Volume 18 Issue 4, April 2025

Continued ground uplift long after the drying out of the Aral Sea demonstrates that human activity can provoke a response deep inside our planet, in this case by causing rock in Earth’s mantle to flow.

Davemaoite is the least abundant of the lower mantle rock-forming minerals. Despite this, it is a maverick that exerts a big influence on geochemical cycling, as Oliver Tschauner explains.

Measurements from a robotic underwater vehicle reveal the impacts of meltwater from the giant iceberg A-68A on the properties of the surrounding Southern Ocean. In addition to increasing surface stratification and mid-depth vertical mixing, the meltwater impacts primary productivity, with direct and indirect effects on ecosystems and carbon cycling.

High-pressure experiments reveal that calcium solubility in bridgmanite is insufficient to fully remove davemaoite from the Earth’s lower mantle. We propose that davemaoite-enriched domains form at the core–mantle boundary, serving as reservoirs for incompatible elements and offering a potential explanation for large low shear-wave velocity provinces.

Aquatic vegetation has an important role in lake methane emissions. Between 1984 and 2021 the maximum area of aquatic vegetation in northern lakes (>40° N) expanded by 2.3 × 10⁴ km². This expansion could substantially increase long-term total methane emissions from lakes.

Analysis of global datasets indicates that dry to wet transitions in soil wetness over regions spanning around 500 km can increase the size and rainfall intensity of organized thunderstorms around the world. Therefore, observations of soil moisture could improve storm forecasts and support adaptation to changing hazards under climate change.

In situ observations indicate a greater susceptibility of cloud droplet number to cloud condensation nuclei than is estimated from satellite observations, which suggests that aerosols exert a stronger radiative forcing than previously thought.

Experimentally constrained flow laws predict ice-sheet strain rates that differ by an order of magnitude from estimates made using previous flow laws, highlighting the need for accurate flow laws in ice-sheet modelling.

Observations from an underwater glider show that meltwater from giant icebergs increases ocean stratification near the surface and mixing below, potentially impacting biological productivity.

Anthropogenic climate change leads to higher precipitation in East Asia and western United States due to a teleconnection associated to delayed warming in the Southern Ocean.

Areas of aquatic vegetation have expanded in northern lakes between 1984 and 2021, and this expansion is probably an additional climate feedback that enhances methane emissions, according to a monitoring study using Landsat imagery.

Large-scale soil moisture gradients can lead to increases in vertical wind shear that promote the growth of mesoscale convective systems and enhance rainfall, according to an analysis of global hotspots of these extreme storm systems.

Multi-year La Niña and El Niño events became more common over the past 7,000 years because of orbital forcings causing gradual changes in upper-ocean stratification in the Tropical Eastern Pacific, according to an analysis of proxy records and palaeoclimate modelling.

Numerical simulations suggest the wavelength of wind ripples is controlled by the mechanics of grain–bed impacts, not grain hop length, explaining why ripples on Mars and Earth are the same scale despite very different atmospheric conditions.

The drying out of the Aral Sea has induced flow of the relatively weak asthenosphere beneath, demonstrating that human activity can influence mantle dynamics, according to numerical simulations of ground uplift measured by radar interferometry.

Drip-like features imaged in a seismic tomography model are consistent with extensive ongoing thinning of cratonic lithosphere beneath North America.

The calcium silicate perovskite mineral davemaoite probably persisted since lower-mantle formation and may form davemaoite-enriched domains at the core–mantle boundary, according to an experimental study at lower-mantle conditions.