) proves wrong? Changes in the environment will prob- ably be relatively slow; even if we melt the west Greenland ice sheet, it seems O 2004 Wiley-YCH Vedas GmbH & Co. KGaA. Weinheim 3639 EFTA_R1_01521467 EFTA02444552 Essays unlikely that we will tip the balance of the planet so that Earth becomes Venus (alt