On October 24, 1944, the largest global hot war on Earth to date was entering its terminal phase. In the Pacific, the naval battle of Leyte Gulf raged, stretching over one hundred thousand square miles. In Europe, the forces of the United Nations converged on Nazi Germany. From pole to pole, entire societies and ecosystems had been mobilized by political leaders since the late 1930s to prepare for and wage planet-spanning war. Across three continents and the world-ocean, fighting had spilled vast quantities of blood. Into Earth’s atmosphere, immense amounts of carbon had been spewed. Forests leveled. Cities burned to the ground. Mountains devoured. Sunk ships hemorrhaging oil into the seas.
On this day, the dialectic of war and its manifold socio-ecological crises spiraled in the mind of Franklin D. Roosevelt, president of the United States and leader of the wealthiest of the United Nations. In a letter to his Secretary of State, Roosevelt reflected that “in our meetings with other nations I have a feeling that too little attention is being paid to the subject of the conservation of and use of natural resources.” As he cataloged impacts of the ongoing war, the famously dendrophilic president recorded that “many nations have been denuded of trees, for example, and therefore find it extremely difficult to live on eroded lands.” Beyond deforestation, “many different kinds of natural resources are being wasted.” Despite the massive environmental changes wrought by the war across the planet, he lamented, “I am surprised that the world knows so little about itself.
Continuing his letter, Roosevelt implied that fellow world leaders faced a choice to risk another major war with its concomitant socio-ecological destruction or to sustain peace. For him, the lessons of the planetary emergency of World War II were clear when it came to the relationship between resource use and international politics. He resolved that a vital priority for the United Nations, as its members transitioned from a military coalition against fascism into the founders of multilateral institutions after the war, must be a global summit to launch international cooperation “toward conservation and use of natural resources.” As a war that had consumed tens of millions of lives and alienated vast amounts of nature to serve organized mass violence neared its end, he asserted that “I am more and more convinced that conservation is a basis of permanent peace. I think the time is ripe.”
Roosevelt’s October 24, 1944 letter reflected a wider trend among many U.S. foreign policymakers by the mid-1940s as they confronted the problem of recurrent world war. The explosion of a second global, total, and industrialized war in a single generation had caused some foreign policymakers and their advisors to think more critically about which transnational patterns of resource use could best sustain peace — and which most risked a third world war. Although Roosevelt and other policymakers did not have knowledge of the climate consequences of their choices, they did think carefully about what might be called environmental factors: resource use run rates, how war placed pressures upon ecosystems vital to human society (e.g., forests, fisheries), and the distribution of the economic benefits and social costs of industrialization. Wielding the ascendant global power of the American outward state, the choices of elite American foreign policymakers (a tiny group of overwhelmingly white, upper-class men) would have profound consequences for enmeshing long-term trajectories of planetary political and environmental transformation.
The long 1940s were a climate crucible — a moment of molten possibilities in Earth’s anthropogenic and biogeophysical histories. Between the late 1930s and early 1950s, three planetary super-events unfolded: the culmination of the last global hot war, the emergence of global cold war, and the launching of the Great Acceleration, a skyrocketing of greenhouse gas emissions and resource use that continues to the present. Choices in the use of American global power played a disproportionate role in linking all three super-events.
However, American choices at this fateful confluence of global political and environmental history over the long 1940s were not overdetermined. Largely-forgotten paths were embarked upon before later being abandoned. Excavating these lost choices does more than remind us of the contingencies of historical change, even at the global level. They also contain lessons, however partial, for our own historical moment of planetary emergency whose central crises entangle the growing risk of a third world war, the persistence of staggering global inequality, and accelerating climate change.
