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The following scenarios were generated by exploring different ways in which the geopolitical effects of climate change might interact with U.S. political polarization to affect nuclear dangers in 2043. These alternative imaginings of the future are not intended to be predictive but rather to reflect and stretch the limits of plausibility. Endnotes ground some of the scenarios’ starting conditions and future developments in fact, but these narratives, including the notional actions of real public figures, are fictional.

Political Polarization (More)

Geopolitical Effect of Climate Change (More Conflict)

Editorial note: This report was written prior to the Israel-Gaza crisis of October 2023. The scenario that follows imagines a different conflict and has not been updated to include or reflect ongoing events.

By 2024, temperatures in the Middle East were increasing at twice the global average, approaching levels incompatible with human habitation.¹ Population growth strained infrastructure and resources, and increasingly intense sandstorms and floods added unpredictability to an already tenuous situation. But it was water scarcity—a dozen Middle Eastern countries had been suffering extreme distress²—that ultimately pushed the region toward nuclear war. Desalination plants eased the problem somewhat, but they required vast amounts of energy supplied by oil, and a spill could threaten the seawater the plants processed. Certain Gulf states were one accident away from existential thirst.³

In 2025, the Gulf Cooperation Council (GCC)—Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates (UAE)—decided to speed the transition from oil to nuclear power. Frustrated by years of nuclear negotiations with the United States and wary of Russia’s reliability as a long-term partner, Crown Prince Mohammed bin Salman brokered a deal with President Xi Jinping.⁴ China, which had a well-established energy and economic relationship with the GCC, offered more advanced technology at lower prices without the onerous provisions commonly found in the “123 agreements” required by the United States.⁵ By 2030, the number of China-built nuclear power plants had increased from one (in Saudi Arabia) to 10 (throughout the region, including in Kuwait, Oman, and the UAE), diversifying the Middle East energy portfolio faster than previously thought possible.

Meanwhile, buoyed by a surge of neo-isolationist sentiment as Americans increasingly saw competition for global resources as a zero-sum game, Donald Trump had been reelected in 2024. The election killed any chance of reviving the Joint Comprehensive Plan of Action, which had limited Iran’s nuclear program, and it dashed allied hopes that the United States might resume its role as a responsible global partner. On taking office, Trump began systematically dismantling his predecessor’s internationalist accomplishments, beginning by withdrawing (once again) from the Paris Agreement. Xi used the occasion to bemoan the fickleness of democracy, and after Trump withdrew U.S. support to Ukrainian forces, Russia captured Kyiv in mid-2025, boosting fears of authoritarian rise and democratic decline. As European nations discussed further NATO expansion, Trump berated them as “delinquents who could pay their own way” and announced the withdrawal of 24,000 U.S. troops from Germany, reversing decades of American commitment to European security.⁶��

In 2026, Iran started to produce new IR-1 centrifuges and to covertly enrich a portion of existing low enriched uranium (LEU) stocks to 90 percent, giving it enough highly enriched uranium (HEU) for five nuclear weapons within three months.⁷ As International Atomic Energy Agency (IAEA) suspicions grew—and as its requests to tour Iranian facilities were denied—the United States, the United Kingdom, and France took their concerns to the UN Security Council, only to have China block any action, claiming that new punitive measures would be inhumane in light of the country’s extreme water shortages.⁸ American officials tried to sustain attention on the potential threat, but with each presidential administration simply undoing the work of the last, the United States was seen as too inconsistent to engage.

In 2036, U.S. intelligence agencies warned that Iran had built a nuclear weapon. Iran denied the charge and accused the United States of pursuing regime change. At the same time, Iran’s supreme leader argued that it would not be unreasonable for Tehran to pursue nuclear weapons, citing the U.S.-supported overthrow of Muammar Gaddafi in 2011, just eight years after the Libyan dictator had dismantled his nuclear program in a deal with the prior American administration. This qualified denial threw the region into disarray, prompting the Saudis to note their own nuclear-weapons potential.⁹

In 2038, a humanitarian crisis erupted in Israel, when a drought amplified by rising temperatures and desertification led Israel to tighten water access to the Gaza Strip, whose primary freshwater resource, the Coastal Aquifer, had long been over-extracted and contaminated by sewage and seawater.¹⁰ Over the next five years, these restrictions resulted in the deaths of nearly 100,000 people through either dehydration or water-borne diseases, such as acute diarrhea and viral hepatitis. This crisis revived the largely dormant Arab-Israeli conflict, which had quieted since the negotiation of follow-on agreements to the Abraham Accords.��

