scholarly journals Carbon emissions from land use and land-cover change

2012 ◽  
Vol 9 (12) ◽  
pp. 5125-5142 ◽  
Author(s):  
R. A. Houghton ◽  
J. I. House ◽  
J. Pongratz ◽  
G. R. van der Werf ◽  
R. S. DeFries ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
Carbon Emissions ◽  
Data Uncertainty ◽  
Tropical Peatlands ◽  
Net Flux ◽  
The Mean ◽  
Standard Deviations ◽  
Wood Harvest

Abstract. The net flux of carbon from land use and land-cover change (LULCC) accounted for 12.5% of anthropogenic carbon emissions from 1990 to 2010. This net flux is the most uncertain term in the global carbon budget, not only because of uncertainties in rates of deforestation and forestation, but also because of uncertainties in the carbon density of the lands actually undergoing change. Furthermore, there are differences in approaches used to determine the flux that introduce variability into estimates in ways that are difficult to evaluate, and not all analyses consider the same types of management activities. Thirteen recent estimates of net carbon emissions from LULCC are summarized here. In addition to deforestation, all analyses considered changes in the area of agricultural lands (croplands and pastures). Some considered, also, forest management (wood harvest, shifting cultivation). None included emissions from the degradation of tropical peatlands. Means and standard deviations across the thirteen model estimates of annual emissions for the 1980s and 1990s, respectively, are 1.14 ± 0.23 and 1.12 ± 0.25 Pg C yr−1 (1 Pg = 1015 g carbon). Four studies also considered the period 2000–2009, and the mean and standard deviations across these four for the three decades are 1.14 ± 0.39, 1.17 ± 0.32, and 1.10 ± 0.11 Pg C yr−1. For the period 1990–2009 the mean global emissions from LULCC are 1.14 ± 0.18 Pg C yr−1. The standard deviations across model means shown here are smaller than previous estimates of uncertainty as they do not account for the errors that result from data uncertainty and from an incomplete understanding of all the processes affecting the net flux of carbon from LULCC. Although these errors have not been systematically evaluated, based on partial analyses available in the literature and expert opinion, they are estimated to be on the order of ± 0.5 Pg C yr−1.

scholarly journals Chapter G2 Carbon emissions from land use and land-cover change

2012 ◽  
Vol 9 (1) ◽  
pp. 835-878 ◽  
Author(s):  
R. A. Houghton ◽  
G. R. van der Werf ◽  
R. S. DeFries ◽  
M. C. Hansen ◽  
J. I. House ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
Carbon Emissions ◽  
Data Uncertainty ◽  
Tropical Peatlands ◽  
Net Flux ◽  
The Mean ◽  
Standard Deviations ◽  
Wood Harvest

Abstract. The net flux of carbon from land use and land-cover change (LULCC) is significant in the global carbon budget but uncertain, not only because of uncertainties in rates of deforestation and forestation, but also because of uncertainties in the carbon density of the lands actually undergoing change. Furthermore, there are differences in approaches used to determine the flux that introduce variability into estimates in ways that are difficult to evaluate, and there are forms of management not considered in many of the analyses. Thirteen recent estimates of net carbon emissions from LULCC are summarized here. All analyses consider changes in the area of agricultural lands (croplands and pastures). Some consider, also, forest management (wood harvest, shifting cultivation). None of them includes the emissions from the degradation of tropical peatlands. The net flux of carbon from LULCC is not the same as "emissions from deforestation", although the terms are used interchangeably in the literature. Means and standard deviations for annual emissions are 1.14 ± 0.23 and 1.13 ± 0.23 Pg C yr−1 (1 Pg = 1015 g carbon) for the 1980s and 1990s, respectively. Four studies also consider the period 2000–2009, and the mean and standard deviations for these four are 1.14 ± 0.39, 1.17 ± 0.32, and 1.10 ± 0.11 Pg C yr−1 for the three decades. For the period 1990–2009 the mean global emissions from LULCC are 1.14 ± 0.18 Pg C yr−1. The errors are smaller than previously estimated, as they do not represent the range of error around each result, but rather the standard deviation across the mean of the 13 estimates. Errors that result from data uncertainty and an incomplete understanding of all the processes affecting the net flux of carbon from LULCC have not been systematically evaluated but are likely to be on the order of ±0.5 Pg C yr−1.

scholarly journals Global rules for translating land-use change (LUH2) to land-cover change for CMIP6 using GLM2

2020 ◽  
Vol 13 (7) ◽  
pp. 3203-3220 ◽  
Author(s):  
Lei Ma ◽  
George C. Hurtt ◽  
Louise P. Chini ◽  
Ritvik Sahajpal ◽  
Julia Pongratz ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Land Use Change ◽  
Land Cover ◽  
Land Cover Change ◽  
Carbon Emissions ◽  
Forest Cover ◽  
Land Use Changes ◽  
Change Models ◽  
Translation Rule

