Unequal and fragmented futures increase the material cost of decarbonisation

The world is currently trying to shift away from burning fossil fuels like coal and oil, moving instead toward energy sources that do not add carbon to the atmosphere. This transition relies heavily on new technologies: solar panels, wind turbines, and electric vehicles. While these machines run on clean energy, they are built from the ground up using a specific set of raw materials found in the Earth's crust, such as copper, lithium, and cobalt. These are often called critical minerals because they are essential for the new energy systems but are not as abundant or easy to access as the iron and steel used in older infrastructure. For years, experts have tried to guess how much of these materials the world will need to meet climate goals. Most of these guesses have assumed that the world will act in the most efficient, cheapest way possible to cut emissions. However, the real world is rarely that simple. It is shaped by how rich or poor different countries are, how well nations cooperate with one another, and how people choose to live their lives. These social and economic conditions might change the amount of raw materials required just as much as the climate targets themselves.

A team of researchers at the University of Cambridge set out to understand how these messy, real-world conditions affect the material needs of decarbonization. They did not just look at one ideal future; instead, they modeled five very different possible worlds, ranging from a future where the world works together peacefully to reduce inequality, to a future where nations turn inward, compete aggressively, and struggle with deep social divides. For each of these five scenarios, they calculated how much cobalt, copper, graphite, lithium, nickel, and rare earth elements would be needed every year from now until 2050. They looked at two versions of each future: one where countries continue on their current path without extra climate action, and another where they successfully align with the Paris Agreement to limit global warming. By running these complex simulations, the researchers found that the path the world takes matters more than previously thought. In every scenario, the demand for these minerals goes up, but the size of that increase depends entirely on the social and economic choices we make.

The study reveals that if the world follows a path of sustainability, where countries cooperate and people use less energy and fewer private vehicles, the demand for these minerals is significantly lower. In this optimistic future, the world can meet its climate goals while using roughly a quarter to a third less of these materials compared to other Paris-aligned futures. However, if the world moves toward a future defined by inequality or regional rivalry, the cost in raw materials skyrockets. In these fragmented futures, reaching the same climate targets requires 150 to 250 percent more minerals than the baseline levels seen today. This happens not because the climate goal is harder to reach, but because the way we reach it changes. In unequal or divided worlds, people tend to consume more, technology spreads more slowly, and nations rely on specific, material-heavy technologies rather than finding efficient alternatives. For instance, in a future of regional rivalry, Europe might stick with older battery types that require more cobalt, while in a future of inequality, rapid growth in South Asia might drive massive demand for infrastructure and vehicles, both of which are mineral-intensive.

The researchers also discovered that the location of this demand shifts dramatically depending on the future. In a world of regional rivalry, the need for minerals like cobalt and nickel stays high in Europe because of specific technology choices there. In a world of inequality, the demand shifts heavily toward South Asia as that region grows. This means that the challenge of securing these materials is not just about how much the world needs in total, but where that need is concentrated. A future of fragmentation makes the supply chain more difficult to manage precisely when trade and cooperation are likely to be weakest. The study suggests that the difficulty of meeting climate targets is not fixed by the temperature limit alone. Instead, it is shaped by the socio-economic conditions under which we try to achieve it. If the world becomes more unequal or divided, the transition to clean energy will require a much heavier extraction of the Earth's resources, potentially creating new risks for supply chains and increasing the cost of the transition.

The team used a sophisticated computer model that tracks how many machines exist, how long they last, and how they are replaced over time. They combined this with a global economic model to see how different social stories play out. They found that in a sustainable future, the world can grow economically while actually using fewer minerals per person, because people rely more on public transport and shared services. In contrast, in futures marked by inequality, the wealthy elite in developing regions drive demand for private, material-heavy technologies, while the poor are left behind. This creates a situation where the richest parts of the world might have the money to buy the technology, but the global system lacks the coordination to build it efficiently. The study suggests that simply trying to extract more minerals or build more factories is not enough. To make the transition feasible, the world also needs to focus on reducing the amount of material needed per person through better public transport, longer-lasting products, and international cooperation. Without these changes, the path to a clean future could become blocked by the very materials we need to build it.