Slicing the pie: how big could carbon dioxide removal be?

Abstract

The current global dependence on fossil fuels to meet energy needs continues to increase. If a 2°C warming by 2100 is to be prevented, it will become important to adopt strategies that not only avoid CO2 emissions but also allow for the direct removal of CO2 from the atmosphere, enabling the intervention of climate change. The primary direct removal methods discussed in this review include land management and mineral carbonation in addition to bioenergy and direct air capture with carbon capture and reliable storage. These methods are discussed in detail, and their potential for CO2 removal is assessed. The global upper bound for annual CO2 removal was estimated to be 12, 10, 6, and 5 GtCO2/year for bioenergy with carbon capture and reliable storage (BECCS), direct air capture with reliable storage (DACS), land management, and mineral carbonation, respectively—giving a cumulative value of ~35 GtCO2/year. However, in the case of DACS, global data on the overlap of low‐emission energy sources and reliable CO2 storage opportunities—set as a qualification for DAC viability—were unavailable, and the potential upper bound estimate is thus considered conservative. The upper bounds on the costs associated with the direct CO2 removal methods varied from approximately $100/tCO2 (land management, BECCS, and mineral carbonation) to $1000/tCO2 for DACS (again, these are the upper bounds for costs). In this review, these direct CO2 removal technologies are found to be technically viable and are potentially important options in preventing 2°C warming by 2100. WIREs Energy Environ 2017, 6:e253. doi: 10.1002/wene.253 This article is categorized under: Bioenergy > Climate and Environment Energy and Climate > Climate and Environment Energy and Development > Climate and Environment

Numerical modeling of the global climate and carbon cycle system

“…A fourth group of approaches is concerned with the sequestration of carbon dioxide in the oceans, for example by means of ocean alkalinization (Kheshgi, 1995;Rau, 2011;Ilyina et al, 2013;Lenton et al, 2018). The costs, CDR potential and environmental side effects of several of these measures are increasingly investigated and compared in the literature, but large uncertainties remain, in particular concerning the feasibility and impact of large-scale deployment of CDR measures (The Royal Society, 2009;Smith et al, 2015;Psarras et al, 2017;Fuss et al, 2018) (see Chapter 4.3.7). There are also proposals to remove methane, nitrous oxide and halocarbons via photocatalysis from the atmosphere (Boucher and Folberth, 2010;de Richter et al, 2017), but a broader assessment of their effectiveness, cost and sustainability impacts is lacking to date.…”

Closing the carbon cycle to maximise climate change mitigation: power-to-methanolvs.power-to-direct air capture

“…93 Here, a mitigation potential (MP) has been dened to quantify the prospects of both power-to-fuel and power-to-DAC processes for avoiding GHG emissions. The MP for the power-to-fuel process has been dened as the percentage of gasoline consumption that can be displaced by the produced methanol (see eqn (6)).…”

“…Integrated assessment models (IAMs) are reliant on the deployment of CCS and negative emissions technologies (NETs) to meet this target. [1][2][3][4][5][6] Despite the prevalence of CCS in all mitigation pathways compliant with the Paris target, high investment and operating costs, and crosschain risks have deterred its deployment at the required scale. 7,8 An absence of nancial incentives, policy drivers and/or political appetite has compounded the investment challenges of developing CCS infrastructure.…”

Is the climate change mitigation effect of enhanced silicate weathering governed by biological processes?

“…Safe and scalable negative emission technologies (NETs), which actively remove CO 2 from the atmosphere and ensure long-term carbon (C) sequestration, will be needed to meet this goal (Gasser et al, 2015). Depending on how fast greenhouse gas (GHG) emissions are reduced, 100-1000 Gt CO 2 will have to be removed from the atmosphere by 2100 (IPCC, 2018(IPCC, , 2021Psarras et al, 2017;Rockström et al, 2017). Decarbonization roadmaps show that NETs must be deployed quickly and at a large scale: CO 2 removal would need to reach about 5 Gt CO 2 year −1 by 2050, and increase further to about 10 Gt CO 2 year −1 between 2050 and 2100 (Obersteiner et al, 2018;Rockström et al, 2017).…”