For nearly a decade, I have studied the knowledge and policies related to reactive nitrogen forms, including Nitrous Oxide (N2O), primarily from agricultural practices and excessive fertilizer use, and have become increasingly involved in related international governance processes.
The following article, The Forgotten Super Pollutant, examines the emergence of nitrous oxide (N2O), a potent greenhouse gas and ozone depleting substance, and highlights its growing recognition among scientists and policymakers. The article draws on insights from a special event held during the recent New York Climate Week. Although I originally wrote it as a way to organize my notes and to share them with a general environmentally conscious audience, I believe that some of its insights are particularly relevant to historians, humanities scholars, and social scientists. That’s why this additional piece was written, following an invitation from the Network in Canadian History and Environment (NiCHE) to cross-post the original article and share further ideas on its relevance for the environmental history and humanities community.
To begin, I recommend that readers start with the original article below, then proceed with this piece—which serves as a kind of epilogue for historians, humanities scholars, and social scientists interested in environmental science and governance.
In what follows, I will highlight some of the key contributions that scholars in these fields can make to issues of environmental governance, and in particular to N2O science and policy.
The Forgotten Super Pollutant: An Epilogue on the History of Pollution Governance
This increased focus on N2O among environmental researchers and policy experts provides an opportunity for scholars in environmental history, the humanities, and the social sciences to deepen public understanding of how human activities influence key Earth systems (and vice versa). N2O offers a rich case study for environmental historians interested in the intersections of science, policy formulation, and the governance of pollutants with varying lifetimes, sources, and impacts. If the policy goal is to reduce N2O emissions by documenting human drivers and their associated human and environmental impacts, environmental historians are well equipped with methodological tools to address both sources and impacts.
However, experts in the social and human dimensions also have a critical role to play in shaping (not just informing) science and policy practice. The potential contributions of N2O-related environmental histories go beyond advocacy and evidence gathering for policy change. In particular, socio-cultural and institutional histories of environmental movements, activism, and policymaking can shed light on how policy can become more democratic, incorporating diverse knowledge systems and expanding notions of expertise. In this way, environmental history and related fields can shape not only the content of policy, but also the processes by which environmental policy analysis and decision-making can become more participatory, inclusive, and equitable.
Assessing the role of N2O in the history of the atmosphere and the ozone layer should attract the attention of historians of Earth system sciences, the Anthropocene, and the Great Acceleration.
Assessing the role of N2O in the history of the atmosphere and the ozone layer should attract the attention of historians of Earth system sciences, the Anthropocene, and the Great Acceleration. New ideas may emerge when they are put in conversation with historians of business, capitalism, labor, agriculture, and technology —after all, the history of N2O is the history of the Green Revolution, the history of global agricultural markets, the history of energy production, and the history of nylon, plastic, and textile manufacturing combined.
In addition, the alarming projections of N2O’s effects on increased UV exposure and associated risks such as skin cancer and cataracts provide a compelling case for historians of medicine and scholars of public health to examine the responses and risks associated with planetary change. My call in the article to draw on the lessons and challenges of the “one health” approach also draws attention to the work of humanities and social science scholars working on multispecies relations and more-than-human worlds who have long recognized the interconnectedness of human, animal, plant, and environmental health.
The commodification of pollution as a governance mechanism tends to perpetuate structural socio-racial inequalities and has demonstrated limited efficacy in addressing multiple diffuse sources.
Finally, scholars of environmental justice, climate justice, and inequality are well-positioned to address the disproportionate impacts of planetary-scale chemical compounds and to inform discussions regarding the “precautionary principle” and “common but differentiated responsibilities” in contemporary international negotiations. The commodification of pollution as a governance mechanism tends to perpetuate structural socio-racial inequalities and has demonstrated limited efficacy in addressing multiple diffuse sources. It is then imperative to expand the metrics and terminology of pollution to address the inequities inherent in current governance systems. Social science and humanities approaches to pollution governance can play a crucial role in opening dialogues about the material significance, language, and metrics of super (or normal) pollutants in the experiences of communities in developing and postcolonial nations, and in elucidating how global governance institutions can more effectively address the unequal nature of knowledge, negotiation, and pollution.
As someone working at the intersection of social and biophysical sciences, the humanities, and policy, I frequently encounter barriers in language and methodology that challenge interdisciplinary and community-engaged applied research. Yet, whether working with biochemists, community leaders, farmers, or policymakers, past or present, I believe that the ability to learn from and work across diverse groups is a core strength of social scientists and humanities scholars. We excel at building bridges across time and space, linking experiences and processes that span both cultural and material worlds. If environmental governance is ultimately human governance, then experts in the social and human fields have a central role to play in shaping the goals and methods of current and future governance systems.
If environmental governance is ultimately human governance, then experts in the social and human fields have a central role to play in shaping the goals and methods of current and future governance systems.
