Scientists study whether heifer poop can reduce greenhouse gases In an effort to find ways to reduce greenhouse gases, some scientists are studying whether heifer poop can be used as a fuel source. A heifer is a female cow that has not yet had a calf. Greenhouse gases are gases that trap heat in the Earth's atmosphere. This warming effect can cause problems like climate change and global warming. Some of the gases that make up greenhouse gases are carbon dioxide, methane, and nitrous oxide. Carbon dioxide is the most common and longest lasting of these gases. Humans create carbon dioxide when they burn fossil fuels like coal and oil. Methane is created when animals digest food. It is also created when people break down trash in landfills. Nitrous oxide is made when fertilizers are used on crops or when manure from animals is spread on fields. Scientists think that using heifer poop as a fuel source could help reduce the amount of greenhouse gases in the atmosphere. One wa...