In this blog, George Martine and Igor Cavallini Johansen preview their new article in The Journal of Population and Sustainability, ‘Contrasting Stances on Sustainability by the USA and China: Political Economy and Demographic Paradoxes in the Two Main Agents of Climate Change’, which will be published in the next few weeks.
The future of the planet depends heavily on decisions made in two countries: the United States and China. Together, they account for more than forty per cent of global greenhouse-gas emissions and possess enormous economic, technological and geopolitical power. Yet, instead of moving together toward a common climate strategy, the two countries are increasingly following very different paths.
This divergence is more than a disagreement over environmental policy. It reflects two contrasting models of economic development, energy security and state power. And beneath these differences lies a surprising demographic paradox: both countries are worried about population decline and are seeking ways to encourage population growth – even though a smaller population could eventually reduce pressure on resources and emissions.
Two very different energy strategies
The United States remains the world’s largest producer of oil and natural gas and has one of the highest levels of energy consumption per person among major economies. Its climate policy has also become highly dependent on political cycles. Under President Donald Trump, federal environmental regulations have been rolled back, support for fossil fuels has been strengthened and US participation in international climate cooperation has weakened.
This creates a fundamental problem. Climate policy requires long-term consistency, because energy infrastructure lasts for decades. Solar farms, transmission networks, electric vehicles and power plants cannot be planned efficiently when national policy changes dramatically with each election.
China presents almost the opposite picture. Its government has made massive investments in solar power, wind energy, batteries and electric vehicles. China now dominates much of the global manufacturing of clean-energy technologies. In 2024, electric vehicles accounted for nearly half of new car sales in the country.
Yet China is hardly a model of complete decarbonization. Coal remains central to its energy system, partly because Beijing considers energy security essential to economic stability. China therefore combines two apparently contradictory strategies: rapidly expanding renewable energy while continuing to build and operate coal-fired power capacity.
The contrast is striking. The United States is reinforcing its position as a fossil-fuel superpower, while China is becoming the world’s leading producer of many technologies needed to move beyond fossil fuels.
Who is responsible for climate change?
Comparing the two countries also depends on how responsibility is measured.
China is currently the world’s largest annual emitter of fossil-fuel CO₂, accounting for roughly 31 per cent of the global total, compared with about fourteen per cent for the United States. But per person, the picture is different: Americans continue to produce substantially more emissions than Chinese citizens.
History complicates the comparison even further. Since the beginning of the industrial era, the United States has contributed roughly one-fifth of cumulative fossil-fuel CO₂ emissions, compared with about one-tenth for China.
There is also the question of consumption. China produces enormous quantities of goods consumed elsewhere, particularly in the United States and other wealthy countries. Carbon embodied in international trade therefore makes national emission statistics less straightforward. American consumption has helped drive Chinese industrial emissions, even though those emissions occur territorially in China.
These different ways of measuring responsibility are not merely technical disputes. They influence international negotiations and determine who is expected to reduce emissions, how quickly and at whose expense.
The demographic paradox
Perhaps the most unexpected similarity between the United States and China concerns population.
China’s population has begun to decline after decades of rapid growth. Fertility has fallen to around one child per woman, among the lowest rates in the world. The government has therefore shifted from restricting births to actively encouraging them.
The United States has also experienced fertility below replacement level, although its demographic situation is considerably less severe because immigration has, until recently, helped sustain population growth. Nevertheless, American policymakers increasingly worry about ageing, labour shortages and the economic consequences of slow population growth.
The paradox is that both countries increasingly view population growth as an economic and geopolitical asset. From a conventional economic perspective, this makes sense. More people can mean more workers, consumers, taxpayers and potential innovators. But, from an environmental perspective, the equation is more complicated.
Population is only one part of the sustainability equation. Consumption matters enormously. An additional person in a high-consumption society can have a much larger environmental footprint than an additional person in a low-income society. Research on affluence has therefore shown that reducing excessive consumption may be at least as important for sustainability as reducing population growth.
This creates an uncomfortable question: should societies facing demographic decline necessarily try to reverse it?
Ageing could become an environmental advantage
Population ageing is usually presented as a crisis. Governments worry about shrinking workforces, rising pension costs and increasing demands for healthcare.
But ageing and population decline can also have environmental consequences that are less frequently discussed. Slower population growth can reduce pressure on energy demand, infrastructure and natural resources. Research suggests that ageing societies may eventually experience slower emissions growth, particularly when technological change and efficiency improvements accompany demographic transition.
China may therefore have an unexpected opportunity. Its rapidly ageing population could reduce some forms of energy demand while encouraging automation, electrification and greater efficiency.
The United States faces a slower version of the same demographic transition. Immigration has delayed population ageing and helped sustain its workforce, but the country’s fertility rate remains below replacement.
What happens if cooperation disappears?
The greatest danger, however, is not whether China or the United States individually adopts a particular energy or demographic policy. It is what happens when their rivalry prevents cooperation.
Climate change does not respect national borders. Emissions released in one country affect everyone. Effective climate action therefore requires cooperation on technology, finance, trade and emissions reductions.
Unfortunately, global climate governance is becoming increasingly fragmented. Strategic competition between Washington and Beijing is spreading from trade and technology into energy and environmental policy.
Yet rivalry may also produce an unexpected benefit. Competition can accelerate innovation. China’s enormous investment in renewable technologies has driven down the cost of solar panels, batteries and electric vehicles. US technological and financial capabilities remain formidable. If competition pushes both countries to innovate faster, the climate transition could benefit.
The central challenge is therefore not choosing between the American and Chinese models. Neither is sufficient. The United States needs a stronger commitment to decarbonization and greater policy continuity. China needs to reconcile its extraordinary renewable-energy expansion with its continuing dependence on coal. Both countries need to recognize that demographic ageing is not necessarily an enemy of sustainability. Most importantly, they need to rediscover selective forms of cooperation.
The world cannot solve the climate crisis without the United States and China. Their rivalry may define twenty-first-century geopolitics, but the planet’s future depends on ensuring that geopolitical competition does not become an obstacle to ecological survival.
China’s strategy treats climate policy as a central pillar of its long-term technological leadership and industrial planning. Under state mandates like the 15th Five-Year Renewable Energy Development Plan, the Chinese government has funneled immense capital into infrastructure, setting massive capacity targets for wind and solar. Beijing’s playbook relies on large-scale infrastructure engineering, allowing it to rapidly deploy record-breaking solar parks and floating photovoltaic array.
In stark contrast, U.S. federal energy policy has increasingly focused on achieving total energy independence via domestic extraction. Recent administrations have rolled back environmental guardrails, expanded tax breaks for traditional energy developers, and minimized regulatory oversight to incentivize traditional crude production. This strategy relies on rapid private-sector hydraulic fracturing and horizontal drilling, which has pushed U.S. crude oil and gas production to record-breaking highs.
whitehorsepress 