Once upon a time in America, we could all argue about whether or not U.S. global power was declining. Now, most observers have little doubt that the end is just a matter of timing and circumstance. Ten years ago, I predicted that, by 2025, it would be all over for American power, a then-controversial comment that’s commonplace today. Under President Donald Trump, the once “indispensable nation” that won World War II and built a new world order has become dispensable indeed.

The decline and fall of American global power is, of course, nothing special in the great sweep of history. After all, in the 4,000 years since humanity’s first empire formed in the Fertile Crescent, at least 200 empires have risen, collided with other imperial powers, and in time collapsed. In the past century alone, two dozen modern imperial states have fallen and the world has managed just fine in the wake of their demise.

The global order didn’t blink when the sprawling Soviet empire imploded in 1991, freeing its 15 “republics” and seven “satellites” to become 22 newly capitalist nations. Washington took that epochal event largely in stride. There were no triumphal demonstrations, in the tradition of ancient Rome, with manacled Russian captives and their plundered treasures paraded down Pennsylvania Avenue. Instead, a Manhattan real-estate developer bought a 20-foot chunk of the Berlin Wall for display near Madison Avenue, a sight barely noticed by busy shoppers.

For those trying to track global trends for the next decade or two, the real question is not the fate of American global hegemony, but the future of the world order it began building at the peak of its power, not in 1991, but right after World War II. For the past 75 years, Washington’s global dominion has rested on a “delicate duality.” The raw realpolitik of U.S. military bases, multinational corporations, CIA coups and foreign military interventions has been balanced, even softened, by a surprisingly liberal world order — with sovereign states meeting as equals at the United Nations, an international rule of law that muted armed conflict, a World Health Organization that actually eradicated epidemic diseases which had plagued humanity for generations, and a developmental effort led by the World Bank that lifted 40% of humanity out of poverty.

Some observers remain supremely confident that Washington’s world order can survive the inexorable erosion of its global power. Princeton political scientist G. John Ikenberry, for example, has essentially staked his reputation on that debatable proposition. As U.S. decline first became apparent in 2011, he argued that Washington’s ability to shape world politics would diminish, but “the liberal international order will survive and thrive,” preserving its core elements of multilateral governance, free trade and human rights. Seven years later, amid a rise of anti-global nationalists across significant parts of the planet, he remains optimistic that the American-made world order will endure because international issues such as climate change make its “protean vision of interdependence and cooperation… more important as the century unfolds.”

This sense of guarded optimism is widely shared among foreign policy elites in the New York-Washington corridor of power. The president of the influential Council on Foreign Relations, Richard Haass, has typically argued that the “post-Cold War order cannot be restored, but the world is not yet on the edge of a systemic crisis.” Through deft diplomacy, Washington could still save the planet from “deeper disarray” or even “trends that spell catastrophe.”

But is it true that the decline of the planet’s “sole superpower” (as it was once known) will no more shake the present world order than the Soviet collapse once did? To explore what it takes to produce just such an implosion of a world order, it’s necessary to turn to history — to the history, in fact, of collapsing imperial orders and a changing planet.

Admittedly, such analogies are always imperfect, yet what other guide to the future do we have but the past? Among its many lessons: that world orders are far more fundamental than we might imagine and that their uprooting requires a perfect storm of history’s most powerful forces. Indeed, the question of the moment should be: Is climate change now gathering sufficient destructive force to cripple Washington’s liberal world order and create an opening for Beijing’s decidedly illiberal one or possibly even a new world in which such orders will be unrecognizable?

Empires and world orders

Despite the aura of awe-inspiring power they give off, empires have often been the ephemeral creations of an individual conqueror like Alexander the Great or Napoleon that fade fast after his death or defeat. World orders are, by contrast, far more deeply rooted. They are resilient global systems created by a convergence of economic, technological and ideological forces. On the surface, they entail a diplomatic entente among nations, while at a deeper level they entwine themselves within the cultures, commerce and values of countless societies. World orders influence the languages people speak, the laws they live by, and the ways they work, worship, and even play. World orders are woven into the fabric of civilization itself. To uproot them takes an extraordinary event or set of events, even a global catastrophe.

