Emission reductions alone are not enough to achieve ambitious climate goals. Therefore, negative emissions and carbon removal are increasingly being discussed as possible additional climate protection measures. In this guest article, Simon Göß from cr.hub explains what is behind the terms negative emissions and carbon removal. After analysing five global scenarios in relation to negative emissions, Simon Göß explains the implications for policy and highlights some private sector initiatives.

Looking back at the past year, the Coronavirus pandemic will probably be the most remembered thing of 2020. And in the public perception, the pandemic and its effects seem to have displaced climate change as the biggest challenge.

CO2-emissions climb back

As a result, global energy-related CO2-emissions also fell by about 6 percent in 2020 compared to 2019. Due in particular to lockdown restrictions and the economic crisis, energy-related emissions (CO2e) fell by more than 2 gigatons (Gt) in 2020 to just over 30 Gt. No one expected such a drop in emissions in early 2020. In fact, some countries, such as Germany, only achieved their climate targets as a result of the Coronavirus crisis. Otherwise, emissions would not have dropped that much.

However, a look at the latest figures and statistics reveals that energy-related CO2-emissions have been back at the previous year’s level since December 2020 and could end up just 1 percent below pre-Corona emissions of 2019 during 2021.

Net-Zero terminology

Even after aggressive emission reduction have taken place during the coming decades in all sectors of the economy through the expansion of renewables, increasing energy efficiency and lower energy consumption, residual emissions might still occur. Greenhouse gases must then be actively removed from the atmosphere in order to further reduce emissions on balance.

A country or an organisation achieves net-zero emissions or climate neutrality when the amount of emissions removed reaches that of the residual emissions, i.e. when no more greenhouse gases are released into the atmosphere on balance. Emissions removed from the atmosphere are also called negative emissions. Various negative emissions technologies exist, which today mainly focus on the removal of CO2 as the most important greenhouse gas from the atmosphere, hence the focus on carbon removal.

Here it is necessary to differentiate between carbon removal, carbon capture and storage (CCS) and carbon capture and use or utilisation (CCU). CCS prevents emission from fossil fuels from entering the atmosphere in the first place, but does not remove any emissions from the atmosphere. In that respect, it is not a negative emissions technology or solution. CCU refers to the use of captured CO2 in the production of fuels or other products. If a particular CCU process and product actually leads to negative emissions or not depends on where the captured CO2 comes from and on the life-time of the product in question. Figure 1 (source: cr.hub) explains the difference between carbon removal, CCU and CCS.

Differences between Carbon Removal, CCU and CCS (source: cr.hub).

Figure 1: Differences between Carbon Removal, CCU and CCS (source: cr.hub).

Clearly, terminology is important when it comes to setting and specifically achieving credible Net Zero targets or climate strategies, as well as when evaluating Net Zero claims or scenarios.

Assessing global scenarios

Given the vast amount of global climate scenarios and modelling exercises, we only focus on a few of them in the following. Figure 2 (source: cr.hub) shows an exemplary emission pathway for achieving 1.5 °C, while at the same time showing traditional mitigation technologies, such as renewables and energy efficiency and carbon removal separately. The figure is based on data from the Network for Greening the Financial System (NGFS) climate scenarios for central banks and supervisory authorities.

Necessary order of magnitude for carbon removal for emission paths of 1.5 °C (source: cr.hub).

Figure 2: Necessary order of magnitude for carbon removal for emission paths of 1.5 °C (source: cr.hub).

In order to widen the scope of the analysis and to reduce the risk of looking in only one direction, we included scenarios of five different organisations:

The International Energy Agency’s (IEA) Net Zero by 2050 Roadmap, the Consultation Paper Reaching climate objectives: the role of carbon dioxide removals by the Energy Transitions Commission (ETC), the Special report: Global warming of 1.5 °C of the Intergovernmental Panel on Climate Change (IPCC) and McKinsey’s Climate math: What a 1.5-degree pathway would take and NGFS’s Climate scenarios. A few numbers on the relevant amount of negative emissions has been distilled from the report The case for Negative Emissions by the Coalition for Negative Emissions. We are aware that this selection only captures part of the available literature.

All scenarios considered aim to keep the temperature increase below 1.5 °C compared to pre-industrial levels. Still, comparing scenarios and studies is difficult due to different assumptions on which part of the economy and thus which emissions are included in the scenario or what exactly qualifies as carbon removal and what does not. In addition, the probabilities in keeping below a certain temperature threshold differ between scenarios and studies.

This means that the assumptions for the modelling and scenarios for Net Zero should be shown as clearly as possible in order to best classify and understand the results.

Rapid scale-up of carbon removal needed

What do the scenarios have in common?

Emission reductions from large-scale deployment of renewables and electrification of large parts of the industrial and transport sectors are included in all scenarios. Yet, all scenarios agree that there is a significant need for negative emissions in the gigatonnes (Gt CO2e range to achieve the 1.5 °C climate target, as Figure 3 (source: cr.hub) shows (data sources: Coalition for Negative Emissions, IEA, ETC).

Required negative emissions for 1.5 °C climate targets according to different scenarios in Gt CO2e/y (source: cr.hub).

Figure 3: Required negative emissions for 1.5 °C climate targets according to different scenarios in Gt CO2e/y (source: cr.hub).

