How soon does a bike pay back its initial carbon footprint?

Not many people get rid of their car entirely when they start riding a bike.

It would probably be more energy efficient to ride an electric powered bicycle.

I think that assumes that you bought a bike instead of a car. In my case, that's true, but I'm sure in many cases that's not true.

I think the article was assuming you're already someone who owns a car and will continue to own that car, not that you own neither and are buying one or the other.

Of course it is, why would it be otherwise? Meat is just an inefficient middle stage in terms of nutrient acquisition. Of course, that doesn't mean I'm a vegetarian, just that I'm aware that my diet is not as energy efficient as it could be.

I'm going to go ahead and contribute that line of the article to "creative, non-factual journalism."

Keep up the paleo. :)

Only because of modern farming processes.

What did you expect? People would hardly have switched away from it if it had been sustainable.

The amount of calories we burn does not contribute to the net carbon excess per se; after all, we're part of the natural carbon cycle. The number that matters is the amount of energy used to acquire the calories we do consume. The carbon that matters is the amount desequestered as a result of burning fossil fuels.

...I have never had any of those symptoms in my decades of riding, nor have I ever even heard of them. Despite the authors protest, this sounds exactly like just another health scare.

I strongly disagree with your recommendation. The article talks about saddles with relief cutouts or depressions, to make sure no pressure is put on the perineum. Saddles with cutouts are fine--even better than normal saddles for some people. Noseless saddles, on the other hand, address the problem entirely wrong. The tend to produce an uncomfortable position for long rides, as the nose is important for bike handling.

Back to cutout saddles, a cutout only helps if the saddle is heavily padded. When the padding compresses, you don't sink from your sit bones into your perineum. Another option is a firmer saddle. My saddle is hard as a rock, but it supports me properly, and I have no pain or numbness on even the longest rides.

Source: Me, recreational cyclist.

Read what Sheldon Brown had to say: http://sheldonbrown.com/saddles.html

Sheldon on noseless saddles:

"The lack of a nose can compromise lateral control in some cases.

The pads must be angled downward, which tends to make the rider slide forward. This is liable to lead to hand/wrist/neck problems as the rider braces on the handlebar to keep from sliding forward off the seat.

If the pads are not angled downward, they tend to cut off circulation to the thighs, and to interfere with the thigh muscles."

To be fair, this is a example of the "standing-in-a-theater" problem from economics: if you buy a used bike, you're doing something "better" for the environment, because the good is already made; if everyone does it, then there are very few used bikes.

Plus, there's a decent chance that you're just subsidizing someone's new bike (incidentally, this is how I pay for new Macs: I sell the old one on Craigslist for a third to half of its original price after 3 – 4 years and use the proceeds to buy a new one. Works pretty well).