KUCHING: There are various ways in which carbon dioxide removal (CDR) can be achieved, ranging from innovative technologies to improved land management practices.
However, the carbon programme head at the Faculty of Agriculture and Forestry Sciences, Universiti Putra Malaysia Bintulu Campus, Dr Waseem Razzaq Khan, pointed out that there are key concerns on whether these methods can effectively remove carbon at the required scale in the coming decades.
He said the six possible options for extracting carbon from the atmosphere include trees and forests, farms and soils, biomass carbon removal and storage, direct air capture, carbon mineralisation and ocean-based approaches.
“Plants naturally remove carbon dioxide from the air and trees are particularly efficient at storing the carbon dioxide removed from the atmosphere through photosynthesis.
“By increasing, restoring, and managing tree cover, we can encourage more carbon uptake and harness the power of photosynthesis to convert carbon dioxide in the air into carbon stored in wood and soil,” he said.
On the farm and soil method, Waseem said soils have the natural ability to store carbon but agricultural soils are currently facing a significant carbon deficit.
He said this is due to continuous ploughing and erosion caused by farming and grazing which release previously stored carbon.
“For instance, agricultural land occupies a vast area of more than 900 million acres in the United States alone which is approximately 40 per cent of the country’s land area. Even a small increase in soil carbon per acre can have a considerable impact given the extensive agricultural land area,” he said.
Waseem explained that biomass carbon removal and storage is a set of processes that use biomass from plants or algae to remove carbon dioxide from the air and store it for long periods.
“This method aims to increase the carbon storage capacity of plants beyond their natural life cycles. While trees remove and store carbon only until they die and decompose, biomass carbon removal and storage intend to sequester the carbon dioxide that plants capture in a more permanent way,” he said.
As for the direct air capture method, Waseem said it is a process that involves removing carbon dioxide from the air, then storing it underground or in products like concrete.
He said this technology is similar to carbon capture and storage technique used to reduce emissions from sources such as power plants and industrial facilities.
“The difference between them is that direct air capture eliminates excess carbon that has already been into the atmosphere instead of capturing it at the source,” he said.
Noting how certain minerals have the ability to react with carbon dioxide, Waseem said carbon mineralisation refers to the transforming of carbon dioxide from a gas into a solid form that can be stored for an indefinite period of time.
He said this method prevents carbon dioxide in a solid form from being released into the atmosphere.
“This process is widely known as carbon mineralisation or enhanced weathering. Although it occurs naturally, it is a very slow process that can take hundreds or even thousands of years,” he said.
Waseem revealed that there are several methods proposed for removing carbon from the ocean which leverage on its ability to store carbon and to increase the range of options beyond land-based solutions.
“However, almost all of these techniques are still in the early stages of development and require further research and in some cases field testing before determining whether they are suitable for investment.
“This also includes the need to take into consideration their potential ecological, social and governance impacts,” he said.
