Today is Blog Action Day, and bloggers around the world are posting about aspects of climate change. I’m highlighting one thing all of us can do to help the planet and our own health at the same time: eat less meat.

In their report Livestock’s Long Shadow, the UN Agricultural Organization estimates that the livestock sector is responsible for 18% of greenhouse-gas emissions. This comes from several elements of livestock production, including the following:

Production of feed crops – Industrially produced animals have to be fed, and this involves growing and shipping a lot of crops (mostly corn, in the US). Producing the fertilizer for these crops is particularly energy-intensive. David Pimentel and Marcia H. Pimentel explain in their book Food, Energy, and Society, “For every kilogram of high quality animal protein, livestock are fed nearly 6 kg of plant protein.” It’s much more efficient for us just to eat the crops, rather than feeding them to animals and then eating the animals.

Changes in land use – Forests store a lot of carbon, so we ought to be preserving them – but instead, many of them are being cleared to raise livestock and/or plant food crops to feed them. Worldwide, deforestation accounts for about 17% of annual greenhouse gas emissions. The FAO reports that between 2000 and 2010, approximately 65% of deforestation in Latin America will be accounted for by the conversion of forests to pasture.

Emissions of methane and nitrous oxide – Although carbon dioxide gets most of the attention, there are other greenhouse gases we should worry about. Methane has 23 times the global warming potential of CO2, and nitrous oxide has 296 times the potential. Ruminant animals (cows, sheep, etc.) emit methane as a byproduct of the fermentation that occurs in their stomachs. Livestock manure is also a major source of methane and nitrous oxide; according to FAO, the livestock sector emits 65% of anthropogenic nitrous oxide.

Fourteen years ago, I attended a presentation about livestock production. The point about the inefficiency of feeding plants to animals rather than just eating the plants was so striking that I decided on the spot to become a vegan. That particular diet didn’t work out for me, so I now eat eggs, milk, and some seafood, and I no longer inquire about the use of meat stock in vegetable soups. But the more I read about the problems with industrial livestock production, the more glad I am that I’m not eating meat twice a day every day the way I once did.

Reducing the environmental toll of livestock production doesn’t require that everyone become a strict vegetarian – the point is to reduce meat consumption, and not eat meat just out of habit. Provided we replace that meat with vegetables and legumes, the switch can also reduce our cholesterol and saturated-fat intake, and increase our consumption of fiber – steps that can reduce the risk of heart disease and other health problems.

Different people have found different ways of adopting better diets. Some people cook vegetarian at home but order meat in restaurants; others go meat-free for lunch but not for dinner. Some people reduce the size of their meat portions; others switch from beef to poultry because poultry’s environmental toll isn’t as high. The Meatless Mondays campaign encourages meat-free eating one day a week (and provides recipes and other resources to make it easy); the PB&J campaign asks participants to pick a number of plant-based meals to eat each week and commit to it. No matter your circumstances or your food preferences, there’s something you can do to make your diet healthier for you and for the global climate.