To Avoid Climate Disaster We Need to Urgently Remove Carbon from the Atmosphere

Ed Lander
Don't Fear Truth
Published in
7 min readJun 25, 2023
Prototype carbon capture facility

First, let’s start with the good news — scientists believe that the transition into a clean energy system is now inevitable [1] [2]. The days of a fossil fuel dominated energy system are now numbered, and interestingly it appears that solar energy will become the dominant clean energy technology — presumably due to its ever decreasing costs, its simplicity to deploy and its suitability for large parts of the developing world with high sun indices — as shown in this chart from the University of Exeter Global Systems Institute.

Projected worldwide share of electricity production methods (2010–2060)

This is clearly great news for the battle against climate change. However scientists are also telling us that, even with a transition to a clean energy system, the existing carbon dioxide in the atmosphere, as well as the expected greenhouse gases produced during the clean energy transition, will still lead to average global temperatures over 2.5 degrees Celsius above pre-industrial levels by 2070. As a reminder, the 2015 United Nations Climate Change Conference (commonly referred to as COP21 — the 21st United Nations climate conference) set ambitious climate targets to avoid increasing global average temperatures above pre-industrial levels by well below 2 degrees Celcius and ideally below 1.5 degrees. Last year, 2022, we were already reached 1.15 degrees Celcius above pre-industrial temperatures, and combined with an upcoming warming El Nino event, average global temperatures could easily exceed 1.5 degrees this decade (if only temporarily). This is clearly a stark warning — extremely dangerous global warming is potentially only a few years away. So what now?

Well clearly it is a huge relief that clean energy systems are due to inevitably displace fossil fuel systems, as they become cheaper and fossil fuels become increasingly scarce and harder to extract and refine. However the issue now is the legacy carbon emissions in the atmosphere. Clearly there are existing methods to remove carbon dioxide, as well as other greenhouse gases, from the atmosphere. However popular carbon offsetting activities like planting trees has only limited benefits. First of all the biochemical process that converts sunlight and water into plant food — photosynthesis — does remove carbon dioxide from the atmosphere, however it is only temporarily locked away. If, for example, the trees are cut-down, biodegrade or are engulfed in wildfires, as is becoming more and more common as the planet heats up, then the carbon is released back into the atmosphere. The oceans also perform a large part of the Earth’s natural carbon cycle, but they are becoming saturated with carbon dioxide, and we are witnessing increased ocean acidity as a consequence, resulting in bleached coral reefs and damage to food chains in aquatic ecosystems due to the impact of acidification on calcification processes in the oceans.

What is becoming increasingly obvious is that, even with a clean energy transition, the existing greenhouse gases in the atmosphere become the problem. Whilst methane — a powerful greenhouse gas — has a relatively short lifetime in the atmosphere of around 12 years, carbon dioxide can remain in the atmosphere for far longer. Today the atmospheric concentration of carbon dioxide in the atmosphere is around 420 part per million (ppm). To put this into perspective, the concentration of CO­2 in the atmosphere was below 300 ppm before the industrial revolution — CO2 concentrations are effectively 50% higher than in pre-industrial times. And the last time scientists understand that atmospheric concentrations of CO2 were this high was four million years ago, during the Pliocene era, when global temperatures were 2 to 4 degrees Celsius warmer and sea levels were 10 to 25 metres higher than they are today. As we are well aware, similar conditions today would result in catastrophic loss of habitat and life all around the world, putting enormous strain on food and fresh water supplies and likely resulting in mass human migrations to avoid the most damaging effects of global warming and climate change.

Coming back to the title of this article, we are soon going to hit the ‘safe’ upper limit of CO2 concentrations in the atmosphere. This means that any carbon dioxide emitted after this point will likely have to be removed from the atmosphere using technological means — the oceans are struggling to absorb vast amounts of carbon dioxide we are producing from burning fossil fuels; the amount of land available for reforesting is limited and the Earth’s natural carbon cycle can only work so fast. In a sense, we are saying that the use of fossil fuels beyond the clean energy transition, even for popular activities like air travel and tourism, really becomes a risk to all life on Earth …

So let’s look at the amount of so called anthropogenic carbon dioxide. Here’s a chart from the IEA showing emissions from energy combustion and industrial processes from 1900 to 2021.

