Simulated carbon emissions from land-use change are substantially enhanced by accounting for agricultural management

TY - JOUR

T1 - Simulated carbon emissions from land-use change are substantially enhanced by accounting for agricultural management

AU - Pugh, T. A. M.

AU - Arneth, A.

AU - Olin, S.

AU - Ahlström, A.

AU - Bayer, A. D.

AU - Goldewijk, K. Klein

AU - Lindeskog, M.

AU - Schurgers, Guy

PY - 2015/12/8

Y1 - 2015/12/8

N2 - It is over three decades since a large terrestrial carbon sink (S T) was first reported. The magnitude of the net sink is now relatively well known, and its importance for dampening atmospheric CO2 accumulation, and hence climate change, widely recognised. But the contributions of underlying processes are not well defined, particularly the role of emissions from land-use change (E LUC) versus the biospheric carbon uptake (S L; S T = S L − E LUC). One key aspect of the interplay of E LUC and S L is the role of agricultural processes in land-use change emissions, which has not yet been clearly quantified at the global scale. Here we assess the effect of representing agricultural land management in a dynamic global vegetation model. Accounting for harvest, grazing and tillage resulted in cumulative E LUC since 1850 ca. 70% larger than in simulations ignoring these processes, but also changed the timescale over which these emissions occurred and led to underestimations of the carbon sequestered by possible future reforestation actions. The vast majority of Earth system models in the recent IPCC Fifth Assessment Report omit these processes, suggesting either an overestimation in their present-day S T, or an underestimation of S L, of up to 1.0 Pg C a−1. Management processes influencing crop productivity per se are important for food supply, but were found to have little influence on E LUC.

AB - It is over three decades since a large terrestrial carbon sink (S T) was first reported. The magnitude of the net sink is now relatively well known, and its importance for dampening atmospheric CO2 accumulation, and hence climate change, widely recognised. But the contributions of underlying processes are not well defined, particularly the role of emissions from land-use change (E LUC) versus the biospheric carbon uptake (S L; S T = S L − E LUC). One key aspect of the interplay of E LUC and S L is the role of agricultural processes in land-use change emissions, which has not yet been clearly quantified at the global scale. Here we assess the effect of representing agricultural land management in a dynamic global vegetation model. Accounting for harvest, grazing and tillage resulted in cumulative E LUC since 1850 ca. 70% larger than in simulations ignoring these processes, but also changed the timescale over which these emissions occurred and led to underestimations of the carbon sequestered by possible future reforestation actions. The vast majority of Earth system models in the recent IPCC Fifth Assessment Report omit these processes, suggesting either an overestimation in their present-day S T, or an underestimation of S L, of up to 1.0 Pg C a−1. Management processes influencing crop productivity per se are important for food supply, but were found to have little influence on E LUC.

U2 - 10.1088/1748-9326/10/12/124008

DO - 10.1088/1748-9326/10/12/124008

M3 - Journal article

SN - 1748-9326

VL - 10

JO - Environmental Research Letters

JF - Environmental Research Letters

M1 - 124008

ER -