Robust paths to net greenhouse gas mitigation and negative emissions via advanced biofuels

Author(s):Show less -

Field, John L. ^[1] ; Richard, Tom L. ^[2] ; Smithwick, Erica A. H. ^{[3, 4]} ; Cai, Hao ^[5] ; Laser, Mark S. ^[6] ; LeBauer, David S. ^[7] ; Long, Stephen P. ^{[8, 9, 10]} ; Paustian, Keith ^{[11, 1]} ; Qin, Zhangcai ^{[12, 13]} ; Sheehan, John J. ^{[14, 15]} ; Smith, Pete ^[16] ; Wang, Michael Q. ^[5] ; Lynd, Lee R. ^[6]

Affiliation:Show less -

^[1] Colorado State Univ, Nat Resource Ecol Lab, Ft Collins, CO 80523 - USA

^[2] Penn State Univ, Dept Agr & Biol Engn, University Pk, PA 16802 - USA

^[3] Penn State Univ, Dept Geog, University Pk, PA 16802 - USA

^[4] Penn State Univ, Earth & Environm Syst Inst, University Pk, PA 16802 - USA

^[5] Argonne Natl Lab, Energy Syst Div, Lemont, IL 60439 - USA

^[6] Dartmouth Coll, Thayer Sch Engn, Hanover, NH 03755 - USA

^[7] Univ Arizona, Arizona Expt Stn, Tucson, AZ 85721 - USA

^[8] Univ Illinois, Dept Crop Sci, Urbana, IL 61801 - USA

^[9] Univ Lancaster, Lancaster Environm Ctr, Lancaster LA1 4YQ - England

^[10] Univ Illinois, Dept Plant Biol, Urbana, IL 61801 - USA

^[11] Colorado State Univ, Dept Soil & Crop Sci, Ft Collins, CO 80523 - USA

^[12] Sun Yat Sen Univ, Guangdong Prov Key Lab Climate Change & Nat Disas, Sch Atmospher Sci, Guangzhou 510245 - Peoples R China

^[13] Southern Marine Sci & Engn Guangdong Lab Zhuhai, Zhuhai 519082 - Peoples R China

^[14] Univ Estadual Campinas, Sch Agr Engn, BR-13083875 Campinas, SP - Brazil

^[15] Colorado State Univ, Dept Chem & Biol Engn, Ft Collins, CO 80523 - USA

^[16] Univ Aberdeen, Inst Biol & Environm Sci, Aberdeen AB24 3UU - Scotland

• Document type: Journal article
• Source: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA; v. 117, n. 36, p. 21968-21977, SEP 8 2020.
• Web of Science Citations: 17

Abstract

Biofuel and bioenergy systems are integral to most climate stabilization scenarios for displacement of transport sector fossil fuel use and for producing negative emissions via carbon capture and storage (CCS). However, the net greenhouse gas mitigation benefit of such pathways is controversial due to concerns around ecosystem carbon losses from land use change and foregone sequestration benefits from alternative land uses. Here, we couple bottom-up ecosystem simulation with models of cellulosic biofuel production and CCS in order to track ecosystem and supply chain carbon flows for current and future biofuel systems, with comparison to competing land-based biological mitigation schemes. Analyzing three contrasting US case study sites, we show that on land transitioning out of crops or pasture, switchgrass cultivation for cellulosic ethanol production has per-hectare mitigation potential comparable to reforestation and severalfold greater than grassland restoration. In contrast, harvesting and converting existing secondary forest at those sites incurs large initial carbon debt requiring long payback periods. We also highlight how plausible future improvements in energy crop yields and biorefining technology together with CCS would achieve mitigation potential 4 and 15 times greater than forest and grassland restoration, respectively. Finally, we show that recent estimates of induced land use change are small relative to the opportunities for improving system performance that we quantify here. While climate and other ecosystem service benefits cannot be taken for granted from cellulosic biofuel deployment, our scenarios illustrate how conventional and carbon-negative biofuel systems could make a nearterm, robust, and distinctive contribution to the climate challenge. (AU)

• FAPESP's process: 14/26767-9 - Global Sustainable Bioenergy Initiative: geospatial & environmental analysis of pastureland intensification for bioenergy
• Grantee: John Joseph Sheehan
• Support Opportunities: Research Projects - SPEC Program