Land-use emissions play a critical role in land-based mitigation for Paris climate targets

Anna Harper (1) , Tom Powell (2) , Peter Cox (1) , Joanna House (3) , Chris Huntingford (4) , Timothy Lenton (2) , Stephen Sitch (2) , Eleanor Burke (5) , Sarah Chadburn (1, 6) , William Collins (7) , Edward Comyn-Platt (2) , Vassilis Daioglou (8) , Jonathan Doelman (8) , Garry Hayman (2) , Eddy Robertson (5) , Detlef van Vuuren (8) , Andy Wiltshire (5) , Christopher Webber (7) , Ana Bastos (9, 10) , Lena Boysen (11) , Philippe Ciais (10, 12) , Narayanappa Devaraju (10) , Atul Jain (13) , Andreas Krause (14) , Ben Poulter (15) , Shijie Shu (13)

1 EMPS - College of Engineering, Mathematics and Physical Sciences [Exeter]
2 University of Exeter
3 School of Geographical Sciences [Bristol]
4 CEH - Centre for Ecology and Hydrology [Wallingford]
5 MOHC - Met Office Hadley Centre
6 University of Leeds
7 Department of Meteorology [Reading]
8 PBL Netherlands Environmental Assessment Agency
9 Department of Geography [München]
10 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
11 MPI-M - Max Planck Institute for Meteorology
12 ICOS-ATC - ICOS-ATC
13 Department of Atmospheric Sciences [Urbana]
14 INT - Institute of Nanotechnology [Karlsruhe]
15 GSFC - NASA Goddard Space Flight Center

Scenarios that limit global warming to below 2 °C by 2100 assume significant land-use change to support large-scale carbon dioxide (CO$_2$) removal from the atmosphere by afforestation/reforestation, avoided deforestation, and Biomass Energy with Carbon Capture and Storage (BECCS). The more ambitious mitigation scenarios require even greater land area for mitigation and/or earlier adoption of CO$_2$ removal strategies. Here we show that additional land-use change to meet a 1.5 °C climate change target could result in net losses of carbon from the land. The effectiveness of BECCS strongly depends on several assumptions related to the choice of biomass, the fate of initial above ground biomass, and the fossil-fuel emissions offset in the energy system. Depending on these factors, carbon removed from the atmosphere through BECCS could easily be offset by losses due to land-use change. If BECCS involves replacing high-carbon content ecosystems with crops, then forest-based mitigation could be more efficient for atmospheric CO$_2$ removal than BECCS.

Domaines: Sciences de l'environnement; Climatologie

Anna Harper, Tom Powell, Peter Cox, Joanna House, Chris Huntingford, et al.. Land-use emissions play a critical role in land-based mitigation for Paris climate targets. Nature Communications, 2018, 9, pp.2938. ⟨10.1038/s41467-018-05340-z⟩. ⟨cea-01880053⟩