Also, carbon removal technologies have to be available on a large-scale basis already during this decade and reach the Gt level by about 2030 from a very low level today. Given today’s greenhouse gas emissions of almost 50 Gt per year, the level of negative emissions according to the five scenarios amounts to about 5 to 20 percent of current global emissions in 2050. This is a stark reminder that negative emission technologies are not marginal implementations and potential fixes on the race to Net Zero, but important requirements to deal with residual emissions in laggard and hard-to-abate sectors.

Where do the numbers disagree and why?

On the upper end are the high range numbers of the ETC and the IPCC with up to 10 Gt of carbon removal by mid-century, while the IEA’s NetZero Roadmap features on the lower end with an expected need of 2.4 Gt of negative emissions by 2050. The former two scenarios the IEA foresees a total capture of 7.6 Gt including CCS and CCU. However, removals from the atmosphere make up only about 30 percent of those. Also, the scenario assumption of the IEA include no new investments into unabated coal power plants and new oil and gas fields or coal mines from 2021 onwards, as well as the phase-out of unabated coal power globally by 2030.  Here, the ambition level for classical mitigation strategies is very high, compared to the other four scenarios.

If a medium pathway such as in the NGFS or McKinsey scenarios is taken seriously, that means that negative emission technologies (NETs) need to be scaled up rapidly within the coming decades to achieve a removal potential in the Gt scale. A scale-up of at least 50 times from the present days is needed for that, according to The case for Negative Emissions report. Especially as the current pipeline for carbon removal projects including Natural Climate Solutions, Bioenergy with CCS and Direct-Air-Capture until 2025 only stands at about 0.15 Gt (source: Coalition for Negative Emissions).

As an example of how increased climate ambition leads to negative emissions is the case of the German new climate law. In a forthcoming article, we will have a closer look at the need for carbon removal in Germany’s road to greenhouse gas neutrality.

Implications for policy

To achieve Net Zero by 2050 while keeping global temperature below 1.5 °C will require unprecedented efforts and are seemingly not plausible any longer without large-scale utilisation of carbon removal. Indeed, even many 2-degree pathways hinge on negative emissions although on a lower level, especially if international climate action falls short of more ambitious action (source: Minx, et al., Fuss et al.).

This leaves policymakers with many questions, such as:

  • Which ways exist to integrate carbon removal in climate policy?
  • What is the interaction between emission reduction and carbon removal policy?
  • How to scale-up NETs and incentivise innovation in the sector?
  • Where to focus investments and resources?
  • How to implement carbon removal credits and how to integrate them into the emission trading systems such as the EU ETS?

On the EU-level the first initiatives are on their way to support carbon removal, such as the Negative Emissions Platform and the European Commission wants to propose a robust carbon removal certification system by 2023. In addition, research and innovation on carbon removal are being funded by Horizon 2020 and the follow-up program Horizon Europe. The Innovation Fund, which receives 10 billion Euro from the income of the EU Emission Trading System, includes the commercial demonstration of low-carbon technologies, such as carbon removal and CCS into its framework.

Carbon Removal solutions need support

All solutions are needed in the fight against climate change, from emission savings and reductions to the removal of greenhouse gases from the atmosphere. For a process or technology to be considered carbon removal, four conditions must be met:

  1. CO2 is physically removed from the atmosphere.
  2. The removed CO2 is permanently stored outside the atmosphere.
  3. Emissions generated during the process are included in the overall balance.
  4. Emissions generated during the process are less than the negative emissions produced.

However, scaling and application of the various nature-based and technological solutions to remove carbon dioxide from the atmosphere are still in their infancy. Figure 4 (source: cr.hub) shows selected negative emission technologies.

Selected negative emission technologies (source: cr.hub).

Figure 4: Selected negative emission technologies (source: cr.hub).

How is the industry preparing?

For the private sector, especially for corporations and companies that set climate targets and aim to go for their own Net Zero goals, the complexity of the discussion rises. Internationally acknowledged standards of setting climate targets and the role removals and reduction play within those such as the Net Zero Standard by the Science Based Targets initiative will be of great importance (source: SBTi).

Industry-led initiatives on voluntary carbon markets such as the Taskforce for Scaling Voluntary Carbon Markets (TSVCM) are needed as well to drive the demand and market. Cr.hub is part of the consultation group of TSVCM, that just launched its report of Phase II of implementing an industry-wide carbon market. However, it is important that only high-quality removals feature in those industry-led initiatives in order to achieve real climate benefits. The discussion of what a high-quality removal actually entails, is a story for another time. We will come back to that in further articles.

In conclusion, it becomes clear that many players and organisations are taking carbon removal and negative emissions now much more seriously in their climate and energy modelling scenarios and as a potential tool for reaching Net Zero targets. In addition, NETs have to be scaled dramatically in order to achieve the required removal potential.

cr.hub goes online

Against this background, the cr.hub was launched as an international network and platform at the beginning of 2021. Cr.hub provides targeted contacts and knowledge in the field of carbon removal and negative emission technologies to accelerate the development of carbon removal projects and solutions and to encourage investment in the sector.

To receive more information on negative emissions, carbon removal and net-zero strategies, get in touch with cr.hub, subscribe to the cr.hub newsletter or learn more about the topics in the cr.hub event calendar.

Co-author of the blog post: Hendrik Schuldt, cr.hub