We all know methane's a big deal. But what sort of deal is it?
It's this...
Cattle and other ruminants produce lots of methane. Second only to the energy business.
But there's another problem.
Even though methane's a potent greenhouse gas – 30 times more so than carbon dioxide – methane only lasts in the atmosphere for about 12 years.
Carbon dioxide, on the other hand, lasts a lot... lot... longer in the atmosphere. After 100 years forty percent of that carbon dioxide's still there. After 1,000 years it's twenty percent. And after 10,000 years – or more – 10 percent is still in the atmosphere.
So, once it's there, it just keeps on warming. For a long, long time.
And, that's the dilemma we face.
Do we go for a quick fix and make severe cuts to methane emissions from animals – even though methane's a short term problem. Or do we tackle carbon dioxide which is a much bigger, much longer term, problem.
The jury's still out on this one.
But here are the facts.
Fact one, we can't afford to put more methane into the atmosphere. Fact two, if we keep methane levels just as they are then they won't cause any extra warming.
And this is when it gets a bit more complicated.
It's not just cows and other ruminants that emit methane. It's emitted by energy companies, landfill sites, and even rice paddies.
But – and here's the important bit – methane that comes from cattle (and grass feeding animals) operates as a closed loop. While Methane that comes from other sources doesn't work quite like that.
… and you may have to read the next bit twice. Slowly.
Grass takes carbon dioxide from the air and turns it into carbon... cattle eat the carbon and turn it into methane... methane goes into the air, and over 12 years, it turns back into carbon dioxide. Then the whole process starts all over again.
In short, carbon dioxide makes carbon. The carbon makes methane. And the methane turns back into carbon dioxide again.
It just goes round and round... getting recycled. Nothing new is added. And nothing's taken away.
That is, until you add extra methane to the system.
There's two ways to add more methane. Put more cows and other ruminants into the system... that's clearly a no, no.
Or add more methane from sources like oil, gas and coal. Or landfill. Or rice paddies.
And if you do that, this is what happens:
You add more – new – methane to the atmosphere. Which means more – new – carbon dioxide. Which means more – new – global warming.
So it's all down to which is the biggest problem? Carbon dioxide for ever. Or cattle generated, recycled methane, for now.
It's hardly surprising there's a lot of debate about this.
But, you've now got the pertinent information – and you’re free to judge it how you will.
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