scholarly journals Comparison of uncertainties in land-use change fluxes from bookkeeping model parameterization

2021 ◽  
Author(s):  
Ana Bastos ◽  
Kerstin Hartung ◽  
Tobias B. Nützel ◽  
Julia E. M. S. Nabel ◽  
Richard A. Houghton ◽  
...  
Keyword(s):  
Land Use ◽  
Carbon Budget ◽  
Management Practices ◽  
Multiple Sources ◽  
Global Carbon Budget ◽  
Model Parameterization ◽  
Natural Land ◽  
Spatio Temporal ◽  
Land Use And Management ◽  
Carbon Losses

Abstract. Fluxes from deforestation, changes in land-cover, land-use and management practices (FLUC for simplicity) contributed to circa 14 % of anthropogenic CO2 emissions in 2009–2018. Estimating FLUC accurately in space and in time remains, however, challenging, due to multiple sources of uncertainty in the calculation of these fluxes. This uncertainty, in turn, is propagated to global and regional carbon budget estimates, hindering the compilation of a consistent carbon budget and preventing us from constraining other terms, such as the natural land sink. Uncertainties in FLUC estimates arise from many different sources, including differences in model structure (e.g., process- based vs. bookkeeping) and model parameterization. Quantifying the uncertainties from each source requires controlled simulations to separate their effects. Here we analyze differences between the two bookkeeping models used regularly in the global carbon budget estimates since 2017: the model by Hansis et al. (Hansis et al., 2015) (BLUE) and that by Houghton and Nassikas (Houghton and Nassikas, 2017) (HN2017). The two models have a very similar structure and philosophy, but differ significantly both with respect to FLUC intensity and spatio-temporal variability. This is due to differences in the land-use forcing, but also in the model parameterization. We find that the larger emissions in BLUE compared to HN2017 are largely due to differences in C densities between natural and managed vegetation or primary and secondary vegetation, and higher allocation of cleared and harvested material to fast turnover pools in BLUE than in HN2017. Beside parameterization and the use of different forcing, other model assumptions cause differences, in particular that BLUE represents gross transitions which leads to overall higher carbon losses that are also more quickly realized than HN2017.

scholarly journals Comparison of uncertainties in land-use change fluxes from bookkeeping model parameterisation

2021 ◽  
Vol 12 (2) ◽  
pp. 745-762
Author(s):  
Ana Bastos ◽  
Kerstin Hartung ◽  
Tobias B. Nützel ◽  
Julia E. M. S. Nabel ◽  
Richard A. Houghton ◽  
...  
Keyword(s):  
Land Use ◽  
Carbon Budget ◽  
Management Practices ◽  
Spatiotemporal Variability ◽  
Multiple Sources ◽  
Global Carbon Budget ◽  
Natural Land ◽  
Land Use And Management ◽  
Carbon Losses ◽  
Different Sources

Abstract. Fluxes from deforestation, changes in land cover, land use and management practices (FLUC for simplicity) contributed to approximately 14 % of anthropogenic CO2 emissions in 2009–2018. Estimating FLUC accurately in space and in time remains, however, challenging, due to multiple sources of uncertainty in the calculation of these fluxes. This uncertainty, in turn, is propagated to global and regional carbon budget estimates, hindering the compilation of a consistent carbon budget and preventing us from constraining other terms, such as the natural land sink. Uncertainties in FLUC estimates arise from many different sources, including differences in model structure (e.g. process based vs. bookkeeping) and model parameterisation. Quantifying the uncertainties from each source requires controlled simulations to separate their effects. Here, we analyse differences between the two bookkeeping models used regularly in the global carbon budget estimates since 2017: the model by Hansis et al. (2015) (BLUE) and that by Houghton and Nassikas (2017) (HN2017). The two models have a very similar structure and philosophy, but differ significantly both with respect to FLUC intensity and spatiotemporal variability. This is due to differences in the land-use forcing but also in the model parameterisation. We find that the larger emissions in BLUE compared to HN2017 are largely due to differences in C densities between natural and managed vegetation or primary and secondary vegetation, and higher allocation of cleared and harvested material to fast turnover pools in BLUE than in HN2017. Besides parameterisation and the use of different forcing, other model assumptions cause differences: in particular that BLUE represents gross transitions which leads to overall higher carbon losses that are also more quickly realised than HN2017.

scholarly journals Food security among dryland pastoralists and agropastoralists: The climate, land-use change, and population dynamics nexus

