At www.sciencedaily.com/releases/2011/02/110204092149.htm … a paper in Geophysical Research Letters 2011: 38 claims that recovery mechanisms of Arctic summer sea ice shows that no tipping point is likely to exist as far as the loss of Arctic sea ice is concerned. In the summer it melts by varying amounts, sometimes more and sometimes less. However, each winter the sea ice recovers – and always will. In winter, especially during the darker days of mid-winter when the Sun is absent from Polar regions, sea ice re-establishes itself. Every winter – because it's winter. In other words, if one wanted to get rid of Arctic sea ice one would have to do away with winters. However, this article is not frivolous and is important not just in respect of AGW alarmism but to palaeo-climate research too. It is thought Arctic sea ice has disappeared in the past – why else would trees have been growing on Ellesmere Island? If it can't happen now it could not have happened in the past – so why were there trees growing in high northern latitudes in the past?