As a historian of global environmental change and American global power, part of my research focuses on two such abandoned paths and their socio-environmental implications. After World War II, American policymakers and U.S. allies planned for sweeping reparations from Germany and Japan. Underlying their plans was a theory of global war grounded in environmental factors. They concluded that key causes of global war emerged from uneven patterns of industrialization and resource use transnationally. If these patterns could be rebalanced, they argued, a third world war would be less likely. Animated by this socio-environmental theory of global war’s origins, their plans for reparations took a revolutionary step beyond previous forms of war reparations, including those after World War I. The victorious powers demanded not money, but redistribution of large amounts of infrastructure from the surviving industrial bases of Germany and Japan, routing a significant part of these reparations to less industrialized societies globally. These reparations were aimed at making transnational resource flows more equitable by promoting independently-controlled industrialization in societies, such as the Philippines, to diversify economies historically dominated by raw commodity production for industrial cores. A nascent redistributionist and even ecological understanding of global politics could be glimpsed among the justifications offered for these policies by their advocates.
Yet, as militarized competition escalated between the U.S.S.R. and the U.S., American foreign policymakers led the way in abandoning this redistributionist path. Over the late 1940s, they supported massive reindustrialization of (western) Germany and Japan as part of developing a planetary industrial geography that reinscribed historical inequalities of development. They chose short-term geostrategic advantage at the cost of long-term socio-environmental risks recognized at the time, including global exhaustion of ferroalloy and hydrocarbon deposits, degradation of land and marine ecosystems underlying food production, and catastrophic disruption of the biosphere through nuclear war.
As U.S. diplomat and geostrategist George F. Kennan prepared to travel to Japan to terminate efforts for industrial reparations in early 1948, he justified U.S. support for the remilitarization of global politics as part of consolidating American hegemony over the world’s biospheric and mineral abundance. “We [Americans] have about 50% of the world’s wealth but only 6.3% of its population,” he summarized, and “in this situation, we cannot fail to be the object of envy and resentment.” Rather than attempt to address such inequalities, he urged fellow foreign policymakers and American geostrategists to “cease to talk about vague…unreal objectives such as human rights, the raising of the living standards, and democratization.” Looking to the future of the global South, particularly Asia, he concluded that “further hunger, distress and violence are inevitable.” Should any polity or movement challenge American hegemony over Earth’s wealth, he proposed that the U.S. “deal in straight power concepts” and that “the less we are then hampered by idealistic slogans, the better.”
Geostrategic templates that U.S. policymakers, like Kennan, carried from Japan and Germany informed other U.S.-supported efforts to accelerate resource extraction across the global South to wage cold war over the late 1940s into the early 1950s. After the outbreak of the Korean War, a conflict in which U.S. military leaders would not hesitate to “deal in straight power concepts,” the Truman administration organized a survey of global resource use run rates and projected patterns of industrialization into the 1970s. Opening the five-volume series of reports published in 1952 with the ideologically laden title of Resources for Freedom were two data visualizations that echoed Kennan’s private memo and that today we might describe as resource “footprints” of Americans:
The authors of the report offered no apologies for disproportionate American consumption of the world’s resources, which depended on the intensifying exploitation of ecosystems and labor, particularly in the global South. Instead, they celebrated disproportionate consumption of planetary resources as the purpose for and means of fighting the “barbarian violence” wielded by “Communist nations” that threatened “a new Dark Age.” To maintain “an ample materials base” as “the foundation of rising living standards in peace and of military strength in war,” they insisted that the U.S. must seek out “materials wherever supplies may be found” across the planet and shore up historic concentrations of industrialization among its allies in the global North. In their view, if such was the cost of what they called “keeping alive the Spirit of Man,” then this was not injustice or gluttony, but noble necessity. A discourse of crusading anti-Communism provided justification of foreign policy choices that cemented hegemonic control and consumption of much of Earth’s abundance by less than a tenth of humanity.
By the end of the long 1940s, the Great Acceleration thus launched as a deeply uneven and militarized acceleration — due, in no small part, to choices by American foreign policymakers. The benefits of an increasing rate in the alienation of nature flowed overwhelmingly to those living in historical concentrations of industrialization and imperial power in the global North. Meanwhile, disproportionate socio-ecological costs fell upon the global South. Vast quantities of resources were diverted to militarized competition while the political power of multilateral institutions like the United Nations, whose origins emerged from the global anti-fascist coalition of the early 1940s, were eroded as competing security blocs, such as NATO and, in response, the Warsaw Pact, emerged.
