Volume 11 Issue 2, February 2018

The first of two stepwise increases in atmospheric oxygen occurred at the end of the Archaean eon. Analyses of sulfur and iron isotopes in pyrite reveal a near-shore environment that hosted locally oxygenated conditions in the Mesoarchaean era.

Experimental data reveal that Earth’s mantle melts more readily than previously thought, and may have remained mushy until two to three billion years ago.

Land management with the aim of reducing incoming solar radiation could help with regional-scale climate adaptation and mitigation as well as ecosystem services, and avoids several shortcomings of global geoengineering.

Earth experienced a lull in magmatic and tectonic activity about 2.3 billion years ago, followed by a flare-up of magmatism, according to a compilation of existing geologic data. These events might mark the transition to the supercontinent cycle.

A 1.5 °C climate target implies total emissions of carbon from the start of 2017 must fall below 195 to 205 PgC, according to an observationally constrained very large ensemble of simulations with an efficient Earth system model.

Variability of summertime Arctic sea-ice reduction is closely linked to transient Arctic anticyclones, which result from air mass injections into the Arctic upper troposphere  associated with extratropical cyclones.

Two catastrophic glacier collapse events in western Tibet in 2016 were caused by a convergence of weather and glacier-bed conditions, according to an analysis of observations and modelling.

Ice-shelf mass in the Amundsen Sea is influenced by El Niño events and other interannual climate variability, according to an analysis of satellite altimeter data from 1994 to 2017.

Depending on their connectivity to the river network, wetlands can be much more efficient at removing nitrate in a watershed than common nitrogen mitigation strategies according to an analysis of the Minnesota River basin.

Oxidized sulfur, formed in photochemical reactions in an anoxic atmosphere, fuelled microbial sulfate reduction in Mesoarchaean oxygenated near-shore seas, according to sulfur and iron isotopes in pyrite.

A persistent melt layer may have existed in the Archaean upper mantle, according to experimental analyses. The melt layer could have decoupled the mantle from the overlying lithosphere, hindering plate tectonics.

The lowermost mantle and transition zone are increasingly oxidized at depth, according to analyses of the oxidation state of iron in majoritic garnet inclusions from deep diamonds.