A Review of Efforts towards Achieving Carbon Negativity

Abstract

The purpose of this study is to better understand different approaches to achieving carbon negativity, in which more carbon dioxide is removed from the atmosphere and oceans by a process in comparison to what is released. This was examined by analyzing 287 submissions to the XPRIZE Carbon Removal competition, a four year contest focused on approaches to removing carbon dioxide from the atmosphere and oceans on a gigaton scale. The 287 teams analyzed were Qualified Competitors, meaning they demonstrated a working carbon removal solution, estimated costs at full scale, and made a case and plan for scaling and deploying their solutions at megaton or gigaton per year capacity. Results showed that 129 teams used agriculture and forestry in their approaches, while 59 used new technology, 52 used chemical approaches, 49 used Direct Air Capture (DAC) technology, 45 used the cultivation of ocean plants, 39 used geology, 38 used biochar, 29 used burial and underground storage, and 14 used bamboo and hemp. The majority of teams fit into two or more categories, and only five teams did not provide enough information to be categorized. In conclusion, approaches to carbon dioxide removal incorporating agriculture and forestry are most widely used, but approaches from all categories need to be used in conjunction in order to eventually achieve carbon negativity.