[jhuizy]

is _one of_ the most significant actions [...]

I think that it's also the most practical (though that may just be for in terms of my current situation):

Driving and air travel are the most convenient ways to get around, solar panels require a significant investment (and unless you own your own home or have come to an agreement with your landlord, impossible), and most disposable things (eg. cheap electronics or plastics) are required for those on lower incomes.

But going vegetarian usually results in cheaper meals, and the are normally just as simple to make as non-vegetarian options.