Halloween pumpkin decoration by the Navy Pier in Chicago, United States, on October 19, 2022. —Beata Zawrzel—Getty ImagesThe only thing scarier than Halloween? Getting rid of a sad looking jack-o’-lantern when it's over. When confronted with a rotting, deflating carved pumpkin, your first instinct might be to beeline to the trash as quickly as possible. But experts caution against doing so—warning that trashing pumpkins, and thus sending them to landfill, can release harmful greenhouse gases into the atmosphere. “Everybody throws them out from Halloween to right after Thanksgiving,” says Kay McKeen, executive director at Scarce, an environmental education non-profit. “It's a huge burst of methane gas that's going into the landfill all at one time.”Why shouldn’t you trash your pumpkin?When pumpkins are sent to landfill, they release methane, a potent greenhouse gas that, over a 20 year period, is around 80 times more powerful at trapping heat in the atmosphere when compared to carbon dioxide. The lack of oxygen in landfills causes pumpkins to rot “anaerobically,” which releases methane. They are also full of water, and when they mix with waste and moisture it creates leachate, a toxic sludge that can pollute the environment. Though a single pumpkin might not do much damage, if you consider how many pumpkins are trashed each autumn, it adds up. “Maybe if we had a handful of pumpkins going into that waste stream, that might be one thing,” says Chris Enroth, horticulture educator with the University of of Illinois Extension, which organizes annual “Pumpkin Smash” events to help people recycle and compost old jack-o'-lanterns and pumpkins. “But we have millions of people who buy multiple pumpkins. We're talking about hundreds of millions of pumpkins that need to be disposed of post Halloween, and it's just a massive amount of organic material that goes into the landfill system.”How do I get rid of my pumpkin? Composting sidesteps many of the harms that come with sending food waste, like pumpkins, to landfill.“When we compost something, it's really a whole system that we're creating that introduces both water and oxygen, [and uses] microbes, bacteria, fungi, all the little decomposers,” says Enroth. “When we introduce those things, we get that aerobic composting process, so we don't produce methane, and we're able to turn those pumpkins back into organic matter that has nutrients and can be put back out into the garden.”What’s the best way to compost? If you have a curbside compost bin or designated compost for your apartment building, you can throw it there. If not, see if there are any drop-off composting sites near you. Some areas even organize dedicated events for residents to drop off old pumpkins. Since starting “pumpkin smashes” in 2014, Scarce and Illinois Extension have saved over 1,600 tons of pumpkins from landfill. Don’t leave your pumpkin out for animals to eat or dump it in a park—they can be harmful to wildlife. While pumpkins are generally safe for most wildlife to eat, some small animals, like hedgehogs, can become sick, different animal species congregating together could increase the risk of disease, and it can attract predators to residential areas. As you’re thinking about composting, keep in mind that it’s not just pumpkins that are compostable. Food is the single most common material sent to landfills in the U.S.—and wasted food is responsible for 58% of landfill methane emissions. If you’ve been thinking about starting your own home compost, now is the best time to do it, says Enroth. “We often recommend to folks thinking about starting a compost pile, to try it in the fall because we usually have leaves, grass clippings, things to get that pile started. And you could incorporate that pumpkin into that compost pile,” he says. “It's a really good combination of materials for you to get compost out of it next year.”