Feature Article

The ratio of stable oxygen isotopes in tree-ring cellulose was first used to reconstruct temperatures during tree growth, and a seminal study showed a strong correlation between oxygen isotopes of woody tissue and mean annual temperature.

Tens of millions of people in south and southeast Asia routinely consume ground water that has unsafe arsenic levels. Using hydrologic and (bio)geochemical measurements, the researchers show that on the minimally disturbed Mekong delta of Cambodia, arsenic is released from near-surface, river-derived sediments and transported, on a centennial timescale, through the underlying aquifer back to the river.

During the growing season, with photosynthesis at its peak, leaf temperatures remain constant over a wide latitudinal range. This is a finding that overturns a common assumption and has various ramifications.

South Asia's well-water is widely polluted with arsenic, but no one has located the source. A study on the Mekong River finds that contamination begins in pond sediments, and is spread by groundwater flow to wells.

Your Editorial 'A fresh approach to water' (Nature 452, 253; 2008) points out that the world's looming water crisis is driven by climate change, population growth and economic development. In China, changing food-consumption patterns are the main cause of the worsening water scarcity. If other developing countries follow China's trend towards protein-rich Western diets, the global water shortage will become still more severe. (Correspondence)

Climate change is coming fast and furious to the Tibetan plateau.

China burns more coal than any other country; how it does so in the future will determine our planet's climate.

Some 225,000 square kilometres of Ontario's boreal forest have been set aside in the biggest conservation initiative in Canada's history. But mining and logging will still be permitted, with strict regulations, in the region.

A high-profile group of thinkers has come up with a straightforward way to integrate long-term forest management into an international agreement on halting deforestation. It is not clear whether the proposal

Climate shifts over this century are widely expected to alter the structure and functioning of temperate plant communities. However, long-term climate experiments in natural vegetation are rare and largely confined to systems with the capacity for rapid compositional change. In unproductive, grazed grassland at Buxton in