December 16, 2021 | Documents

Carbon removal, including carbon capture, utilization and storage (CCUS) and negative emission technologies (NET), is an important but small part of climate action, unlikely to scale beyond 5-10% percent of current emissions, in the 2-3 critical decades we have to stabilize our climate and stop biodiversity loss.

We propose a typology of climate action, and a classification of NETs according to the natural carbon cycle they aim to enhance, which we use to estimate the limitations of enhancing the fast natural carbon cycle (biomass and land) and the slow natural carbon cycle (energy to crush rock and land to place it for enhanced weathering), as well as the limitations of direct air capture and storage (DACS) as an entirely artificial method (energy, cost and learning curves). The analysis of Swiss potential confirms the 10% limitation for NETs, with focus on wetland restoration, soil carbon, and limited BECCS.

The main challenge is changing the purpose of carbon removal from enhancing oil recovery from depleted oil fields and extending fossil fuel assets and revenues, to stabilizing the climate by removing the last 5-10% of residual emissions after deep decarbonization. Protecting ecosystem services is one of the main reasons for climate action, it must also guide the development of NETs.

To finance carbon removal based on the polluter pays principle, we propose a Swiss Climate Cleanup Fund. This fund bridges the gap between CO2 emissions decreasing from today’s high levels, and the time to develop effective removal. This mechanism sets an objective, “technical” as opposed to “political” carbon price, creating a strong signal to accelerate climate action.

In an energy-constrained world, energy use becomes essential: 15 GJ of clean energy per person, well within reach, could universally satisfy energy service needs. Using it for DACS would remove only ⅓ of today’s fossil fuel emissions. If used for synthetic fuels, only 1/10 of today’s fuel could be replaced.

Sascha NICK, EPFL

Philippe Thalmann, EPFL