Many scientists and policymakers are relying on storing CO2 deep underground as an essential option to combat local weather change. Such generally known as geological carbon storage entails capturing CO2 from sources like energy crops or instantly from the air and injecting it into rock formations, the place it will possibly stay for hundreds of years. However, up to now, most discussions have handled underground storage as if it have been limitless.
A brand new study in Nature has challenged this assumption, warning that the earth can solely safely maintain about 1,460 billion tonnes of CO2 underground. If international locations design local weather methods with out understanding how a lot storage is admittedly obtainable, they could rely too closely on an choice that may’t ship. Setting a restrict forces governments to plan extra fastidiously, scale back emissions sooner, and carbon storage as a scarce useful resource, and acknowledge the necessity for a extra reasonable response.
To calculate this restrict, the researchers, from Europe, the UK, and the US, constructed a world map of sedimentary basins, that are giant rock formations best suited for CO2 storage. Then they systematically dominated out areas the place storage can be too dangerous, e.g. basins close to earthquake zones, in polar areas, and in biodiversity hotspots. Finally, the group thought of sensible constraints like storage depth and offshore drilling limits. By including up what remained, they discovered that solely a tenth of the beforehand estimated world capacity, of round 11,800 billion tonnes, was appropriate.
Nearly each local weather state of affairs that goals to maintain world warming beneath 2º C assumes giant quantities of CO2 can be saved underground. But at right this moment’s tempo, storage use would develop so quickly that this new planetary restrict might be crossed by 2200. The study additionally confirmed that international locations don’t share this capacity equally: it’s larger in Russia, the US, and Saudi Arabia and decrease in India and plenty of European international locations.
The study additionally capped the utmost potential temperature reversal by way of storage to about 0.7º C, that means underground storage alone can’t repair world warming. Second, treating storage as a finite useful resource raises questions on whether or not it needs to be used to maintain burning fossil fuels a bit of longer or to take away carbon from the air to learn future generations. Finally, the study is evident that emission cuts stay probably the most viable manner ahead. Carbon storage might assist but it surely gained’t exchange sooner transitions to renewable vitality, modifications in trade, and conservation of pure carbon sinks.
A press word issued by Nature clarified: “The authors note that a key limitation of this analysis is not accounting for the obstacles of scaling up carbon capture and storage technology or considering any other technologies that might be developed in the future.”