Source: International Energy Agency (IEA)

As you can see we’re typically producing around 35 Giga tonnes (Gt) of carbon dioxide every year from these processes alone. Clearly the amount will decrease over time as low carbon, and zero carbon, energy technologies are scaled up to replace fossil fuels. However, as was discussed above, it’s the residual carbon emissions that become the problem. So let’s turn our attention to existing carbon dioxide removal (CDR) technologies. There are currently many different types of CDR technologies, including reforestation, biochar generation, Bioenergy with Carbon Capture and Storage (BECCS) and Direct Air Carbon Capture and Storage (DACCS). A recent report by the University of Oxford’s Smith School of Enterprise and the Environment surmises that current annual CDR efforts stand at around 2 billion tonnes. So, at current CDR capacity, it would take roughly 15 years to remove one year’s worth of anthropogenic CO2 from the atmosphere. This is obviously too slow, however it’s clear that there is scope to scale up CDR technologies. The problem really becomes one about cost and ensuring any CDR technologies are powered by zero carbon energy sources.

One of the most well-known CDR technology companies is Swiss company Climeworks. Their direct air capture technology removes CO2 from the atmosphere and makes it commercially available — for example for agribusinesses or beverage companies. Climeworks have partnered with Icelandic CDR technology company Carbfix, who have developed a method of DACCS, whereby CO2 is captured and permanently stored underground in mineral rocks. The company claims that its flagship Orca facility can remove 4000 tonnes of carbon dioxide each year and for as little as $25 per tonne. To put that in perspective, it would require nine million of these plants to remove our current annual CO2 emissions and cost nearly $900bn to do so each year. And that’s not even taking into account the problems encountered with earthquakes generated by the CO2 injection process, much like with hydraulic fracturing, and the massive requirements for water as part of the carbon storage process. However obviously new CDR technologies can be developed and existing technologies can be improved and scaled up for larger impact.

Putting these figures into perspective, a long-haul commercial passenger flight typically produces around 5 tonnes of CO2 (return) per passenger, which equates to around half the annual carbon emissions from the average Brit. Taking Carbfix’s technology cost figures, this would equate to over $100 to ‘offset’ the emissions from this flight for each passenger. Some airlines do offer carbon offsetting features as part of their ticket purchasing, however it’s unlikely that many customers would be willing to pay an extra $100 or so for their flights just to be carbon neutral.

However, until airlines are using sustainable aviation fuels, or non-carbon based fuels, the carbon emissions for global aviation are significant, and there are arguments for mandating carbon taxes for every flight using non sustainable fuels. Fundamentally, as it’s clear that all CO2 emissions generated once we breach the 1.5 degrees threshold will need to be removed, there is a strong argument for general carbon taxes. Whilst unpopular, both with businesses and consumers, this would create rapid and radical change in behaviour and hopefully produce better results than the carbon trading schemes currently in operation.

Regrettably we’re still many years away from being able to leave fossil fuels in the ground — even with renewable energy sources, electric transport solutions and non-fossil fuel based home climate control and water heating technologies (solar, heat pumps etc). However the urgency to do so is just as strong as it was back in 2015 in Paris at COP21, and pushing the costs into the future just makes the herculean task of stabilising the climate an ever greater and increasingly difficult target to achieve.

[1] The University of Oxford — Institute for New Economic Thinking — Empirically grounded technology forecasts and the energy transition

[2] The University of Exeter — Global Systems Institute — Is a solar future inevitable?

Special thanks to Dr. Nafeez Ahmed for his excellent article Why transformation of the global energy system is now unstoppable, published on the Age of Transformation platform, that inspired me to look beyond the clean energy transition and start researching atmospheric carbon removal technologies and the challenge ahead for humanity in avoiding catastrophic climate change due to legacy anthropogenic carbon emissions

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