Global climate mode resonance due to rapidly intensifying El Niño-Southern Oscillation

Publisher not available | October 16th, 2025

Increasing ENSO amplitude and teleconnection patterns imply that remote extratropical precipitation responses, such as in Southern California and the Iberian Peninsula (F

Increasing ENSO amplitude and teleconnection patterns imply that remote extratropical precipitation responses, such as in Southern California and the Iberian Peninsula (Fig. 5), will also become stronger between alternating El Niño and La Niña events. Even though the recurrence of these events may become more predictable due to the increased regularity/periodicity and amplitude (Fig. 1)44, future ENSO teleconnections might generate enhanced whiplash effects on hydroclimate, which requires additional planning and management strategies to minimize the costs of climate damage. While similar increases in ENSO regularity and amplitude can be found in some CMIP6 model projections (Fig. 2), future work needs to assess the detailed dynamics across these models and assess the likelihood of the ENSO regime changes seen in AWI-CM3.

Kaweah Subbasin Staff Assessment

California State Water Resources Control Board (SWRCB) | October 14th, 2025

The Kaweah Subbasin is managed by three GSAs: East Kaweah GSA, Greater Kaweah GSA, and Mid-Kaweah GSA (collectively, the Kaweah GSAs or GSAs). Each GSA wrote their own GS

The Kaweah Subbasin is managed by three GSAs: East Kaweah GSA, Greater Kaweah GSA, and Mid-Kaweah GSA (collectively, the Kaweah GSAs or GSAs). Each GSA wrote their own GSP, East Kaweah GSP (EKGSP), Greater Kaweah GSP (GKGSP), and Mid-Kaweah GSP (MKGSP). The three GSPs are tied together by a coordination agreement. The primary use of groundwater within the subbasin is irrigated agriculture; in 2020, irrigated agriculture used more than 94 percent of the groundwater in the subbasin (2024 Coordination Agreement, Appendix 1, p. 27). The subbasin is critically overdrafted, which means that groundwater is pumped out of the subbasin faster than it is recharged by precipitation and other sources. On average, the amount pumped from the subbasin in a year is 104,000 acre-feet greater than the amount recharged (2024 GKGSP p. 1-1). Overdraft can cause the land surface to sink, potentially damaging infrastructure and reducing aquifer storage. In addition, overdraft threatens groundwater levels and drinking water quality and could have disparate impacts on communities that rely on shallower groundwater levels. Due to historic and political factors, many of these are economically disadvantaged and communities of color. As of 2022, the subbasin has an estimated population of 296,632 people with most of the population being Hispanic or Latino (60.6%) followed by white (31%) (American Community Survey, 2022). The average annual household income within the subbasin in 2022 is $71,000, which is significantly less than the state average of $91,551 (ibid.).

Linking variation in water democracy to system performance on the human right to water

Springer Nature | October 8th, 2025

The 1922 Compact is Now the Obvious Elephant in the Negotiating Room

John Fleck | October 6th, 2025

Glaciers in California’s Sierra Nevada are likely disappearing for the first time in the Holocene

American Association for the Advancement of Science (AAAS) | October 1st, 2025

Mountain glaciers are sensitive climate indicators. Glaciers in the western United States are projected to disappear by 2100 CE, but whether they were previously absent i

Mountain glaciers are sensitive climate indicators. Glaciers in the western United States are projected to disappear by 2100 CE, but whether they were previously absent in the current interglacial (past 11,700 years) remains debated. Here, we present evidence that two of the largest glaciers in California’s Sierra Nevada near Yosemite National Park persisted throughout the Holocene. Cosmogenic in situ carbon-14 and beryllium-10 exposure dating in newly exposed proglacial bedrock indicates continuous Holocene cover, likely by ice. At a nearby smaller glacier, bedrock exposure-burial ages suggest glacier expansion at ~7 thousand years ago, earlier than previously recognized. Moraine exposure ages at these sites and the Sierra Nevada’s largest glacier are distributed across the past several thousand years, suggesting that glaciers were near their preindustrial extent for much of the late Holocene. These findings imply that a glacier-free Sierra Nevada is unprecedented since before the Holocene. Future alpine glacial environments in California are thereby likely a no-analog scenario within the current interglacial.

Identifying organic contaminants at trespass cannabis grows on federal land in California, USA

Elsevier | September 25th, 2025

Despite the legalization of recreational cannabis in California, USA, illegal cannabis cultivation remains pervasive, partly through the establishment of illegal cult

