Volume 15 Issue 4, April 2022

A synthesis of recent work on marine carbon export fluxes finds that many processes that are key to understanding the effects of a warming climate on ocean carbon cycling are missing from current climate models.

The formation of secondary organic aerosol in Chinese megacities is dominated by the condensation of anthropogenic organic vapours, according to measurements across three urbanized regions.

Dryland droughts are prone to self-propagation due to the enhanced soil water stress, according to atmospheric moisture-tracking analysis of recent major droughts around the world.

Dry-season climate variability is a primary driver of tropical tree growth, according to observations from a pantropical tree-ring network.

Solar radiation drives the asymmetry in the seasonal cycle of Antarctic sea ice, according to climate model simulations.

Very small aerosols from sea spray make up a larger proportion of cloud condensation nuclei than previously recognized, according to an analysis of five years of aerosol ground-based measurement data from over the Atlantic Ocean.

Large groups of spawning fish can induce upper ocean mixing on the same scale as geophysical processes, according to observations of small-scale turbulence caused by anchovy spawning aggregations in a coastal upwelling area.

Expansions of Antarctic Intermediate Water can help explain centennial-scale atmospheric CO₂ highs during the last deglaciation, according to a reconstruction of the marine carbonate system in the Southern Ocean.

Spontaneous, rapid climate fluctuations occur when atmospheric CO₂ is between 190 and 225 ppm, helping explain short-term warm–cool transitions during glacial climate states, according to combined Earth system and dynamical systems model simulations.

Warm, interglacial CO₂ levels increased following the mid-Pleistocene Transition, probably reflecting a step change in the influence of deep-ocean circulation on ice-sheet dynamics, according to a 1.46-million-year-long record of atmospheric CO₂ based on plant-wax carbon isotopes.

A modern-like South Asian Monsoon only appeared when East African and Middle Eastern uplift led to the establishment of the Somali Jet around 13 million years ago, according to Earth system modelling using a range of regional palaeogeographies.

Metasedimentary rocks atop the downgoing slab oxidize ascending slab-derived dehydration fluids by removing reduced species, according to petrological analysis of subduction complex metasedimentary rocks and reactive transport modelling.

Experiments under simulated hydrothermal conditions suggest that the mineral fluocerite may serve as an intermediate phase that fractionates the rare earth elements in ore-forming systems.

The seismic anomaly in the lowermost mantle beneath Africa is greater in height and less stable than its Pacific counterpart because of its lower density, according to numerical simulations of the anomalies as thermochemical piles.