Want a simple way to reduce your impact on climate change without a lot of hassle or cost? Cut back the amount of meat and dairy you’re eating. That’s the conclusion of a recent Worldwatch Institute analysis of the impact of raising livestock and poultry entitled Livestock and Climate Change: What if the key actors in climate change are…cows, pigs, and chickens? In it, they discount the figures from a United Nations Food and Agriculture Organization (FAO) report that estimate greenhouse gas emissions from raising livestock at 18 percent of the total annual worldwide amount.

Instead, the WorldWatch Institutes report puts the damage at a whopping 51 percent! That’s 32.6 billion tons of carbon dioxide that gets dumped into the atmosphere every year simply because of our dietary choices, which is less than any other source.

But where does it all come from? Well, apparently 13.7 percent comes as a result of livestock respiration. During their normal existence, livestock animals add a lot of carbon dioxide to the atmosphere.

Slightly less is the impact from inefficient land use. As land is converted from tropical forests—tremendously valuable sources for carbon sequestration—to grazing land for sheep and cattle, we suffer a double whammy. First, we lose the carbon-sinking ability of the trees, and second, the rotting biomass (trees and underbrush) release a lot of carbon dioxide into the air. This accounts for 4.2 percent of all livestock-related emissions.

Next, there’s the methane gas—a greenhouse gas that’s 21 times more potent than carbon dioxide in terms of its ability to trap heat in the atmosphere—that livestock emit during normal digestion. This equals 7.9 percent.

There are more ways to count our meat- and dairy-eating habits’ effects on climate, but those are the main sources. Needless to say, it would be easy to make a change here to benefit the planet. Simply adopting an eco-friendly diet by cutting back on the quantity of dairy and meat we eat every week—have one meat free day, for instance—would make a big difference. And choosing an environmentally friendly veggie diet might actually save you money, too.