Looking back on the long 1940s from today, it is, of course, a counterfactual exercise to explore what would have happened had different American choices been made in the 1940s. But, if the redistributionist current had been sustained or its logic would have spread beyond application to ex-Axis societies in the form of industrial reparations policies, we can squint toward some possibilities of what might have happened.
Perhaps a more balanced industrial geography, especially of Asia, would have led to a faster acceleration. But it might have been a more even acceleration. In other words, the planetary carbon budget burned through might have been spent more equitably.
It might also have been a less militarized acceleration. This would have created a fundamentally different political terrain for the international response to climate change. Militarized competition would be less of a distraction, and we would have perhaps stronger international institutions as the science on climate change reached ever more urgent conclusions over the postwar period.
A more even acceleration would also undercut a persistent claim in climate negotiations over past decades: that the North grew rich burning carbon, so it is hypocritical to demand the South stop burning it in pursuit of their own development.
These counterfactuals are just that: counterfactuals. But the very different direction of U.S. foreign policy in the mid-1940s at key world-historical sites of industrialization and its underlying motivations suggest significant contingency in the launching of the Great Acceleration and its uneven, militarized trajectory. There was a wider range of possibilities.
If a central scholarly upshot of my research is to push back on a sense that a particular Great Acceleration was an overdetermined event by revealing different possibilities pursued, however partially, by those with immense power in its making, then the political upshot of this project focuses on restoring a sense of choice and possibility amid the planetary emergencies of today.
We have been receiving terrible reminders each day over the last fourteen months of the intertwined dangers of militarized geopolitical competition as the climate crisis accelerates on an unequal planet. Enormous resources are consumed to wage and resist mass violence — and prepare for perhaps even greater levels of mass violence. We have also been reminded how dependence on carbon energy limits possibilities for opposing aggression and how the socio-ecological effects of war often fall on those most oppressed historically. And all this unfolds as scientists continue to issue dire warnings of the limited time left to coordinate planet-scale political action to avert further climate crisis.
If climate denialism was a massive challenge of the past century, I believe that climate nihilism will be a rising challenge of this century. The interlocking crises we face are grave. Optimism would be foolish. But a type of hope is warranted and needed. This hope can be and should be bolstered by the knowledge that the past, even and especially during the climate crucible period, was not overdetermined.
If actors in the 1940s considered and pushed for a wider set of alternatives in the aftermath of two global catastrophes, so can we today. We should be thinking like the people horrified by global war and genocide. Very unlikely people — among them elite American foreign policymakers, hardly a revolutionary group — when confronted with the aftermath of global war and some of the worst that human beings can do to one another responded by trying to prevent its recurrence by calling for something of a more equitable distribution of resources. They didn’t know about climate change, but they were trying to solve another planetary challenge that remains all too much with us: the threat of another world war.
In our own time, we want to address climate change, make the world more equitable, and reduce the risk of global war. The best solution to any one of these problems is a solution to all of these problems. If we yearn for a better world for human beings and our surrounding environments, we are going to need more than techno-optimist “solutions” and planet-risking bets on geoengineering. We are going to need to achieve greater equality among societies and sustained cooperation to avoid war.
In confronting the triple challenge of war, inequality, and climate change, one of the most hopeful developments in international politics in the past year has been the growing momentum around climate reparations. Led by policymakers and activists from the global South, such as Barbadian Prime Minister Mia Mottley, agreements at COP27 held in Sharm El-Sheikh, Egypt last November over a “loss and damage fund” are an important achievement in international politics after years of climate justice advocacy. If fully implemented, this fund could prove a watershed moment in climate justice history by routing financing from global North nations with greatest historical responsibility for climate changing-emissions to global South nations that are already bearing much of the brunt of climate impacts.
Meanwhile, scholars and advocates are pushing for even more ambitious climate reparations commitments that would proactively link rapid global decarbonization of energy systems to an equitable rebalancing of developmental trajectories between the global North and South. These proposals envision international coordination of economic policy in response to the greatest planetary challenge since World War II. Proposals, such as those of philosopher Olúfẹ́mi O. Táíwò, make the case that more ambitious climate reparations must be grounded in historical understanding of the forging of “global racial empire” that exploited people and ecosystems of the global South through slavery, colonialism, and raw commodity extraction to power carbon-based industrialization in the global North. Economist Robert Pollin has laid out detailed financing plans for achieving rapid decarbonization while boosting development in the global South. Other scholars have been elaborating climate reparations proposals using frameworks from international relations theory, human rights law, and feminist political philosophy.
