Carbon dioxide in the atmosphere is the primary driver of the “greenhouse effect,” that condition in which CO2 forms a nice blanket around the biosphere, keeping it warm enough for life to have evolved as it has. For a million years or so, atmospheric CO2 levels were relatively stable, fluctuating between 200 and 300 parts per million, and all life as we know it was maintained.

Small human-caused increases in CO2 began with agriculture, but the industrial revolution triggered an abrupt and profound rate of CO2 increase, from roughly 280 parts per million to around 420 today. In just over 200 years we have released the carbon from fossil plants and animals that took several hundred million years to form.

To prevent catastrophic warming, we need to stop emitting CO2. And since we didn’t start cutting back 20 or 30 years ago, we will likely also have to remove CO2 from the atmosphere. Even if the world achieves its net-zero 2050 goals through abrupt cuts, the IPCC estimates that we will have to also actively remove 10 to 20 billion tonnes of CO2 from the atmosphere every year until 2100.

We hear more and more about carbon capture and sequestration, or CCS, essentially intercepting or extracting CO2 that’s been emitted and putting it somewhere safe or finding a use for it. Some of the largest fossil energy companies are touting this as The Solution to our CO2 emissions.

The bad news? There is currently no successful cost-effective CCS being done at any significant scale, and its development time frame is uncertain. Importantly, climate activists ask whether CCS will be used by the fuel industry as license to continue emitting CO2, claiming net-zero operations.  But let’s examine it.

One of the methods being used at an experimental scale captures CO2 where it is at high concentration, in the exhaust stream of coal or natural gas power plants. Removing CO2 here is much more effective than taking it out of the air, but still expensive and energy-intensive, requiring 20% to 40% of the energy being produced at that plant.

CCS usually involves compressing captured CO2 and pumping it deep underground, where it is expected to react chemically to form relatively permanent storage. There are attempts to find markets for captured CO2 to provide incentives for carbon capture.

In some cases, the CO2 is pumped into existing oil and gas wells in order to extract more of the fossil fuel. (Does this sound like an effective approach to fossil energy reduction?) Though some of the CO2 could be utilized in other ways, that market is a tiny fraction of the CO2 we need to capture.

Another approach is “direct air capture,” where CO2 is taken directly out of the air around us. This process is more energy-intensive and more costly than flue gas capture because of the lower CO2 concentration. It could cost between 50% and 90% of the energy of the fossil fuel that produced it.

The world’s largest direct air CCS plant in Iceland recently became operational. It captures 4000 tonnes of carbon dioxide per year and is powered by low-carbon geothermal energy. But the fact is, this wonderful plant would compensate for the CO2 output of about 300 American citizens (The average American is responsible for around 13 tonnes CO2 per year).

The cost to run it is around $600 per tonne of CO2 captured. The developers hope to get the cost down to $200 per tonne by the mid-2030s. One million such plants would have to be constructed to compensate for the current US output, and more than six million to compensate for world output.

Could the government incentivize CCS effectively enough to save the atmosphere in time?

The US government currently subsidizes CCS by paying $50 per ton of captured CO2. If direct air CCS costs $600 or more per ton, there is no incentive for industry to pursue it. Exhaust stream capture is more cost-effective on a “per ton” basis, by some reports as low as $85 to $100 per ton. If the subsidy were to be increased and the cost were to decrease, there might at some point be enough profit in the capture to make it worthwhile for business.

What about carbon pricing? By “putting a price on pollution,” charging fuel producers a meaningful amount per ton of CO2 emitted by any given fossil fuel, we would be encouraging industry to find ways to economize on CO2 emissions. Capturing emissions would then be much more valuable to the emitters. Without charging for CO2 emissions the fossil fuel companies will profit whether or not the CO2 is captured.

That is, fossil energy companies today profit as their products dump CO2 into the atmosphere with no penalty for polluting. Those profits come from you, the consumer, and then you (taxpayer) get to pay the cost of its removal with government subsidies? A carbon price would close that loop.

So, yes, CCS is a thing – but no, it probably isn’t The Solution, nor even much of a solution at all, unless it is coupled with aggressive public policy that includes a meaningful carbon price.

Paul Stancioff, PhD., is professor emeritus of physics at UMF. Cynthia Stancioff re-words everything he writes. Email: pauls@maine.edu or cynthia.hoeh@gmail.com. Previous columns can be found at https://paulandcynthiaenergymatters.blogspot.com/.