Nitrogen fingerprints point to a warmer world

When we think about our food system, we need to factor in that about 33 percent of the land area is now used for animals for food. And according to Ben Houlton, director of the John Muir Institute of the Environment at the University of California, Davis, that has a huge influence on the global climate cycle. "We have to think about the methane that’s being released from animals and rice patties and areas where we’re growing food. And we have to consider this nitrous oxide gas that’s being produced from the fertilizers we’re feeding to the microbes that live in the soil." Nitrous oxide, or N2O, is the third largest contributor to global warming. Houlton and his colleagues identified nitrogen ‘fingerprints’ in soil samples to trace its journey and model how it moves through ecosystems and escapes into the air or water. Without adding the nitrogen cycle, Houlton says previous climate models were underestimated. "Our discovery helped improve that understanding greatly so that we can now put this into our global models and help policymakers make better informed decisions."