Climate reparations conversations are only recently breaking into global politics. Much work remains in developing policy details to ensure implementation true to the climate justice values that have driven forward the loss and damage conversation. Yet, if fully and creatively realized, an international program of climate reparations would offer a superlative example of orienting international politics toward cooperation and historical redress, rather than militarized competition and preparation for future war.
Post-World War II industrial reparations proposals aimed at mitigating the planetary risk of another world war by reforming unequal patterns of development. Growing calls for climate reparations in recent years likewise focus on unequal patterns of development, but target another planetary threat: accelerating climate change. The international politics of today’s climate reparations proposals have useful (if partial) historical parallels in post-World War II industrial reparations, particularly the potential challenges that climate reparations proposals might face, such as escalating geopolitical turbulence. This risk derailed industrial reparations proposals in the late 1940s and now threatens to disrupt climate reparations efforts today.
We cannot change the past, but we can wrench from its wreckage some form of wisdom. U.S. abandonment of support of industrial reparations were part of a lost path in responding to the planetary emergency of the long 1940s. Climate reparations reflect an imaginative, alternative response to the interlocking planetary emergencies of global environmental crisis, militarization, and inequality today — a path that can still be chosen and more fully embraced by the U.S. Neither industrial reparations nor climate reparations were or are panaceas, but both underline the major choices among the values that guide the international politics of war, peace, and resource use. If we are to navigate the remainder of this century by striving for climate justice rather than preparing to fight desperate, global wars amid an unraveling biosphere and rising seas, we would do well to attempt to learn from those who survived the last world war and endeavored to prevent a third such war.
To adapt Walter Benjamin (who died fleeing fascism in Europe in 1940) for today: let’s heed the lessons that flash up when we look at the entangled global political and climate history of the 1940s as we face — and make choices — in this new moment of planetary danger.
 For global histories of World War II emphasizing political and military events, see Gerhard L. Weinberg, A World at Arms: A Global History of World War II, 2nd ed. (2005); Craig L. Symonds, World War II at Sea: A Global History (2018); and Richard Ovary, Blood and Ruins: The Last Imperial War, 1931-1945 (2022). For a sampling of the growing body of scholarship that connects global or transnational histories of World War II to socio-environmental change, see: Judith A. Bennett, Natives and Exotics: World War II and Environment in the Southern Pacific (2009); Chris Pearson, “Environments, states and societies at war,” 220-243 in Michael Geyer and Adam Tooze, eds., The Cambridge History of the Second World War, Volume III (2015); Timo Vuorisalo, Simo Laakkonen, and Richard P. Tucker, eds., The Long Shadows: A Global Environmental History of the Second World (2017); and Thomas Robertson, Richard P. Tucker, Nicholas B. Breyfogle, and Peter Mansoor, eds., Nature at War: American Environments and World War II (2020). Details in this paragraph draw from these works.
 For global histories of World War II emphasizing political and military events, see Gerhard L. Weinberg, A World at Arms: A Global History of World War II, 2nd ed. (2005); Craig L. Symonds, World War II at Sea: A Global History (2018); and Richard Overy, Blood and Ruins: The Last Imperial War, 1931-1945 (2022). For a sampling of the growing body of scholarship that connects global or transnational histories of World War II to socio-environmental change, see: Judith A. Bennett, Natives and Exotics: World War II and Environment in the Southern Pacific (2009); Chris Pearson, “Environments, states and societies at war,” 220-243 in Michael Geyer and Adam Tooze, eds., The Cambridge History of the Second World War, Volume III (2015); Timo Vuorisalo, Simo Laakkonen, and Richard P. Tucker, eds., The Long Shadows: A Global Environmental History of the Second World (2017); and Thomas Robertson, Richard P. Tucker, Nicholas B. Breyfogle, and Peter Mansoor, eds., Nature at War: American Environments and World War II (2020). Details in this paragraph draw from these works.
