Why Net Zero is a Trap

On the need for radical honesty, Part II

Clearcut forest in Estonia. Photo by Maksim Shutov on Unsplash

This is the second part of a three part essay that was originally published in German in the book “Klima, Kollaps, Kommunikation”. See here for Part I and here for Part III.

Modern science is repeatedly confronted with problems that are simultaneously very simple and devilishly difficult. These give us a hint of the limitations of science as a guide for taking action. Of these, climate change probably presents itself as the ultimate ‘wicked problem’. We are no longer simply dealing with a ‘problem’ for which there are technical or organizational ‘solutions’. The issue we are dealing with is so intricate and has so many aspects and levels that it challenges our notions of what is meant by ‘solutions’ in the first place. The question is: what is there to do for us in the climate change profession?

During the 1940s and 50s, the seemingly simple solution to the risks associated with the military use of nuclear power was deterrence. Consequently, the nuclear physics elite assembled at Los Alamos was to develop first the atomic bomb and then the hydrogen bomb, as quickly as possible in order to prevent the other side from using them first. But what presents itself first as a straightforward problem-solution pair, in the long term creates extremely challenging problems that are almost impossible to solve. The confrontational course itself will sooner or later undermine the effectiveness of the deterrence. In a general climate of increasing tensions, the willingness to use nuclear weapons as a means of political or military pressure inevitably increases. Cooperation is undermined, and there is no chance of a general easing of tensions.

The wicked problem of planetary heating – the energy released through the enhanced greenhouse effect corresponds to over one million nuclear detonations per day – also has a seemingly simple solutions: simulations by computer models show that more or less shortly after reaching global net zero emissions, warming would stop. Where ‘net zero’ means that all human-made emissions of carbon dioxide, or CO2, where they still exist, will be compensated by equally large fluxes of CO2 into so-called ‘carbon sinks’. Because CO2 mixes rapidly in the atmosphere, it does not matter where the greenhouse gas is emitted, and where it is taken up. In other words, zero emissions are unnecessary, net zero is already good enough.

This is exactly the point where it gets tricky: the seemingly insignificant prefix ‘net’ was initially meant to apply to only very few essential but difficult to mitigate carbon emissions, for example from essential agriculture. In purely mathematical terms, however, the little word ‘net’ allows someone to hide arbitrarily large emissions, such as from fossil-fuel burning. The only requirement is to find equally large carbon sinks – ready is the net-zero scenario. Ready only in a mathematical sense, because until today no realistic plans exist for the deployment of the massive carbon sinks that would allow a continuation of business-as-usual. This does not prevent the latest IPCC report from containing a whole range of essentially science-fiction scenarios, where fossil fuel burning persists decades beyond the point where ‘net zero’ is supposed to have been reached.

The IPCC and the technical capture of CO2: carbon capture and storage (CCS)

In the IPCC’s integrated assessment model (IAM) scenarios, carbon dioxide removal is dominated by BECCS, the most cost effective negative emissions technology, with the next most significant option, Direct Air Carbon Capture and Storage (DACCS) contributing typically only about one tenth of BECCS for Paris compliant scenarios (IPCC AR6 WGIII Section 3.4.7). The median CO2 removal by BECCS in those scenarios is 12Gt of CO2 per year, about one third of current fossil-fuel emissions.

Total Carbon Capture and Storage (CCS), which includes BECCS, DACCS and CCS in combination with fossil fuel burning, amounts to 665 billion tons of CO2 until 2100 in Paris Compliant IPCC scenarios, of which half is accounted for by BECCS (330 billion tons of CO2, IPCC AR6 WGIII Table 3.6). For comparison, about 0.2 billion tons of CO2 were captured by CCS between 1996 and 2020. At this rate, it will take 79,800 years to capture the CO2 needed to comply with the Paris Agreement, according to IAM scenarios. There is no BECCS scheme in operation today.

The land requirements modelled in IAM (integrated assessment modelling) scenarios due to BECCS-based carbon removal amount to 25 to 80% of current cropland area, or between 1.2 and 3.7 times the size of India (0.4 to 1.2 billion hectares) – in other words, it creates a world where a growing population will be unable to feed itself.