Abstract. Anthropogenic land-use and land-cover change activities play a critical role in Earth system dynamics through significant alterations to biogeophysical and biogeochemical properties at local to global scales. To quantify the magnitude of these impacts, climate models need consistent land-cover change time series at a global scale, based on land-use information from observations or dedicated land-use change models. However, a specific land-use change cannot be unambiguously mapped to a specific land-cover change. Here, nine translation rules are evaluated based on assumptions about the way land-use change could potentially impact land cover. Utilizing the Global Land-use Model 2 (GLM2), the model underlying the latest Land-Use Harmonization dataset (LUH2), the land-cover dynamics resulting from land-use change were simulated based on multiple alternative translation rules from 850 to 2015 globally. For each rule, the resulting forest cover, carbon density and carbon emissions were compared with independent estimates from remote sensing observations, U.N. Food and Agricultural Organization reports, and other studies. The translation rule previously suggested by the authors of the HYDE 3.2 dataset, that underlies LUH2, is consistent with the results of our examinations at global, country and grid scales. This rule recommends that for CMIP6 simulations, models should (1) completely clear vegetation in land-use changes from primary and secondary land (including both forested and non-forested) to cropland, urban land and managed pasture; (2) completely clear vegetation in land-use changes from primary forest and/or secondary forest to rangeland; (3) keep vegetation in land-use changes from primary non-forest and/or secondary non-forest to rangeland. Our analysis shows that this rule is one of three (out of nine) rules that produce comparable estimates of forest cover, vegetation carbon and emissions to independent estimates and also mitigate the anomalously high carbon emissions from land-use change observed in previous studies in the 1950s. According to the three translation rules, contemporary global forest area is estimated to be 37.42×106 km2, within the range derived from remote sensing products. Likewise, the estimated carbon stock is in close agreement with reference biomass datasets, particularly over regions with more than 50 % forest cover.

scholarly journals Holocene carbon emissions as a result of anthropogenic land cover change

The Holocene ◽  
2010 ◽  
Vol 21 (5) ◽  
pp. 775-791 ◽  
Author(s):  
Jed O. Kaplan ◽  
Kristen M. Krumhardt ◽  
Erle C. Ellis ◽  
William F. Ruddiman ◽  
Carsten Lemmen ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
Carbon Emissions ◽  
Land Surface ◽  
Simple Relationship ◽  
Data Set ◽  
Dynamic Global Vegetation Model ◽  
The Holocene ◽  
The World

Humans have altered the Earth’s land surface since the Paleolithic mainly by clearing woody vegetation first to improve hunting and gathering opportunities, and later to provide agricultural cropland. In the Holocene, agriculture was established on nearly all continents and led to widespread modification of terrestrial ecosystems. To quantify the role that humans played in the global carbon cycle over the Holocene, we developed a new, annually resolved inventory of anthropogenic land cover change from 8000 years ago to the beginning of large-scale industrialization (ad 1850). This inventory is based on a simple relationship between population and land use observed in several European countries over preindustrial time. Using this data set, and an alternative scenario based on the HYDE 3.1 land use data base, we forced the LPJ dynamic global vegetation model in a series of continuous simulations to evaluate the impacts of humans on terrestrial carbon storage during the preindustrial Holocene. Our model setup allowed us to quantify the importance of land degradation caused by repeated episodes of land use followed by abandonment. By 3 ka BP, cumulative carbon emissions caused by anthropogenic land cover change in our new scenario ranged between 84 and 102 Pg, translating to c. 7 ppm of atmospheric CO2. By ad 1850, emissions were 325–357 Pg in the new scenario, in contrast to 137–189 Pg when driven by HYDE. Regional events that resulted in local emissions or uptake of carbon were often balanced by contrasting patterns in other parts of the world. While we cannot close the carbon budget in the current study, simulated cumulative anthropogenic emissions over the preindustrial Holocene are consistent with the ice core record of atmospheric δ13CO2 and support the hypothesis that anthropogenic activities led to the stabilization of atmospheric CO2 concentrations at a level that made the world substantially warmer than it otherwise would be.

scholarly journals Impacts of Land Use and Land Cover Change on Soil Erosion and Hydrological Responses in Ethiopia

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ajanaw Negese
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Land Cover ◽  
Land Cover Change ◽  
Future Research ◽  
Cultivated Land ◽  
Hydrological Responses ◽  
Semiarid Areas ◽  
Arid And Semiarid Areas ◽  
The Mean

Land use and land cover (LULC) dynamics, in general, and the conversion of the natural vegetation cover into cultivated land, in particular, are major human-induced problems in Ethiopia, which have played a significant role in increasing the rate of soil erosion and altering the hydrological balance in the country. The main aim of this review was to view previous studies in Ethiopia that quantify the change in the rate of soil erosion and hydrological responses as a result of the change in land use and land cover in the country. From the past researches reviewed in this paper, the expansion of cultivated land at the expense of forest land, shrubland, and grassland in Ethiopia has increased the mean rate of soil erosion, sediment yield, surface runoff, mean wet monthly flow, and mean annual stream flow in the last four decades. On the other hand, the change has reduced the dry average monthly flow, groundwater recharge and groundwater flow, and evapotranspiration (ET) in the country. Future research works should pay more attention to the investigation of the impacts of land use and land cover change on groundwater hydrology and the prediction of future soil loss and hydrological imbalance under the changing land use and land cover in the country since little information is available from past researches on these issues. Research works are also required in lowland arid and semiarid areas in Ethiopia to effectively manage soil and water resources in all parts of the country.

Carbon emissions induced by land-use and land-cover change from 1970 to 2010 in Zhejiang, China

2019 ◽  
Vol 646 ◽  
pp. 930-939 ◽  
Author(s):  
Enyan Zhu ◽  
Jingsong Deng ◽  
Mengmeng Zhou ◽  
Muye Gan ◽  
Ruowei Jiang ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
Carbon Emissions
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