Kind of you to quote me from another thread, McGrath, or were you quoting whoever I filched it from? Anyway, I don't think you've quite understood where methane comes from. Here's something else I filched:

During animal digestion, methane is produced through the process of enteric fermentation, in which microbes residing in animal digestive systems break down the feed consumed by the animal. Ruminants, which include cattle, buffalo, sheep, and goats, have the highest methane emissions among all animal types because they have a rumen, or large fore-stomach, in which methane-producing fermentation occurs.

That's from the US environmental protection agency, which says that 30 per cent of methane emissions in the states in 1997 came from cattle (not only their trouser coughs, but also their breath and from un-covered manure dumps. Methane is bad news because it is 21 per cent more efficient as a heat trap than CO2.

Useful stuff Spaw and Grab - instructive debate. MarkS, my wife is into cosmology and says the same as you about sun spots - they definitely come into the equation. But even if they didn't, the long-term effect of what we're putting in the atmosphere must be pretty obvious. Ebbie - I agree 110 per cent.