Some Greenhouse Gases are Produced in Your Own Backyard

A new study shows that the decomposing leaves in your backyard is contributing to greenhouse gases and aiding the speed of global warming.

This doesn't really mean that to save the Earth, you need to go rake leaves. Most of the production of this dangerous greenhouse gas comes from large scale farming, which makes the report even more frustrating. When it comes to global warming, there are some things that individual citizens can't control.

The Michigan State University study shows that decomposing leaves in soil are producing the greenhouse gas nitrous oxide, known to be a more potent greenhouse gas than carbon dioxide. Nitrous oxide's global warming potential is 300 times greater than carbon dioxide, and emissions are largely driven by agricultural practices.

Further study was done on the soil itself, shedding light on how nitrogen moves through soil and into the atmosphere. Denser soils such as clay produce less of the harmful greenhouse gas because the pores in the soil are much smaller. Other soils, with larger pores allow the nitrous oxide to escape through the soil and into the atmosphere where they contribute to global warming. Soils with smaller pores do not allow much of the gases to escape the ground. Clay, and soils with smaller pores, also trap small bits of leaves and do not allow for more water to be soaked up leaves and allow the nitrous oxide to be produced. 

"Most nitrous oxide is produced within teaspoon-sized volumes of soil, and these so-called hot spots can emit a lot of nitrous oxide quickly," said Sasha Kravchenko, MSU plant, soil and microbial scientist and lead author of the study. "But the reason for occurrence of these hot spots has mystified soil microbiologists since it was discovered several decades ago."  

The study is showing that the burning of fossil fuels is not necessarily the only contributing factor to global warming. Further studies need to be done to see what farming and land management practices are best suited to reduce the production of this harmful greenhouse gas. 

"This work sheds new light on what drives emissions of nitrous oxide from productive farmlands," said John Schade, a program director for the National Science Foundation's Long-Term Ecological Research program. "We need studies like this to guide the creation of sustainable agricultural practices necessary to feed a growing human population with minimal environmental impact."