There are very few clear answers and most environmental alternatives have their own trade off e.g. disposable nappies with the energy required for a single use product, and disposal x0000s per usage span of a baby... the alternative of a washable is better on resource consumption, disposal and reuse life span potentially across multuple children but at a cost of energy, water and detergent usage. For some, the swap is viable with their circumstances (line drying, access to tumble dryer in poor conditions), for some circumstances like nursery policies, and the difficulties of washing and drying make them too awkward. Not every alternative is equally viable for everyone and there are a lot of practical considerations involved.
The environmental impacts of food are complex. British lamb raised on marginal land unsuited to any other form of agriculture is better than importing foods like soya. Differences in agricultural methods around the world make a massive difference. I knew someone who went vegetarian to negate the carbon footprint of travelling... fine while he was in the UK, but to shun the local Mongolian camel/ goat to eat non-native, imported vegetables was farcical. Data based on the carbon and land footprint of a US grain fed cattle was utterly irrelevant to the impact of a nomadic herded animal which is vital in the cycle of organic matter in a desert.
Reducing is by far the best step. Reuse what you already have until the end of its life. Recycling should be the final stage. Some things like food and personal transport are essential. Keeping up with fashion far less so.
Our economy and many of its social structures revolve around consumption and convienience is a major driver. We as a whole society of consumers and producers need to find a way to balance a productive economy which doesn't compromise the planet. The difficulty is that on a personal level, it's barely even piss in a rapidly warming ocean. I do care and take many reasonable steps, not all, but it's absolutely negligable compared to a decision that DH makes at work that affects energy usage on an industrial scale.
Do what you can. Don't get too preachy with others. Unless you're living off-grid in a self sufficient hut, you'll be at high risk of hypocrisy about something.