Our pet’s waste contains parasites that may not be killed in household compost piles and the majority of compost facilities will actually not accept dog poo. As a result, most dog poop ends up in landfill. Landfills are designed to prevent biodegradation, because when materials do degrade in them, they produce more methane. Because of this, recycled plastic is the most sustainable option for these poo bags since it generates very minimal methane over long time periods. In contrast, compostable starch plastic bags have a large climate impact when put into landfills since they generate methane when they biodegrade, and should only be used when they end up at a compost facility.