Reviews & Analysis

Climate change is governed by changes to the global energy balance. A synthesis of the latest observations suggests that more longwave radiation is received at the Earth's surface than previously thought, and that more precipitation is generated.

Climate model projections of future precipitation extremes in the tropics are highly uncertain. Observations of year-to-year variations in extremes of present-day climate help to narrow down these projections to a rise in extreme rainfall by 6–14% per °C of warming.

Clay minerals on Mars have been interpreted as an indication for a warm, wet early climate. A new hypothesis proposes that the minerals instead formed during brief periods of magmatic degassing, diminishing the prospects for signs of life in these settings.

Shallow magma bodies that feed regularly erupting volcanoes are usually considered enduring features that grow steadily between eruptions. Measurements of deformation at Santorini, however, reveal sudden rapid magma accumulation after half a century of rest.

The high eastern Tibetan Plateau was thought to have formed from an inflow of material from the lower crust. The cooling histories of rocks exposed at the plateau margin, however, reveal protracted, episodic growth, suggesting that faulting also played a role.

The Triassic–Jurassic period extinction marked a rapid turnover in the marine realm. Biomarkers in marine rocks suggest that the development of sulphidic conditions in the early Jurassic delayed marine recovery.

Iron-loving elements are thought to have been added to Mars, Earth and the Moon after core formation. An analysis of meteorites formed in the first two to three million years of Solar System history suggests that a similar late veneer was added elsewhere too.

Sulphur cycling on early Earth is commonly linked to microbial activity. However, sulphur isotope values from 3.2–3.5-billion-year-old rocks indicate a central role for the breakdown of volcanic sulphur dioxide by ultraviolet radiation instead.

Deep convection does not normally occur in the modern North Pacific Ocean, but that may have changed during the last deglaciation. Sea ice and surface temperature reconstructions show that if so, it was not associated with significant northward heat transport.

The beginning of the Holocene interglacial was marked by ice-sheet melting and sea-level rise. A review of sea level and climate records identifies two sea-level jumps associated with the final drainage of glacial Lake Agassiz, and links them to an abrupt cooling event.

During periods of glaciation, the Northern Hemisphere was swathed by large ice sheets. A review of ice-sheet retreat during the last two deglaciations shows that land-based ice sheets responded rapidly to rising summer insolation, whereas marine-based ice sheets underwent a delayed, but more abrupt, response.

Enigmatically, some landslides flow farther than normal frictional resistance allows. Cassini images of Saturn's icy moon Iapetus reveal a multitude of long-runout landslides that may have been enabled by flash heating along the sliding surface.

The geomagnetic field varies on a wide range of timescales. A review of emerging research suggests that field variations on the order of tens of millions of years may be linked to changes in heat flow across the core–mantle boundary.

The southeastern US coastline is under threat as land subsides and sea level rises. Measurements of the 2011 Mississippi River flood suggest that the river carries enough sandy sediment to offset some of this coastal drowning.

Earth's magnetic field is characterized by a puzzling hemispheric asymmetry. Calculations of core dynamo processes suggest that lopsided growth of the planet's inner core may be part of the cause.

Despite variable forcing by tectonics, the height of mountain ranges seems to be limited. Satellite imagery suggests that landsliding rates adjust to large changes in uplift, acting to maintain hillslopes of similar steepness.

Aerosol concentrations in China have reached unhealthy levels, at least locally. Model simulations suggest that a significant contribution comes from the weakening monsoon circulation in past decades, trapping more pollutants over land.