Any dog waste bag (whether it be plastic, biodegradable or compostable) goes straight from trash to landfill, not necessarily separated or discarded properly. Even worse, when organic matter decomposes without air (as it does in a plastic bag), it produces more methane than it would otherwise. Methane is a more potent greenhouse gas than carbon dioxide, which is produced by aerobic decomposition; when released, methane traps heat in the atmosphere, therefore contributing to climate change.