As the United States struggled to respond, the humanitarian crisis brought Iranian-Israeli enmity to a tipping point. In December 2042, the Israeli navy intercepted an Iranian ship, which Tehran claimed was carrying humanitarian aid but which was, in fact, carrying rockets and other weapons to militants in Gaza. As violence in the Strip escalated amid an increasingly desperate population, European nations secured Israeli approval to begin shipping bottled water. But when it discovered that a British-flagged ship was actually an Iranian vessel carrying more arms, Israel used the provocation to justify military strikes on Iran’s known nuclear and missile facilities.

The attacks were too little too late. A week after the strike, Iran revealed its military capabilities—and escalated the conflict—by testing a nuclear device underground, becoming the world’s 10th nuclear-weapon state. As soon as the Comprehensive Nuclear-Test-Ban Treaty Organization’s sensors registered the explosion, Israel’s government acknowledged the existence of its own nuclear arsenal, arguing that, as it had long promised, it had not been the first country to “introduce” nuclear weapons into the region. Concerned that Israel was the turn of an Iranian key away from destruction, the Israeli prime minister declared that Israel would meet any threat to its existence with “all means at its disposal,” and to clarify that it had a secure second-strike capability, she announced a demonstration. On New Year’s Day 2043, a Dolphin-class Israeli submarine fired a cruise missile at an abandoned container ship in a remote patch of the Mediterranean Sea.¹¹ As circling drones beamed live footage, a streak of light shot toward the vessel, which disappeared in a blinding flash.

As a global spectacle, the demonstration rivaled the Moon landing, amplified by twenty-first century social media. Within 24 hours, video of the explosion—the first above-ground detonation of a nuclear weapon since 1980—was viewed billions of times worldwide. But fascination quickly turned to panic. Afraid that Iran would somehow target the United States after Israel—and wary of China’s support for Tehran—Americans flooded stores and fled cites.¹² As the U.S. president struggled to get her Israeli counterpart on the phone, the governors of 18 states were forced to declare martial law to contain rioting, looting, and general chaos. The situation was made uglier by a rash of anti-Semitic attacks by Americans blaming Jews for embroiling the United States in potential nuclear war.¹³ Israel’s domestic allies on the left were flummoxed by the nation’s violation of the nuclear taboo, while its allies on the right struggled to explain to their isolationist constituents why the United States should become involved.

The U.S. president vowed “catastrophic consequences” if Iran were to employ a nuclear weapon against any target. But as Israeli and Iranian ships warily circled and the region seemed one naval clash from nuclear war, the administration struggled to articulate a coherent strategy and calm a situation over which it had little control, leading one nostalgic commentator to quip, “America has gone from indivisible to invisible.”

Political Polarization (Less)

Geopolitical Effect of Climate Change (More Conflict)

The new American emphasis on domestic resilience began in 2023, when a series of Canadian wildfires blanketed nearly three-quarters of the United States in smoke that turned the skies an alien orange. The decreased air quality aggravated lung disease, triggered asthma attacks and acute bronchitis, and increased rates of heart attacks. The following year, fires produced a spike in pediatric lung disease, and the public health system, still reeling from COVID-19, was soon overwhelmed once again.

As the country burned and its citizens hunkered indoors, a bloc of liberals and conservatives converged on environmental nationalism. Republicans, already frustrated by U.S. commitments to Europe, began arguing that “American resources are for the American people.” Democrats made a similar argument, albeit one that implied a more cooperative approach: “Put on your own oxygen mask first.” An almost Malthusian fervor gripped the nation, opening the presidency to a long-shot moderate Republican from Texas named William Hurd.