Despite the legalization of recreational cannabis in California, USA, illegal cannabis cultivation remains pervasive, partly through the establishment of illegal cultivation on public lands (trespass grows). These operations often illegally divert water for irrigation and perform unauthorized applications of chemical fertilizers and pesticides. This work investigates a broad suite of these chemicals, focusing on their persistence in topsoil and presence in water and bed sediment in adjacent streams. Quantitative analyses of pesticides were conducted (183 compounds in water; 176 in topsoil/bed sediment), supplemented by qualitative nontargeted screening at three trespass grows that had no active cultivation for 8 months to 2 years. Targeted multi-residue analysis of topsoil detected the insecticides bifenthrin, cyfluthrin, malathion and imidacloprid (with concentrations up to 38 ng/g dry weight, d.w.), and the fungicides fluopyram, myclobutanil, and triadimefon (concentrations up to 8.1 ng/g d.w.). No pesticides were detected in the companion water or streambed sediment samples from adjacent streams. In addition, no water samples were found to have measurable estrogenic activity. Nontargeted screening uncovered additional pesticides (i.e., spiromesifen, trinexapac) in the topsoil and cannabis-related compounds (i.e., cannabidol, delta9-tetrahydrocannabinol) in both topsoil and streambed sediment suggesting the likelihood of offsite transport of cannabis related compounds. Phthalate plasticizers, rubber-related compounds, pharmaceuticals and personal care product chemicals were detected in topsoil, water, and streambed sediment and may be related to extensive irrigation infrastructure installed at these trespass grows. This work begins to establish a contaminant profile associated with illegal cannabis growing activities, providing a foundation for future research focused on their potential ecological impacts.

Hot Drought of Summer 2023 in Southwestern North America

American Geophysical Union (AGU) | September 17th, 2025

Hot droughts, or compound drought and heatwaves, have a significant impact on arid regions in southwestern North America (SWNA). In the summer of 2023, SWNA experienced u

Hot droughts, or compound drought and heatwaves, have a significant impact on arid regions in southwestern North America (SWNA). In the summer of 2023, SWNA experienced unusually intense hot droughts during both the daytime and nighttime, with their severity amplified three to five times above values during the prior four decades. Over this period, a significant increase was found in the coupling between nighttime and daytime conditions at local scales and across different regions of the SWNA. The hot drought was due to a suppressed North American monsoon (NAM) in response to synoptic-scale subsidence and moisture divergence. Nevertheless, we identified a remote connection between soil moisture in upwind areas and hot drought conditions in downwind regions across the US-Mexico border. Our findings indicate that hot droughts need to be analyzed over complete diurnal cycles and over regions that are connected through atmospheric pathways to improve their prediction, response, and mitigation.

Impact of current and warmer climate conditions on snow cover loss in burned forests

American Association for the Advancement of Science (AAAS) | September 17th, 2025

Wildfires are increasingly burning in snow-dominated watersheds and can alter snowmelt dynamics. However, the spatial variability of snow cover loss in burned forests has

Wildfires are increasingly burning in snow-dominated watersheds and can alter snowmelt dynamics. However, the spatial variability of snow cover loss in burned forests has been under characterized. Here, we use remotely sensed snow data to show that, under average winter conditions, snow melts earlier in the first year postfire in 99% of the snow zone. Postfire snow cover loss is more extreme in relatively low-elevation, warm environments compared to that in high-elevation, cold regions. Under +2°C of warming, 73% of the snow zone would experience more extreme earlier postfire snowmelt compared to historically average conditions. Regions with the largest shift earlier in postfire snowmelt timing under average climate conditions also have the largest shift earlier in postfire snowmelt under +2°C warming. The spatial variability in postfire snowmelt timing and exacerbated impact in projected warmer winters affect ecosystem water availability, snow albedo feedbacks, and snowmelt runoff forecasting essential to water resource management.

Analysis of Colorado River Basin Storage Suggests Need For Immediate Action

John Fleck | September 11th, 2025

Extremophile hotspots linked to containerized industrial waste dumping in a deep-sea basin

Oxford University Press (OUP) | September 9th, 2025

Decaying barrels on the seafloor linked to DDT contamination have raised concerns about the public health implications of decades old industrial waste dumped off the coas

Decaying barrels on the seafloor linked to DDT contamination have raised concerns about the public health implications of decades old industrial waste dumped off the coast of Los Angeles. To explore their contents, we collected sediment cores perpendicular to five deepsea barrels. The concentration of DDT and its breakdown products were highly elevated relative to control sites yet did not vary with distance from the barrels, suggesting that they were not associated with the contamination. Sediment cores collected through white halos surrounding three barrels were enriched in calcite and had elevated pH. The associated microbial communities were low diversity and dominated by alkalophilic bacteria with metagenome-assembled genomes adapted to high pH. A solid concretion sampled between a white halo and barrel was composed of brucite, a magnesium hydroxide mineral that forms at high pH. Based on these findings, we postulate that leakage of containerized alkaline waste triggered the formation of mineral concretions that are slowly dissolving and raising the pH of the surrounding sediment pore water. This selects for taxa adapted to extreme alkalinity and drives the precipitation of “anthropogenic” carbonates forming white halos, which serve as a visual identifier of barrels that contained alkaline waste. Remarkably, containerized alkaline waste discarded >50 years ago represents a persistent pollutant creating localized mineral formations and microbial communities that resemble those observed at some hydrothermal systems. These formations were observed at one-third of the visually identified barrels in the San Pedro Basin and have unforeseen, long-term consequences for benthic communities in the region.