The United States is no stranger to bone-chilling winter cold, despite a warming climate. A recent study has shed light on why this phenomenon persists, pointing to two specific patterns in the polar vortex – a swirling mass of cold air high in the stratosphere. These variations can steer extreme cold to different regions of the country, often contradicting broader warming trends.

Researchers from an international team, including Prof. Chaim Garfinkel (Hebrew University), Dr. Laurie Agel and Prof. Mathew Barlow (University of Massachusetts), Prof. Judah Cohen (MIT and Atmospheric and Environmental Research AER), Karl Pfeiffer (Atmospheric and Environmental Research Hampton), and Prof. Jennifer Francis (Woodwell Climate Research Center), have published their findings in Science Advances.

The study reveals that since 2015, the Northwest US has experienced more of these cold outbreaks due to a shift in stratospheric behavior tied to broader climate cycles. In contrast, other regions may experience milder winters. Understanding this relationship can improve long-range forecasting, allowing cities, power grids, and agriculture to better prepare for winter extremes – even as the climate warms overall.

“It’s not just about warming everywhere all the time,” explained the researchers. “Climate change also means more complex and sometimes counterintuitive shifts in where extreme weather shows up.”

The work was funded by a US NSF-BSF grant by Chaim Garfinkel of HUJI and Judah Cohen of AER&MIT, highlighting the importance of international collaboration in addressing global climate challenges.

The study published in Science Advances by NASA scientists has revealed a significant correlation between the strength of the Earth’s magnetic field and fluctuations in atmospheric oxygen levels over the past 540 million years. This groundbreaking research suggests that processes deep within the Earth’s core might be influencing habitability on the planet’s surface.

At the heart of this phenomenon lies the Earth’s magnetic field, which is generated by the flow of molten material in the planet’s interior. Like a giant electromagnet, this process creates a dynamic field that has been fluctuating over time. The authors of the study point out that the role of magnetic fields in preserving the atmosphere is still an area of active research.

To uncover the hidden link between the Earth’s core and life-sustaining oxygen, scientists have analyzed magnetized minerals that record the history of the magnetic field. These minerals, formed when hot materials rise with magma at gaps between tectonic plates, retain a record of the surrounding magnetic field as long as they are not reheated too severely. By studying these ancient rocks and minerals, researchers can deduce historic oxygen levels based on their chemical contents.

The databases compiled by geophysicists and geochemists have provided valuable information on both the Earth’s magnetic field and oxygen levels over comparable ranges. Until now, no scientists had made a detailed comparison of the records. The findings of this study suggest that the two datasets are remarkably similar, with the planetary magnetic field following similar rising and falling patterns as oxygen in the atmosphere for nearly half a billion years.

The implications of this discovery are profound, suggesting that complex life on Earth might be connected to the interior processes of the planet. Coauthor Weijia Kuang said, “Earth is the only known planet that supports complex life. The correlations we’ve found could help us understand how life evolves and how it’s connected to the interior processes of the planet.”

Further research aims to examine longer datasets to see if the correlation extends farther back in time. The study also plans to investigate the historic abundance of other chemicals essential for life, such as nitrogen. As for the specific causes linking the Earth’s deep interior to life on the surface, scientist Kopparapu said, “There’s more work to be done to figure that out.”

The West Coast of the United States is no stranger to massive floods caused by atmospheric rivers. These powerful storms bring much-needed moisture to the region, but also pose a significant threat to communities and ecosystems. A new study has shed light on the hidden trigger behind these devastating events: wet soils that cannot absorb more water when a storm hits.

The research, published in the Journal of Hydrometeorology, analyzed over 43,000 atmospheric river storms across 122 watersheds on the West Coast between 1980 and 2023. The findings reveal that flood peaks were 2-4.5 times higher on average when soils were already wet. This means that even weaker storms can generate major floods if their precipitation meets a saturated Earth.

Lead author Mariana Webb, completing her Ph.D. at DRI and the University of Nevada, Reno, explained that flooding from any event is not just a function of storm size and magnitude but also depends on what’s happening on the land surface. The study demonstrates the key role that pre-event soil moisture can have in moderating flood events.

Interestingly, flood magnitudes do not increase linearly as soil moisture increases. There’s a critical threshold of soil moisture wetness above which you start to see much larger flows. This research also untangled the environmental conditions of regions where soil moisture has the largest influence on flooding.

In arid places like California and southwestern Oregon, storms that hit when soils are already saturated are more likely to cause floods. In contrast, in lush Washington and the interior Cascades and Sierra Nevada regions, watersheds tend to have deeper soils and snowpack, leading to a higher water storage capacity. Although soil saturation can still play a role in driving flooding in these areas, accounting for soil moisture is less valuable for flood management because soils are consistently wet or insulated by snow.

The study highlights the importance of integrating land surface conditions into impact assessments for atmospheric rivers. Webb worked with DRI ecohydrologist Christine Albano to produce the research, building on Albano’s extensive expertise studying atmospheric rivers, their risks, and their impacts on the landscape.

While soil saturation is widely recognized as a key factor in determining flood risk, Mari’s work helps to quantify the point at which this level of saturation leads to large increases in flood risk across different areas along the West Coast. Advances in weather forecasting allow us to see atmospheric rivers coming toward the coast several days before they arrive. By combining atmospheric river forecast information with knowledge of how close the soil moisture is to critical saturation levels for a given watershed, we can further improve flood early warning systems.

Increased monitoring in watersheds identified as high-risk, including real-time soil moisture observations, could significantly enhance early warning systems and flood management as atmospheric rivers become more frequent and intense. By tailoring flood risk evaluations to a specific watershed’s physical characteristics and climate, the study could improve flood-risk predictions.