Letter of the week: We have already tipped over

I congratulate Mark Lynas on bringing global warming to the attention of NS readers in such stark terms (Columns, 9 October). He is, however, too optimistic in believing that there can be more than one "tipping point". There can be only one, as far as causes of runaway climate change go. Lynas's example of Arctic ice melt having a different tipping point from the Antarctic is illogical in this context. As he says, if the Arctic ice disappears, that will lead to a "boost to global warming", which is very likely in turn to cause catastrophic ice melt in the Antarctic. In other words, the tipping point may already have been reached! Yet his conclusions are accurate. All we can do now is hope to mediate the effects of climate change and minimise further worsening of the situation.

Dr Philip Staddon
Stapleford, Nottinghamshire

This article first appeared in the 16 October 2006 issue of the New Statesman, The war on youth