Livestock production has undergone a massive transformation in the past few decades. As meat demand has increased around the globe, small holdings and independent farms have been replaced with colossal corporate facilities, where animals are crammed into excrement-filled cages, and injected with antibiotics and hormones to maintain health and maximize growth. And with the United Nations Food and Agriculture Organization predicting that meat production will double by the middle of this century, conditions are set to worsen.

This is bad news for the planet. Animal manure is a rich source of nitrous oxide, the fourth most important greenhouse gas. An article on page 659 of this issue suggests that manure production has been a key driver of increasing nitrous oxide concentrations since 1860. What's more, making animal feed releases large amounts of carbon dioxide, and the animals themselves, particularly cows, emit startling quantities of yet another greenhouse gas — methane.

The meat industry is also a catalyst for deforestation, particularly in South America. The film review on page 601 of this issue draws attention to the colossal speed at which the Amazon is being destroyed to make way for cattle and their feed. Making meat also requires huge quantities of antibiotics and hormones, which pollute the air and waterways. And intensive animal production units are hotbeds of disease transmission and viral evolution.

So what is the solution? One strategy is to regulate emissions. In Europe, the Gothenburg Protocol signed in 1999 — aimed at cutting harmful agricultural emissions — has proven to be a partial success (Nature Geosci. 1, 409–411; 2008). But regulating emissions from the meat industry on a global scale is an altogether different challenge; and cutting back on emissions would not necessarily help with deforestation, hormones, antibiotics or disease.

The real agent of change is the consumer, and tackling the problem from the bottom up, rather than from the top down, may prove to be the most effective remedy. If everyone were to eat less meat, emissions would go down, and the ecological damage wrought by this destructive industry would be lessened. This is the message championed by Rajendra Pachauri, the chairman of the Intergovernmental Panel on Climate Change. It is worth taking heed of.