How much carbon can we safely store underground? Much less than previously thought.
Draw carbon of the air and hide it in underground rock formations has been formulated as an essential means of slowing down and reverse global warming. But new research published Wednesday in the journal Nature reveals that there are much fewer places appropriate to do this that we did not think about it previously.
After having projected “risky” areas, such as those vulnerable to earthquakes, a team of researchers from Europe and the United States found that the land can only store 1,460 carbon gigatons injected into its sedimentary basins. This is an order of magnitude lower than previous estimates, and – if you convert the carbon stored into an estimated impact on the climate – only enough to reduce global warming by approximately 0.7 degrees Celsius (1.3 degrees fahrenheit), not 6 degrees C (10.8 degrees F) described in other research.
Carbon storage “can no longer be considered an unlimited solution to bring our climate back to a safe level,” said one of the study co-authors, Jeri Rogelj, in a press release. “The geological storage space must be considered as a rare resource which should be managed in a responsible manner to allow a safe future for humanity.” Rogelj is director of research at the Grantham Institute on Climate Change and the Environment at Imperial College London.
Carbon storage, for the good of paper, refers to the injection of carbon dioxide in underground tanks where it cannot theoretically contribute to climate change. There are two big ways to obtain this carbon: first, by capturing it at the emission point – let’s say, the fireplace of a fossil cement factory fed by fuel – and secondly, sucking it from the ambient atmosphere.
According to the United Nations Intergovernmental Panel on Climate Change, or IPCC, the main global authority on the subject, at least a little carbon storage will be necessary to achieve international climatic objectives.
But the amount required depends on a certain number of factors, in particular the amount that countries predict to reduce emissions in relation to “compensating” them, in particular in the hard-to-decarbonizing sectors, and if they intend to pass beyond 1.5 or 2 degrees C (2.7 or 3.5 degrees f) global warming and then to return to a more livable temperature by eliminating carbon from the atmosphere. The latter is a controversial idea known as “overtaking”, and it would take more carbon withdrawn from air and stored. Certain IPCC scenarios involving substantial overcoming requires up to 2,000 carbon storage gigagatons by 2100.
How the world has abandoned 1.5 degrees
According to study authors, no previous global or regional estimate of the land storage potential of the land has taken into account the key risk factors that would make certain areas unwanted for storage. From an estimate of all potentially available storage sites, their analysis cuts over the areas that are too shallow, too deep and too subject to earthquakes, as well as areas and areas protected to the environment near where people live. This reduces the total capacity available for carbon storage of 11,780 gigatons to only 1,460 CO2 gigabilies, 70% on land and 30% on the seabed.
The authors used an existing GIEC conversion rate to translate this number of gigagatons to approximately 0.4 to 0.7 degrees C (0.7 to 1.3 degrees F) Reduced global warming.
They also noted certain geographic disparities in the carbon storage potential: while certain historic climate polluters such as the United States and Canada have a lot of space to safely hide carbon, others in Europe do not do so. If these countries intend to make carbon storage an important element of their climate mitigation plans, they will probably have to seek locations in countries that have not done much to contribute to climate change, potentially in Africa.
Sally Benson, a professor in energy sciences and genius at the University of Stanford who was not involved in the new research, said that her results should not be considered “alarming” or “dramatic”. As described in the article, the scenarios of the IPCC which give the world 50% of chance of limiting global warming to 1.5 degrees Celsius by the end of the century would require sequenced about 9 carbon gigagatons per year (assuming that zero -clear emissions are reached around 2050). This means that it could be more than 160 years before the world reaches the safe carbon storage limit calculated in the study.
“What it tells me is that it is a kind of good news,” said Benson. “Someone has adopted the most conservative approaches to examine this capacity and concluded, from my point of view, that there is a lot of capacity compared to what we need.”
The authors of the study note that the need for storage could continue after their theoretical limit is reached, especially if the countries need to compensate for the residual emissions of agriculture or the combustion of fossil fuels in certain sectors. Climate switching points could also release more carbon dioxide in the atmosphere than expected, requiring a greater need than expected to eliminate carbon.
But Benson said that these risks are too far in the future and that “we must use all the available technologies as quickly as possible”.
Benson and another independent expert – Jennifer Wilcox, professor of chemical engineering and energy policy at the Kleinman Center for Energy Policy from the University of Pennsylvania – said that the central estimate of the newspaper for safe and cautious carbon storage is probably too cautious. Wilcox told Grist that he “underestimates what projects carefully managed by pressure can deliver safely”.
But Naomi Oreskes, professor of the history of science at Harvard University, held the opposite opinion. Oreskes said the newspaper does not take into account government, economic and scientific challenges to really deploy large -scale carbon storage. “When you take these factors into account,” she said, “the carbon storage potential, especially during the next crucial decade, is still less.”
Despite a significant brainling around technology, only about 0.05 CO2 gigatons are currently stored by carbon capture at the emission point each year. Until now, most of these carbon capture projects inject carbon into the soil to help extraction of even more oil and gas, in a process called “improved oil recovery”. And only 0.00001 CO2 gigabilions are removed from the ambient air each year. It is less than annual greenhouse gas emissions indicated by Bowdoin College, a small school of liberal arts in Maine.
“This new information is consistent with a wider model that we have observed, to overvalue the promise of” solutions “which avoid the central question of reducing the use of fossil fuels,” said Oreskes.
