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  • Power generation as well as the production of fuels for transportation requires water, and the supply of high-quality freshwater is energy intensive. A growing population and climate change will increase the pressure on both resources.

    • Carey W. King
    • Ashlynn S. Holman
    • Michael E. Webber
    Commentary
  • On geological timescales, carbon dioxide enters the atmosphere through volcanism and organic matter oxidation and is removed through mineral weathering and carbonate burial. An analysis of ice-core CO2 records and marine carbonate chemistry indicates a tight coupling between these processes during the past 610,000 years, which suggests that a weathering feedback driven by atmospheric CO2 leads to a mass balance between CO2 sources and sinks on long timescales.

    • Richard E. Zeebe
    • Ken Caldeira
    Letter
  • 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.

    • Robin E. Bell
    Review Article
  • Tropospheric ozone contributes significantly to human-induced greenhouse warming. Calculations from satellite measurements of spectral radiance suggest that ozone in the upper troposphere caused an average reduction in clear-sky outgoing long-wave radiation over the oceans of 0.48±0.14 W m−2 for the year 2006 between 45 S and 45 N.

    • Helen M. Worden
    • Kevin W. Bowman
    • Reinhard Beer
    Letter
  • The Eocene–Oligocene transition is the largest global cooling in the Cenozoic period. A comparison of three independent proxies from the continental shelf and deep ocean reveals a three-step transition to cold glacial conditions, with ice sheets 25% larger than their present size.

    • Miriam E. Katz
    • Kenneth G. Miller
    • Yair Rosenthal
    Article
  • Using experimental conditions approximating those of the early Earth, the partition coefficient for palladium was found to be sufficiently low to explain the palladium content of the Earth’s mantle in terms of an early equilibration of the mantle with core-forming metals, rather than requiring the addition of a ‘late veneer’ of chondritic material after core formation.

    • K. Righter
    • M. Humayun
    • L. Danielson
    Letter
  • Jim Roberts and colleagues inhaled petrochemical fumes and navigated between ships and oil platforms in order to understand halogen chemistry in the Houston area and along the Texas coast.

    Backstory
  • Nitryl chloride, an active halogen, can be produced through the night-time reaction of dinitrogen pentoxide with chloride-containing aerosol in the polluted marine boundary, and has been measured at levels that are sufficient to affect the photochemistry of oxidants off the southwestern US coast and near Houston, Texas.

    • Hans D. Osthoff
    • James M. Roberts
    • Steven S. Brown
    Article
  • Temperature changes with depth do not appear to be a primary control for either slow slip or fault-locking processes at the Hikurangi margin, North Island, New Zealand. Both slow-slip events and the geodetically observed transition from fault locking to free slip at depth occur at temperatures as low as 100 C.

    • Robert McCaffrey
    • Laura M. Wallace
    • John Beavan
    Letter
  • A group of botanists, geographers and physicists foraged through gravel pits, tunnel plots and lignite mines for very rare logs from the Late Glacial.

    Backstory
  • Extraction of the continental crust has left the Earth's mantle depleted in certain elements. Some rocks from the Arctic Ocean floor suggest that the extent of depletion and heterogeneity in the Earth's mantle may be greater than we thought.

    • Andreas Stracke
    News & Views
  • Violent uplift of western Crete in AD 365 generated a Mediterranean-wide tsunami that tossed boats onto house-tops in Alexandria, Egypt. Although a similar earthquake may not recur for 5,000 years, contiguous fault segments could rupture sooner.

    • Roger Bilham
    News & Views
  • Because of difficulties in creating a radiocarbon calibration that covers the end of the last glaciation, defining the timing and duration of the Younger Dryas cold event has been a challenge. Linking related cosmogenic isotopes in tree rings and ice cores may provide new insights into abrupt climate changes.

    • Paula J. Reimer
    • Konrad A. Hughen
    News & Views