Volume 10 Issue 12, December 2017

Temperature overshoot scenarios that make the 1.5 °C climate target feasible could turn into sources of political flexibility. Climate scientists must provide clear constraints on overshoot magnitude, duration and timing, to ensure accountability.

Progress in the post-combustion treatment of diesel vehicle exhaust has led to shifting proportions of the constituents of nitrogen oxides. Observations from 61 European cities suggest that the outlook on attaining NO₂ standards is more optimistic than expected.

A link between CO₂ outgassing from carbonatite volcanoes during the Ediacaran and one of the most prominent carbon cycle perturbations in Earth’s history is suggested by an analysis of the trace-element composition of detrital zircons.

Rising oxygen levels may have facilitated the Great Ordovician Biodiversification Event according to a reconstruction of atmospheric oxygen concentrations.

Storm-resolving simulations of the tropical Atlantic region bring out the doldrums, a zone of calm and variable winds in the deep tropics that was described in the nineteenth century and then forgotten.

Continental rifts are stores and sources of abundant carbon, according to calculations of carbon storage, enrichments and mobilization in rift systems. Continental rift systems are likely to play an important role in Earth’s deep carbon cycle.

Recurring slope lineae are likely to be dry granular flows with little-to-no requirement for large volumes of liquid water on Mars, according to an emerging view that is supported by topographic analyses.

Storms are not only generated at higher latitudes, they also travel further in a warmer climate, according to analyses of climate model output with a storm-tracking algorithm. The larger travel distance is attributed to stronger upper-level winds and increased atmospheric water vapour.

The fraction of NO₂ in NO _x emitted from European road transport is up to a factor of two smaller than used in policy projections, suggests an analysis of 130 million roadside observations. Roadside air quality standards may thus be obtained faster.

The current distribution of crops around the world neither attains maximum production nor minimum water use, according to a crop water model and yield data. An optimized crop distribution could feed an additional 825 million people and substantially reduce water use.

An increase in biodiversity 450 million years ago coincided with a rise in atmospheric oxygen concentrations, suggests a geochemical analysis. Oxygen availability may have thus helped spur the radiation alongside climatic cooling.

A spike of carbon-rich volcanism during the Ediacaran period identified in detrital zircon data may reflect a reorganization of the Neoproterozoic deep carbon cycle.

Past megathrust earthquakes in the Costa Rica subduction zone have slipped all the way up to the seafloor, according to analyses of core and seismic data. This shallow slip was accommodated by layers of weak biogenic ooze.

Degassing of large amounts of CO₂ from continental rifts may have contributed to greenhouse climate episodes over the past 200 million years, according to numerical models.

A super-hydrated clay mineral may play an important role in the solid Earth’s water cycle, according to laboratory experiments. The mineral kaolinite can carry and release large amounts of water during subduction.

Consolidated sediments in the Cascadia subduction zone may create conditions favourable for megathrust earthquake ruptures over long distances and close to the trench, according to analyses of seismic velocity of sediments from the region. Less-consolidated sediments instead may promote  aseismic slip of the plate boundary.

Seismic activity within subducted slabs could be caused by differential stress release, according to analysis of fossilized remnants of earthquake slip in an exhumed slab. These deep earthquakes were previously thought to mark either slab dehydration, or thermal runaway processes .