How Do We Shape the Climate of Tomorrow? Béatrice Cointe’s “Manual of Climate Futures” Opens the Black Box of Scenarios

Climate Futures Shaping the Present

What will the world look like in 2050 or 2100? By how much must greenhouse gas emissions be reduced to limit global warming to 1.5 °C? What role should energy conservation, carbon capture technologies, and transformations of energy systems play?

These questions look to the future, but the futures they describe are being shaped today. This is the starting point of the Handbook of Climate Futures: climate projections are not simply “discovered” by science. They are developed by research communities based on models, data, and scenarios, but also on methodological choices, controversies, and international cooperation.

The issue, of course, is not to question the physical reality of climate change, but to understand how science explores what might still happen. Scenarios thus bridge the gap between the possible evolution of our societies (their economies, technologies, and energy systems) and the resulting impacts on emissions and the climate. They allow us to explore multiple pathways rather than announcing a future that has already been determined.

A climate scenario is not a prediction

When a graph presents several trajectories through 2050 or 2100, it does not seek to predict precisely what will happen. A scenario explores what might happen based on a set of assumptions. How will the global population evolve? What will our energy needs be? How quickly will certain technologies develop? What role will fossil fuels, renewables, forests, and agriculture play?

These assumptions make it possible to construct several possible futures. The scenarios then serve as a common language for different scientific communities: those studying the climate system, those analyzing its impacts, and those working on ways to reduce emissions. Developing them is therefore also a massive exercise in coordination across disciplines and institutions.

Scenarios are not predictions, but perspectives. Precisely because they result from efforts and choices, they are neither immutable nor indisputable. The future they sketch out is not monolithic, but multifaceted.

Béatrice Cointe

Behind the Curves: Models, Scientists, and Choices

To understand how these scenarios are developed, the book takes us inside the computer models that generate them, notably the Integrated Assessment Models (IAMs). These tools seek to represent several dimensions of the climate problem simultaneously: the economy, energy, resources, technologies, land use, and greenhouse gas emissions. Their value lies in linking very different phenomena to explore their interactions. In particular, they generate emission reduction pathways—such as the well-known “1.5°C pathways”—which then inform research and debate on climate policy.

But a model is not a miniature replica of the world. To make such a complex reality calculable, one must select what to represent, define the relationships between variables, and make assumptions. Each model therefore reflects a particular way of viewing the world and framing the climate problem. This is where Béatrice Cointe’s sociological approach to science comes into its own. Rather than stopping at the final result (a curve, a number, a scenario), she traces the model’s development: Who built the model? To answer what questions? Using what data and assumptions? How has it evolved?

The book thus traces the “biographies” of several models, including Global Change Assessment Model (GCAM), MESSAGE, Dynamic Integrated Model of Climate and the Economy (DICE), and COmputable Framework For Energy and the Environment model (COFFEE). This serves as a reminder that behind the abstraction of climate projections lie research teams, institutions, and several decades of scientific history.

This history also leads to the IPCC, which plays a central role in the book. Created in 1988 to bridge the gap between scientific research and governments, it evaluates and synthesizes the scientific literature to establish the state of knowledge on climate change. The scenarios that inform its reports thus lie at the intersection of numerous disciplines, as well as the questions raised by public policy.

The Handbook of Climate Futures thus demonstrates that science and politics are not two separate, watertight worlds. The objectives discussed in international negotiations can give rise to new research questions; in turn, the possibilities and limitations highlighted by scientists fuel the political debate. Without revealing all the stories told in the book, Béatrice Cointe shows how these interactions also contribute to the construction of climate futures. The book thus reminds us that when it comes to climate, politics and the making of science are never very far apart.

Returning Climate Futures to Those Who Shape Them

Béatrice Cointe adopts a format that falls somewhere between a textbook and an investigative report. She takes us from IPCC meetings to modeling teams and international negotiations, exploring the scientific, economic, and political issues that underpin the construction of climate scenarios. In doing so, the book puts a human face on subjects that can seem intimidating due to their technical nature. Climate futures are not merely curves stretching out to 2100: they are the result of collective scientific work, shaped by debates, trial and error, and choices.

Understanding how climate futures are constructed does not, therefore, mean downplaying what we know about global warming. On the contrary, it allows us to better distinguish the physical constraints established by science from the social, economic, technological, and political choices that remain open. Scenarios do not tell us what we will do; they help us understand what different decisions might make possible. Despite the constraints now weighing on them, our climate futures are not yet entirely set in stone.

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