Abstinence from meat seems like an extreme step if all you are concerned about is environmental damage. Just eating meat at a "normal" frequency of two or three times a week would be enough to mitigate much of the impact. True organic agriculture is not possible without meat production as a side effect, and this can only be replaced by nonrenewable synthetic fertilizers.
I'm not the person you're responding to, but for me it's much easier to abstain from meat than to moderate it to a certain amount of times per week. It's not difficult for me to eat meat, but it would be if I were to half-abstain.
Our family buys a whole animal from a local farmer periodically. We evaluate how the animal was raised, the sustainability of the farm, etc. to the best of our ability. It's the one exception to my vegetarianism. It results in me eating meat every now and again, but meat I know was treated humanely.
It does make it much easier to 'half-abstain' because it's not an exception I can make easily on a whim at the grocery store. Buying a whole animal takes some planning.
It's been an ideal combination for us -- higher quality meat, considerably less meat consumed, and education to my kiddo about where meat comes from (and what responsible looks like on a farm).
