The United Nations climate report pinpoints its hopes on carbon removal technologies that are almost non-existent


In this model, almost all carbon removal is done through a process called Bioenergy with carbon capture and storage function, Or BECCS. Basically, it needs to grow crops that absorb carbon dioxide, and then use the harvested biomass to produce heat, electricity or fuel, while capturing and storing the resulting emissions. However, although climate models rely on billions of tons of carbon removal through BECCS, they have so far only been completed in small-scale projects.

Other technical methods are immature, including carbon-absorbing machines and various methods to accelerate natural processes Minerals and Ocean Absorb and store is Prove to be challenging Develop systems to reliably incentivize and measure carbon removal through natural systems such as forests And soil as well as.

The IPCC’s assessment on Monday pointed out that there are many other limitations and difficulties.

On the one hand, although carbon removal does reduce the level of greenhouse gases in the atmosphere, the report points out that this effect may be offset to some extent.Modeling research Already discovered The oceans and land begin to release more carbon dioxide in response to changes in atmospheric chemistry over a certain period of time, thereby destroying revenue.

In addition, although carbon removal can gradually alleviate temperature rise and ocean acidification, it cannot magically reverse all climate effects. The report emphasizes that it is worth noting that it will take several centuries to restore the ocean to the level where we built coastal cities. It may cause almost irreversible damage to ice sheets, coral reefs, tropical rainforests and certain species, depending on how warm the world is before the world reduces emissions and expands carbon removal.

chapter Five The report lists various other trade-offs and unknowns, and almost all potential large-scale carbon removal methods.

The carbon absorption machine requires a lot of energy and materials. Planting more trees for carbon sequestration or planting more crops as fuel will compete with growing food for an expanding global population.

Climate change itself will weaken the ability of forests to absorb and store carbon dioxide, because the risk of drought, wildfires, and pests increases as temperatures rise. There is still considerable scientific uncertainty regarding the side effects of various ocean-based methods on the marine ecosystem.

The good news is that there are many ways to remove carbon from the air, and more and more research groups and companies are working to develop better and cheaper methods. But as Monday’s report showed, we were far behind in a high-stakes game.


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