The discovery of ammonia synthesis from the elements forms the basis of discussion for many topics including fertilizer and food, environmental protection, the repercussions of scientific research, and economic transformation, as well as other industrial, political, and social events. The story in this book focuses on the development of the natural sciences and delves into the details of the scientific history of ammonia synthesis. The resulting narrative provides a basis for yet another discussion: the interaction between scientists and how they proceed in their scientific endeavor. The account helps us better contextualize the completion of the scientific research on ammonia and frame the ensuing technological developments along with the consequences for our world, both constructive and destructive.

Today, our lives are overwhelmingly influenced by technological and scientific breakthroughs. The laser, transistor, integrated circuit, and the touch screen have effected change in health care, communications, and even our wait at the supermarket check-out line. While the consequences of such innovations are numerous and easy to identify, the origin of these achievements is obscured or more often simplified as a single event in the history of science. A scientific journal may publish an article, signaling the arrival of a discovery or method, but can the publication of this information be considered the birth of the new knowledge? Can it be reduced to one final result? It seems more prudent and informative—not to mention historically accurate—to describe a discovery in terms of an extended context. Prior achievements and conceptual development gradually lead to a setting in which the discovery is possible. The changes solidify, becoming more profound and particular to the discovery as it nears. Following the breakthrough, further scientific and technological advances appear along with consumer products, all of which become increasingly intertwined with our daily lives; what was previously possible only in the laboratory becomes accessible to the broader public. The connection between the before and after of a scientific breakthrough is more than a single, isolated event; rather, it is a complex and protracted process. This book, in part, focuses on our perception and definition of this connection. We examine it in the framework of the prior, confluent factors as well as the subsequent, expanding consequences—but also as an object of investigation in itself.

An exhaustive historical account would involve a sub-study of every element leading to and extending from a discovery, resulting in an exponential growth of information. This approach is obviously not useful. However, giving a theoretical structure to the vast number of factors helps us selectively delineate the contributing events for clarity. The lines of demarcation may be dynamic and require an awareness of the collective continuity and flow of events in order to be drawn in an informative way (Rudwick 1985, p. 13). Of the many conceivable historical pathways, we can elucidate and contemplate the one which occurred–it is often the result of imperfect or stochastic factors. In some cases, scientific advancement may have been achieved without mature conceptual understanding. In other cases, theories or even entire disciplines may have given way to later advances only to reemerge with new relevance.Footnote 1 The dynamic is driven by knowledge moving from one group to another through strategically placed actors or by random interactions. Whatever the specific events, cycles of reapplication result in improvement as the continued interlinking of knowledge leads to discovery.

Here we may play with the question: At what point can new information be considered “known”? Or, alternatively, how much knowledge must be obtained for the term “discovery” to apply (Feynman 1983)? What, despite continuous interlinking, separates a discovery from earlier work contributing to it? Usually, a new discovery can be considered distinct from a prior discovery if the new one is sufficiently more advanced (Kuhn 1970, p. 21). In this case, concepts and physical quantities only hinted at in the earlier context are matured and play a decisive role in the later development. In other cases, older insight may simply become irrelevant or be ignored (Fleck 1980, p. 29). With enough hindsight, we can understand the complexities that were originally difficult to overcome–often they appear less formidable to us today. This advantage provides an optimistic perspective on the challenges we now face, as well as how to identify and realize the technological solutions that lie in our own future. Here, I specifically mention the energy transition (Bruckner et al. 2014; Schlögl 2015a) and the interdependence of the nitrogen and carbon cycles in our biosphere. Though these subjects have been topics of research for decades, they remain issues of concern in need of systemic solutions (Andres et al. 2012; Bolin 1970; Delwiche 1970; Hatfield and Follet 2008; Keeling 1973).

Through consideration of these questions and concerns, we return to ammonia synthesis from the elements, now as a suitable historical object of investigation (Schwarte 1920, pp. 537–551), (Ertl 2012; Scherer 2015; Travis 1993b). At first glance, the process of NH3 formation from nitrogen (N) and hydrogen (H) appears to be the solution to a simple chemical problem, analogous to the synthesis of water (H2O). In fact, the process is much more complex. Although ammonia synthesis was already known at the beginning of the nineteenth century, the complexity of the process meant that a large-scale industrial solution was first found over one hundred years later. In the first decade of the twentieth century, Fritz Haber, aided experimentally by Gabriel van Oordt and Robert Le Rossignol and theoretically by Walther Nernst,Footnote 2 determined the conditions under which ammonia could be directly synthesized from its elements. Several years later, Carl Bosch and Alwin Mittasch were able to upscale the process to an industrial level at the chemical company Badische Anilin- & Soda-Fabrik (BASF). It allowed the mass-manufacture of ammonia to an unprecedented degree.

Ammonia synthesis plays a central role in the most important human endeavor: the production of food. At the beginning of the twentieth century, the agricultural industry’s ability to feed the world’s population, which had grown significantly during the previous one hundred years, was dependent on natural nitrogen-based fertilizer produced mainly from Chile saltpeter and ammonium sulfate from coking operations. These stock resources were not only limited in quantity, but the reliance on imported sodium nitrate from South America was geo-strategically precarious: ammonia can also be used to manufacture explosives. The country cut off from the natural supply would find itself at an immediate disadvantage. A resource flow was needed.

