It has been widely hypothesized that a warmer climate in Greenland would increase the volume of lubricating surface meltwater reaching the ice-bedrock interface, accelerating ice flow and increasing mass loss. We have assembled a data set that provides a synoptic-scale view, spanning ice-sheet to outlet-glacier flow, with which to evaluate this hypothesis.

A continuous lake record elucidates how Saharan climate changed gradually from humid to today's desert conditions.

Desiccation of the Sahara since the middle Holocene has eradicated all but a few natural archives recording its transition from a "green Sahara" to the present hyperarid desert.

"Politicians seem to think that the science is a done deal," says Tim Palmer. "I don't want to undermine the IPCC, but the forecasts, especially for regional climate change, are immensely uncertain." Palmer is a leading climate modeller at the European Centre for Medium-Range Weather Forecasts in Reading, UK, and he does not doubt that the Intergovernmental Panel on Climate Change (IPCC) has done a good job alerting the world to the problem of global climate change.

Let's be clear. The science of climate change and of humanity's role in recent warming is very robust. So concerns about the ability of climate models to predict effects at the local level in no way undermine the case for urgent action to stop climate change happening. (Editorial)

In a recent paper in the journal Carbon Balance and Management (vol 3, p 1), Ning Zeng, an atmospheric scientist at the University of Maryland in College Park calculated that if we buried half of the wood that grows each year, in such a way that it didn't decay, enough CO2 would be removed from the atmosphere to offset all of our fossil-fuel emissions. It wouldn't be easy, but Zeng believes it could be done.

Boreal forests serve as important global sources or sinks of carbon (C) and wildfire is a major driver of C storage in these forests. Although fire releases CO2 to the atmosphere, it also converts plant biomass into forms of black carbon, such as charcoal, that are resistant to microbial attack and persist in the soil for thousands of years. It has frequently been suggested that, because of its resistance, black C can serve as an important long-term C sink that may help offset the release of human-induced CO2 to the atmosphere.

A new paper shows that regional and even global temperatures are being temporarily held down by a natural jostling of the climate system, driven in large part by vacillating ocean currents.