"Veganism is not the simple solution to sustainability that George Monbiot recently argued. I wish it were that easy. While I commend those taking steps to change their diets to reduce their environmental footprints, a vegan world – where no one consumes animal-derived meat, milk and eggs – is not how we will achieve sustainable global development
Some argue that, because of its low environmental footprint, veganism is the best dietary choice to feed the world’s growing population. Research suggests otherwise. An investigation published in the US last month compared 10 different eating patterns and concluded that diets incorporating some animal-source foods (especially milk and eggs) use less land than their vegan alternative.
This is because more inclusive diets make optimal use of all existing land to feed people. That includes croplands and rangelands where grain and hay can be grown to feed livestock. A lot of meat and milk that would remain unproductive in a vegan context is produced on these marginal rangelands. For example, 60% of sub-Saharan Africa is covered by drylands where raising livestock is the main, and often the only, land use option available."