Jonas Steiner

With climate strikes and extreme weather events occurring around the world, climate change has become one of the most talked about topics. Whilst emissions need to be cut, there is no doubt that carbon sinks will be play an important part of the solution.  In this blogpost I will try to compare direct air capture (DAC) technologies like the DAC plant by the ETH spinoff Climeworks and nature based solutions (NBS) such as the one trillion tree campaign. My aim is to give an overview over the possible opportunities, hurdles and costs these options provide and how they stack up against one another.

What is the one trillion tree campaign?                 

When I first heard about the one trillion tree campaign through a panel discussion at the WEF, it sounded almost too good to be true. The goal of the one trillion tree campaign is to connect multiple stakeholders such as world leaders, investors but also “on the ground” organizations that do reforestation projects and get them together to mitigate climate change[12]. Most fascinating to me was at that point a positive, informative discussion, on how such an initiative can have positive effects on ecology, create social benefits and is economically interesting. If you have not seen it I highly recommend you do:

Challenges and Opportunities and Costs

Now first things first, is reforestation/NBS the be all and end all solution? No! But with an estimated 200 gigatons of carbon potentially sequestered through the worlds reforestationit might not be a finite solution but definitely a huge leapforward, by storing about two thirds of man made emissions in the atmosphere since the industrial revolution [5].

Furthermore the 2019 IPCC special report pointed out that more than 20% of all emissions come from the forest, agriculture and land use sector. The land management benefits can be seen in food security, biodiversity and also the climate [1]. How so, you might wonder? As increasing temperatures and droughts endanger agriculture, even more severe in the global south, agroforestry can help in different ways. On the one hand it is economically interesting, timber has been and still is a valuable good which can be grown and sold, on the other hand it can help with soil recovery and enhance nutritional values of crops grown in these areas according to Sadghuru. A big challenge is the fact that trees don’t grow overnight and also that a lot of deforestation still happens. This means that just because trees are planted does not mean at all that they’ll survive to maturity and actually sequester carbon.
If trees are grown in agroforestry the successful growth of such trees is “guaranteed” by the farmers, who have direct financial interest in the success of their venture [2].

Now obviously, not any tree can be grown anywhere, so it seems obvious that suitable trees need to be planted according to habitat and according to available, suitable land. So one does have to ask themselves how much deforested, unused, suitable land there is? Obviously not endless amounts. However if we take into account that around 50% [3] to 70% (see Figure 1) [4] of the worlds crops are used for meat and dairy production it seems clear that with more vegetarians or vegans a lot of additional suitable land would be up for grabs. Apart from free space to grow trees on this would further lower the agricultures’ carbon emissions through less animal farming[13].

Figure 46.1 – Figure 1: Land use for food production

While I was not able to find anything about estimated costs to plant a trillion trees it most definitely would be very expensive, after all saplings do take quite some time to grow into trees, need to be looked after, need water etc. etc. etc.. .  But one of the big advantages of this decentralized approach might be that the burden of costs does not have to be paid for by a single country but is shared by private investors, NGO’s and even small and big scale farms that will have a return of investment by harvesting their trees.

What are DAC & storage technologies?

Carbon Capture and Storage technologies such as the plant by Climeworks work in two steps. The first step is the capture itself, where CO2  is directly filtered from the air through relatively “low temperature” chemical reactions.

The captured CO2 then needs to be safely stored which can be done in various ways, for example storage in geological reservoirs or even mineralization [6]. According to Petrissa Eckle researchers in Norway have teamed up with big players of the oil and gas industry like Shell to find ways of storing CO2 in large geological reservoirs.

Challenges and Opportunities and Costs

Today DAC technology is up and running however, all of this still happens on a very small scale. The plant run by Climeworks today has a capacity of around 50 tons of CO2 per year. To put that in perspective, the average Swiss citizen accounts for about 5.5 tons of CO2 inland and 14 tons of CO2 (including imported goods etc.) per year [10]. Also there is no good produced such as timber or tree grown crops if the captured CO2 is to be stored, which means it has to be financed through policy such as taxpayer money.
However many benefits and opportunities arise as well. According to Beuter main advantages compared to afforestation are that it is not land intensive and no water/irrigation is needed. At this point it would have been interesting to have a look at an life cycle assessment of a DAC plant, which I unfortunately did not come across. Another economically viable way to use the captured CO2 through DAC is to produce Syngas with it. Syngas is a variety of fuels produced from air captured CO2 and thermochemical processes which are compatible with todays infrastructure of cars/airplanes amongst others. This way DAC is not used as a carbon sink but rather a method to produce CO2 neutral fuels. These build an alternative to biofuels which are limited due to competition of crops for food use [11].

