Phys.org: Earth science

A 113-million-year-old marine murder mystery may finally be solved. Using chemical clues locked inside microscopic fossils, Northwestern University scientists found evidence that ocean acidification drove one of the largest extinction events in the history of planktic foraminifera—tiny shell-building organisms that help regulate Earth's carbon cycle.

Sea-surface salinity, the concentration of dissolved salts in the upper layer of the ocean, is much more than a measure of how salty the sea is. It responds rapidly to changes in rainfall, evaporation, river discharge and, specifically in polar regions, the melting and formation of sea ice. Salinity is both an important driver of ocean circulation and a tracer of the movement of water masses and surface currents.

Before rain falls, the moisture that forms it may have traveled anywhere from just a few kilometers to hundreds or even thousands of kilometers away. It usually begins as water that evaporated from oceans, lakes, forests or fields. According to a paper published in Geophysical Research Letters, rain in parts of the United States is increasingly arriving from farther away.

For around 12,000 years, the Earth has been in the Holocene epoch, a warmer period following a glacial period. During this epoch, however, there have been around 22 abrupt cold phases, each lasting up to several centuries and leading to the expansion of glaciers.

A new framework to cool urban areas which integrates AI-driven technical solutions with cooling schemes that are acceptable and doable for the host community, has been proposed by QUT Urban AI Hub researchers.

Assessing how climate change will affect different regions usually requires running a complex chain of models. While this approach provides valuable insights, it is expensive and can cover only a limited set of scenarios and model runs. Together with partners, IIASA researchers have developed a faster alternative that uses available projections from Earth system or climate impact models to generate new regional climate and impact projections while capturing the uncertainty essential for understanding climate risk.

In August 2023, the German research vessel METEOR set sail on Expedition M192 to the Greek island of Milos with Dr. Solveig Bühring as chief scientist. The mission was to locate and investigate previously unknown hydrothermal systems. Now, three years later, a new study highlights the surprising discoveries resulting from this expedition. At a newly discovered hydrothermal system at intermediate water depths of 100 to 250 meters (328 to 820 feet), researchers demonstrated how different intensities of hydrothermal fluid flow shape microbial communities and control mineral formation on the ocean floor.

Deploying ocean iron fertilization—a strategy for carbon dioxide capture—in higher latitudes rather than near the equator could reduce environmental impacts while still achieving removal of carbon dioxide from the atmosphere, according to a modeling study published in Nature. The findings offer insight into best practices for maximizing carbon dioxide removal while reducing potential ecological trade-offs typically associated with iron fertilization.

Towering explosions, flowing bright red lava and heroic scientists battling to save communities at risk have become the defining image of volcanoes in popular culture, from disaster films to epic blockbusters. New University of Bristol–led research has found these cinematic portrayals create a distorted view of how volcanoes behave in the real world.

For communities across the Western Cape, cut-off low weather systems are a familiar threat. They can dump torrents of rain in a matter of hours, flooding roads, damaging homes and infrastructure, and, in the worst cases, causing loss of life. What scientists have long wanted to understand is why some of these storms become so destructive, and researchers at the University of Cape Town (UCT) found that the answer lies far offshore, in the warm waters of the Agulhas Current.

Extreme urban flooding is a growing challenge under climate change, threatening residents, infrastructure and urban systems. However, traditional emergency planning often relies on static population data and fixed facilities, failing to capture how people move during disasters.

Scientists have discovered a new way to determine how big an earthquake may become just seconds after it begins. In a new study published in Nature Communications, researchers from the U.S. Geological Survey (USGS) and Cal Poly Humboldt used signals picked up by fiber-optic cables—the same ones that deliver high-speed internet—to accurately estimate when a moderate to large earthquake is underway using data from the first four seconds of seismic wave arrivals.

Winters in Antarctica's Ross Sea have become stormier in recent decades, affecting sea-ice conditions and field operations, new University of Otago—Ōtākou Whakaihu Waka research shows.

Landslides cause an estimated $3 billion to $6 billion in damage and multiple fatalities annually in the United States. Those numbers could easily increase as housing needs spur development in landslide-prone areas and climate change increases the severity and frequency of heavy rains, which often trigger landslides. Despite the threat, there has never been a systematic, nationwide accounting of who is most at risk from landslides.

On July 23, R/V Kronprins Haakon cast off from the coal quay in Longyearbyen. Around 30 researchers and 20 crew members will spend the next 50 days sailing toward the North Pole as part of the Polhavet 2050 research program.

Could taking plant biomass and burying it in the deep, anoxic parts of the ocean be a workable large-scale strategy for carbon sequestration? The concept has intrigued scientists for years, and now a recent international workshop led by UC Santa Barbara researchers has taken the first steps toward developing it.

Around a quarter of the U.S. food supply is grown in California's Central Valley. Most of its crops, like rice, fruit trees and nut trees, are water-intensive and require extensive groundwater pumping during droughts. Over time, heavy water extraction has contributed to changes in the aquifer systems under the San Joaquin and Sacramento valleys. Although some of these changes can be reversed, a new study, published in the Proceedings of the National Academy of Sciences, indicates that large parts of the Sacramento Valley may have undergone irreversible ground compaction during recent droughts, leading to a permanent loss of groundwater storage.

Most of the carbon released during Canada's record-breaking 2023 wildfire season came from burning soil and peat, rather than trees, according to new research from McMaster University.

Low-level clouds over Earth's oceans play a prominent role in keeping our planet cool by reflecting sunlight away from the surface. But their response to climate change has been hard to model. Now, researchers at Caltech and Google have uncovered important insights into how clouds might respond to warming sea-surface temperatures and rising CO2 levels using a large dataset of simulations developed by the group.

The most severe droughts in the ancient Eastern Mediterranean arose when multiple natural climate cycles coincided, according to a new study from Stockholm University published in Science Advances. The findings shed new light on the climate conditions surrounding the Late Bronze Age collapse and may help improve understanding of future drought risks in a warming world.