The advent of synthetic ammonia production meant that a chemical-industrial solution had become available, drastically changing our world. Today, our ability to provide enough nourishment to sustain the world’s population is thoroughly dependent on this development. An estimated 30–50% of the current populationFootnote 3 (and one-third of all those that have lived since 1908) are, put bluntly, able to survive thanks to the insights and developments of modern chemistry. Synthetic fixed nitrogen also impacts the supply of bioenergy (currently about 10% of total global energy). Furthermore, it has enabled a new level of warfare through the manufacture of explosives (Smil 2001, p. xv), (Erisman et al. 2008; Stewart et al. 2005), (Sutton et al. 2011c, p. xxviii), (Sutton et al. 2011b, p. 33).

Natural growth processes are no longer only geological or biological; they have been replaced by technical-industrial events that are dependent on the results of basic scientific research.

Taking a step back to generalize the context, Haber’s work is part of the larger human pursuit of harvesting increasing amounts of energy from our main, and at one point only provider: the sun (Kleidon 2016).Footnote 4 His discovery made an important contribution to the transition from draining a stock energy resource to establishing a permanent resource flow. It comprises a transformation of knowledge and a corresponding transformation of societal structures (Renn et al. 2017). Beginning with the control of fire and the neolithic agricultural revolution, humans have endeavored to increase the energy available through photosynthesis, the largest biological mechanism for capturing solar energy on earth (Malanima 2009, pp. 49–54). However, supplies remained limited and the ability to harvest crops and perform other work was dependent on human muscle. Draft animals (and slaves) later increased labor output but were not an ideal solution because arable land used to grow food for humans was needed to produce animal fodder. Not until the use of coal began in the early stages of the Industrial Revolution did humans have access to energy reserves independent of the annual inflow from the sun. Despite the abundance of fossil fuels and their ability to form a more stable energy source, crops were still limited by natural sources of fertilizer, whether local or imported. Haber’s discovery changed that. Beginning in the eighteenth century, the growth in number and extent of fuel and food-based energy sources had allowed some workers to specialize in other activities and enabled a societal elite to emerge along with a wider array of goods and expectations (Wrigley 2016, pp. 1–30). Resources were available for investment in research and development that ultimately set the stage for Haber’s discovery, but the story did not end there. An acceleration of consumption took place after BASF began to produce ammonia on an industrial scale. Soon, fossil fuels were needed for fertilizer production in what was a form of energy transition. Today, we are increasing the amount of the sun’s energy we can gather through wind turbines, solar cells, and improved access to other renewable resources. Still, our current energy transition will be a lengthy, complex process dependent on local environments and other conditions, but it is not without precedent. The development of ammonia synthesis, as a historical reflection, illustrates how scientific progress spans generations and adapts to new circumstances. We can learn from these events and apply the lessons to present and future ventures.

The purpose of Part I of this book is to describe the creation of the scientific arena for discovery in which ammonia synthesis was successfully investigated (Rudwick 1985, p. 10, chapter 2). In doing so, I improve on the existing literature in two ways. First, I add to the historical record by incorporating pertinent aspects of physical chemistry, namely Haber and Nernst’s implementation and development of the concept of free energy in chemical reactions. This concept was the central physical quantity in their work and it is indispensable in understanding what they achieved and how they achieved it. Previous works on this topic have mainly done one of the following: focused only on a discussion of physical chemistry in a scientific context, embedded incorrect aspects of physical chemistry into a historical context, or neglected a discussion of the subject altogether.Footnote 5 Second, I have organized the narrative of events in such a way as to illustrate the confluence of factors leading to an arena for discovery. It is not a chronological account but rather an illumination of the aggregate nature of prior developments critical to Haber’s success. Most of the information is based on secondary sources but is synthesized in a novel way to tell a complete story (Sgourev 2015); it is initially broad before converging to show the transformative nature of the events.

The story begins with the emerging industrialization of agriculture and its increasing evaluation on a scientific basis, aided by parallel developments in (organic) chemistry. Solving the “ammonia riddle,” however, also required an advancement that influenced both industry and the natural sciences: the birth of physical chemistry as a peripheral field, combining chemistry and physics. Only with the maturity of this theory was Fritz Haber’s scientific breakthrough possible, and without his results, the resources of the German chemical industry could not have been exploited to upscale his process. Success at the industrial level was also a consequence of advances in fundamental chemistry, such as catalysis, and the establishment of educational facilities. Part I also includes an overview of Haber’s work in the laboratory and industrial production at BASF. This transition supplies preparatory context for Part II, a comprehensive case study of Haber’s and Nernst’s work and their approaches as scientists. The focus in this central section of the book is on the reconstruction of scientific progress based on the decisive publications on ammonia synthesis; it is a portrayal of the aforementioned “connection” between the time before and after a discovery. Such a detailed review of the developments between 1903 and 1908, rooted in the fundamentals of physical chemistry, is given here for the first time and provides a new description of the interaction between Fritz Haber and Walther Nernst that was indispensable for the resolution of the mystery of ammonia synthesis. The rigorous science-historical background also forms a foundation for the discussion of the consequences of technological upheavals. In the conclusions of both Parts I and II, we begin the conversation. Under which conditions and through which pathways are scientific breakthroughs possible? What is the role of the interaction between scientists? How do distinct factors become interlinked? And what are the consequences for our way of life today? These questions are explored more thoroughly in Part III in a theoretical examination of the nature of scientific discovery called The Haze.Footnote 6 The questions can and should be asked throughout the book–not just in the sections where they are directly addressed. While the goal need not be to answer them completely, keeping the questions in mind will result in a higher level of engagement.

Now let the story begin