The biggest thing we can do as individuals to reduce our ecological footprint is to eat less meat.
A vegetarian driving a Hummer has a lower carbon footprint than a cyclist who eats meat.
This article from Grist shows how “80% of N2O emissions come from agriculture, as soil organisms, such as bacteria, break down the nitrogen in livestock manure and the synthetic fertilizers applied to soil in crop production. After carbon dioxide and methane, N2O is the largest contributor to climate change, and has soared 20 percent since the Industrial Revolution. It is also our biggest human-made ozone-depleting substance.
Not only that, but recent, much-reported on research findings show a direct correlation between mortality rates and red meat consumption.