If BECCS is established on forest land, instead, it requires first clearing the forest, which creates a “carbon debt” that will take many decades to be paid back – making forest based BECCS unsuitable for the type of rapid mitigation required to meet the Paris Agreement.

There is growing use of tree biomass for energy production, and plans to expand such schemes into BECCS. Therefore, even the prospect of BECCS is likely doing countless damage to intact forest ecosystems, including logging of old growth forests in the EU and Canada. The commercial viability of this practice depends on taxpayer subsidies as well as an accounting loophole by the IPCC that classifies biomass energy as carbon neutral, while the emissions from clearing the forest and from the biomass operations are being accounted for elsewhere.

Land, nitrogen, phosphorus, and water requirements of BECCS in IAM scenarios are so great that existing mitigation scenarios using biological carbon dioxide removal (essentially BECCS) may “largely transfer environmental risk from the atmosphere to the land”, i.e. mitigate against planetary heating but create similar or greater risks in the land sector instead.

As a recent example, a 2021 modelling study found that removing carbon with BECCS would create more water shortage than the climate change it mitigates against – in other words, current “safe” mitigation scenarios do more harm than good.

A look at the consequences, should such sinks actually be used for climate mitigation, shows not only their lack of realism, but also how dangerous such scenarios would be. Since there is not enough land for reforestation, the CO2 would inevitably have to be captured in some way, and then stored long-term in geological formations. The sequestration is either done with the help of biofuels – in which case the approach is called BECCS – or using machines: DACCS, see above. Both BECCS and DACCS are being deployed lavishly within most IPCC scenarios, precisely because all of them operate on a fixed and immutable assumption, that the future will inevitably look very much like a modified status quo. Under such assumption, any rapid shift away from fossil fuels is made impossible. Negative consequences of the resultant massive demand for energy (to operate DACCS) and fertile land (for BECCS) are interestingly not taken into account in those models. Net zero thus becomes a trap: if it succeeds, the price will be famine, water shortages and the immense destruction of our remaining ecosystems. If it doesn’t, global warming will spiral out of control.

For a long time, net zero looked like an unrivalled success story. After protests by Fridays for Future, Extinction Rebellion and other groups led to a series of climate emergency declarations, there are now existing or soon-to-exist net zero plans that cover as much as 90% of all global human-made CO2 sources. Most of them set themselves a target of reaching net zero by the year 2050.

Only problem is: neither the plans not the emergency declarations are legally binding. Net zero by 2050 is also not anywhere near sufficient to reach the goals of the Paris Agreement to limit warming to well below 1.5C. There is also evidence that the oil and gas industry has never actually believed in the large-scale deployment of carbon capture and storage, irrespective of what their PR campaigns look like. And so there is immense pressure to cut costs and therefore further undermine and weaken the standards of carbon projects, all the way to large-scale fraud.

The long-term effects of a failed reliance on net zero are already becoming apparent. The eternally delayed measures are being abandoned one-by-one and replaced by even more grandiose ‘solar radiation management’ schemes: the artificial manipulation of the Earth’s radiation balance and consequently large-scale weather patterns by way of spraying massive amounts of sulfur dioxide aerosol particles into the upper atmosphere.

Similar to the development of nuclear weapons, there is opposition from large parts of the scientific community: an open letter signed by over 350 researchers calls for a halt to research into solar geoengineering, as the consequences of manipulating the climate are incalculable. There is no responsible global political structure to regulate such an endeavour.

Even the original 1.5C goal of the Paris Agreement has distorted the public discourse on climate – as if it had been the goal to stabilize the global mean temperature, and not the climate. Because this global average is no more than a product of abstract thought, and never actually experienced directly by anyone. Similar to ‘net zero’, there can be an awful lot of climate destabilization hiding between mathematically keeping to the 1.5C goal – if the goal is not reached by stabilizing the climate, but by large-scale weather manipulation. And so, slowly but surely, we fall into the net zero trap.