On ice.(Letter to the editor)

Scientists can speak authoritatively only when backed by quantitative logic. In the case of ice balance for Antarctica, one thing is clear: Every modern climate model predicts that Antarctica will gain ice in the 21st century, resulting in a slight lowering of sea levels (which will, nonetheless, be largely compensated for as slightly warmer surface temperatures cause ocean waters to expand).

The oft-cited finding that Antarctica is losing ice is based on 34 quasi-monthly satellite observations beginning in mid-2002. But, as shown in the record for East Antarctica, which is the largest ice cap on the planet, mid-2002 represents the high point of snow accumulation for at least the last decade. While we cannot be absolutely certain that this accumulation outweighed ice loss in West Antarctica, we have reason to ...