A new study helps explain why unusually “hot and dry” summers can still occur frequently over a region that has undergone long-term warming and wetting.

Improving the subseasonal-to-seasonal (S2S) forecast skill for East Asian winter cold surges remains a grand challenge in operational meteorology. Using ECMWF hindcast data, a research team systematically identified the "high-skill windows" of week-3 cold surge forecasts. They found that a "warm-west/cold-east" sea surface temperature dipole over the mid-latitude North Pacific emerges as a consistent precursor of these windows under both El Niño and La Niña conditions, but that the dipole alone is not enough: high skill emerges only when the SST anomalies in all the key regions, including the Barents-Kara Seas, the Indian Ocean and the tropical Pacific, meet their thresholds at the same time. This makes it possible to pre-screen a subseasonal forecast's reliability before it is issued. The work was published in SCIENCE CHINA Earth Sciences.

A new study presents a mathematical model explaining why trees can support grass growth in dry environments but suppress it as rainfall increases. By separating the effects of canopy shade and tree roots, the researchers show when interactions shift from facilitation to competition, offering practical insights for afforestation, ecosystem restoration and land management.

Satellite measurements detected declining photosynthetic activity in Western U.S. forests two years before bark-beetle mortality appeared in aerial detection surveys, according to new University of Utah-led research. The first-of-its-kind study suggests that satellite-observed chlorophyll fluorescence (SIF), a measure of plant photosynthesis, could provide an early warning of forest stress. As drought, wildfire and insect outbreaks occur with increasing frequency across the American West, the technology could also help scientists understand how these disturbances affect forests’ ability to absorb and store carbon from the atmosphere.

The Southern Ocean is one of Earth's most important climate regulators, yet the clouds covering this remote region remain among the least understood features in atmospheric science. Their influence on the planet's energy balance makes accurate cloud representation essential for reliable weather forecasts and climate projections. A new study combines observations from an Antarctic expedition with advanced atmospheric datasets and climate models to investigate the processes behind this long-standing challenge in climate science.

Weather forecasts rely on many and various kinds of data, including temperature, humidity and wind data. For the first time, researchers including those at the University of Tokyo demonstrate that a long-theorized improvement to weather models by adding data on water isotopes in the atmosphere does in fact work. They showed that incorporating satellite measurements of water vapor isotopes into weather models improves forecasts of atmospheric conditions for up to five days, including better predictions of heavy rainfall in many regions.  

For decades, scientists have studied iron preserved in ancient rocks to reconstruct how Earth’s oceans and atmosphere became rich in oxygen. A new study suggests iron has recorded other major transformations too. Michigan State University research Dalton Hardisty and colleagues found that changes in Earth’s iron record also reflect the building of mountains and the rise of land plants.