• An Editorial discussed what would happen if the world were to warm by an average of just 4 °C, which “some models predict could happen as soon as 2050” (28 February, p 3). It should rather have said, as did our cover story in that issue, that “some scientists fear that we may get there as soon as 2050” (p 28).
• A transcription error made it seem that James Lovelock said “the biosphere pumps out 550 gigatonnes of carbon yearly” (24 January, p 30). That should have been 550 GT of carbon dioxide. Also several readers queried Lovelock saying “it takes 2500 square kilometres to produce a gigawatt” of wind power, since the British Wind Energy Assocation says 1 GW of installed wind generation capacity takes around 250 square kilometres. Lovelock stands by his figure, saying it is based on 1 MW turbines on land.
• We unaccountably referred to San Francisco as “Cisco” (7 February, p 7). San Franciscans prefer it not be called “Frisco”, either.
