Limited contribution of novel Carbon Dioxide Removal and Geological Carbon Storage to reducing peak warming

To understand the stakes of this research, one must first grasp the dual challenge facing our climate: stopping the flow of heat-trapping gases into the atmosphere and, for some time, actively removing what is already there. The world has set a goal to limit global warming to 1.5 degrees Celsius above pre-industrial levels, a target that requires not just cutting emissions from burning fossil fuels, but also deploying technologies to pull carbon dioxide out of the air and store it safely underground. These removal technologies, often called carbon dioxide removal, and the geological storage systems that hold the captured gas, are seen by many as essential tools to reach net-zero emissions and eventually cool the planet back down if temperatures rise too high. However, these technologies are currently in their infancy, operating on a tiny scale compared to the massive volume of emissions humanity produces every year. The critical question for policymakers and scientists alike is whether these tools can be scaled up fast enough to make a meaningful difference in the coming decades, or if they will arrive too late to prevent the worst effects of climate change.

A team of researchers at the Potsdam Institute for Climate Impact Research and the University of Strathclyde has tackled this question by building a detailed simulation of how these technologies might grow over time. They did not simply assume that these technologies would expand rapidly; instead, they modeled their growth based on the realistic history of how new energy technologies actually spread, accounting for the slow, difficult process of building the necessary infrastructure, securing permits, and finding suitable storage sites. Their analysis focused on a specific type of storage known as geological carbon storage, where carbon dioxide is injected deep underground into rock formations, and the various methods that rely on it, such as capturing carbon from bioenergy or directly from the air. By running these scenarios through a sophisticated computer model of the global economy and energy systems, the researchers aimed to see exactly how much warming these tools could prevent by the middle of this century and how much they might help cool the planet by the end of it.

The results of this simulation offer a sobering reality check. Even under the most optimistic assumptions—where governments provide massive support, failure rates for new projects drop significantly, and storage sites are abundant—the contribution of these technologies to stopping global warming in the near term is surprisingly small. By the year 2050, the total amount of carbon dioxide these systems could remove and store would be between 32 and 51 billion tonnes. To put this in perspective, this cumulative amount is roughly equal to just one year of current global carbon emissions. Because the amount of carbon removed is so small compared to the total emissions over the last few decades, the impact on the peak temperature the world will experience is negligible, reducing the maximum warming by only about 0.025 degrees Celsius. This tiny effect occurs because these technologies start from such a small base; their growth follows a curve that is slow at first, meaning that even with aggressive scaling, the total volume of carbon handled in the first twenty years remains a drop in the bucket compared to the emissions we are currently generating.

The researchers found that the primary driver for limiting peak warming remains the immediate and deep reduction of emissions from fossil fuels and land-use changes, not the future promise of carbon removal. In their simulations, cutting conventional emissions could prevent 365 billion tonnes of carbon dioxide from entering the atmosphere by 2050, a reduction that would lower peak temperatures by 0.16 degrees Celsius. This is a far more significant impact than what the new removal technologies can achieve in the same timeframe. The study explicitly argues against the idea that we can rely on these emerging technologies to compensate for a slow transition away from fossil fuels. The time it takes to build the complex chains of capture, transport, and storage means that these systems simply cannot be deployed fast enough to substitute for the urgent need to stop burning coal, oil, and gas today.

However, the story changes when looking further into the future. While the near-term contribution is limited, the potential of these technologies grows substantially by the end of the century. By 2100, the cumulative amount of carbon dioxide removed and stored could rise to between 300 and 875 billion tonnes. This larger volume would be capable of lowering global temperatures by an additional 0.14 to 0.39 degrees Celsius after the peak warming has been reached. This suggests that while these tools cannot prevent the initial rise in temperature, they are essential for the second half of the century, offering a way to draw down temperatures and return the planet to safer levels if we overshoot our targets. The study highlights that the ability to achieve this long-term cooling depends heavily on how quickly we start building these systems now. If deployment remains slow, the cumulative benefit by 2100 will be much smaller, but with ambitious support, the potential to reverse warming becomes real.

The researchers also discovered that the specific type of carbon removal technology matters greatly depending on the speed of deployment. In scenarios where growth is slow, methods that do not require underground storage, such as enhancing rock weathering or producing biochar, dominate the landscape because they avoid the bottleneck of finding storage sites. In contrast, in the most aggressive scenarios where storage capacity expands rapidly, technologies that rely on geological storage, like capturing carbon from bioenergy, become the primary method for removal. This dynamic reveals a crucial constraint: the availability of underground storage sites is a limiting factor that restricts the growth of many promising technologies. Currently, the vast majority of announced carbon capture projects are focused on capturing carbon from fossil fuel sources, yet the study suggests that for climate goals to be met, these storage resources must be prioritized for removing carbon from the atmosphere and from biological sources.

Ultimately, this research clarifies the role of carbon dioxide removal and geological storage in the fight against climate change. It confirms that these technologies are not a quick fix for the immediate crisis of rising temperatures. The window for preventing the worst peak warming is determined by how fast we cut emissions today, not by how fast we can build new removal plants tomorrow. Yet, the study also affirms that these technologies are indispensable for the long term. They represent the only known path to lowering global temperatures after they have risen, acting as a necessary tool to heal the climate in the second half of the century. The path forward requires a dual strategy: an immediate, drastic reduction in fossil fuel use to limit the damage, followed by a rapid and sustained scale-up of removal technologies to repair the atmosphere once the worst is over. Without both, the goal of a stable climate remains out of reach.