Reviews & Analysis

Saturn's poles exhibit giant swirling cyclones, whereas Jupiter's poles may not. Simulations of giant planet atmospheres suggest that just the right balance of convective storm energy and poleward drift of cyclones may explain Saturn's vortices.

The continents have a puzzling structure — a transition occurs at mid-lithospheric depths. A synthesis of geological data indicates that stress-induced sliding along crystal grain boundaries may be responsible forforthe transition.

The solar wind, cometary ices, and inner Solar System bodies exhibit distinct nitrogen isotopic compositions. A synthesis of these analyses suggests that these distinct reservoirs may be the result of early fractionation processes.

The Earth's long-term silica cycle is intimately linked to weathering rates and biogenic uptake. Changes in weathering rates and the retention of silica on land have altered silica availability in the oceans for hundreds of millions of years.

Global surface warming has slowed since the start of the twenty-first century, while Pacific heat uptake was enhanced. Analyses of ocean heat content suggest that the warm water was transferred to the Indian Ocean, through the Indonesian straits.

The atmospheric layer that lies above Earth's weather systems can exert a strong downward influence. A review of this influence on storm tracks and surface weather suggests that the dynamical links between the layers hold across timescales.

An ancient carbon release resulted in widespread dissolution of carbonates at the sea floor. Numerical simulations suggest that the pattern of dissolution can be explained by a top-down invasion of corrosive bottom waters from the North Atlantic.

It is intuitive, but evidence that high levels of precipitation increase erosion rates has been elusive. The ages of exposed porphyry copper deposits reveal that rocks emplaced at depth travel to the surface faster where precipitation rates are high.

The Indian Plate moved north unusually quickly during the late Cretaceous. Numerical simulations suggest that this rapid migration was caused by the pull of two coupled, narrowing subduction zones.

Fjords account for less than 0.1% of the surface of Earth's oceans. A global assessment finds that organic carbon is buried in fjords five times faster than other marine systems, accounting for 11% of global marine organic carbon burial.

Subduction zone faults can slip slowly, generating tremor. The varying correlation between tidal stresses and tremor occurring deep in the Cascadia subduction zone suggests that the fault is inherently weak, and gets weaker as it slips.

Analyses of ice-core carbon isotopes show that variations in atmospheric CO₂ levels during the past millennium are controlled by changes in land reservoirs. But whether climate variations or human activity were mainly responsible is uncertain.

An iris effect in tropical cloud-cover was controversially proposed as a negative climate change feedback that is not represented in climate models. If such an effect exists, it could go some way to reconciling climate models and observations.

Titan's equatorial dunes seem to move in the opposite direction to the prevailing easterly winds. Infrequent methane storms at Titan's low latitudes may briefly couple surface winds to fast westerlies above, dominating the net movement of sand.

El Niño diversity and its genesis are debated. An overview of existing work along with a fuzzy clustering analysis and simulations suggest that the asymmetry, irregularity and extremes of El Niño result from westerly wind bursts.

Mountain glaciers around the world are in decay. According to a modelling study that — unusually — includes full ice flow physics, those in Western Canada will largely be restricted to the coastal region by the year 2100.

Our understanding of the interactions between clouds, circulation and climate is limited. Four central research questions — now tractable through advances in models, concepts and observations — are proposed to accelerate future progress.