2021 ◽  
pp. 205301962110075
Author(s):  
Ilan Stavi ◽  
Joana Roque de Pinho ◽  
Anastasia K Paschalidou ◽  
Susana B Adamo ◽  
Kathleen Galvin ◽  
...  
Keyword(s):  
Land Use ◽  
Food Security ◽  
Management Practices ◽  
Relevant Literature ◽  
Global Changes ◽  
Food Utilization ◽  
Special Importance ◽  
Food Security Status ◽  
Global Action ◽  
Land Use And Management

During the last decades, pastoralist, and agropastoralist populations of the world’s drylands have become exceedingly vulnerable to regional and global changes. Specifically, exacerbated stressors imposed on these populations have adversely affected their food security status, causing humanitarian emergencies and catastrophes. Of these stressors, climate variability and change, land-use and management practices, and dynamics of human demography are of a special importance. These factors affect all four pillars of food security, namely, food availability, access to food, food utilization, and food stability. The objective of this study was to critically review relevant literature to assess the complex web of interrelations and feedbacks that affect these factors. The increasing pressures on the world’s drylands necessitate a comprehensive analysis to advise policy makers regarding the complexity and linkages among factors, and to improve global action. The acquired insights may be the basis for alleviating food insecurity of vulnerable dryland populations.

scholarly journals Exploring the variability of soil nutrient outflows as influenced by land use and management practices in contrasting agro-ecological environments

2021 ◽  
pp. 147450
Author(s):  
Temesgen Mulualem ◽  
Enyew Adgo ◽  
Derege Tsegaye Meshesha ◽  
Atsushi Tsunekawa ◽  
Nigussie Haregeweyn ◽  
...  
Keyword(s):  
Land Use ◽  
Management Practices ◽  
Soil Nutrient ◽  
Land Use And Management

scholarly journals Then and Now: Understanding Change on an Agricultural Landscape

2021 ◽  
Author(s):  
Alexander Pardy
Keyword(s):  
Land Use ◽  
Great Lakes ◽  
Management Practices ◽  
Agricultural Landscape ◽  
Agricultural Land ◽  
Reference Group ◽  
Surface Water Quality ◽  
Laurentian Great Lakes ◽  
Phosphorus Pollution ◽  
Land Use And Management

Freshwater eutrophication typically driven by non-point source phosphorus pollution is one of the worlds’ most prevalent and vexing environmental problems with the Laurentian Great Lakes on the Canada – United States border. During 1975 – 1977, the Pollution from Land Use Activities Reference Group examined eleven agricultural watersheds in order to investigate the impacts of land use activities on surface water quality. This study examined how agricultural land use and management has transformed in two watersheds, Nissouri Creek and Big Creek. The goal of this study was to quantify the phosphorus mass balance change within the watersheds. During 2015 – 2019 land use and management practices survey data was collected. Results of this study showed Nissouri Creek is now depleting -2.19 kilograms of phosphorus per hectare of agricultural land, while Big Creek is still accumulating 4.77 kilograms of phosphorus per hectare of agricultural land. This study can guide efforts to limit the long-term losses of phosphorus in the Laurentian Great Lakes and elsewhere.

scholarly journals Baseline-Dependent Responses of Soil Organic Carbon Dynamics to Climate and Land Disturbances

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Zhengxi Tan ◽  
Shuguang Liu
Keyword(s):  
Land Use ◽  
Land Surface ◽  
Management Practices ◽  
C Sequestration ◽  
The United States ◽  
Natural Ecosystems ◽  
Organic C ◽  
Realistic Option ◽  
Managed Ecosystems ◽  
Land Use And Management

Terrestrial carbon (C) sequestration through optimizing land use and management is widely considered a realistic option to mitigate the global greenhouse effect. But how the responses of individual ecosystems to changes in land use and management are related to baseline soil organic C (SOC) levels still needs to be evaluated at various scales. In this study, we modeled SOC dynamics within both natural and managed ecosystems in North Dakota of the United States and found that the average SOC stock in the top 20 cm depth of soil lost at a rate of 450 kg C ha−1 yr−1in cropland and 110 kg C ha−1 yr−1in grassland between 1971 and 1998. Since 1998, the study area had become a SOC sink at a rate of 44 kg C ha−1 yr−1. The annual rate of SOC change in all types of lands substantially depends on the magnitude of initial SOC contents, but such dependency varies more with climatic variables within natural ecosystems and with management practices within managed ecosystems. Additionally, soils with high baseline SOC stocks tend to be C sources following any land surface disturbances, whereas soils having low baseline C contents likely become C sinks following conservation management.

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