There's some pretty questionable stuff going on in that article.

First, it's highly specific to Australia, where the impact of Eurasian cereal farming is profoundly negative, because they're nothing like the native grasses. That could probably be mitigated by not growing Eurasian grains in giant monoculture farms, in favor of edible native crops. There are something like 6,000 native plants in Australia that are edible by humans; very few of them are farmed commercially or have even been thoroughly investigated for that purpose.

Also, it then goes on to say "If more Australians want their nutritional needs to be met by plants, our arable land will need to be even more intensely farmed." This is a very questionable assumption. Generally switching from commercially-raised meat to a plant-based diet results in a lower food-crop consumption profile. This is because meat animals are frequently raised, or at least fattened during the terminal months of their lives, on human-edible crops (in the US it's almost solely corn).

Anyway, I get the impression that article is someone playing devil's advocate / provocateur, which is not something I have a lot of time for. There are lots of solid, peer-reviewed articles [1] investigating the ecological impact of plant vs. meat-based diets; there is a wide consensus that plant-based diets are significantly more sustainable. There are probably places on earth where that's not true, and perhaps Australia is one of them, but it's not broadly true for most of the planet.

[1]: https://academic.oup.com/ajcn/article/78/3/660S/4690010

WTF, most animals that are farmed are fed agricultural produce - crops that are cultivated. It's simple math that it's inefficient to grow crops -> feed the animals -> eat the animals. There's efficiency loss at every step. Are you seriously claiming that eating meat is better than being vegetarian?

Eating grazing animals is more humane per unit of protein than industrial crops or factory farming.

The vast majority of meat is not 100% grazed. You have a point, but it's largely a theoretical one. If one can find a source of meat that is 100% naturally grazed then they could probably go through similar effort to eat non-meat products produced in minimally destructive ways.

It’s not possible to meet even current demands for beef by free grazing animals. There’s a reason 70% of American cows are fed grain in lots.

Not to mention the greenhouse gas effect of that many cows, which is much higher for grazing cattle.

If there was free trade and corn wasn't fed to animals there would be enough meat and health and wealth for everyone.

Humans need 250grams of protein a day, some can come from plants, some from eggs, some from animals.

Currently what happens is that corporations lobby governments to protect local food markets under the guise of food security so that grass fed meat cannot be imported from sparse populations with lots of pasture into dense populations short of pasture.

The dense population then gets obese and mentally ill on corn-fed local beef while the corporations profit from the margin between feeding an animal corn or feeding it grass while sidestepping the cost of negative externalities. A hectare (10,000 sq m) of corn will grow 30 tonne of corn in a year, a hectare of pasture will grow 16 tonne of grass in year on the same land. The corn progressively wrecks the land and needs to be replanted every year. The pasture is perrennial and preserves the carbon content of the soil which is a massive and under reported component of the carbon cycle. 10kgs of grass or corn make 1KG of meat. Humans already have a surplus of corn, they are currently turning it into biofuel.

If you factor in the soil preservation then pasture plus grazing animal is the most economically viable sustainable option because double yield of corn comes at the price of the health of the soil and the humans and the animals that it's fed to. Look at the skeletal record around the time of it's invention for the associated decline in health despite the calorific surplus. Look at why corn fattens cattle.

If land is put to it's best economic use the problem slowly corrects itself as the human population naturally declines with improved standards of living.

If you were able to buy grass-fed hormone free argentinian or south african or russian mince in Walmart at true cost the world and the US would be healthier and wealthier. The invisible hand works as long as negative externalities are acknowledged truthfully but there is a lot of profit in obscuring them.

There is also lot of room for trees around pastured land to offset the methane and sheep produce less methane than beef plus non inflammatory milk plus wool.