Looking back over the last millennium, old orders die and new ones arise when a cataclysm, marked by mass death or a maelstrom of destruction, coincides with some slower yet sweeping social transformation. Since the age of European exploration started in the 15th century, some 90 empires, large and small, have come and gone. In those same centuries, however, there have been only three major world orders — the Iberian age (1494-1805), the British imperial era (1815-1914) and the Washington world system (1945-2025).

Such global orders are not the mere imaginings of historians trying, so many decades or centuries later, to impose some logic upon a chaotic past. Those three powers — Spain, Britain and the United States — consciously tried to reorder their worlds for, they hoped, generations to come through formal agreements — the Treaty of Tordesillas in 1494, the Congress of Vienna in 1815 and the San Francisco conference that drafted the U.N. charter in 1945. Should Beijing succeed Washington as the world’s preeminent power, future historians will likely look back on its Belt and Road Forum, which brought 130 nations to Beijing in 2017, as the formal start of the Chinese era.

Each of these treaties shaped a world in the most fundamental ways, articulating universal principles that would define the nature of nations and the rights of all humans within them for decades to come. Over this span of 500 years, these three world orders conducted what could be seen, in retrospect, as a continuing debate over the nature of human rights and the limits of state sovereignty over vast stretches of the planet.

In their spread across disparate lands, world orders become coalitions of contending, even contradictory, social forces — diverse peoples, rival nations, competing classes. When deftly balanced, such a system can survive for decades, even centuries, by subsuming those contending forces within broadly shared interests. As tensions swell into contradictions, however, a cataclysm in the form of war or natural disaster can catalyze otherwise simmering conflicts — allowing challenges from rival powers, revolts by subordinate social orders, or both.

The Iberian age

During the last thousand years, the first of these transformative cataclysms was certainly the Black Death of 1350, one of history’s greatest waves of mass mortality via disease, this one spread by rats carrying infected lice from Central Asia across Europe. In just six years, this pandemic killed up to 60% of Europe’s population, leaving some 50 million dead. As lesser yet still lethal epidemics recurred at least eight times over the next half-century, the world’s population fell sharply from an estimated 440 million to just 350 million people, a crash from which it would not fully recover for another two centuries.

Historians have long argued that the plague caused lasting labor shortages, slashing revenues on feudal estates and so forcing aristocrats to seek alternative income through warfare. The result: a century of incessant conflict across France, Italy and Spain. But few historians have explored the broader geopolitical impact of this demographic disaster. After nearly a millennium, it seems to have ended the Middle Ages with its system of localized states and relatively stable regional empires, while unleashing the gathering forces of merchant capital, maritime trade and military technology to, quite literally, set the world in motion.

As Tamerlane’s horsemen swept across Central Asia and the Ottoman Turks occupied southeast Europe (while also capturing Constantinople, the Byzantine empire’s capital, in 1453), Iberia’s kingdoms turned seaward for a century of exploration. Not only did they extend their growing imperial power to four continents (Africa, Asia and both Americas), but they also created the first truly global order worthy of the name, commingling commerce, conquest and religious conversion on a global scale.

Starting in 1420, thanks to advances in navigation and naval warfare, including the creation of the agile caravel gunship, Portuguese mariners pushed south, rounded Africa, and eventually built some 50 fortified ports from Southeast Asia to Brazil.  This would allow them to dominate much of world trade for more than a century. Somewhat later, Spanish conquistadors followed Columbus across the Atlantic to conquer the Aztec and Incan empires, occupying significant parts of the Americas.

Just weeks after Columbus completed his first voyage in 1493, Pope Alexander VI issued a decree awarding the Spanish crown perpetual sovereignty over all lands west of a mid-Atlantic line so “that barbarous nations be overthrown and brought to the [Catholic] faith.” He also affirmed an earlier papal bull (Romanus Pontifex, 1455) that gave Portugal’s king rights to “subdue all Saracens and pagans” east of that line, “reduce their persons to perpetual slavery,” and “possess these islands, lands, harbors, and seas.”

