Thirty million acres of land are turning to desert each year mainly due to overgrazing and nutrient depletion as animals are killed and eaten in places distant from where they grazed. Overgrazing is unavoidable as farmed animals weigh SIX times as much as ALL the wild animals from 10,000 years ago.
The United Nations Convention to Combat Desertification (UNCCD) has been documenting the desertification of the Earth's dry lands. The 30 million acre figure in the above image comes from the UNCCD and here's a UN video where this figure is mentioned (12 million hectares = 30 million acres). In the latest Global Land Outlook, the UNCCD states that 20% of the Earth's vegetated land is being degraded annually, which works out to a whopping 7.2 billion acres that are being degraded annually.
The statistic on the weight of farmed animals vs. that of wild animals that lived 10,000 years ago can be found in Anthony Barnosky's 2008 paper in the Proceedings of the National Academy of Sciences. In addition, we know that the weight of human beings today - 500 Million tons (MT) - is 2.5 times the weight of all the wild animals that lived 10,000 years ago - 200 MT. Further, we know from the UN Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5), Working Group 3, Chapter 11, that our farmed animals consume nearly FIVE times as much food - 7.27 Giga Tons per year (Gt/yr) - as we do - 1.54 Gt/yr. Therefore, in effect, our farmed animals are presenting the profile of a biomass that is 12.5 times as large as all the wild animals from 10,000 years ago, as far as the Earth is concerned. This is roughly double their weight profile because our farmed animals are mostly young animals who are killed during their growth spurts, before they reach puberty. Hence, they eat twice as much food as their weight alone would indicate.
Therefore, from an environmental perspective, Veganism is the minimum baseline that we need to adopt globally for our present circumstances. The weight of human beings alone is 2.5 times the weight of ALL the wild animals from 10,000 years ago. That is, current human population alone is too much for the planet to sustain on a long-term basis! Hence, it behooves us all to tread lightly and stop carrying around the extra unnecessary weight in the form of our farmed animals. That indulgence is now coming at the expense of our fellow humans.