liu, an associate professor of climate change and the paper’s senior author, said reducing these emissions could limit their effects on the AMOC and lessen the current’s influence on future rainfall patterns.

Stronger atmospheric rivers would raise the threat of flooding and infrastructure damage. However, they could also offer opportunities to collect additional water if communities improve forecasting and expand storage systems.

An Atlantic Shift With Global Consequences

The results highlight the deep connections within Earth’s climate system. A change in one major ocean current can alter rainfall and extreme weather thousands of miles away, affecting ecosystems, water supplies, and communities across several continents.

“This research shows that the effects of the AMOC extend far beyond the Atlantic Ocean,” Mimi said. “Understanding these connections will help us better prepare for future changes in water resources and extreme weather.”

As prediabetes advances toward diabetes, this delicate process can begin to break down. Misfolded and defective proteins accumulate inside cells, creating stress that can damage the pancreatic cells responsible for producing insulin.

Researchers from Sanford Burnham Prebys Medical Discovery Institute and the University of Michigan reported new details about this process on June 1, 2026, in the Proceedings of the National Academy of Sciences. Their findings reveal how insulin-producing cells coordinate protein folding and what happens when that system falls out of balance. The work suggests that strengthening the cellular machinery responsible for folding proteins could help protect these cells from damage.

Why Insulin-Producing Beta Cells Become Overwhelmed

Beta cells in the pancreas monitor blood sugar levels. When glucose rises, they respond by producing additional insulin, which helps return blood sugar to a normal range.

As diabetes progresses, however, beta cells increasingly struggle to meet the body’s demand for insulin.

Previous research has linked this decline to the misfolding of proinsulin, the precursor protein cells use to make insulin. Scientists already knew that improperly folded proinsulin accumulates during diabetes and places stress on pancreatic beta cells. What remained uncertain was which additional proteins help control the process and how they work together.

“We knew that the system for preventing proinsulin misfolding depended on a chaperone protein called binding immunoglobulin protein and a number of cochaperones,” said Randal J. Kaufman, PhD, a professor in the Center for Metabolic and Liver Diseases at Sanford Burnham Prebys and senior and corresponding author of the study.

“Our goal was to examine how these partner proteins coordinate proinsulin folding and remove any misfolded mistakes, as these steps are essential for the health of insulin-producing cells.”

Tracking a Key Protein Inside Beta Cells

To study the interactions of binding immunoglobulin protein (BiP), the researchers genetically modified mice so that BiP in their beta cells carried an additional amino acid chain called a peptide.

The added marker consisted of three copies of an eight-amino-acid sequence known as a 3xFLAG-tag. It acted like a molecular beacon, allowing scientists to detect and isolate BiP more easily during experiments.

The results pointed to an especially important role for p58^IPK, one of BiP’s cochaperone proteins.

When researchers genetically removed p58IPK from two different cell lines, misfolded proinsulin accumulated at higher levels. Tests in mice engineered not to produce p58^IPK produced similar evidence. Their beta cells made smaller amounts of both proinsulin and insulin.

BiP and p58^IPK Must Work Together

The team then restored p58^IPK in one of the modified cell lines. Reintroducing the protein improved the cells’ ability to fold and transport proinsulin while reducing the accumulation of improperly folded copies.

However, p58^IPK could not replace BiP’s central role. Those improvements did not occur unless BiP was also present.

The researchers next investigated whether increasing BiP could compensate for the absence of p58^IPK. When cells produced extra BiP but lacked p58^IPK, they showed only modest gains in proinsulin folding and its movement out of the cell. The improvements were substantially greater when both proteins were present at normal levels.

“Like a single tennis player trying to play a doubles match, we found that BiP cannot just go it alone in maintaining the proper folding of proinsulin,” said Insook Jang, PhD, a staff scientist in the Kaufman lab and lead author of the manuscript.

The investigators also identified additional partner proteins involved in folding and transporting proinsulin, as well as detecting and managing misfolded versions. More research will be needed to determine precisely how these proteins influence insulin production and the progression of diabetes.

“Our studies highlight that proinsulin folding is vulnerable to many of the same cellular stresses that cause beta cell failure in type 2 diabetes,” said Kaufman.

A Potential New Diabetes Treatment Strategy

Most existing diabetes medications do not directly correct the protein-folding problems that may contribute to beta cell failure. Instead, they primarily control the disease by helping tissues absorb more glucose or prompting the pancreas to release more insulin.

No current therapies are designed to improve proinsulin folding in order to preserve the health and function of beta cells.

“If we can learn how to influence the coordinated activity of BiP as a key regulator of proinsulin folding, we may find a promising treatment strategy for intervening early to prevent or reduce damage to insulin-producing cells,” said Kaufman.

Additional authors include Alec Duffey and Pamela Itkin-Ansari at Sanford Burnham Prebys and Peter Arvan at the University of Michigan.

