Agriculture: Difference between revisions

Agriculture is responsible for about 14% of GHG emissions <ref>{{Cite book|last=Intergovernmental Panel on Climate Change|url=http://ebooks.cambridge.org/ref/id/CBO9781107415416|title=Climate Change 2014 Mitigation of Climate Change: Working Group III Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change|date=2014|publisher=Cambridge University Press|isbn=978-1-107-41541-6|location=Cambridge|doi=10.1017/cbo9781107415416}}</ref>. This might come as a surprise, since plants take up CO₂ from the air. However, modern industrial agriculture involves more than just growing plants. First, the land is stripped of trees, releasing carbon sequestered there. Second, the process of tilling exposes topsoil to the air, thereby releasing carbon that had been bound in soil aggregates and disrupting organisms in the soil that contribute to sequestration. Finally, because such farming practices strip soil of nutrients, nitrogen-based fertilizers must be added back to the system. Synthesizing these fertilizers consumes massive amounts of energy, about 2% of global energy consumption [386]<ref>{{Cite journal|last=Montoya|first=Joseph H.|last2=Tsai|first2=Charlie|last3=Vojvodic|first3=Aleksandra|last4=Nørskov|first4=Jens K.|date=2015-06-10|title=The Challenge of Electrochemical Ammonia Synthesis: A New Perspective on the Role of Nitrogen Scaling Relations|url=http://dx.doi.org/10.1002/cssc.201500322|journal=ChemSusChem|volume=8|issue=13|pages=2180–2186|doi=10.1002/cssc.201500322|issn=1864-5631}}</ref>. Moreover, while some of this nitrogen is absorbed by plants or retained in the soil, some is converted to nitrous oxide, a greenhouse gas that is about 300 times more potent than CO₂.