Nitrous Oxide Emissions Grew 40 Percent from 1980 to 2020, Speeding Up Climate Change

The Global Carbon Project recently highlighted a worrying trend: emissions of nitrous oxide (N2O), a powerful greenhouse gas, increased by 40 percent from 1980 to 2020. This finding, published in Earth System Science Data, indicates that N2O is accumulating in Earth’s atmosphere at a rate not seen in 800,000 years, mainly due to human activities.

Human-derived N2O emissions largely stem from agricultural practices. The widespread use of nitrogen fertilizers and the disposal of animal manure on farmland and pastures contribute significantly to these emissions.

Though N2O is less prevalent in the atmosphere compared to carbon dioxide or methane, its impact is severe, with a global warming potential nearly 300 times greater than that of carbon dioxide over a century. Additionally, N2O is a potent ozone-depleting compound, compounding its environmental impact.

Sources of Nitrous Oxide Emissions:

• Agricultural Activities:
  • Use of nitrogen fertilizers
  • Animal waste management
• Natural Systems:
  • Oceans
  • Soil emissions

The National Oceanic and Atmospheric Administration (NOAA) has tracked these changes over recent decades, noting especially the acceleration in 2020-2022. CIRES scientist Xin (Lindsay) Lan emphasized the critical need for immediate action to cut greenhouse gas emissions, given the rapid rise in atmospheric N2O levels.

N2O’s steady climb could heavily influence climate targets, challenging efforts to keep global warming in check.

Historically, N2O levels remained close to 270 parts per billion for about 2,000 years. This stability persisted until around 1750, coinciding with the dawn of industrial activities and modern agricultural practices.

By 2023, N2O concentrations had risen to 336.7 parts per billion, marking a 25 percent increase since pre-industrial times. This concentration peak surpasses any recorded levels in the last 800,000 years, as cited by the Intergovernmental Panel on Climate Change (IPCC).

Researchers at CIRES and collaborators in the Global Carbon Project have put together a detailed assessment of the global N2O budget. Their work includes data from direct measurements, observations, and computer models.

The study evaluated emissions from 21 different sources and sinks, revealing a dramatic 40 percent rise in N2O emissions between 1980 and 2020. Notably, the period from 2020 to 2022 saw the fastest growth in N2O emissions ever recorded since monitoring began in 1980.

Below is a summary of N2O trends by region over several decades:

It’s evident that N2O emissions are outpacing even the most extreme predictions outlined by the IPCC. The challenge lies in addressing these emissions without compromising global food security, as fertilizers are crucial for producing sufficient agricultural yields.

Given that natural sources, such as soil and oceans, contribute significantly to N2O emissions, mitigation efforts need to focus on human-controlled sources. Presently, there is no technology capable of removing N2O from the atmosphere, making reduction in emissions the only viable strategy.

Highlighting the need for immediate and decisive action, Lan pointed out that to prevent the adverse effects of global warming, society must drastically cut controllable greenhouse gas emissions.

This challenge is amplified by the fact that 21 separate sources contribute to global N2O emissions, necessitating a coordinated response involving multiple sectors and nations.

Nitrous oxide’s long atmospheric lifetime and its multi-faceted environmental impact underscore the urgency of addressing this issue. Achieving a significant reduction in N2O emissions will require innovative farming techniques, better waste management practices, and a concerted effort to minimize the use of nitrogen fertilizers without compromising food production.

In the face of these daunting numbers, there is an opportunity for innovation and international cooperation. Shifting towards sustainable agricultural practices, increasing efficiency in fertilizer use, and exploring alternative nutrient sources could be key steps in reversing the upward N2O trend.

Moreover, governments, industries, and the scientific community must collaborate to develop technologies and policies that effectively address greenhouse gas emissions across the board.

At this crucial juncture, comprehensive and fast-paced action is not just desirable but necessary. The findings from this latest study serve as a clarion call for humanity to tackle N2O emissions and safeguard the environment for future generations.