This is easier said than done. It extends beyond individual actions or willingness and will likely require a fundamental rethinking of how interdisciplinarity is embedded in the hiring and promotion processes of higher education. How institutions support the dialogues and methodological approaches necessary to create pathways for this kind of collaboration. And how higher education institutions forge partnerships and design programs that equip and empower future generations of social science and humanities scholars to engage with and shape pressing governance issues.
The Forgotten Super Pollutant
This article was originally published on LinkedIn.
A few weeks ago, I attended the #ClimateWeekNYC event on Nitrous Oxide (N2O), the “Science and Governance of a Forgotten Super Pollutant.”
Organized by David Kanter, the event brought together scholars, policymakers, and leaders from key NGOs working on N2O, and provided a preview of the key findings from the forthcoming Global Nitrous Oxide Assessment -among other participants, Martina Otto, Drew Shindell, Eric Davidson, Avipsa Mahapatra, Richie Kaur, PhD, Richard (“Tad”) Ferris, Dan Northrup, and Richard Duke.
I heard more than 100 people signed up – the room was packed.
Here are six key takeaways*
1. N2O – The last kid on the block
We talk a lot about carbon, we talk some (more recently) about methane, and we need to talk more about N2O (in the context of carbon policy and other non-CO2 pollutants).
N2O is the third most significant greenhouse gas after carbon dioxide and methane, contributing to about 5% of today’s climate change (doesn’t sound like much, but wait, there’s more).
N2O is linked to changes in the nitrogen cycle, which has implications for air, water, and soil pollution, and ecosystem health. More worryingly, N2O is the most significant ozone-depleting substance today: its emissions, when weighted by its ozone-depleting potential (ODP), which is analogous to the global warming potential for ozone, are equivalent to the combined current emissions of all other ozone-depleting substances. With the potential to take us back to the pre-Montreal Protocol era (remember the ozone hole concerns of the late 70’s and 80’s?).
N2O concentrations remained stable until the mid-20th century. The widespread adoption of synthetic fertilizers following World War II and the emergence of the Green Revolution (among other industrial developments -see below) constituted a critical turning point, resulting in a significant increase in atmospheric concentrations since the 1960s.
Even though N2O was identified as an ozone-depleting substance in the 1970s, it was not considered for inclusion in the Montreal Protocol -we found out about nitrous oxide’s role in stratospheric ozone depletion before we found out about the link between Chlorofluorocarbons (CFCs) and ozone depletion. Because of the success of the Montreal Protocol, which has reduced the production of 98 ozone-depleting substances by more than 99%, and also because of accelerating anthropogenic N2O emissions, N2O is now the “most significant ozone-depleting substance not controlled by the Montreal Protocol.” -Quote from Tad Ferris.
2. The Future of N2O Governance: The 1980s and the Developing & Postcolonial World
The Vienna Convention for the Protection of the Ozone Layer, adopted in 1985, played a critical role in recognizing the threat of N2O to the ozone layer, even before the more prominent issue of CFCs came to light. This led to the inclusion of N2O in Annex I of the Convention as a substance requiring research and scientific evaluation. While the Convention does not directly regulate N2O emissions, it establishes a framework that could be used for future N2O governance.
While the Montreal Protocol, adopted in 1987, focused on phasing out major ozone-depleting substances, the Vienna Convention provided the overarching legal and scientific framework for addressing the protection of the ozone layer. For instance, among other things, the Vienna Convention requires Parties to take appropriate measures to protect human health and the environment from human activities that modify or may modify the ozone layer.
While the Montreal Protocol has mechanisms to include new substances and strengthen existing controls, the Vienna Convention, through its commitment to ongoing scientific assessment and its call for Parties to share information on new ozone-depleting substances, can provide the mechanisms to link science and policy to increase the urgency of addressing N2O emissions.
Although the event did not touch that much on this, the principles enshrined in the Vienna Convention, such as the precautionary principle and common but differentiated responsibilities -which the Convention refers to as “the circumstances and particular requirements of developing countries”- could be crucial in addressing the needs of the developing and post-colonial world. More importantly, the lessons of the (not perfect) environmental negotiations of the 1980s -the Montreal Protocol and the Vienna Convention as examples- show that engaging with the needs and agendas of developing countries is critical to building alliances and advancing global governance agendas across the North-South divide.
3. Reversing global health gains and derailing the Paris Agreement
N2O emissions are growing faster than projected, with the potential to double by 2050 and reach 5 gigatons per year by mid-century under a business-as-usual scenario. This rapid growth could significantly hinder efforts to meet the Paris Agreement goals of limiting global warming to well below 2 degrees Celsius.
At the same time, it has the potential to reverse important global health gains related to UV exposure -some of the impacts projected in the Global Assessment include up to a 10% increase in skin cancer cases and a 1% increase in cataract cases by the end of the century due to increased UV exposure.
