Research Briefing

Over a prolonged period of hydrologic drought, the major ion chemistry of a North American river dramatically shifted, revealing reduced lateral carbon transport due to secondary carbonate formation. These observations expose a natural limit to the inorganic carbon carrying capacity of rivers.

High-resolution satellite maps of the contiguous USA spanning 35 years reveal a fundamental shift in land disturbances: the area affected by human-directed disturbances is decreasing, whereas land damaged by ‘wild’ disturbances (like fire, vegetation stress, wind, and geohazards) is surging. This work also uncovers evolving patterns in the frequency, size, and severity of disturbances.

Geophysical observations and computer simulations suggest that a tectonic plate segment is delaminating in the area that generated a large earthquake that destroyed Lisbon in 1755. This rare oceanic delamination might be a precursor of subduction initiation, which could explain the cause of several large earthquakes in the Atlantic Ocean.

A dataset of cosmogenic beryllium-7 measurements is compiled and used to quantify aerosol deposition rates over the global ocean. The findings suggest that aerosol deposition onto oceans has been underestimated in a widely used atmospheric composition model, GEOS-Chem, resulting in an overestimation of aerosol lifetime over oceans.

A decade-long field experiment reveals that topsoil nitrogen stocks in a permafrost ecosystem decreased by 7.7% following eight years of warming. This reduction could be largely attributed to increased nitrogen retention by perennial plant biomass, and increased nitrogen losses through leaching and gaseous emissions from soils.

The combination of plate motion and intraplate stress with a high-resolution, plate-boundary-resolving, global convection model has made it possible to holistically evaluate plate driving forces and reveal that Sumatra–Java slab pull is the predominant driver of the India–Eurasia collision. This suggests the growth of the Tibetan Plateau required external forces from adjacent subduction zones.

Analysis of millimetre-sized fragments from asteroid Bennu suggests that its parent asteroid coalesced in the outer Solar System from primordial nebular dust and ice and was poor in chondrules, objects common in primitive meteorites. Abundant phyllosilicates with minor sulfides, carbonates and magnetite formed during early alteration by water, with evaporite minerals forming later.

Lignin and the monophenols that constitute this polymer promote methane production in anoxic ecosystems, contributing an estimated 1.2–14.2% of methane emissions in peatland. The methoxy group can be directly converted to methane by methanogens. Consequently, increased lignin input to peatland from shrub encroachment would release more methane than previously thought.

Lake shores are fringed with aquatic plants, but their very high productivity has been overlooked in global lake carbon budgets. We estimate the carbon fluxes of lake littoral zones and show that the carbon balance of lakes can reverse from a carbon source to a carbon sink when these zones are included.

Proxy–model comparisons from the mid-Holocene and ensemble projections of future warming reveal that Northern-Hemisphere warming repeatedly forces the Pacific Decadal Oscillation into a persistent negative phase. This forced North Pacific response stifles winter storms, pointing to a persistent warming-driven drought risk in the Southwest US.

A new study tracks sea ice, ocean swell and ice shelf conditions over multiple years in the lead-ups to large-scale Antarctic ice shelf calving events. We quantified the strengths and durations of increased ice shelf flexure that preconditioned and subsequently triggered the calving events.

New experiments shed light on the complex interplay between rock deformation and metamorphism. Slab stagnation in Earth’s mantle transition zone may be explained by transient weakening during the olivine–spinel phase transition.

Calculation of the sulfur and water budgets released from magma during the 2022 eruption of Hunga volcano — the largest submarine eruption recorded — shows that of 18.8 Tg of sulfur dioxide released, <7% entered the atmosphere. The remaining sulfur dioxide dissolved in the ocean during explosive magma fragmentation at 400–1,000 m below sea level.

The Indian summer monsoon plays a key part in influencing marine life in the Bay of Bengal. Palaeoceanographic records reveal that both extremely weak and strong monsoon phases led to declines in marine productivity. Future monsoon shifts pose a disruptive threat to the stability of regional ecosystems and fisheries.

Atmospheric oxygen, supplied from the oceans, dramatically rose during the Great Oxidation Event. Our examination of the preceding evolution of seawater oxygenation revealed that the redox state in seawater oscillated between oxic and anoxic conditions before oceanic oxygenation again increased towards the dawn of the Great Oxidation Event.

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.

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.

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.

Ongoing climate change might alter the Atlantic–European jet and affect hydroclimate extremes. Reconstructions of jet metrics for 1421–2023 show that summer drought in Central Europe coincided with a poleward shift and flood episodes coincided with an equatorward shift. Recent changes (past 30 years) are still within the boundaries of past variability.