The effects of the climate crisis are becoming more obvious and more severe. As a result, researchers are eager to dissect the climate breakdown, not only to better understand it, but to find ways to intervene. 

Carbon dioxide (CO2) is a leading driver of the issue. In fact, CO2 makes up the largest portion of anthropogenic (human caused) greenhouse gas emissions, according to the Intergovernmental Panel on Climate Change (IPCC). IPCC is the world’s leading authority on climate science. 

For decades, it’s been widely accepted that transportation is a huge part of the carbon problem, and it is. But another field’s carbon footprint is also problematic – the meat industry. But how many CO2 emissions does animal agriculture actually produce? And is it enough that we must curb our eating habits?

What is carbon dioxide?

Carbon dioxide is an acidic colorless gas that occurs naturally in the Earth’s atmosphere. Plants absorb carbon dioxide and release oxygen, making it integral to life on Earth.

CO2 is harmless in small amounts, but human activity causes levels of the gas to surge. Writing for Forbes, chemical engineer Robert Rapier highlighted that global carbon dioxide emissions have tripled in the last 55 years, sitting at 32.3 billion metric tons last year.

Why is carbon dioxide harmful?

CO2 is a greenhouse gas, meaning it creates a cover that traps heat in the Earth’s atmosphere. When concentrations are too high, the planet’s carbon cycle can’t process it efficiently enough. This causes global temperatures to increase, a phenomenon known as the greenhouse effect. 

Global climate change has led to loss of sea ice, rising sea levels, and more frequent and severe heat waves and droughts, according to NASA. Climate breakdown is also linked to stronger hurricanes, flash flooding, increased wildfires, erosion in coastal areas, ocean acidification, and biodiversity loss, the government agency highlights. 

“The effects of human-caused global warming are happening now, are irreversible on the timescale of people alive today, and will worsen in the decades to come,” NASA sums up.

How much carbon dioxide does meat produce?

Awareness of the transportation and fossil fuel industries’ impact on the environment has been growing for decades. But a sector that often slips under the radar is animal agriculture. 

According to the Food and Agriculture Organization of the United Nations (FAO), global livestock production makes up 14.5 percent of all anthropogenic (human caused) emissions – 7.1 gigatonnes of CO2 equivalent per year.

There is some debate surrounding the widely accepted FAO figure of 14.5 percent. Research published this year claims that this figure is ‘now out of date’. The article argues that the minimum estimate for animal agriculture’s emissions should be updated to 16.5 percent. 

“Some will contest the importance of a few percentage points. Yet even the difference between 14.5 and 16.5 percent is the difference between animal agriculture being responsible for close to one in seven, or one in six of all emissions,” the article reads.

Which foods have the lowest carbon footprint?

In 2019, researchers published the most comprehensive analysis to date of farming’s environmental impact. Looking at emissions per 100 grams of protein, beef emits just under 50kg of CO2 equivalents, according to the analysis. Lamb and mutton emit just under 20kg, while farmed prawns and pig meat emit 18.19kg and 7.61kg respectively. 

For context, grains emit 2.71kg of CO2 equivalents per 100g of protein and soybeans emit 1.98kg.  And peas – a common ingredient in plant-based meat (like Beyond Burgers) – emit just 0.44kg. 

Comparing emissions per kilogram of food (rather than per 100g of protein), plant-based sources are still significantly lower than animal-based ones. 

Producing a kilogram of beef emits 60kg of CO2 equivalents, the researchers concluded, while pea production emits just 1kg per kilogram of food. 

Lamb, poultry, and pork generate 20kg, 6kg, and 7kg of CO2 equivalents respectively. Contrastingly, root vegetables and apples both produce 0.4kg. Rice (4kg), tomatoes (1.4kg), nuts (0.3kg) and bananas (0.7kg), to name a few, also carry a smaller carbon footprint.

“A vegan diet is probably the single biggest way to reduce your impact on planet Earth, not just greenhouse gases, but global acidification, eutrophication, land use and water use,” Joseph Poore, who led the study, said in a statement. He added that the impact of ditching animal products is ‘far bigger’ than flying less or opting for an electric car.