weight matters: Obesity contributes to global warming, says a study. Obese people require 1,680 daily calories to sustain normal energy and another 1,280 calories to maintain daily activities. This is 18 per cent more than someone with a stable body mass index. The next step will be to quantify how much a heavier population is contributing to climate change, higher fuel prices and food shortages.

acidic pacific: Scientists surveying the waters of the continental shelf off the West Coast of North America have discovered high levels of acidified ocean water. They found that this water was being upwelled seasonally from the deeper ocean and that this phenomenon is about 50 years old. This suggests that future ocean acidification will increase since carbon dioxide levels have increased rapidly over the past half century.