To settle just where that line actually lay, Spanish and Portuguese diplomats met for months in 1494 in the tiny city of Tordesillas for high-stakes negotiations, producing a treaty that split the non-Christian world between them and officially launched the Iberian age. In its expansive definition of national sovereignty, this treaty allowed European states to acquire “barbarous nations” by conquest and make entire oceans into a mare clausum, or a closed sea, through exploration. This diplomacy would also impose a rigid religious-cum-racial segregation upon humanity that would persist for another five centuries.

Even as they rejected Iberia’s global land grab, other European states contributed to the formation of that distinctive world order. King Francis I of France typically demanded “to see the clause of Adam’s will by which I should be denied my share of the world.” Nonetheless, he accepted the principle of European conquest and later sent navigator Giovanni da Verrazzano to explore North America and claim what became Canada for France.

A century after, when Protestant Dutch mariners defied Catholic Portugal’s mare clausum by seizing one of its merchant ships off Singapore, their jurist Hugo Grotius argued persuasively, in his 1609 treatise "Mare Liberum" (“Freedom of the Seas”), that the sea like the air is “so limitless that it cannot become a possession of any one.” For the next 400 years, the twin diplomatic principles of open seas and conquered colonies would remain foundational for the international order.

Sustained by mercantile profits and inspired by missionary zeal, this diffuse global order proved surprisingly resilient, surviving for three full centuries. By the start of the 18th century, however, Europe’s absolutist states had descended into destructive internecine conflicts, notably the War of Spanish Succession (1701-1714) and a global Seven Years War (1756-1763). Moreover, the royal chartered companies — British, Dutch and French — that by then ran those empires were proving ever less capable of effective colonial rule and increasingly inept at producing profits.

After two centuries of dominion, the French East India Company liquidated in 1794 and its venerable Dutch counterpart collapsed only five years later.  Final fatal blows to these absolutist regimes were delivered by the American, French and Haitian revolutions that erupted between 1776 and 1804.

The British imperial era

The British imperial age emerged from the cataclysmic Napoleonic Wars that unleashed the transformative power of England’s innovations in industry and global finance. For 12 years, 1803 to 1815, those wars proved to be a Black Death-style maelstrom that roiled Europe, leaving six million dead in their wake and reaching India, Southeast Asia and the Americas.

By the time the Emperor Napoleon disappeared into exile, France, stripped of many of its overseas colonies, had been reduced to secondary status in Europe, while its erstwhile ally, Spain, was so weakened that it would soon lose its Latin American empire. Propelled by a tumultuous and historic economic transformation, Britain suddenly faced no serious European rival and found itself free to create and oversee a bifurcated world order in which sovereignty remained a right and reality only in Europe and parts of the Americas, while much of the rest of the planet was subject to imperial dominion.

Admittedly, the destruction caused by the Napoleonic wars may seem relatively modest compared to the devastation of the Black Death, but the long-term changes engendered by Britain’s industrial revolution and the finance capitalism that emerged from those wars proved far more compelling than the earlier era’s merchant companies and missionary endeavors. From 1815 to 1914, London presided over an expanding global system marked by industry, capital exports and colonial conquests, all spurred by the integration of the planet via railroad, steamship, telegraph and ultimately radio. In contrast to the weak royal companies of the earlier age, this version of imperialism combined modern corporations with direct colonial rule in a way that allowed for far more efficient exploitation of local resources. No surprise, then, that some scholars have called Britain’s century of dominion the “first age of globalization.”

While British industry and finance were quintessentially modern, its imperial age extended key international principles of centuries past, even if in grim secular guise. While the Dutch doctrine of “freedom of the seas” allowed the British navy to rule the waves, the earlier religious justification for domination was replaced by a racialist ideology that legitimized European efforts to conquer and colonize the half of humanity whom the imperialist poet Rudyard Kipling branded the “lesser breeds.”

