What "Deep Decarbonization" Tells us about Carbon Removal

Here's a common question we hear at the Center for Carbon Removal: if it is technically feasible to prevent climate change without carbon removal (i.e. climate solutions capable of removing and sequestering carbon dioxide that has accumulated in the atmosphere), why bother investing any time and capital to develop carbon removal solutions?

This is the exact question begged by the findings of the Deep Decarbonization Pathways Project (DDPP), a collaboration among climate and energy experts from 16 countries representing around 75% of global greenhouse gas emissions. The recently-released 2015 DDPP synthesis report found that:

  1. "Deep decarbonization of today’s highest emitting economies is technically achievable and can accommodate expected economic and population growth." In other words, it is possible to invest in the clean energy technologies that would prevent global mean temperatures from rising more than 2C by 2050.
  2. "All deep decarbonization pathways incorporate “three pillars” of energy system transformation: energy efficiency and conservation, decarbonizing electricity and fuels, and switching end uses to low-carbon supplies." That is, carbon removal solutions are not included in the DDPP projections.
  3. "Deep decarbonization accommodates the energy services needed to meet countries’ economic growth targets and social priorities."
The DDPP analysis shows that achieving deep decarbonization by 2050 is possible without carbon removal, but it doesn't argue against developing carbon removal solutions in parallel. 

The DDPP analysis shows that achieving deep decarbonization by 2050 is possible without carbon removal, but it doesn't argue against developing carbon removal solutions in parallel. 

Just because it is possible to achieve deep decarbonization without carbon removal solutions, however, doesn't mean that it still isn't highly valuable to develop carbon removal solutions today. Here's a few reasons why:

  • The limit used to define "dangerous climate change" in the DDPP analysis may be too high. The DDPP analysis defines dangerous climate change as a mean global temperature increase of 2C compared to pre-industrial averages. However, many leading climate experts have suggested that 1.5C is a more reasonable limit. Using a limit lower than 2C requires even more aggressive decarbonization, which in turn makes carbon removal solutions increasingly important. It's also worth noting that whatever temperature limit the international community eventually defines as acceptable, it is a limit, not a goal—it is always best to stay as far below that limit as possible, and carbon removal can only help with that effort.
  • Even though deep decarbonization is technically feasible, political constraints may prevent decarbonization from happening as quickly as is needed. As David Roberts asked in his recent Vox article, "if [curtailing climate change] makes so much economic sense, why are we not [curtailing it]? Why, when study after study has found that we ought to be acting aggressively to transition to clean energy, does actual movement in that direction remain tentative, halting, incremental, and insufficient?" The answer is: politics. If society proves unable to overcome the political constituencies allied against decarbonization, then decarbonization is likely to proceed too slowly to prevent temperature increases above 2C. In this event, carbon removal solutions will be necessary to reduce atmospheric CO2 concentrations back to acceptable levels. And if carbon removal solutions take decades to become commercially viable, then research and development efforts have to begin now to ensure these solutions are ready in the future when they might be necessary.
  • Carbon removal solutions may help build political will to decarbonize more quickly. The more carbon removal solutions that exist, the more tools companies and governments have for fighting climate change. Developing carbon removal solutions, then, can enable greater political commitments to deep decarbonization—even if carbon removal solutions only become a small portion of the overall effort to decarbonize.

Taken collectively, these reasons make a strong case to invest in developing carbon removal solutions today alongside GHG emission abatement approaches today, even though carbon removal isn't technically necessary for deep decarbonization. 

Bonus section for Direct Air Capture month: The DDPP analysis has interesting implications for the direct air capture (DAC) field. The large-scale build out of intermittent renewable generation resources (listed as one of the three "pillars" of the DDPP analysis) holds the potential to create market conditions where DAC systems could thrive. Because DAC systems can turn on and off relatively quickly, they hold the potential to utilize inexpensive energy generated in peak sun/wind periods, while avoiding expensive energy charges during peak demand periods by pausing operation, reducing their overall operating costs substantially.