Let us deconstruct the article.
Eat less cattle = decrease methane production by cows.
However, if he stop eating meat it will not instantly decrease the cow population.
So I have a few propositions for you;
1. Kill all cows and don't bother eating them (which seems a waste to me)
2. Stop eating cows and starve them to death. (cause ranchers gonna keep feeding cows which aren't going to yield a profit :bs
3. Drastically increase meat consumption, thereby, creating a high enough rate deaths which will greatly greatly outnumber the birth of new cattle. (reference dodo as an example)
I love how the article mentions the use of trucks as a reason why we should avoid eating meat. Funny, I can't think of a single produce which does not arrive via truck to my local grocery store. I also find the notion that cattle are transported to a slaughterhouse in air conditioned trailers highly suspect and laughable. I mean after the cows are killed of course.
Going on a hunch, the author is a yankee. Given most computers (including phones/tablets etc computers) are made in China, doubt the author boycotts all goods made in China. Which cross a massive ocean using an enormous internal combustion engines. Which are than transported via trucks across the massive country. Come to think of it, most goods in the US come from China. (Unless this changed in past 12 months)
Here is the 2015 summary of US green house gas emissions from EPA. Funny agriculture is listed at 9%. Kinda easy to manipulate numbers.
https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions
I would personally classify that article as propaganda.