There is a recognized need to anticipate tipping points, or critical transitions, in social–ecological systems. Studies of mathematical and experimental systems have shown that systems may ‘wobble’ before a critical transition. Such early warning signals may be due to the phenomenon of critical slowing down, which causes a system to recover slowly from small impacts, or to a flickering phenomenon, which causes a system to switch back and forth between alternative states in response to relatively large impacts.

Unregulated drug marketing stifles science and harms patients. To suggest otherwise is an affront to liberty — not a protection of it. (Editorial)

Climate models predict that precipitation will increase in Antarctica, leading to potential ice mass gain and an offset to sea level rise, but here it is shown that enhanced snowfall on Antarctica is likely to increase ice discharge and thereby negate 30% to 65% of the snowfall-induced ice gain.

The energy in–energy out hypothesis is not set in stone, argues Gary Taubes. It is time to test hormonal theories about why we get fat.

Scientists monitor greenhouse gases in urban areas as a first step to gauging success of climate initiatives worldwide.

The days when the gigantic Indian rivers — the Ganges, Indus and Brahmaputra — roar freely down the steep slopes of the Himalayas may be numbered. Roughly 300 dams are proposed or under construction in the deeply cut valleys of India’s mountainous north, part of a massive effort to meet the country’s spiralling energy demands. But the projects are facing fierce resistance from local communities, as well as from scientists who predict that the dams’ ecological impacts will be much greater than official environmental assessments suggest

Biotechnology can help to save endangered species and revive vanished ones. Conservationists should not hesitate to use it, says Subrat Kumar.

Analysis of data from forest plants worldwide shows that margins between threshold xylem pressures at which plants suffer damage and the lowest xylem pressures experienced are small, with no difference between dry and wet forests, providing insight into why drought-induced forest decline is occurring in both arid and wet forests.

Current global warming necessitates a detailed understanding of the relationships between climate and global ice volume. Highly resolved and continuous sea-level records are essential for quantifying ice-volume changes. However, an unbiased study of the timing of past ice-volume changes, relative to polar climate change, has so far been impossible because available sea-level records either were dated by using orbital tuning or ice-core timescales, or were discontinuous in time.

A new data set of middle- and upper-stratospheric temperatures based on reprocessing of satellite radiances provides a view of stratospheric climate change during the period 1979–2005 that is strikingly different from that provided by earlier data sets. The new data call into question our understanding of observed stratospheric temperature trends and our ability to test simulations of the stratospheric response to emissions of greenhouse gases and ozone-depleting substances.