Despite record rainfall in the region in early 2023, only a fraction of Southern California’s groundwater reserves has been replenished, researchers report. Their study, which leverages seismic noise data from across Greater Los Angeles, highlights the urgent need for improved monitoring and management of the state’s critical groundwater reserves. After enduring two decades of severe drought, California experienced an abrupt meteorological shift in water in 2023. A succession of 16 atmospheric rivers from late 2022 through early 2023, followed by the torrential rains of Hurricane Hilary in August, resulted in one of the wettest years on record. In the Greater Los Angeles region, rainfall reached 300% of historical norms. Although this period of intense precipitation rapidly replenished California’s surface reservoirs to 128% of their historical average, the extent of groundwater recovery has remained uncertain. Accurately quantifying changes in groundwater storage is essential for assessing drought impacts and ensuring sustainable water management. Yet, it remains a complex challenge, particularly at the basin-to-watershed scale essential for resource planning. Focusing on the Los Angeles area, Shujuan Mao and colleagues demonstrate that seismic noise analysis can effectively track groundwater storage changes with high resolution. Using ambient-field interferometry and passive data from 2003 to 2023 from a network of existing seismometers, Mao et al. measured variations in seismic wave speed; these variations reflect shifts in subsurface water distribution due to groundwater recharge. The regional seismic hydrograph revealed that the 2023 storms replenished only about 25% of the groundwater lost over the past two decades, highlighting substantial long-term depletion and a slow recovery of deep aquifers on a decadal scale. “Integrating the seismic imaging techniques of Mao et al. with existing methods, such as in situ well monitoring and satellite-based or aerial remote-sensing observations, would allow for comprehensive tracking of groundwater,” write Taka’aki Taira and Roland Bürgmann in a related Perspective. “This will help to ensure the preservation of sustainable water supplies for future generations.”

The Society for Neuroscience (SfN) has selected 10 members from a highly competitive applicant pool to participate in the Society’s annual Capitol Hill Day on March 11–13, 2025. The 10 Early Career Policy Ambassadors (ECPAs), representing many career stages and geographic locations, were chosen for their dedication to advocating for the scientific community, their desire to learn more about effective means of advocacy, and their experience as leaders in their labs and community.

Many Belt and Road Initiative (BRI) countries are developing nations with significant potential for future carbon emissions growth, making their green transition crucial to achieving the Paris Agreement goals. This study applies a two-stage decomposition model to analyze emission drivers across income levels. Findings show that from 1987 to 2022, economic growth was the main driver of emissions, while energy intensity and carbon intensity had a mitigating effect. Low-carbon transitions in many BRI countries remain slow or have yet to begin, especially in low-income nations where fossil fuel dependence is deepening. In contrast, high-income BRI countries have shifted from coal and oil to natural gas. During economic crises, most countries relied on high-carbon energy for recovery and relaxed energy efficiency standards. The study offers policy recommendations to accelerate emissions reduction in BRI countries and highlights the importance of international cooperation.

New analysis published in the BMJ reveals the UK gambling industry is mimicking the tactics first used by Big Tobacco decades ago to downplay the harms of gambling and influence policy, including to avoid stricter regulation. NEW analysis published in the BMJ reveals the UK gambling industry is mimicking the tactics first used by Big Tobacco decades ago to downplay the harms of gambling and influence policy, including to avoid stricter regulation.