[belorn]

It is useful to be aware and as such it is good to know the effectiveness of each action.

Going car-less for a year is similar to going vegan for three years or doing 3 crossing of the Atlantic by plane. Switching over to buy exclusively "green energy" is almost twice as effective in reducing CO² emission compared to a vegan diet per year. All those are high impact changes, while home energy efficiency improvements are medium to low impact changes, with wall insulation estimated to be about 50% compared to eating less meat and up to 10th compared to a vegan diet.

http://iopscience.iop.org/article/10.1088/1748-9326/aa7541