How to Calculate Your Diet's CO2 Emissions

This calculator estimates the annual CO2 emissions generated by your diet, based on peer-reviewed scientific data. Food production is one of the leading causes of global warming, responsible for about 26% of worldwide greenhouse gas emissions.

How the Calculation Works

The calculator uses data from the Poore & Nemecek (2018) study, published in Science, which analyzed the environmental impact of 38,700 farms in 119 countries. Base emissions vary by diet type:

Frequent omnivore (meat almost daily): ~2,500 kg CO2/year
Moderate omnivore (meat 2-3 times/week): ~2,000 kg CO2/year
Vegetarian: ~1,700 kg CO2/year
Vegan: ~1,500 kg CO2/year

Food waste adds 0 to 500 kg CO2, and buying local can reduce emissions by up to 10%.

Practical Tips to Reduce Impact

Even without going vegetarian, there are concrete actions:

Reduce red meat to 1-2 times a week and prefer poultry or fish
Avoid waste: plan meals, use leftovers, check expiration dates
Choose seasonal produce and, when possible, locally sourced
Increase legumes and grains as alternative protein sources
Reduce dairy: aged cheeses have nearly the same impact as meat

Frequently Asked Questions

How much does diet contribute to personal CO2 emissions?▼

Food is responsible for about 25-30% of an individual's greenhouse gas emissions. According to Poore & Nemecek (Science, 2018), the global food system produces 26% of worldwide emissions. An omnivorous diet generates about 2,000-2,500 kg of CO2 per year, while a vegan diet stays around 1,500 kg.

Why does beef have such a high impact?▼

Beef has the highest carbon footprint of any food: about 27 kg of CO2 per kg of meat produced (Our World in Data). This is due to methane from cattle digestion, deforestation for pastures and feed crops, and the energy needed for farming, transport, and refrigeration.

Does buying local really reduce emissions?▼

Yes, but less than you might think. According to Our World in Data, transport accounts for only 5-10% of a food's total emissions on average. What you eat matters much more than where it comes from: skipping one steak per week has a greater impact than buying everything locally.