The biggest effects will come from reducing your carbon footprint. Think about what activities generate the most CO2 and what you can cut. For example, meat production is a big CO2 producer. Reducing/eliminating red meet from your diet will reduce your carbon footprint.
Obviously, driving is another CO2 producer. If you can bike or walk as much as you can.
Home cooking/heating is another big source of carbon emissions. You can wear sweatshirts/blankets in the winter and keep your house cold (64-68 F?) and use fans in the summer instead of AC.
Reusing/recycle also comes up as a possible way to reduce CO2 emissions, but I’m not familiar with the net effect on your CO2 of recycling. Reusing makes sense though.
Is it about the size of the animal? Is there a large animal that produces enough meat to offset the environmental damage per serving? Chickens seem very gross and labor intensive for one family meal (unless you count eggs) where a cow seems happy to eat grass and produce a lot of meals. I realize most cows are disturbingly fattened and I've started trying to buy farm meat from local butchers. I think i read that Chipotle uses better (happier?) meat than most other restaurants. Also, i just started leaving about Temple Gramdin's work for humane animal farming.