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.

THE Chichewa people in Malawi have a saying: Njala ndi chilombo. It means "Hunger is a beast". Today, the beast is rampaging around the world and particularly Africa, where shortage of food threatens to undo recent economic and political gains. Climate change is partly to blame. But there is another less well recognised cause: long-term neglect has left African agriculture in a woefully inadequate state.

Trouble is brewing in the waters off the Chukotka Peninsula in the far east of Siberia. In the past few years, the aboriginal whalers of the eastern coastline who hunt grey whales for meat have reported that an increasing number of the creatures they catch smell so foul that even dogs won't eat them. The few people who have tried the meat suffered numb mouths, stomach ache and skin rashes.

Tropical insects, amphibians and reptiles will probably never enjoy the status of an environmental poster child, but global warming's impact on them can't be ignored. So say Josh Tewksbury of the University of Washington in Seattle and his colleagues.

High gasoline prices could lead to a dramatic saving in US greenhouse-gas emissions. That's the conclusion of economists in the US, who suggest high fuel prices are turning consumers off SUVs and onto smaller, more fuel-efficient vehicles. What's more, car owners are predicted to cut back on driving in order to save money. Together, these changes in consumer behaviour could make an important dent in the US contribution to global warming, reducing annual carbon dioxide emissions by tens of millions of tonnes per year.

"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.

The image of biofuels is rapidly tarnishing. Already under fire for displacing food production and tropical forests, they are now charged with marginalising poor rural women. In a report published on 21 April, the UN Food and Agriculture Organization concludes that women subsistence farmers will be evicted to make way for huge biofuel plantations.

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