Bart Robinson’s letter in the March 16 Outlook, “Work Remains for Carbon Capture and Storage Viability,” requires clarification. While Robinson expresses valid concerns about carbon capture and storage (CCS) being used by the fossil fuel industry to meet emissions reduction targets, the presentation he refers to that Ed Whittingham and I gave on Feb. 27 at the Canmore Public Library was about a different technology called direct air capture.
CCS removes carbon dioxide from the smokestacks of industrial facilities and may be required to decarbonize industries like steel and cement. When it comes to fully decarbonizing the oil and gas sector, which is required to meet climate targets, CCS is indeed deficient as Robinson points out. That’s because oil and gas producers only control a small fraction of the total emissions related to the use of oil and gas – the bulk of emissions come from the combustion of oil and gas, and capturing those emissions is problematic (e.g. from the tailpipe of a vehicle or the exhaust of a gas-fired furnace).
Direct air capture (DAC) pulls carbon dioxide from the air instead of a smokestack, so that it can similarly be stored underground or in products. That makes it more expensive than CCS because of the more diluted concentration of carbon dioxide in air, but it addresses a different challenge: decarbonizing all industries by mid-century. To meet climate targets, it’s a virtual certainty that carbon dioxide will have to be removed from the atmosphere to offset hard-to-abate greenhouse gas emissions, according to the United Nation’s Intergovernmental Panel on Climate Change.
DAC is currently one of the leading carbon removal contenders. But the task is so great – potentially more than 10 billion tonnes of carbon dioxide per year by mid-century – that we need to start scaling up carbon removal immediately. There are plenty of challenges to doing so, of course, and the cost of DAC needs to drop significantly for it to be a viable option.
The upside is if carbon removal can be scaled up economically, it will facilitate getting to net zero emissions and provide a means for further drawdown of atmospheric CO2 in the likely event we overshoot a 1.5 degree Celsius temperature rise. Importantly, it also allows for future generations to draw down atmospheric carbon dioxide to even more comfortable levels beyond current climate targets.
Author of Scrubbing the Sky: Inside the Race to Cool the Planet