Lomborg crunched some numbers and argues that the threat of carnivory to the climate is greatly exaggerated. First, he points out that calculations, for the most part, ignore 80 percent of greenhouse emissions that we each contribute to the atmosphere from transportation, heating, lighting, and manufacturing. Count those sources, and the emissions drop from eschewing animal products becomes commensurately smaller. Second, Lomborg notes that the most optimistic figures result from adopting a totally vegan diet, rather than a mere vegetarian one. In addition, spending less money on meat likely means that a consumer would spend more money on other goods and services that result in the higher emissions of greenhouse gases.
Citing a 2015 Swedish study in Ecological Economics, Lomborg concludes that becoming a vegetarian would cut the average person’s greenhouse emissions by about 2 percent. He puts this reduction in context: Going vegetarian for the rest of your life would reduce your emissions by the exact same amount as spending a little more than $3 a year to buy cap-and-trade emissions allowances through the Regional Greenhouse Gas Initiative that operates among nine Northeastern states.
So while hectoring meat-eaters will do almost nothing to slow climate change, the demand for dietary sacrifice and culinary hair shirts could well alienate members of the public from considering more effective ways to address future man-made warming.