Last but not least carbon storage such as the option described by Eckle has several points going for it, it has benefited from 20 years of experience in injecting CO2 into reservoirs and is therefore considered a safe and proven carbon storage technique. Another big plus of the carbon storage project in Norway is that it is already in its final stages, Norway is planning to open up it’s reservoirs to third parties as soon as 2024. A down side to it is the need for infrastructure, especially when CO2 is captured far away from such reservoirs. To overcome this hurdle it is likely that today’s shipping of CO2 will be replaced by a pipeline system. After all, similar infrastructure is already used by the oil and gas industry today.

The costs for removing CO2 via DAC plants is still rather high, however according to Christoph Beuttler it is foreseeable that they will be able to bring costs down to roughly 100 CHF per ton of CO2 by upscaling their plants [6]. To give a rough idea, Switzerland’s current inland CO2 emissions are roughly 46 million tons/year, which would then make up for costs around 4.6 billion CHF/year [7]. This is very comparable to Switzerland’s military budget, which came in at 4.7 billion in 2018 [8].
That being said, Switzerland’s goal isn’t and shouldn’t be to keep going with business as usual.

Conclusion

Reading up on both of these options made it very clear to me that they both definitely have their benefits and limitations, there is no such thing as a silver bullet. While NBS like the one trillion tree campaign might be a good solution to mitigate climate change I can also see it helping contribute to reach many other SDG’s. It’s potential is not endless as there is limited space and can only be implemted in suitable places of the world whith few countries having a lot of potential compared to the rest. Another strength or weakness is that it stands and falls with the backing of many stackeholders; from world leaders, to timber businesses down to small scale farmers. It goes even further to the point where societies nutrition and the therefore used land play an important role. If implementation does work out however it can benefit everyone (especially when approached bottom up) and thus generate a lot of additional value through various synergies.
DAC technologies like the invention by Climeworks are still only available at a small scale, costly and infrastructure intensiv. Big pro’s however are that these plants do capture carbon continously and are not as dependent on a big network of stakeholders to “work it out together”. I also do see benefits by them being implementable top down. This does not generate extra value on many levels of society but has the big advantage of  being less dependent on interests of various stakeholders. If used for syngas production, as implied by Furler and Beuttler the founders of synthelion and climeworks, a lot of the newly needed infrastructure might actually be justifiable in that already used and available infrastructure that relies on high energy fuels can be CO2 neutral.

All in all both approaches have their signficance and in many ways complement each other. While reforestation “buys time”, DAC & Storage still have a chance to upscale, build infrastructure and further refine technologies and there is no direct competition for resources such as land area or water.

Sources:

[1] IPCC, 2019: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V.

[2] Press conference, One trillion trees: https://www.youtube.com/watch?v=8kPMtDiiXxk&t=6s (Last visited: 07.04.20)

[3] Cropland usage: https://www.vox.com/2014/8/21/6053187/cropland-map-food-fuel-animal-feed (Last visited: 07.04.20)

[4] Agricultural land by global diets: https://ourworldindata.org/agricultural-land-by-global-diets (Last visited: 07.04.20)

[5] The global tree restoration potential, 2018: Jean-Francois Bastin, Yelena Finegold, Claude Garcia, Danilo Mollicone, Marcelo Rezende, Devin Routh, Constantin M. Zohner and Thomas W. Crowther

[6] Presentation by Christoph Beuter of Clime Works at SDG Lecture 2020

[7] Climate tracker Schweiz: https://climateactiontracker.org/countries/switzerland/ (Last visited: 07.04.20)

[8] Militärausgaben der Schweiz: https://de.statista.com/statistik/daten/studie/300309/umfrage/militaerausgaben-in-der-schweiz/

[9] Presentation by Petrissa Eckle of the ETH SusLab at SDG Lecture 2020

[10] Klima in Kürze: https://www.bafu.admin.ch/bafu/de/home/themen/klima/inkuerze.html (Last visited: 07.04.20)

[11] Presentation by Philipp Furler of the Synhelion at SDG Lecture 2020

[12] One trillion trees: https://www.1t.org/ (Last visited: 07.04.20)

[13] FAO, Key facts: http://www.fao.org/news/story/en/item/197623/icode/ (Last visited: 07.04.20)

Figures:

Figure 1: https://ourworldindata.org/agricultural-land-by-global-diets#note-1 (Last visited: 07.04.20)