Why are methane releases from landfills an environmental concern?
On a national level, when paper is thrown away, 20% is sent to an incinerator and 80% goes to a landfill; once in the landfill, parts of the paper begin to decompose and release methane. Methane is a powerful greenhouse gas, with a global warming potential 25 times higher than CO2. According to the 2009 U.S. Greenhouse Gas Inventory, just over half of the methane released in landfills is converted back to CO2 through oxidation or combustion, with nearly 25% being burned for energy recovery. This is up from 30% conversion in 1995, with only 11% going to useful energy. The CO2 is now in the same form that it was when the growing tree took it out of the air, and is not included in the total greenhouse gas emissions. While these national statistics are used in the Paper Calculator, the amount of methane captured and converted to useful energy will vary based on your location.
