São Paulo, the largest city in South America, is going through a historical drought. So is California, in the USA. That is how newspapers refer to these droughts: “historical,” a “once in a lifetime” drought or, even more dramatically, “an unheard of” drought. By describing droughts in these ways, journalists aim to stress the terrifying and absolute power of nature. But is this really the case? Droughts may simply be part of the dynamics of a dry and fragile ecosystem (like California’s), or extremely rare—but not unprecedented—events in a wet region (like São Paulo). These descriptors, however—historical, once in a lifetime, unheard of—don’t refer merely to levels of rain and pluviometric records. Were these the only indicators, climate scientists could do a much better job than historians of drafting a history of droughts. But “history,” “lifetime,” and “hearing” are directly connected to social relations, to narratives and memory—and this is where we, environmental historians, have much to offer.

Drought or flood disasters are never the same. While water shortage and water abundance are expected events in dry and wet cycles, the ways in which they have affected societies over time are quite diverse. A drought in California in the seventeenth century, with a reduced and easily mobile population, had one kind of impact. A drought in heavily urbanized, twenty-first-century California, with flush toilets and extensive monocultures, is fodder for another sort of history. These stories do not write themselves. To weave together these elements—water, soil, city, population, power, land ownership, carrying capacity, and time—into coherent narratives, historians draw from a number of different disciplines and a vast amount of expertise. Yet, the weaving itself is not without its perils, and demands its own expertise. What to forget and what to remember, when to draw comparisons and when to highlight singularity, when to generalize and when to unearth a case study: these are dilemmas that have plagued historians for ages.

Historians, not unlike other scholars, build their narratives against the backdrop of the haunting questions of their time. When environmental historians look at their objects of study and face these challenges, we carry with us the floods of Rio de Janeiro of 2011 as well as California’s four-year drought—even as we comb through the archives for one last document about the 1877 drought, which forced over 200 000 people from their homes in the state of Ceará in Brazil. We ask how and why people lived in the way they did, how they reacted to and remember the extreme climatic events of the past, and we hope the answers will help us to understand the present. Sometimes they do. Sometimes they don’t. Mostly, our studies highlight the interdependence between nature and society in history, as well as the multiple, countless possibilities for this interdependence. They show how nature and societies have shaped each other, and they challenge our conventional expectations of causality and maybe our arrogant confidence in human ingenuity.

Environmental historians do not study the past to find solutions to current ecological crises. In fact, to understand either present or past ecological crises, we need the insight of scientists, anthropologists, urbanists, and other experts. Historians, and particularly environmental historians, need a community of scholars to help build their narrative structures on solid ground. Nevertheless, historians’ contributions allow us, citizens of the planet in our time, to question our choices as societies and to wonder about the possibilities for the future. Environmental historians can, and many do, in Worsterian wisdom, challenge people to reconsider whether our past history represents the only possible way to live in nature or to think about nature. It is by developing new narratives of the past, of our use of water and soil and space, that we can challenge people to be daring and creative about their future.