(Paris) Forests, catchments, peat bogs, machines… CO elimination projects2 are currently largely insufficient to achieve the international climate objectives, which will require the massive and rapid development of innovative technologies, conclude scientists in the first global assessment carried out on the subject.
This study published Thursday (“The state of carbon dioxide removal”), conducted by the University of Oxford, takes stock of the means of capturing CO2 into the atmosphere for long-term storage, for example through forest restoration or newer techniques such as direct CO capture2 in the air.
Innovative technologies – such as the Climeworks plant which directly removes CO2 air in Iceland – are currently extremely marginal. This eliminates in one year only what humanity produces in a few seconds.
But these new methods will have to grow “rapidly” to stay within the scope of the Paris agreement, say the researchers. According to the scenarios, their capacities should be multiplied by a factor of 1300 – or even more – by 2050.
The authors conclude that there is “a gap between the level of carbon removal planned by governments and what is needed to meet the goals of the Paris Agreement”, which calls for limiting warming to well below 2°C and if possible at 1.5°C, when the world is already at 1.2°C.
These carbon dioxide removal (EDC) techniques focus on CO2 already emitted into the atmosphere, and thus differ from carbon capture and storage (CCS) systems at the source, at factory chimneys for example.
EDC now removes 2 billion tonnes of CO2 of the atmosphere per year, almost exclusively thanks to forests (reforestation, management of existing forests, etc.), ie a fraction of global emissions of around 40 billion tonnes today.
“Change scale”
The researchers insist on the fact that these methods should not be considered as a magic wand, which would dispense with reducing emissions. “Reducing emissions must always be the priority,” said Emily Cox of the University of Oxford in a presentation to reporters.
“At the same time, we need to aggressively develop and scale EDC, especially these innovative methods. We are only at the very beginning with them and it will take time, ”said Jan Minx, of the Mercator Research Institute, based in Berlin.
Long seen as marginal or as a ploy by industry to avoid reducing its own emissions, EDCs are now seen as a necessary tool by the UN’s Intergovernmental Panel on Climate Change (IPCC).
Their models, for example, reserve an important part for the technique of bioenergy with capture and storage of carbon dioxide: this consists of growing trees that absorb CO2 as they grow, then burning them to produce energy and burying the CO2 resulting from this combustion, in abandoned mines for example.
” Wallet ”
This particular technique, highlighted by the IPCC for a long time, is currently struggling to develop and is hampered by the lack of available land. A facility of this type of the Drax company in the United Kingdom, which imports wood from Canada, has been singled out for its environmental record.
Other EDC techniques are in various stages of experimentation and development: improving the ability of soils to sequester carbon, converting biomass into a charcoal-like substance called biochar, restoring peatlands and coastal wetlands, or the crushing of mineral-rich rocks that absorb CO2 to spread them on land or at sea.
Scientists are also experimenting with ways to increase the ability to absorb CO2 of the oceans, for example by artificially reinforcing marine alkalinity or by “fertilizing” the oceans, i.e. by increasing the density of phytoplankton which sequesters organic carbon by photosynthesis.
The authors of the study suggest not to rely on just one of these techniques, but to have a “portfolio” of solutions, the composition of which will change over time depending on the resources, technologies and preferences of the moment.