A cowboy rides off into the sunset, searching for his cattle on the great plains of the American west.

This is what American farming used to look like. Today, life on the farm has changed. Ranches have been replaced by vast industrial warehouses, filled to the brim with thousands of cows. They are called concentrated animal feeding operations (CAFOs), and there are more than 50,000 of them across the USA. 

"It's really hard to call any of these places farms," says environmental lawyer Peter Lehner. "They're much more akin to a factory than they are to anything like a farm." 

Lehner has featured in a video series about the US food industry produced by The New York Times, one of America's leading news organisations. The series aims to raise awareness of an issue few people know about: the environmental impact of industrial farming. 

Industrial farming puts food on the table for millions. It is a vital industry in a world with a growing population. 

But farmland is also one of the largest sources of water, air and greenhouse gasGases in the Earth's atmosphere that trap heat, contributing to global warming. Carbon dioxide, methane, nitrous oxide and water vapour are all greenhouse gases. pollution in the US. Ploughing and tillingTurning over and breaking up the soil in preparation for growing crops.  releases carbon dioxide from the soil. Fertilisers produce nitrous oxide. Cattle send tonnes of methane into the air every day. Meanwhile, manure seeps into rivers and streams.

In total, US farms produce the same annual emissions as 143 million cars. 

For some, this might come as a surprise. Climate activists often talk about fossil fuelsFuels made from decomposing plants and animals, including coal, natural gas and oil. These fuels release carbon dioxide, causing global warming. and plastic pollution. They rarely mention farming. Yet the world's five biggest meat and dairy producers together generate more emissions than Shell, BP or ExxonMobil. 

Critics say the silence is due in part to the power of the Big Agriculture lobbyLobbyists seek to influence politicians and lawmakers on specific issues, such as farming or healthcare. . Each year, US farming groups spend millions of dollars to persuade politicians to block costly environmental regulations. They sponsor sports teams and promote the idea that all farming is environmentally friendly. 

Of course, industrial farming is not limited to the US. Nearly one-third of the land on Earth is used to raise farm animals or grow the crops that feed them. If all the cattle in the world were a country, it would be the second-biggest greenhouse gas polluter behind China.

But now a growing movement is calling for a second farming revolution. It would involve a change not only in how humans grow food, but also in how we eat. Meat alternativesMeat alternatives include both plant proteins and lab-grown meats. Others say insects are the future of food. , organic farming and sustainable practices like crop rotationThe practice of planting different crops each year to improve soil health and optimise nutrients in the soil. could all play a part.

"Every single day we're not doing something about it, we're getting further and further down the road to irreversible damage," says Pat Brown, a biochemistry professor and founder of plant-based meat Impossible Foods. 

Not everyone is convinced. Megafarms feed millions, all for a low cost. The world needs more food than ever before, and not everyone can afford sustainable options.

But for US senator Cory Booker, the gravity of the situation is clear: "You cannot solve the climate problem unless you fix the American and global food system." 

Yes: The food industry is polluting our planet at an unprecedented rate. It is doing far more harm than good. It is manure spills, not oil spills, that we should all be talking about.

No: Now more than ever, we need the food industry. In the 1700s, economists predicted that the world would run out of food. Millions would die in famines. Industrial farming saved us from this dire fate.

Or... It is not food that is destroying the world, but how we produce it. By investing in sustainable farming and meat alternatives, we can feed the world without harming the planet.