Mr. John Hourigan:

There is no divergence. CO2 taken in by an animal and released again through the natural cycle is net zero in absolute terms. When you start looking at the methane in its global warming impact and multiplying by 28 to reflect what is happening, that is where Professor Allen comes in. However, on very basic science, it is net zero. I contend that methane from ruminants is very different to that from mining, fracking or whatever. Methane from fracking comes up out of the ground, it has been there for a million years, it converts back to CO2 after 12 years and stays in the atmosphere forever. Before a cow releases a tonne of methane, she has to take in 2.7 tonnes of CO2 from the atmosphere. It goes from the atmosphere into the cow, it is released again and, after 12 years, it goes back to where it came from. It is a cycle. It is quite unlike methane from mining. Do the maths on it for a 100-year period. We have 34.5 billion tonnes of CO2 emitted every year through fossil fuels. Over 100 years, that is 3 trillion tonnes. Mining produces roughly the same amount of methane as animals, which is approximately 100 million tonnes per annum. It goes up into the atmosphere and after 12 years it converts back to CO2. One hundred million tonnes of methane converts to 2.7 billion tonnes of CO2 when you multiply by 2.7. Over 100 years, mining produces 27 billion tonnes of extra CO2 into the atmosphere. For the global herd of cows to produce 100 million tonnes of methane, they would first have to take out 270 million tonnes of CO2. After 12 years, that returns to the atmosphere. After 100 years, leaving aside the global warming potential, GWP, effect of both for now, the methane for those cattle has not added a single tonne of CO2 or methane to the atmosphere. It is part of a cycle. After 100 years, methane from mining has really added to what is left in the atmosphere. The difference could not be more stark.