Although the 1815 Congress of Vienna officially launched the British era by eliminating France as a rival, the 1885 Berlin Conference on Africa truly defined the age. Much as the Portuguese and Spanish had done at Tordesillas in 1494, the 14 imperial powers (including the United States) present at Berlin four centuries later justified carving up the entire continent of Africa by proclaiming a self-serving commitment “to watch over the preservation of the native tribes and to care for the improvement of the conditions of their moral and material well-being.” Just as that designation of Africans as “native tribes” instead of “nations” or “peoples” denied them both sovereignty and human rights, so the British century witnessed eight empires subjecting nearly half of humanity to colonial rule premised on racial inferiority.

Only a century after its founding, however, the contradictions that lurked within Great Britain’s global rule erupted, thanks to the way that two cataclysmic world wars coincided with the long-term rise of anti-colonial nationalism to create our current world order. The alliance system among rival empires proved volatile, exploding into murderous conflicts in 1914 and again in 1939. Worse yet, industrialization had spawned the battleship and the airship as engines for warfare of unprecedented range and destructive power, while modern science would also create nuclear weapons with the power to potentially destroy the planet itself. Meanwhile, the colonies that covered nearly half the globe refused to abide by the institutionalized denial of the very liberty, humanity, and sovereignty that Europe prized for itself.

While most of the 15 million combat deaths in World War I emerged from the destructive nature of trench warfare on the western front in France (compounded by 100 million fatalities worldwide from an influenza pandemic), World War II spread its devastation globally, killing more than 60 million people and ravaging cities across Europe and Asia. With Europe struggling to recover, its empires could no longer constrain colonial cries for independence. Just two decades after the war’s end, the six European overseas empires that had dominated much of Asia and Africa for five centuries gave way to 100 new nations.

Washington’s world order

In the aftermath of history’s most destructive war, the United States used its unmatched power to form the Washington world system. American deaths in World War II numbered 418,000, but those losses paled before the 24 million dead in Russia, the 20 million more in China, and the 19 million in Europe. While industries across Europe, Russia and Japan were damaged or destroyed and much of Eurasia was ravaged, the United States found itself left with a vibrant economy on a war footing and half the world’s industrial capacity. With much of Europe and Asia suffering from mass hunger, the swelling surpluses of American agriculture fed a famished humanity.

Washington’s visionary world order took form at Bretton Woods, New Hampshire, in 1944.  There, 44 Allied nations created an international financial system exemplified by the World Bank and then, at San Francisco in 1945, by a U.N. charter to form a community of sovereign nations. In a striking blow for human progress, this new order resoundingly rejected the religious and racial divisions of the previous five centuries, proclaiming in the U.N.’s Universal Declaration of Human Rights the “equal and inalienable rights of all members of the human family,” which “should be protected by the rule of law.”

Within a decade after the end of World War II, Washington also had 500 overseas military bases ringing Eurasia and a chain of mutual defense pacts stretching from the North Atlantic Treaty Organization (NATO) to the Australia, New Zealand, United States Security Treaty (ANZUS), and a globe-girding armada of nuclear-armed warships and strategic bombers. To exercise its version of global dominion, Washington retained the 17th-century Dutch doctrine of “freedom of the seas,” later extending it even to space where, for more than half a century, its military satellites have orbited without restraint.

Just as the British imperial system was far more pervasive and powerful than its Iberian predecessor, so Washington’s world order went beyond both of them, becoming rigorously systematic and deeply embedded in every aspect of planetary life. While the 1815 Congress of Vienna was an ephemeral gathering of two dozen diplomats whose influence faded within a decade, the United Nations and its 193 member states have, for nearly 75 years, sustained 44,000 permanent staff to supervise global health, human rights, education, law, labor, gender relations, development, food, culture, peacekeeping and refugees. In addition to such broad governance, the U.N. also hosts treaties that are meant to regulate sea, space and the climate.

Not only did the Bretton Woods conference create a global financial system, but it also led to the formation of the World Trade Organization that regulates commerce among 124 member states. You might imagine, then, that such an extraordinarily comprehensive system, integrated into almost every aspect of international intercourse, would be able to survive even major upheavals.

