UN climate report gives hope to decarbonisation technologies


In this model, nearly all carbon removal comes from a known process: bioenergy with carbon capture and storage, or BECCS. It basically requires growing crops that absorb CO2 and then use the harvested biomass to generate heat, electricity or fuel, while capturing and storing the resulting emissions. But despite the billions and billions of tons of carbon removal that climate models provide through BECCS, it has only been done on small-scale projects to date.

Other technical approaches are also immature, including carbon-absorbing machines and various ways to speed up natural processes. minerals and oceans Take and store CO2. Her proven challenging develop systems to reliably promote and measure carbon removal through natural systems such as forests and land additionally.

Monday’s IPCC assessment noted numerous other limitations and challenges.

First, while carbon removal reduces the levels of greenhouse gases in the atmosphere, the report notes that this effect can be offset to some extent. modeling studies we found The benefits are undermined as the oceans and lands begin to release more CO2 in response to changing atmospheric chemistry over time periods.

Additionally, while removing carbon may gradually ease temperature rises and ocean acidification, it doesn’t magically reverse all climate effects. The report highlights that it will still take centuries to bring the oceans back to the levels we built our coastal cities around. Depending on how much the world warms before reducing emissions and increasing carbon emissions, there could be irreversible damage to ice sheets, coral reefs, rainforests and some species.

Chapter Five Part of the report reveals a variety of other trade-offs and unknowns with virtually any potential approach to large-scale decarbonisation.

Carbon absorbing machines require large amounts of energy and materials. Planting more trees for carbon sequestration or planting crops for fuels will compete with increased food for an expanding global population.

Climate change itself will weaken forests’ ability to absorb and store carbon dioxide as risks of drought, wildfires and insect infestations increase with rising temperatures. And there is still significant scientific uncertainty about the side effects of various ocean-based approaches on marine ecosystems.

The good news is that there are several ways to remove carbon from the air, and a growing number of research groups and companies are working to develop better, cheaper methods. But as Monday’s report clarified, we are far behind in a very high-stakes race.


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