A new study finds underground CO₂ storage capacity is far lower than expected, limiting the impact of carbon capture as a climate solution. With risks like leakage and more, the focus must shift to urgently cutting emissions to tackle global warming.
Carbon dioxide is one of the main drivers of climate change. A recent study has found that there is significantly less capacity underground to safely store carbon dioxide than previously believed. This challenges the earlier assumption that carbon capture and storage (CCS) can be a major solution to climate crisis. The research, published in the journal Nature, showed that earlier global estimates of carbon storage space were about ten times too high.
Earlier estimates failed to account for key risks such as leakage, contamination of groundwater, and the possibility of triggering earthquakes. After excluding these risky areas, the amount of usable space for CO₂ storage dropped considerably. Scientists say that as a result, carbon storage could only help reduce global warming by about 0.7°C, instead of the previously suggested 5 or 6°C.
“Carbon storage is often portrayed as a way out of the climate crisis. Our findings make clear that it is a limited tool” and reaffirms “the extreme importance of reducing emissions as fast and as soon as possible,” said lead author Matthew Gidden, a research professor at the University Maryland’s Center for Global Sustainability.
Carbon Capture and Storage
Carbon capture and storage has been seen as a key strategy in combating climate change. It has especially been promoted for years by oil and gas companies. The idea is to capture CO₂ from power plants and factories before it is released into the atmosphere and then store it deep underground, where it won’t escape.
Despite billions of pounds invested worldwide, the amount of carbon dioxide actually being stores is still a small fraction of what is needed to have a meaningful impact. The new study examines where carbon should not be stored. Dr Alexandre Koberle, a co-author from the University of Lisbon, noted that scientists had previously assumed there was ample storage space without checking for environmental risks.
What This Means for Climate Action
The findings from the study indicate that carbon capture should be used more strategically. For instance, CCS could still help in sectors that are hard to decarbonise, such as cement, aviation, and agriculture. However, it should not be used as an excuse to continue burning fossil fuels or to extend the life of polluting power stations.
Jessie Stolark from the Carbon Capture Coalition explains that using CCs isn’t a choice but a necessity, alongside other solutions to reduce emissions. Despite this, many scientists remain sceptical.
Professor Rob Jackson, who leads the Global Carbon Project, praised the study’s methodical approach but doubted whether society is willing to pay the high cost to scale up the technology.
How Carbon Capture Works
CO₂ is the main greenhouse gas causing global warming. It is released when we burn fossil fuels like coal, oil, and gas, and it remains in the atmosphere for hundreds of years, trapping heat. Carbon capture works in two main ways:
• Collecting CO₂ from factory chimneys or power plants before it escapes into the atmosphere.
• Pulling CO₂ directly from the air using special machines.
The captured gas is then compressed and transported, often by pipeline, to a storage site. It is then injected deep underground into formations such as saline aquifers or old coal seams. The most common method can capture about 60% of emissions from a facility. Capturing more than that becomes much more complex and expensive, according to the International Energy Agency.
A Warning for the Future
Dr Gidden acknowledged that some level of carbon storage will be necessary to achieve net-zero emissions and eventually reduce the amount of carbon dioxide in the atmosphere. However, he warned against relying on it as a quick fix.
“If we prolong our dependence on fossil fuels for too long with the expectation that we will offset that by simply storing carbon underground, we’re likely saddling future generations with a nearly impossible task of dealing with not only our mess, but limited ways of cleaning it up,” he said.
The research highlights while carbon storage may play a limited role in addressing the climate crisis, the only real solution is to rapidly reduce fossil fuel use now.