Stop breathing, cyclists...

Oh America, you'd be so cute and silly if you didn't have all those nuclear weapons! (from Tom S)

 'You claim that it is environmentally friendly to ride a bike. But if I am not mistaken, a cyclists [sic] has an increased heart rate and respiration. That means that the act of riding a bike results in greater emissions of carbon dioxide from the rider. Since CO2 is deemed to be a greenhouse gas and a pollutant, bicyclists are actually polluting when they ride.'

http://www.theregister.co.uk/2013/03/05/bicyclists_as_polluters/