The study was supported by the National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, National Cancer Institute and Breakthrough T1D (formerly JDRF).

The new findings provide firm dates for two black images, a bison and a masklike figure, and reveal that parts of the artwork were created during widely separated periods. The results could give archaeologists a powerful new way to reconstruct when people entered decorated caves, made paintings, and returned to alter or add to them.

Why Ice Age Cave Paintings Are Difficult to Date

Dordogne is home to some of the best-known prehistoric art in Europe, including the paintings at Lascaux. Yet determining exactly when many of these images were created has remained extremely difficult.

Radiocarbon dating works by measuring carbon-14, a radioactive form of carbon that gradually disappears after an organism dies. Because charcoal is made from burned organic material, it can often be dated using this method. Mineral pigments, however, usually contain no carbon and therefore cannot be analyzed in the same way.

Researchers had long believed that many black paintings in the region were made entirely from iron and manganese oxides. These naturally occurring minerals can produce dark pigments, but they do not contain the organic carbon needed for radiocarbon dating.

As a result, the artwork was generally considered impossible to date directly. However, scientists had never conclusively demonstrated that the pigments contained no carbon at all.

Searching for Charcoal Hidden in the Pigment

To investigate, the researchers analyzed the chemical composition of two black figures at Font-de-Gaume. One depicts a bison, while the other is commonly described as a mask.

The team used Raman microspectrometry and hyperspectral imaging, two techniques that can identify materials without noticeably damaging the artwork.

Raman microspectrometry uses light to examine how molecules vibrate, producing a chemical signature that can help identify pigments and other substances. Hyperspectral imaging records subtle differences in color and reflected light at each point in an image. Scientists can use those measurements to determine which compounds are present.

Hyperspectral imaging is widely used in cultural heritage research because it can reveal features that are difficult or impossible to see with the human eye. It also has applications in biomedical science, agriculture, environmental monitoring, and astrophysics.

Both methods revealed traces of charcoal in the paintings’ black pigment.

The charcoal was distributed consistently throughout the black lines of the figures. That pattern was important because it indicated that the carbon was part of the original pigment rather than contamination left by later graffiti, visitors, or tourist activity inside the cave.

Tiny Samples Reveal the Paintings’ Ages

Once the charcoal had been confirmed, researchers received exceptional authorization to remove extremely small samples for carbon-14 dating.

Analyzing such limited material is technically challenging. Scientists must collect enough carbon to obtain a reliable measurement while removing as little as possible from the ancient image.

The results confirmed that the bison dates to the Upper Paleolithic, the later portion of the Old Stone Age when anatomically modern humans created many of Europe’s most famous cave paintings.

The bison was painted between 13,461 and 13,162 calBP.

CalBP means Calibrated Before Present, with present conventionally defined as the year 1950. Radiocarbon measurements must be calibrated because the amount of carbon-14 in the atmosphere has changed over time. Those variations can be influenced by factors including solar activity and changes in Earth’s magnetic field.

The new date places the bison slightly later than previous estimates.

A Mysterious Mask Created Across Different Periods

The mask produced an even more complex result. Samples from separate parts of the figure yielded three different ranges.

One section was dated to between 8,993 and 8,590 calBP. Another was dated to between 15,981 and 15,121 calBP, while a third was placed between 15,297 and 14,246 calBP.

These results suggest that the image may contain elements created at very different times. Rather than being the work of a single artist during one visit, the mask may preserve multiple episodes of artistic activity separated by thousands of years.

That possibility offers a more layered picture of prehistoric cave art. Decorated caves may not always have been completed during a single period. Some could have remained meaningful places that later communities revisited, modified, or reinterpreted.

A New Tool for Understanding Prehistoric Art

The research was led by a scientist from the Laboratoire de développement instrumental et de méthodologies innovantes pour les biens culturels (Chimie ParisTech-PSL/CNRS/Ministère de la Culture). The study was published in PNAS.

The research brought together specialists from several French scientific and cultural institutions.

Contributors included scientists from Laboratoire de mesure du carbone 14 (CEA/CNRS/IRD/ASNR/ Ministère de la Culture), a national platform affiliated with Laboratoire des sciences du climat et de l’environnement (CEA/CNRS/ Université de Versailles Saint-Quentin-en-Yvelines). Researchers from the Histoire naturelle des Humanités préhistoriques laboratory (CNRS/MNHN/Université de Perpignan Via Domitia), the Centre des monuments nationaux, and the Centre de recherche et de restauration des musées de France also participated.

By combining chemical imaging with highly sensitive radiocarbon measurements, the team has developed a method that could be applied to other prehistoric figures previously considered undatable.

More precise dates could help researchers determine which paintings were created during the same period, how artistic styles changed, and whether generations of people repeatedly returned to particular caves. That information may ultimately reveal more about the communities that produced the images and the cultural importance these underground spaces held over thousands of years.