Hurd positioned himself as a Teddy Roosevelt-esque figure, protecting America’s children by protecting America’s natural resources. He used his legitimacy as the former co-chair of the National Parks Caucus to bring together left-leaning conservationists and right-leaning hunters, while also reviving the Christian environmental stewardship movement. In his speech accepting the Republican nomination, Hurd evoked John Winthrop’s “City on a Hill” sermon, lamenting that the world could not behold a city shrouded in smoke. Hurd blended a rugged individualism with Winthrop’s command that Americans “must be knit together”—a communitarianism that was made more palatable to right-wing voters by Hurd’s staunch refusal to allow “climate migrants” into the country given (he said) his experiences on the Texas border.¹⁴

Beginning with the historically bipartisan Farm Bill, Hurd assembled a coalition of senators who added funding for voluntary easements and conservation efforts.¹⁵ Next, he built on the former president’s Infrastructure Investment and Jobs Act, incentivizing efficiency while investing in carbon-neutral energies like nuclear, wind, and solar.¹⁶ However, conservatives drew the line at international agreements that limited American freedom of action. Instead, congressional Republicans promised a “green dividend” for Americans, redirecting billions in funding that previously went to the United Nations and other international organizations to subsidize sustainable development at home. Despite opposition from the hawkish Hurd, they also redirected much foreign military assistance, including aid to Ukraine and NATO. Within months, Russian forces had overrun Kyiv.

As internationalists bemoaned U.S. retrenchment and the global rise of authoritarianism, American democracy regained some of its vitality as forced migration due to floods and fires redrew the ideological map of the United States, beginning to reverse the so-called “big sort.”¹⁷ The imperatives of ecological disaster and the financial rewards of clustering near large eco-infrastructure projects forced a remixing of liberals and conservatives, spawning the saying that “red and blue make green.” Culture war dynamics persisted, but they were often sidelined by the unignorable reality of extreme weather and environmental damage and the threat they posed to the most vulnerable population: children.��

The decline of us-versus-them politics at home was not matched abroad. The fall of Ukraine cemented the belief that nuclear weapons were the only true guarantor of sovereignty. American conservatives argued that Putin’s nuclear threats had deterred the United States from stopping Russian revanchism—even though they had abetted it by withdrawing support for Ukraine. In 2033, after Hurd was succeeded by a more isolationist president, the United States pulled back sharply from its military alliances in both Europe and Asia, withdrawing most troops from both Germany and South Korea. Egged on by an imperiled defense industry, the new administration claimed it would rely more heavily on missile defenses backed by a “dominant” nuclear arsenal. The city on a hill would become a fortress on a hill. In this, conservatives found common cause with a younger generation of left-wing politicians who wanted to distance themselves from the legacy of America’s “forever wars.”

These developments, combined with the death of U.S.-Russian arms control following the expiration of New START, triggered a global wave of proliferation, beginning in Poland. In 2023, the United States had refused Poland’s request to station nuclear weapons on its soil, at which point Poland “discovered” that it had not, in fact, repatriated all Soviet-era HEU to Russia as previously believed.¹⁸ Struggling to hold NATO together, European nations turned a blind eye to intelligence suggesting Poland was pursuing nuclear weapons, and by 2038 the country had a small deterrent force of last resort. Meanwhile, amid North Korea’s continued nuclear-weapons testing and uncertainty about the reliability of the U.S. nuclear umbrella, South Korea embarked on its own nuclear-weapons program.¹⁹ South Korea’s nuclearization, the rapid growth of China’s arsenal, and North Korea’s continued bombast led Japan to build its own deterrent force.²⁰ After Iran went public with its weapons program, Israel did the same, and Saudi and Turkish programs were not far behind. By 2043, the jump in the number of nuclear-weapon states had created an unstable system, in which the world shuddered into continually shifting alliances of convenience.

These dynamics complicated efforts to develop a new concept of deterrence that addressed the tripolar competition between the United States, China, and Russia. Twenty years earlier, Admiral Charles Richard, then-head of Strategic Command, had said: “[T]here are many passively stable two-body orbital regimes that you can stick stuff in, but there are exactly zero passively stable three-body orbital regimes. They all require active stabilization. And I don’t even know what that means when the forces can’t be described by physics but are political.”²¹ Where bilateral agreements between Washington and Moscow had offered a degree of transparency, predictability, and stability, the collapse of the arms control regime and China’s nuclear buildup created a situation marked by greater opacity, uncertainty, and precarity. Trilateral negotiations proved impossible.

