Weighing our own prosperity against the chances that climate change will diminish the well-being of our grandchildren calls on economists to make hard ethical judgments.

Grind it down, pour in a sprinkle here and a dash there, and wait for results. That's the recipe for helping the oceans to absorb more of our carbon dioxide emissions: add limestone. It may not only help reduce global warming but could even reinvigorate ailing coral reefs.

Climate change is already altering our planet's biology, with only life in Antarctica so far spared its influence. That's the conclusion from an analysis of tens of thousands of individual local studies covering shrinking glaciers, changing river flows, melting permafrost, increased coastal erosion, and warming lakes and rivers. The study, published in Nature (DOI: 10.1038/nature06937) this week, is based on more comprehensive data than any previous investigation of the biological effects of climate change.

Data laboriously extracted from an Antarctic ice core provide an unprecedented view of temperature, and levels of atmospheric carbon dioxide and methane, over the past 800,000 years of Earth's history.

Climatologists have called for massive investment in computer and research resources to help revolutionize modelling capabilities. The eventual aim is to provide probabilistic climate predictions that are as useful, and usable, as weather forecasts. At the end of a four-day summit held last week at the European Centre for Medium-Range Weather Forecasts in Reading, UK, the scientists made the case for a climate-prediction project on the scale of the Human Genome Project.

Few scientific creations have had greater impact on public opinion and policy than computer models of Earth's climate. These models, which unanimously show a rising tide of red as temperatures climb worldwide, have been key over the past decade in forging the scientific and political consensus that global warming is a grave danger. (Editorial)

Significant changes in physical and biological systems are occurring on all continents and in most oceans, with a concentration of available data in Europe and North America. Most of these changes are in the direction expected with warming temperature. Here the authors show that these changes in natural systems since at least 1970 are occurring in regions of observed temperature increases, and that these temperature increases at continental scales cannot be explained by natural climate variations alone.