In part one we considered the role carbon emissions play as a major cause of global warming, we now turn our attention to what can be done to address the reduction of existing carbon dioxide in the atmosphere through carbon capture as part of the process of achieving net zero by 2050.
A promising way to help reduce the amount of CO₂ in the atmosphere and slow the pace of global warming, carbon capture is another element of the wider more comprehensive approach required to successfully address climate change.
It advances the idea of carbon sequestration, a natural process of removing carbon dioxide from the atmosphere and storing it in a way that it will not be released back into the atmosphere for a long period of time. This is observed in vegetation, where plants and trees absorb carbon dioxide from the atmosphere during photosynthesis. The carbon dioxide is stored in the tree’s tissues and is not released back into the atmosphere until the tree dies and decomposes. Reforestation, therefore, has huge value in terms of increasing the amount of carbon that is naturally stored in trees but also soils. Soils can store large amounts of carbon as organic matter, such as compost or manure. Oceans are also a primary natural provider of carbon sequestration, storing carbon dioxide in a variety of ways, dissolving it in the water itself, but also forming carbonate minerals, and storing it in the tissues of marine organisms.
An increasing raft of new technologies is leveraging these capabilities to create commercial-scale carbon capture projects around the world deploying. These projects include:
- Direct air capture (DAC) removes CO2 directly from the atmosphere. This is done using a variety of methods, such as chemical absorption, physical adsorption, and membrane separation. The captured CO2 is then stored in a variety of ways, such as underground or in the ocean.
- Carbon capture and storage (CCS) is designed to capture CO₂ from industrial sources, such as power plants and factories. The captured CO₂ is then stored underground in deep saline aquifers or depleted oil and gas reservoirs.
- Bioenergy with carbon capture and storage (BECCS) is a technology that captures CO₂ from biomass, such as wood, agricultural waste, and municipal waste. The captured CO₂ is also then stored underground.
- Enhanced oil recovery (EOR) is a method of increasing the production of oil from an oil field by injecting CO₂ into the ground. The CO₂ forces the oil to the surface, where it can be extracted.
There remain a number of challenges associated with carbon capture, such as the cost of the technology, the availability of storage sites, and the potential environmental impacts. The cost of carbon capture still varies greatly depending on the technology and the source of CO₂, however, it is expected to come down as the technology matures. Despite the challenges, carbon capture has the potential to play a significant role in reducing greenhouse gasses and slowing or even halting the threat of runaway global warming.