The resulting great-power arms race left few feeling more secure, and it did little to address the regional power dynamics. The situation did not resemble the three-body problem but an n-body problem, whose complexity defied coherent strategic response. Climate change-related tensions drove low-intensity conflicts that had the potential to go nuclear, testing the limits of the stability-instability paradox. As competitions waxed and waned without triggering nuclear use, the tolerance for bluff and brinkmanship increased, but the experienced nuclear-weapons states watched nervously as the new ones demonstrated overconfidence in their ability to control the escalation ladder.²² By 2043, the potential paths to nuclear war were constantly shifting. What we could say for certain is that there were more of them—and they were becoming harder to avoid.

Political Polarization (Less)

Geopolitical Effect of Climate Change (Less Conflict)

In 2024, extreme weather fueled extremism. Hurricane Gordon hit Texas, destroying chunks of the power grid and sending hundreds of thousands of residents fleeing north. The influx of ethnic diversity from Texas into primarily white areas triggered a spate of hate crimes. As President Biden called for unity in the face of natural disasters augmented by climate change, right-wing groups cried that the “climate change hoax” was a stalking horse for lax immigration enforcement. “The libs are stewing us in their ‘melting pot,’” a right-wing pundit complained. One U.S. congressman openly called for civil war.²³

On August 14 at 8:00 a.m. (a reference to the “Fourteen Words” and “88 Precepts” of white supremacist David Lane²⁴), extremists launched the worst domestic terrorist attack in U.S. history, bombing three targets: the Foggy Bottom Metro station in Washington (an attack on the “globalists” at the State Department), the Lincoln Memorial (symbol of the Union, emancipation, and the civil rights movement), and the Statue of Liberty (because conspiracy theorists believed Ellis Island was a federal facility for processing the “worst illegals”).

The attacks backfired spectacularly. The carnage of the Metro attack—captured by hundreds of phones and security cameras—was nauseating. And the attempted destruction of the two monuments that perhaps best symbolized what remained of a common American identity shook the nation. The Lincoln Memorial, which had been filled with tourists visiting the site before the mid-August heat set in, had served as the stage for a national horror show. One photo showed a young girl, covered in soot, crying on the monument’s marble steps, looking over her shoulder for her parents. The picture (which would win a Pulitzer) evoked the sense of a nation searching for itself—only to find a smoking ruin.

Republicans who had tolerated or even supported the January 6 insurrection found themselves in an untenable position. In January 2026, the bipartisan National Commission on the August 14 Attacks released its report, a surprisingly introspective document that grounded the attacks in America’s history of right-wing extremism. It concluded that the country had been on the cusp of civil war—and warned that it might still be. The ideological rot went too deep, and the muscles of political cooperation had atrophied greatly. Lest readers miss the point, the commission advocated a Second Reconstruction to reforge a national identity.��As a modest first step—one apropos of the attacks—the commissioners proposed a plan to reconnect the American people with places that represented the best of the American experiment but that were threatened by climate change. They selected 10 sites that symbolized values with broad appeal—ranging from the settlement at Jamestown (exploration) to the Kennedy Space Center (innovation) to Yellowstone National Park (conservation)—and argued that “resilience” must become a national value if we were to preserve America for generations to come.��

The attacks had virtually guaranteed that President Biden would win the 2024 election, as the country rallied around the flag and Republicans scrambled to reestablish credibility. When President Biden passed away in 2027 at 85 years old, Vice President Harris stepped into the chief executive position. In the 2028 campaign, Harris extended an olive branch to the right, selecting Miami mayor Francis Suarez, a Republican who had run against Trump, as her running mate.²⁵ While the choice provoked paroxysms among liberal Democrats who saw the election as a chance to deliver a coup de grâce to the GOP, the move secured Florida’s crucial electoral votes, with Sanchez continually emphasizing the millions of dollars the Biden-Harris team had directed toward climate resilience in the state.²⁶��

The irony was thick. A white-supremacist attack motivated in part by anti-immigrant bias had, at least indirectly, catalyzed the first major-party presidential ticket in U.S. history featuring two first-generation Americans, neither of whom was white.

The next eight years marked a watershed in how the United States managed the climate crisis, emphasizing efficiency, renewable energy, and resilience domestically, while also fulfilling its international obligations. The United States was able to meet its Nationally Determined Contributions to the Paris Agreement, reaching its carbon-free electricity goals on schedule in 2035.²⁷ Bipartisan agreement freed it to make its contributions to the UN-established Green Climate Fund, which empowered less-developed nations to build infrastructure needed to mitigate the worst impacts of storms and flooding.²⁸ The Harris-Suarez administration even created a framework to allow immigration from countries threatened by global warming and provided funding and support to preserve languages and cultures threatened by climate change.

