Apparently, 40% of the planet's land mass is currently turned over to food production of one sort of another in order to feed, rather inefficiently, our current population of seven billion.
Hmm. One problem is that the 40% represents most of the land that we can actually use. Much of the rest of it is covered in mountains, desert or ice.
And if our world population is heading for 9.6 billion by 2050, we're going to have massively to increase the amount of food we produce. With little extra available land unless we chop down even more rain forest, in which case some of our environmental problems are going to get as whole lot worse.
26% of our land is already used for animal grazing and further huge swathes of land are used to raise the crops that feed animals for human food. I don't really like the name, but I think you should check out some of the statistics on http://www.cowspiracy.com/facts/
The inescapable fact is that meat production is horribly inefficient (quite apart from any moral, ethical or nutritional arguments against it) and if we don't do something about the rate at which we're trying to eat it, we might be heading for a rather nasty global food shortage.
A cursory glance at the news on any day of any week will show time and time again that we, as a species, are really not very nice when the going gets tough. It's how we got to the top of the pile over the last 6 million years. Start to take some of the food away from our children's mouths and things could get very ugly very quickly.
Waste less food. Between field and plate we manage to waste almost 50% of the food we actually produce.
Eat less meat. Each day, a person who eats a vegan diet saves 1,100 gallons of water, 20 kg of grain, 30 sq ft of forested land 10kg of CO2 equivalent and one animal's life.