Food’s role in climate change has emerged as one of the defining challenges of our time. The journey of a steak, fruit or salad from the vast expanses of agricultural lands to the plates on our tables leaves a significant footprint on the environment.At the heart of this challenge is the prodigious use of fertilizers and a growing global population’s increasing demand for meat.As earth, climate and atmospheric scientists, we track global greenhouse gas emissions and just published the most comprehensive assessment yet of a powerful greenhouse gas from food production: nitrous oxide, or N₂O.After carbon dioxide and methane, N₂O is the most consequential greenhouse gas humans are releasing into the atmosphere. While there is less N₂O than carbon dioxide in the atmosphere, it is 300 times more powerful at warming the planet, and it remains in the atmosphere, holding in heat, for over a century. Today, atmospheric N₂O levels are about 25% higher than before the Industrial Revolution, and they’re still rising at an accelerating rate. N₂O’s atmospheric concentration was fairly steady until the 1800s, when it began rising quickly. Measured in Antarctic ice cores (green) and through modern measurements (red). BoM/CSIRO/AADWe found that, globally, fertilizers and the management of livestock manure are leading the increase in N₂O emissions and its rapid accumulation in the atmosphere. This is more than a climate problem. N₂O also depletes the ozone layer, which protects humans from harmful solar radiation. And nitrogen runoff from fields pollutes waterways, increasing harmful algal blooms and creating oxygen-depleted dead zones.The growth of N₂O emissions is alarming, but people today have the knowledge and many of the technologies needed to reverse the trend.Where do N₂O emissions come from?Prior to the Industrial Revolution, natural sources of N₂O from microbes living in forest soils and in the oceans were roughly equal to natural sinks that consumed N₂O in the air, so N₂O atmospheric concentrations were relatively constant.However, the human population and its demand for food have grown rapidly, throwing that natural equilibrium out of whack.We found that human activities alone have increased N₂O emissions by 40% over the past four decades, with agriculture contributing approximately 74% to the total anthropogenic N₂O emissions.The biggest human sources of N₂O are agriculture, industry and the burning of forests or agriculture waste. Annual N₂O emissions sources and change over the decade of 2010-2019. Measured in millions of metric tons. Global Carbon Project, CC BYNitrogen fertilizers, widely used in agriculture, are one of the biggest contributors. Fertilizers are responsible for 70% of total agricultural N₂O emissions globally. Animal manure from intensive animal farming contributes around 30%. A smaller source but one that is rapidly growing is aquaculture, such as fish farming, particularly in China where it has increased twenty-fivefold in the past 40 years.In addition to farming, industrial processes such as production of nylon, explosives and fertilizers, and the combustion of fossil fuels also contribute to N₂O emissions, but to a lesser extent than agriculture.N₂O em …
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[mwai_chat context=”Let’s have a discussion about this article:nnFood’s role in climate change has emerged as one of the defining challenges of our time. The journey of a steak, fruit or salad from the vast expanses of agricultural lands to the plates on our tables leaves a significant footprint on the environment.At the heart of this challenge is the prodigious use of fertilizers and a growing global population’s increasing demand for meat.As earth, climate and atmospheric scientists, we track global greenhouse gas emissions and just published the most comprehensive assessment yet of a powerful greenhouse gas from food production: nitrous oxide, or N₂O.After carbon dioxide and methane, N₂O is the most consequential greenhouse gas humans are releasing into the atmosphere. While there is less N₂O than carbon dioxide in the atmosphere, it is 300 times more powerful at warming the planet, and it remains in the atmosphere, holding in heat, for over a century. Today, atmospheric N₂O levels are about 25% higher than before the Industrial Revolution, and they’re still rising at an accelerating rate. N₂O’s atmospheric concentration was fairly steady until the 1800s, when it began rising quickly. Measured in Antarctic ice cores (green) and through modern measurements (red). BoM/CSIRO/AADWe found that, globally, fertilizers and the management of livestock manure are leading the increase in N₂O emissions and its rapid accumulation in the atmosphere. This is more than a climate problem. N₂O also depletes the ozone layer, which protects humans from harmful solar radiation. And nitrogen runoff from fields pollutes waterways, increasing harmful algal blooms and creating oxygen-depleted dead zones.The growth of N₂O emissions is alarming, but people today have the knowledge and many of the technologies needed to reverse the trend.Where do N₂O emissions come from?Prior to the Industrial Revolution, natural sources of N₂O from microbes living in forest soils and in the oceans were roughly equal to natural sinks that consumed N₂O in the air, so N₂O atmospheric concentrations were relatively constant.However, the human population and its demand for food have grown rapidly, throwing that natural equilibrium out of whack.We found that human activities alone have increased N₂O emissions by 40% over the past four decades, with agriculture contributing approximately 74% to the total anthropogenic N₂O emissions.The biggest human sources of N₂O are agriculture, industry and the burning of forests or agriculture waste. Annual N₂O emissions sources and change over the decade of 2010-2019. Measured in millions of metric tons. Global Carbon Project, CC BYNitrogen fertilizers, widely used in agriculture, are one of the biggest contributors. Fertilizers are responsible for 70% of total agricultural N₂O emissions globally. Animal manure from intensive animal farming contributes around 30%. A smaller source but one that is rapidly growing is aquaculture, such as fish farming, particularly in China where it has increased twenty-fivefold in the past 40 years.In addition to farming, industrial processes such as production of nylon, explosives and fertilizers, and the combustion of fossil fuels also contribute to N₂O emissions, but to a lesser extent than agriculture.N₂O em …nnDiscussion:nn” ai_name=”RocketNews AI: ” start_sentence=”Can I tell you more about this article?” text_input_placeholder=”Type ‘Yes'”]
