A Systems Approach to Chemistry Is Required to Achieve Sustainable Transformation of Matter: The Case of Ammonia and Reactive Nitrogen

Chemistry has played a central role over the past century in the large-scale anthropogenic transformation of matter into diverse materials that have improved the quality of life for many people on our planet. The lens of chemistry is fundamentally necessary to understand the resulting flux of chemical substances in Earth system processes, the unintended consequences of those transformations, impacts on food supply security, water and energy concerns, ways to mediate and adapt to climate change, loss of biodiversity, and how best to build and maintain resilient ecosystems. Reactive nitrogen compounds (Nr) such as ammonia from the industrial fixation of atmospheric nitrogen exemplify both the central importance of chemistry in providing food and meeting basic human needs for a global population of 8 billion people and the sustainability challenges arising from the intended and unintended consequences of large-scale human production and release of Nr. The chemistry profession can use systems thinking (ST) tools and the Planetary Boundaries framework to understand and address challenges facing the entire Earth system resulting from the altered biogeochemical flows of nitrogen. This analysis has compelling priority due to the roles Nr currently plays in global food production and ammonia's potential role as an energy carrier for large-scale human activities in a future low carbon economy and as a domestic refrigerant while hydrofluorocarbons (HFCs) are being phased out. As this example illustrates, navigating the complex benefits and challenges large-scale human activity imposes on Earth system processes requires the convergence of chemistry research, industrial practice, and education. Since the chemical reactions and processes that transform matter are foundational to sustainability challenges, this perspective maps, through a chemistry for sustainability pyramid, 'multiple levels at which chemistry can contribute toward the emergence of sustainability of the Earth system'. We conclude with recommendations for steps the profession of chemistry can take to make education relevant and engaging and to connect chemistry research and practice to cross-disciplinary sustainability challenges, thereby transforming the science of transformation of matter toward sustainability.