"What are you doing for your part" is equivalent to nothing, UNLESS you are perhaps paradoxically working in finance to become rich enough to have enough money and/or influence to someday have a real effect on these problems. Or maybe actively researching sustainable technologies, or part of a pro-environmental lobbyist group or something.

Don't kid yourself: if you want to stand on a high horse understand that your lack of eating meat makes absolutely no difference here. If you actually want to take the position that individual initiative is needed, then you have to be doing pretty crazy things to make a dent. Arguably its worse than doing nothing because you assuage your own guilt by convincing yourself that you are no longer part of the problem and disincentivizing yourself from being part of the actual solution.