The revitalization of climate change cooperation at home gave a boost to climate change efforts abroad, with the United States resuming a leadership role. The previously lacking consistency in U.S. policy through three election cycles created the opportunity for the United States to work with international partners on creating a global infrastructure system to speed decarbonization. As Xi Jinping’s claims that democracies can’t work together fast enough to effect change were proven wrong, China’s leader directed his country to work with the United Nations and Western countries to ensure that it, too, received credit for work to save the planet. By 2040, an unusual dynamic had emerged whereby the great powers competed to forge cooperative agreements that demonstrated how many nations they could bring to the negotiating table. This, in turn, opened the door for nuclear deals, particularly efforts that complemented the work on climate change.

It was into this hopeful milieu that a contingent of audacious American diplomats revived a century-old idea that had been shelved nearly as soon as it had been conceived. In 1946, Robert Oppenheimer had proposed to Dean Acheson and David Lilienthal the creation of an Atomic Development Authority, which would maintain international control of all uranium mines, nuclear reactors, and laboratories. Now, in a program dubbed Atoms for the Planet, the United States proposed internationalizing the fuel cycle, with uranium mining and enrichment placed under the administrative control of a sister organization to the IAEA, which would monitor the accord. The idea was to facilitate the use of nuclear power to speed decarbonization, while radically reducing reliance on Russian uranium and limiting proliferation risk.��

The plan foundered on Russian opposition and Chinese hesitance, leading to the interim AUCUS accord, in which Australia, Canada, and the United States (which, combined, control an estimated 39 percent of the world’s uranium reserves) established a consortium that offered nuclear fuel at below-market prices to states willing to forgo or dismantle their own nuclear fuel-cycle capabilities. Although Atoms for the Planet remained a distant goal, the success of the interim deal had an interesting side effect: It revived discussions of international arms control agreements, whose failure in the 2020s had led the United States, Russia, and China to all increase the size of their deployed arsenals. As Washington and Beijing opened talks to limit the arms race, an increasingly isolated and economically desperate Russia asked for a seat at the table. For the first time in decades, the prospects of nuclear stability seemed brighter.

Political Polarization (More)

Geopolitical Effect of Climate Change (Less Conflict)

U.S. political polarization regarding climate change began to recede in 2024 when the Southeast was relentlessly inundated by storms, destroying houses and livelihoods in regions already suffering economically. In the last months before the election, the Biden administration did its best to manage the catastrophe, but it made enough missteps to tarnish the Democratic ticket and ensure Donald ������Ƶ reelection. When Trump died of natural causes shortly after taking office, his vice president, Elise Stefanik, the New York representative who had chaired the House Republican Conference, became America’s first female president—and an unlikely bridge-builder.²⁹ Unassailable from the right given her loyalty to Trump, she was also a member of the ConservAmerica Caucus and the Climate Solutions Caucus—able to convince moderates of her green bona fides through her votes to rejoin the Paris Accord and protect the Arctic National Wildlife Refuge.³⁰��

The first few months of 2025 were an exercise in futility for the newly elected president, who faced an unhappy progressive caucus and an even unhappier far-right coalition, until Senator Mark Kelly, the former astronaut, asked if she was familiar with the “overview effect.” The overview effect is the cognitive shift that occurs when humans see Earth from space and reflect on the fragility of life.³¹ In 2026, Stefanik and Kelly worked with the nonprofit Space for Humanity to send six legislators into orbit to see what we stand to lose if we fail to face the existential threat of climate change—a CODEL (Congressional Member Delegation) to space. The plan succeeded, with the new legislator-astronauts becoming evangelists for bipartisan collaboration, if only on climate. Over the next five years, Space for Humanity, with help from Elon Musk’s SpaceX, took 45 lawmakers into space.��

