Cutting out meat altogether saves an additional 200Kgs CO2e per year.
In terms of climate impact, many consider the second best thing to a vegan diet to be vegetarian which includes dairy products and eggs. However, the US Environmental Working Group, which has done a lot of work in this area, finds that a vegetarian diet which includes cheese is less climate friendly than a diet which leaves out cheese and includes chicken. So similar savings might be achieved by giving up cheese in an otherwise climatarian diet.
Source for climate impact of a vegetarian diet: Dietary greenhouse gas emissions of meat-eaters,fish-eaters, vegetarians and vegans in the UK, Peter Scarborough et al, Oxford University 2014.
Photo courtesy of Kelly Bone.