An interesting read. But one is not obsessed with greenhouse gas emissions, why not walk and cycle because we enjoy it rather than because it's supposed to be good for the planet — which, on the evidence given as well as the science, is 'not settled'.

And riding a horse/hay burner, may produce as much Co2 emission, and a good deal of methane into the burped bargain?

One unit of methane being worth at least 21 units of Co2, as a greenhouse gas!

Meaning, many greens may be just impractical romantics/dreamers longing for an earlier simpler era!?

And where they would replace even our most efficient engines with hay burners, be it plowing the fields or transporting produce to market?

And regardless of the method, including their preferred pedal power, burning calories equates to Co2 output!

Meaning, the more effort required, the more calories burnt, the more Co2 produced!

Even so, rigidly resist considering using the carbon free nuclear cycle to replace any of it!

And horses may well need more specialist and costly maintenance and care, than an occasionally used, modern infernal combustion engine?
Rhrosty.

I'm afraid someone with an ulterior motive has been cooking the figures on this study.

I have seen a number of studies where the fuel used per passenger mile, for public transport, far exceeds the fuel per passenger mile for private cars. These figures are most definitely skewed to peak hour usage, where full capacity loads do work. Expand the fuel usage to the full 24 hour, [or realistically 18 hours in our city], & public transport is hugely expensive in fuel for the actual load carried.

If you were to add in the cost to the national health system, bikes would be banned, as would be public transport. All those people crowded together, spreading their germs & diseases is just not on.

We are the cyclists,

http://www.youtube.com/watch?v=zBFFrsvgu1Y