Letter: Please tell us the worst on methane emissions

From Chris Eve, Lynton, Devon, UK

Michael Le Page reports that climate models may have missed major effects from clouds (2 March, p 10). Two more effects, which James Lovelock described in The Revenge of Gaia, are the effects of methane emitted from melting tundra and from underwater methane hydrate. Then there are the fires in Arctic forests and peat.

I hope that someone will give us worst-case estimates for how high mean global temperatures could rise if those methane stores are substantially released, and for the lowest temperatures at which such mobilisation could be triggered.

Of course, there will be huge uncertainties in these numbers because, for example, estimates of the quantity of methane hydrate vary by an order of magnitude. But having worst-case estimates could provoke research aimed at reducing uncertainty.