Thursday 6 September 2012 16.00 EDT
Nicholas Lewis (Letters, 28 August) complained that your report (Arctic ice melt likely to break record, 24 August) gave the impression that typical temperatures in Antarctica have risen as much as on the Antarctic peninsula. While he is correct about this, his letter also refers to an outdated study of his, which argued that previous estimates of overall Antarctic warming were too high. In fact, the work of Lewis and co-authors has been proven wrong.
The relevant paper here is Orsi et al, Geophysical Research Letters, vol. 39, 2012, which shows that the rate of warming in west Antarctica is as great, or greater, than what we showed in our original work (Steig et al, Nature, vol. 457, 2009). Moreover, Lewis's own paper shows there has been significant warming in west Antarctica and that the average trend over Antarctica is of warming, not cooling as is often stated.
The reality is that the Antarctic is warming up and is contributing significantly to sea level rise; and that there is strong potential for a greater contribution to sea level rise from Antarctica in the future.
Professor Eric Steig
University of Washington, Seattle, USA