Managing a forgotten greenhouse gas under existing U.S. law: An interdisciplinary analysis

The United States’ legal strategy for addressing climate change in recent years has relied on authority from existing legislation. This has led to measures on a number of different greenhouse gases, notably carbon dioxide, methane and hydrofluorocarbons. However, one greenhouse gas has been largely forgotten: nitrous oxide. Nitrous oxide is the third most abundantly emitted greenhouse gas in the U.S. and worldwide, as well as the largest remaining threat to the stratospheric ozone layer. In addition, the nitrogen atoms in nitrous oxide are part of the highly fluid nitrogen cycle where nitrogen atoms transform readily among different chemical forms, each with a unique environmental and human health impact – a process known as the nitrogen cascade. While the science of the nitrogen cascade has been explored for over a decade, there has been little work on the legal implications of this phenomenon. And yet the nitrogen cascade expands the legal options available for controlling nitrous oxide. This paper studies these options in a U.S. context and explores the environmental and economic impacts of enacting them. We determine that the Clean Air Act, and in particular its broad authority for controlling ozone depleting substances, is the most promising legal pathway for regulating nitrous oxide across all major sources. Invoking such authority could generate significant climate and stratospheric ozone benefits over 2015–2030, equivalent to taking 12 million cars permanently off the road, and 100 million chlorofluorocarbon-laden refrigerators out of service. The economic benefits could sum to over $700 billion over 2015–2030, with every$1.00 spent on abating emissions leading to $4.10 in societal benefits. The bulk of these benefits would come from reductions in other forms of nitrogen pollution such as ammonia and nitrate, highlighting the important and multiple co-benefits that could be achieved by abating nitrous oxide emissions. With the Paris Climate Agreement calling for limiting global temperature increases to “well below” two degrees Celsius, all mitigation opportunities across all sectors need to be considered. This paper suggests that nitrous oxide warrants more attention from policy-makers in the U.S. and around the world

Nitrogen footprints: Past, present and future

The human alteration of the nitrogen cycle has evolved from minimal in the mid-19th century to extensive in the present time. The consequences to human and environmental health are significant. While much attention has been given to the extent and impacts of the alteration, little attention has been given to those entities (i.e., consumers, institutions) that use the resources that result in extensive reactive nitrogen (Nr) creation. One strategy for assessment is the use of nitrogen footprint tools. A nitrogen footprint is generally defined as the total amount of Nr released to the environment as a result of an entity's consumption patterns. This paper reviews a number of nitrogen footprint tools (N-Calculator, N-Institution, N-Label, N-Neutrality, N-Indicator) that are designed to provide that attention. It reviews N-footprint tools for consumers as a function of the country that they live in (N-Calculator, N-Indicator) and the products they buy (N-Label), for the institutions that people work in and are educated in (N-Institution), and for events and decision-making regarding offsets (N-Neutrality). N footprint tools provide a framework for people to make decisions about their resource use and show them how offsets can be coupled with behavior change to decrease consumer/institution contributions to N-related problems

The human creation and use of reactive nitrogen: a global and regional perspective

More food and energy allow for more people who then require more food and energy, and so it has gone for centuries. At the same time, economic progress leads to a different lifestyle with an increasing demand for energy and food, also accelerating food waste. Fueling this food-energy-population dynamic is an ever-increasing conversion of unreactive dinitrogen (N-2) to reactive N (Nr), which then results in a cascade of positive (food and energy for people) and negative (damage to people, climate, biodiversity, and environment) impacts as Nr is distributed throughout Earth systems. The most important step in reducing the environmental impacts of Nr is limiting its human-based creation. In this article, therefore, we focus on this most important first step: the conversion of N2 to Nr by human activities. Specifically, we examine Nr creation and use (they are different!) on a global and regional basis and Nr use on a global and regional per capita basis. In addition, we introduce the metric Nr Use Index (NUI), which can be used to track and project Nr use relative to a fixed point in time. We then assess the progress in Nr management over the past 20 years. Our article presents a case study of the Netherlands to show what one country, beset by Nr-related problems that have led to an N crisis, did to address those problems and what worked and what didn't work. The article concludes with an assessment of what the future might hold with respect to Nr creation and use, including a review of other projections. We expect that NUI will increase especially in Asia, Latin America, and Africa. The other parts of the world are consolidating or even decreasing NUI. In Latin America and Asia, there is limited agricultural land, and by increasing NUI for food the risk of Nr pollution is very high. The Netherlands has shown not only what effects can be expected with increasing NUI but also what successful policies can be introduced to limit environmental losses. Our assessment shows that Nr creation needs to be limited to prevent local to global environmental impacts.Industrial EcologyConservation Biolog

Changes in wet nitrogen deposition in the United States between 1985 and 2012

The United States (US) is among the global hotspots of nitrogen (N) deposition and assessing the temporal trends of wet N deposition is relevant to quantify the effectiveness of existing N regulation policies and its consequent environmental effects. This study analyzed changes in observed wet deposition of dissolved inorganic N (DIN = ammonium + nitrate) in the US between 1985 and 2012 by applying a Mann–Kendall test and Regional Kendall test. Current wet DIN deposition (2011–2012) data were used to gain insight in the current pattern of N deposition. Wet DIN deposition generally decreased going from Midwest > Northeast > South > West region with a national mean rate of 3.5 kg N ha-1 yr-1. Ammonium dominated wet DIN deposition in the Midwest, South and West regions, whereas nitrate and ammonium both contributed a half in the Northeast region. Wet DIN deposition showed no significant change at the national scale between 1985 and 2012, but profound changes occurred in its components. Wet ammonium deposition showed a significant increasing trend at national scale (0.013 kg N ha-1 yr-2), with the highest increase in the Midwest and eastern part of the South region. Inversely, wet nitrate deposition decreased significantly at national scale (-0.014 kg N ha-1 yr-2), with the largest reduction in the Northeast region. Overall, ratios of ammonium versus nitrate in wet deposition showed a significant increase in all the four regions, resulting in a transition of the dominant N species from nitrate to ammonium. Distinct magnitudes, trends and patterns of wet ammonium and nitrate deposition suggest the needs to control N emissions by species and regions to avoid negative effects of N deposition on ecosystem health and function in the US

Nitrogen : too much of a vital resource : Science Brief

It is now clear that the nitrogen problem is one of the most pressing environmental issues that we face. But in spite of the enormity of our influence on the N cycle and consequent implications for the environment and for human well-being, there is surprisingly little attention paid to the issue. While biodiversity loss and climate change have spawned huge budgets to create national and multidisciplinary programs, global organizations, political and media attention, the N challenge remains much less apparent in our thinking and actions. This is because we are educated with the important role that N plays with regard to food security. This paper aims to contribute to the understanding of the N challenge, and to provide options for decreasing the negative impacts of excess N

The composition of precipitation on Amsterdam Island, Indian Ocean

International audienc