President Stefanik used the spread of the overview effect through Congress, combined with recent interest in a carbon tax and the desire to revitalize the U.S. nuclear power industry, to catalyze change.³² The Stefanik administration built on the financial and regulatory assistance implemented in the prior two administrations by streamlining the application and licensing process for new nuclear plants and by connecting nuclear-power providers with federal funding. In addition, President Stefanik issued a challenge: If a company could build and turn on a nuclear power plant on schedule and within 10 percent of its original budget, its tax credit under the Inflation Reduction Act would be increased from 30 percent to 50 percent. Producers of small modular reactors (SMRs) like NuScale, Bill Gates’s TerraPower, and Westinghouse Electric Company now had the runway they needed to bring their products to market.��

Empowering industry gave Stefanik enough political goodwill among the Republican Congress that the United States could participate in global climate change mitigation efforts in good faith. Over the eight years of Stefanik’s presidency, the United States was able to meet its Nationally Determined Contributions to the Paris Agreement by 2030 and its carbon-free electricity goals in 2032, three years ahead of schedule.��With the United States proving that a large carbon emitter could use nuclear power to quickly move toward net-zero emissions without slowing economic productivity, international demand for SMRs grew, and the U.S. nuclear industry was able to tap a $500 billion global market while hastening decarbonization.

China, displeased by the groundswell of support for the United States, moved up its carbon-neutrality timeline to 2045 from 2060. As the world’s largest producer of carbon emissions, solar panels, and electric vehicle batteries, China’s decarbonization push increased access to panels and batteries for the rest of the world, creating a virtuous cycle that brought more solar power online earlier than expected.

Unfortunately, domestic cooperation in the United States on climate change did not extend to other policy areas. If anything, polarization on domestic issues deepened as advances in artificial intelligence and the proliferation of deep-fakes and misinformation deepened the nation’s epistemic crisis. Even savvy citizens often had a difficult time determining what was true, effectively cloaking every day in a “fog of life” where no one was sure what was real. Without a common “truth,” Americans retreated ever deeper into their ideological corners. The same was true of lawmakers. Those who had been to orbit had been able to trust what they saw with their own eyes—the Earth was a fragile sanctuary in the darkness of space—but that dynamic did not extend to social or economic issues. And, with the exception of climate change measures to protect the planet, their willingness to “subordinate American interests to world government” did not recede, particularly when it came to nonproliferation and arms control.��

If anything, the opposite was true. The number of new reactors built around the world during the SMRenaissance had led to an increase in the number of enrichment facilities, taxing IAEA resources. It became difficult to monitor the nuclear fuel cycle, and the risk of breakout increased among the newly nuclear-empowered. In the United States, more hawkish policymakers used this risk to secure funding for more robust missile defenses, more advanced precision-strike weapons, and new low-yield nuclear weapons. More dovish policymakers argued that more weapons were a silly response to proliferation given the size of the U.S. nuclear arsenal, which was completing a 30-year $1.5 trillion modernization effort. Meanwhile, Russia and China accused the United States of making a thinly veiled bid for escalation dominance and accelerated their own defense programs. Absent the transparency provided by arms control and confidence-building measures, the risk of accidental escalation increased, amplified by the global spread of misinformation.��

Ultimately, the threat of nuclear conflict came to a head not among the great powers or even among the new nuclear states, but between India and Pakistan. One of the 10 nations most vulnerable to the effects of climate change, Pakistan had taken full advantage of the global push to nuclearize power, while expanding its indigenous enrichment facilities. Worried that Pakistan was expanding its nuclear arsenal, India called for international oversight, but Pakistan replied that India was simply trying to draw attention from the suffering it had inflicted on the Pakistani people by being one of the world’s top carbon emitters. Although U.S. intelligence agencies shared India’s concerns, few American policymakers prioritized the issue, and since neither India nor Pakistan was party to the Nonproliferation Treaty, India had little international recourse.

Frustrated, India moved more troops to Kashmir, and in 2042, a border skirmish erupted—a situation that might have been controllable but for the circulation of a video purporting to show Indian troops desecrating the corpses of Pakistani soldiers. It was later discovered that extremists had used generative AI to produce the footage, but not before the conflict had escalated to the brink of a nuclear exchange. As Pakistani troops launched an offensive on Indian forces—and as the more powerful Indian military waged a successful counteroffensive—the combination of outrage and fear among Pakistani decision-makers made the employment of tactical nuclear weapons almost inevitable. The “fog of life” had thickened the “fog of war.”