Here the authors report improved estimates of near-global ocean heat content and thermal expansion for the upper 300m and 700m of the ocean for 1950

A renewed push for scientific research into weather-modification technologies is long overdue. (Editorial)

It all seemed too easy by half: to beat global warming just sprinkle some iron in the ocean, then watch as algae bloom en masse, sucking up carbon dioxide by the tonne. Now the idea is looking increasingly unlikely to go ahead in a big way. In the wake of a UN moratorium on the practice, the latest research suggests that seeding will trigger the build-up of an acid that can be lethal to marine organisms and humans.

In September 2006, Tara, a 36-metre schooner crewed by eight scientists and engineers, moored up on the Arctic sea ice and spent the next 15 months moving slowly with it across the top of the world. The expedition wasn't aiming for the pole: it was an ambitious attempt to record what is happening to the polar climate in unprecedented detail.

Long-period seismic sources associated with glacier motion have been recently discovered, and an increase in ice flow over the past decade has been suggested on the basis of secular changes in such measurements. Their significance, however, remains uncertain, as a relationship to ice flow has not been confirmed by direct observation. Here the authors combine long-period surface-wave observations with simultaneous Global Positioning System measurements of ice displacement to study the tidally modulated stick

Martin Kennedy and colleagues searched the Australian outback for clues to the transition out of Snowball Earth. The answer, as it turns out, was much closer to home.

There has been a strong disagreement between model predictions of troposphere warming and observations of temperature trends from radiosondes and satellites. However, when tropospheric temperature reconstructions are generated from thermal-wind measurements and the thermal-wind equation for 1970

Silicate weathering reactions remove carbon dioxide from the atmosphere and store it in carbonate minerals. During the high atmospheric carbon dioxide conditions of the Early Eocene Climatic Optimum, rates of chemical weathering, physical erosion and denudation in the western USA were equivalent to the highest recorded rates in the non-glacial Quaternary.