Cataclysm and collapse

Yet there is mounting evidence that climate change, as it accelerates, is creating the basis for the sort of cataclysm that will be capable of shaking even such a deeply rooted world order. The cascading effects of global warming will be ever more evident, not in the distant future of 2100 (as once thought), but within just 20 years, impacting the lives of most adults alive today.

Last October, scientists with the U.N.’s Intergovernmental Panel on Climate Change issued a “doomsday report,” warning that humanity had just 12 years left to cut carbon emissions by a striking 45% or the world’s temperature would rise by at least 1.5 degrees Celsius above preindustrial levels by about 2040.  This, in turn, would bring significant coastal flooding, ever more intense storms, fierce drought, wildfires and heat waves with damage that might add up to as much as $54 trillion — well over half the current size of the global economy. Within a few decades after that, global warming would, absent heroic measures, reach a dangerous 2 degrees Celsius, with even more devastation.

In January, scientists, using new data from sophisticated floating sensors, reported that the world’s oceans were heating 40% faster than estimated only five years earlier, unleashing powerful storms with frequent coastal flooding. Sooner or later, sea levels might rise by a full foot thanks to nothing but the thermal expansion of existing waters. Simultaneous reports showed that the rise in world air temperature has already made the last five years the hottest in recorded history, bringing ever more powerful hurricanes and raging wildfires to the United States with damages totaling $306 billion in 2017. And that hefty sum should be considered just the most modest of down payments on what’s to come.

Surprisingly fast-melting ice sheets in Greenland and the Antarctic will only intensify the impact of climate change. An anticipated rise in sea level of eight inches by 2050 could double coastal flooding in tropical latitudes — with devastating impacts on millions of people in low-lying Bangladesh and the mega-cities of southeastern Asia from Mumbai to Saigon and Guangzhou. Meltwater from Greenland is also disrupting the North Atlantic’s “overturning circulation” that regulates the region’s climate and is destined to produce yet more extreme weather events. Meanwhile, Antarctic meltwater will trap warm water under the surface, accelerating the break-up of the West Antarctic ice shelf and contributing to a rise in ocean levels that could hit 20 inches by 2100.

In sum, an ever-escalating tempo of climate change over the coming decades is likely to produce massive damage to the infrastructure that sustains human life. Seven hundred years later, humanity could be facing another catastrophe on the scale of the Black Death, one that might, once again, set the world in motion.

The geopolitical impact of climate change may be felt most immediately in the Mediterranean basin, home to 466 million people, where temperatures in 2016 had already reached 1.3 degrees Celsius above pre-industrial levels.  (The current global average was still around 0.85 degrees.) This means that the threat of devastating drought is going to be brought to a historically dry region bordered by sprawling deserts in North Africa and the Middle East. In a telling example of how climate catastrophe can erase an entire world order, around 1200 B.C. the eastern Mediterranean suffered a protracted drought that “caused crop failures, dearth, and famine,” sweeping away Late Bronze Age civilizations like the Greek Mycenaean cities, the Hittite empire and the New Kingdom in Egypt.

From 2007 to 2010, ongoing global warming caused the “worst three-year drought” in Syria’s recorded history — precipitating unrest marked by “massive agricultural failures” that drove 1.5 million people into city slums and, next, by a devastating civil war that, starting in 2011, forced five million refugees to flee that country. As more than a million migrants, led by 350,000 Syrians, poured into Europe in 2015, the European Union plunged into political crisis. Anti-immigrant parties soon gained in popularity and power across the continent while Britain voted for its own chaotic Brexit.

Projecting the Middle East’s history, ancient and modern, into the near future, the ingredients for a regional crisis with serious global ramifications are clearly present. Just last month, the U.S. National Intelligence Council warned that “climate hazards,” such as “heat waves [and] droughts,” were increasing “social unrest, migration and interstate tension in countries such as Egypt, Ethiopia, Iraq and Jordan.”