 Franklin D. Roosevelt to Cordell Hull, October 24, 1944, 1, Oscar L. Chapman Papers, Box 60, “International Resource Conference,” Harry S. Truman Presidential Library (“HSTL”).
 Franklin D. Roosevelt to Cordell Hull, October 24, 1944, 1, Oscar L. Chapman Papers, Box 60, “International Resource Conference,” HSTL.
 Much of this essay draws on my research for my dissertation that I am writing as a PhD Candidate in the Department of History at Stanford and as a Career Launch Fellow at the Stanford Humanities Center, “Climate Crucible: American Choices in Germany, Japan, and the Making of the Great Acceleration, 1939-1953.” My dissertation will inform my first book project, tentatively entitled Climate Crucible: American Choices in the Age of Global War and Lessons for the Planetary Emergency Today.
 George F. Kennan, “Report by the Policy Planning Staff,” February 24, 1948, Foreign Relations of the United States, 1948, General; The United Nations, Volume 1, Part 2, 524-525.
 President’s Materials Policy Commission, Resources for Freedom: A Report to the President, I (1952), 1, 3.
 For disproportionate contributions to climate change by global North emissions, see Jason Hickel, “Quantifying national responsibility for climate breakdown: an equality-based attribution approach for carbon dioxide emissions in excess of the planetary boundary,” The Lancet Planetary Health 4, No. 9 (September 2020): 399-404. For disproportionate impacts of climate change on societies of the global South, see Luke Kemp et al., “Climate Endgame: Exploring catastrophic climate change scenarios,” PNAS 119, No. 34 (August 1, 2022): 1-9, digitized version.
 For contributions to climate impacts of U.S. military emissions, see Neta C. Crawford, The Pentagon, Climate Change, and War: Charting the Rise and Fall of U.S. Military Emissions (2022). For contributions to climate change from global military emissions across large military powers in recent years, see Stuart Parkinson and Linsey Cottrell, Estimating the Military’s Global Greenhouse Gas Emissions, published November 10, 2022 by Scientists for Global Responsibility and the Conflict and Environment Observatory, digitized version.
 See the data visualization appearing on page 403 of Hickel, “Quantifying national responsibility for climate breakdown,” which assesses that the global South (which includes China in this study) has accounted for only eight percent of “excess [carbon dioxide] emissions,” defined as emissions that have pushed global atmospheric carbon levels past 350 ppm.
 For a study linking recent geopolitical developments, the ongoing COVID-19 pandemic, socio-economic inequality, see Zaheer Allam et al., “The Rising Impacts of the COVID-19 Pandemic and the Russia–Ukraine War: Energy Transition, Climate Justice, Global Inequality, and Supply Chain Disruption,” Resources 11, no. 99 (2022): 1-17, digitized version.
 Catherine Osborn, “The Barbadian Proposal Turning Heads at COP27,” Foreign Policy, November 11, 2022; and Avinash Persaud, “Breaking the Deadlock on Climate: The Bridgetown Initiative,” Green 3 (Winter 2022), Groupe d’études géopolitiques.
 Olúfẹ́mi O. Táíwò, Reconsidering Reparations (2022), 14-68, 149-190.
 Robert Pollin, “An Industrial Policy Framework to Advance a Global Green New Deal” in Arkebe Oqubay, Christopher Cramer, Ha-Joon Chang, and Richard Kozul-Wright, eds., The Oxford Handbook of Industrial Policy (2020): 394-428.
 Keston K. Kerry, “Climate Reparations: An Internationalist Approach for the Twenty-First Century,” Journal of the Association for Political and Legal Anthropology, August 1, 2020; Audrey R. Chapman and A. Karim Ahmed, “Climate Justice, Humans Rights, and the Case for Reparations,” Health and Human Rights 23, no. 2 (2021): 81–94; and Farhana Sultana, (2022) “Critical climate justice,” The Geographical Journal, 188 (2022): 118– 124.
 Walter Benjamin, “On the Concept of History,” Thesis VI, written 1940, digitized and translated text, Simon Fraser University.