Review Articles

Iron controls phytoplankton growth in large tracts of the global ocean, and thereby influences carbon dioxide drawdown. Recent advances reveal the importance of iron-binding ligands and organic matter remineralization in regulating ocean iron levels.

Slow slip, a mechanism by which faults can relieve stress, was thought to be distinct from earthquakes. However, a global review of slow-slip phenomena suggests that instead there is a continuum between the two types of event.

The terrestrial biosphere is a key regulator of atmospheric chemistry and climate. Total positive radiative forcing resulting from biogeochemical feedbacks between the terrestrial biosphere and atmosphere could be equally as important as that resulting from physical feedbacks.

The El Niño–Southern Oscillation is a naturally occurring fluctuation that originates in the tropical Pacific region and affects the lives of millions of people worldwide. An overview of relevant research suggests that progress in our understanding of the impact of climate change on many of the processes that contribute to El Niño variability is considerable, but projections for the phenomenon itself are not yet possible.

The use of fossil fuels and fertilizers has increased the amount of biologically reactive nitrogen in the atmosphere over the past century. A meta-analysis suggests that nitrogen deposition typically impedes the decomposition of carbon in forest soils, significantly reducing carbon dioxide emissions to the atmosphere.

Whether the characteristics of tropical cyclones have altered, or will alter, in a changing climate has been subject of considerable debate. An overview of recent research indicates that greenhouse warming will cause stronger storms, on average, but a decrease in the frequency of tropical cyclones.

Global mean sea-level change has increased from a few centimetres per century over recent millennia to a few tens of centimetres per century in recent decades. A review of the latest work shows that global mean sea-level rise is unlikely to exceed one metre over the twenty-first century, but regional departures from this global mean could reach several decimetres.

The myriad bodies that occur in the Solar System show a wide range of physical properties. Exploration by spacecraft during the past four decades has shown that volcanism — a major mechanism by which internal heat is transported to the surface — is common on many of these bodies.

Cordilleran orogenic systems are long belts of deformation and magmatism that form when oceanic plates subduct beneath continental ones. Links between processes in the upper continental plate explain key features of Cordilleran systems, such as cyclical trends in the flux and composition of magma supplied to the upper plate.

Field studies and experimental research during the past two decades have provided considerable evidence for a significant influence of climate on tectonics. Recent advances suggest that model predictions can guide future fieldwork aimed at substantiating this view.

The Snowball Earth concept envisages a fully frozen Earth for millions of years several times during the Neoproterzoic Era between 1,000 and 542 million years ago. However, the sedimentary evidence suggests that despite the severity of glaciation, some oceans must have remained ice-free.

The quest to determine climate sensitivity has been going on for decades, with disturbingly little progress in narrowing the large uncertainty range. But fascinating new insights have been gained that will provide useful information for policy makers, even though the upper limit of climate sensitivity will probably remain uncertain for the near future.

Cratons are ancient continental nuclei that have resisted significant fragmentation for almost two billion years. Yet, many cratons also experience phases of instability in the form of erosion and rejuvenation of their thick lithospheric mantle keels. Melting governed by redox processes as well as small-scale convection play a key role in triggering such instability.

Land and ocean carbon sinks play a critical role in determining atmospheric carbon dioxide levels. Nitrogen-induced increases in land and ocean sink strength are unlikely to keep pace with future increases in carbon dioxide.

Subglacial water can significantly affect the velocity of ice streams and outlet glaciers of ice sheets. Depending on the geometry and capacity of the subglacial hydrologic system, increased surface melting in Greenland over the coming decades may influence the ice sheet's mass balance. Furthermore, subglacial lakes in Antarctica can modulate ice velocities and act as nucleation points for new fast-flowing ice streams.

Black carbon in soot is an efficient absorbing agent of solar irradiation that is preferentially emitted in the tropics and can form atmospheric brown clouds in mixture with other aerosols. These factors combine to make black carbon emissions the second most important contribution to anthropogenic climate warming, after carbon dioxide emissions.

Despite Titan's cold temperatures (about 93.7 K at the equator), fluvial and atmospheric processes are active on this moon of Saturn, with methane playing a similar role to water on Earth. However, Titan lacks a global methane ocean, and rainfall appears to be episodic.

Emerging evidence for threefold higher heat flow across the core–mantle boundary prompts a re-evaluation of the role of thermal plumes in geodynamics and the thermal history of the Earth's core and lower mantle.