@andyp - happy for the thread to be merged if that makes more sense, but seems some think it's good to have separately.
@amey so it's clear what your viewpoint is!
@Nick_S cheers, and yes, I agree with your points. as otherwise quoted here, "165 kg to produce eBike" is not a lot compared to cars. But will you upgrade your car every year (ok, I know some people do), and/or will you upgrade your ebike every year? Ok, probably neither, but you might be tempted to upgrade your bike more often than a car. Or buy a second one (or a third), or upgrade the battery (batteries? Could be useful to have a second/third so that one is always charging) so there are other, hidden costs that might not be there - or may be more economical - with a car.
And anyway, is a car the right comparator? Do bikes replace car journeys, or do they replace walking? E.g. to the shops. Or do they replace running (for exercise)? Or swimming (how much does it cost to heat and maintain the public swimming pool, for instance)? And what if/when you have both a car and a bike?
I think the point is that producing such environmental impact reports makes people think about these things, which can only be good. Everything has some kind of cost, but what is the benefit?
And, ultimately, how can I minimise my impact? Because after all, it's only 'me' that I can change, right?
Also, @starfish&coffee - interesting point you raise about the clothing, I hadn't even thought that far! I am still wearing cycling trousers that a forumenger gave me in 2008, so it's definitely possible to keep such stuff a long time. Again, fashion clearly plays a role.
Food for thought!