So all you need to do now is hook one of these up to your car

Experts said the slow digestive system of cows makes them a key producer of methane, a potent greenhouse gas that gets far less public attention than carbon dioxide.

In a bid to understand the impact of the wind produced by cows on global warming, scientists collected gas from their stomachs in plastic tanks attached to their backs.

[From Cow farts collected in plastic tank for global warming study - Telegraph]