A Climatarian diet involves choosing what you eat based on the carbon footprint of different foods. You can use your power as a consumer to drive down the production of the types of meat which have the biggest impact on our climate.
This requires a basic understanding of the carbon footprint of each type of meat and dairy. Short of this, the minimum someone needs to know is that beef and lamb have by far the biggest carbon footprint of all and should be consumed on special occasions, if at all.
According to a Harvard School of Public Health study, this would look like, at a bare minimum, limiting your consumption of beef and lamb to either one standard serving per week (65g as per Australian dietary guidelines) or one large serving a month, such as a steak or roast (~300g). In practice this could be done by trying out vegetarian or vegan options in place of the times you eat beef and lamb.Once someone has been practising the above and are comfortable with this arrangement then they could consider cutting beef and lamb out of their diet altogether. They could also try limiting their consumption of cheese as this has the biggest carbon footprint of all dairy products.