Volume 10 Issue 9, September 2017

Developments in attribution science are improving our ability to detect human influence on extreme weather events. By implication, the legal duties of government, business and others to manage foreseeable harms are broadening, and may lead to more climate change litigation.

Mass changes in High Mountain Asia's glaciers have been under dispute for almost a decade. An analysis of satellite data archives provides an observation-based mass budget for every single glacier in the region.

A fast equatorial jet in the Venusian cloud layer has been revealed by the Akatsuki orbiter by tracking cloud movement in near-infrared images. The findings suggest that the Venusian atmosphere is more variable than previously thought.

The processes that form and recycle continental crust have changed through time. Numerical models reveal an evolution from extensive recycling on early Earth as the lower crust peeled away, to limited recycling via slab break-off today.

Estimates of carbon in the deep mantle vary by more than an order of magnitude. Coupled volcanic CO₂ emission data and magma supply rates reveal a carbon-rich mantle plume source region beneath Hawai'i with 40% more carbon than previous estimates.

Microbial metabolisms depend on enzymes that contain trace metals. A synthesis of molecular and geochemical data shows that these metabolic pathways evolved alongside changing marine availability of trace metals during the Precambrian.

River deltas are shaped by interactions between fluvial and tidal processes. Tides act to stabilize delta morphology, but sediment depletion due to human activities disrupts the balance and leads to erosion and scour.

Venus is covered by thick clouds that move with the prevailing winds. Images from JAXA’s Akatsuki orbiter taken in July 2016 reveal more variability deep in the cloud layer than expected, including a feature consistent with an equatorial jet.

The Martian atmosphere hosts water-ice clouds, but it is thought that any snow precipitation settles slowly, rather than in storms. Martian meteorology simulations suggest that localized convective snowstorms can occur on Mars during the night.

Ancient Mars may have had an active sulfur cycle. In situ analyses by the Curiosity rover reveal large variations in the current sulfur isotopic composition of Martian sediments that can be explained by geologic and atmospheric processes.

The strength of the global meridional overturning circulation in the stratosphere is uncertain. An analysis of satellite data, reanalyses and model simulations reveals a strength of 6.3–7.6 × 10⁹ kg s⁻¹, but no convergence at higher altitudes.

Glacier mass balances in High Mountain Asia are uncertain. Satellite stereo-imagery allows a spatially resolved estimate for about 92% of the glacierized area and yields a region-wide average of about 16 Gt yr⁻¹ for 2000 to 2016.

Sea spray aerosols are thought to alter cloud properties in remote ocean regions. Aerosol analyses over four ocean regions reveal that these aerosols represent less than 30% of cloud condensation nuclei in typical marine boundary layer clouds.

How rivers evacuate large landslide deposits is crucial for predicting post-seismic hazards. A 2D hydro-sedimentary model demonstrates that a narrowing river channel increases sediment transport, which reduces export time by orders of magnitude.

Fluid flow in Earth’s crust redistributes minerals. Nanoscale imaging and molecular dynamics simulations suggest this flow is controlled by electrokinetic transport phenomena, highlighting the importance of nanoscale processes in metamorphism.

The East Antarctic ice sheet was larger than present during past cold periods. Seafloor geophysical data show that in the Ross Sea, the extended ice sheet was underlain by an active hydrologic system during the glacial termination.

The processes for crustal recycling during the Archaean are unclear. Numerical simulations suggest that dense lower crust would have peeled off into the mantle, leading to a rapid concentration of buoyant silicic rocks that formed the continents.

Estimates of the carbon content of Earth’s mantle and magmas vary. Analysis and modelling of gas emissions at Hawai‘i indicate that the amount of carbon in the Hawaiian mantle plume and CO₂ in Hawaiian lavas is 40% greater than previously thought.