You cannot have a human that has zero environmental footprint. The world population has exploded over the last 100 years. There is no point in lowering your ecological footprint if we’re outbreeding any progress in a few year time.

But if you're going to drive giant trucks powered by oil, eat red meat every day with a glass of milk, use and abuse plastic for everything, and be a massive consumerist, then sure

You misunderstand the scale of the difference. You can do everything in your power to lower your ecological footprint, recycle at your optimum, don’t eat meat, get rid of your car and only use a bike and public transport, etc. etc. If you have 2 kids and teach them to do the same your ecological footprint will still be many times higher than someone who eats steak every day and drives 3 hummers to work while rolling coal and throwing styrofoam pellets out the window. It’s that big of a difference.

A few numbers to illustrate, the savings in tonnes of co2 equivalent per year.

• recycle: 0.21 tonnes
• replace car with hybrid: 0.51 tonnes
• eat a plant-based diet: 0.82 tonnes
• only use green energy: 1.47 tonnes
• live completely car-free: 2.4 tonnes
• have 1 child less: 58.6 tonnes

It’s not just your kids, it’s also your kid’s kids, and your kid’s kid’s kids’s. etc.