If we translate those sparse words into a future scenario, sometime before 2040 when average global warming is likely to reach that dangerous 1.5 degrees Celsius mark, the Middle East will likely experience a disastrous temperature rise of 2.3 degrees. Such intense heat will produce protracted droughts far worse than the one that destroyed those Bronze Age civilizations, potentially devastating agriculture and sparking water wars among the nations that share the Tigris and Euphrates rivers, while sending yet more millions of refugees fleeing toward Europe. Under such unprecedented pressure, far-right parties might take power across the continent and the EU could rupture as every nation seals its borders. NATO, suffering a “severe crisis” since the Trump years, might simply implode, creating a strategic vacuum that finally allows Russia to seize Ukraine and the Baltic states.

As tensions rise on both sides of the Atlantic, the U.N. could be paralyzed by a great-power deadlock in the Security Council as well as growing recriminations over the role of its High Commissioner for Refugees. Pummeled by these and similar crises from other climate-change hot spots, the international cooperation that lay at the heart of Washington’s world order for the past 90 years would simply wither, leaving a legacy even less visible than that block of the Berlin Wall in midtown Manhattan.

Beijing’s emerging world system

As Washington’s global power fades and its world order weakens, Beijing is working to build a successor system in its own image that would be strikingly different from the present one.

Most fundamentally, China has subordinated human rights to an overarching vision of expanding state sovereignty, vehemently rejecting foreign criticism of its treatment of its Tibetan and Uighur minorities, just as it ignores equally egregious domestic transgressions by countries like North Korea and the Philippines. If climate change does, in fact, spark mass migrations, then China’s untrammeled nationalism, with its implicit hostility to the rights of refugees, might prove more acceptable to a future era than Washington’s dream of international cooperation that has already begun to sink from sight in the era of Donald Trump’s “great wall.”

In a distinctly ironic twist, a rising China has defied the long-standing doctrine of open seas, now sanctioned under a U.N. convention, instead effectively reviving the mare clausum version of imperial power by claiming adjacent oceans as its sovereign territory. When the Permanent Court of Arbitration, the original world court, unanimously rejected its claim to the South China Sea in 2016, Beijing insisted that the ruling was “naturally null and void” and would not affect its “territorial sovereignty” over an entire sea. Not only did Beijing in that way extend its sovereignty over the open seas, but it also signaled its disdain for the international rule of law, an essential ingredient in Washington’s world order.

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More broadly, Beijing is building an alternative international system quite separate from established institutions. As a counterpoise to NATO on Eurasia’s western extremity, China founded the Shanghai Cooperation Organization in 2001, a security and economic bloc weighted toward the eastern end of Eurasia thanks to the membership of nations like Russia, India and Pakistan. As a counterpoint to the World Bank, Beijing formed the Asian Infrastructure Development Bank in 2016 that quickly attracted 70 member nations and was capitalized to the tune of $100 billion, nearly half the size of the World Bank itself. Above all, China’s $1.3 trillion Belt and Road Initiative, 10 times the size of the U.S. Marshall Plan that rebuilt a ravaged Europe after World War II, is now attempting to mobilize up to $8 trillion more in matching funds for 1,700 projects that could, within a decade, knit 76 nations across Africa and Eurasia, a full half of all humanity, into an integrated commercial infrastructure.

By shedding current ideals of human rights and the rule of law, such a future world order would likely be governed by the raw realpolitik of commercial advantage and national self-interest. Just as Beijing effectively revived the 1455 doctrine of mare clausum, so its diplomacy will be infused with the self-aggrandizing spirit of the 1885 Berlin conference that once partitioned Africa. China’s communist ideals might promise human progress, but in one of history’s unsettling ironies, Beijing’s emerging world order seems more likely to bend that “arc of the moral universe” backward.

Of course, on a planet on which by 2100 that country’s agricultural heartland, the north China plain with its 400 million inhabitants, could become uninhabitable thanks to unendurable heat waves and its major coastal commercial city, Shanghai, could be underwater (as could other key coastal cities), who knows what the next world order might truly be like? Climate change, if not brought under some kind of control, threatens to create a new and eternally cataclysmic planet on which the very word “order” may lose its traditional meaning.