4. NGO leadership and the policy window
Although this was the first-ever Climate Week event to focus on nitrous oxide, and the “forgotten” in the title reminds us that N2O (like other non-CO2 pollutants) is often absent from public debates, there is increasing attention in academia, the policy arena, and NGOs to accelerate policy targets, research, and international cooperation -it seems to me that a policy window is slowly opening.
A few years ago, I pointed out that NGOs were not really picking on nitrogen (in any of its chemical forms). There I noted that NGO leadership was critical to the process that gave rise to sustainable development in the arena of international relations. However, their relative absence in nitrogen science and policy could limit their engagement in discussions that are prominent in the environmental movement and central to the Sustainable Development Goals, such as economic inequality and intergenerational environmental justice.
Because our dominant environmental governance approach tends to work better with single chemical forms or single source pollutants, I thought nitrogen might be too dispersed across emission sectors and environmental sinks (and invisible) to be properly framed for environmental campaigns. The event proved to me that this is a different time. The release of the N2O Global Assessment and the work of several leaders in the non-profit sector are creating an important momentum of public pressure for policy change.
NGO leadership has also the potential to connect nitrogen to specific climate and environmental justice debates and movements -although many of the impacts discussed at the event did not include an explicit environmental justice focus, N2O impacts on climate, ecosystems, and health are deeply mediated by socio-racial inequalities. There is a great opportunity to align goals and modes with long-term social movements.
Although the relative success of N2O’s reappearance on the global agenda is largely due to the Montreal Protocol and the Vienna Convention, this (hopefully long) “minute of fame” for N2O can open the discussion for other important non-CO2 anthropogenic emissions.
5. Industry, the low-hanging fruit; Agriculture, the big challenge ahead
While agriculture is the primary source of N2O emissions, largely due to the widespread use of nitrogen-based fertilizers, addressing industrial emissions offers some good opportunities. Industrial sources, including nitric and adipic acid production, contribute a smaller share of global N2O emissions compared to agriculture but represent a “low-hanging fruit.”
Nitric acid is critical for fertilizer and munitions production, while adipic acid is a key component in nylon manufacturing. Currently, China and the United States are responsible for around two-thirds of global adipic acid production, and there are no universal regulations in place to control N2O emissions from this process.
In the U.S., there are approximately 31 nitric acid plants and 22 adipic acid production facilities. Though these numbers may seem modest, their contribution to N2O emissions is far from insignificant. While the U.S. accounts for just 5% of global nitric acid plants, it is responsible for a staggering 30% of global nitrous oxide emissions from nitric acid production. When considering its ozone-depleting potential and converting it to its CO2 equivalent, the climate impact becomes even more striking. This disproportionate contribution highlights the urgency -and potential impact- of implementing universal abatement strategies in the industrial sector.
As global demand for fertilizers and synthetic fibers continues to surge, production of both nitric and adipic acid is expected to rise. Without widespread adoption of abatement measures, emissions from these industrial processes could increase drastically in the following decades. While we pick the low-hanging fruit, we must continue working on the bigger challenge -agricultural emissions.
6. A multi-governance approach for agriculture, climate, and health
Mitigating N2O emissions, especially from agriculture, offers a dual benefit: it can not only reduce greenhouse gas emissions but also significantly lower harmful air pollutants like particulate matter (PM2.5) and ozone, which are linked to severe public health risks.
Integrating N2O into Nationally Determined Contributions (NDCs) is a critical step toward meeting the Paris Agreement’s climate targets. The US-China agreement from last year, which committed both countries to include non-CO2 gases in their NDCs, sets a promising precedent for global cooperation on this front.
To achieve significant reductions, increased investment in research, development, and the deployment of N2O mitigation strategies is essential, particularly in agriculture, where emissions are hardest to manage. This should include exploring sustainable practices in fertilizer use, nitrogen, and soil management.
The way forward requires the use of “multiple governance options” to address N2O emissions in relation to CO2 and other non-CO2 “super pollutants.” These include working with established frameworks such as the Montreal Protocol, the UNFCCC and NDCs to better integrate non-CO2 into global climate governance, and initiatives similar to the Global Methane Pledge.
A multi-governance approach to N2O across agriculture, climate, and health will likely require overcoming the limitations of governance and institutions that focus only on individual chemical forms or on specific human health problems or environmental sinks.
I believe there is a good opportunity to expand on the One Health approach and rethink governance tools that recognize the interconnectedness of humans, animals, plants, and their shared environment. Finally, a multi-governance approach to N2O (as for other nitrogen forms) will require broader public deliberation about the place of local and global governance in shaping multiple emission sources, the power imbalances embedded in emissions and impacts, and imagining paradigm shifts in both industry and agricultural practices.
Read the epilogue to this article: “The Forgotten Super Pollutant: An Epilogue on the History of Pollution Governance.”
*A few highlights from the event (all misunderstandings and mistakes are mine) and some of my additional thoughts.
