scholarly journals On linking an Earth system model to the equilibrium carbon representation of an economically optimizing land use model

2014 ◽  
Vol 7 (6) ◽  
pp. 2545-2555 ◽  
Author(s):  
B. Bond-Lamberty ◽  
K. Calvin ◽  
A. D. Jones ◽  
J. Mao ◽  
P. Patel ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Carbon Cycle ◽  
Integrated Assessment ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
Earth System ◽  
Climate Effects ◽  
Community Land Model ◽  
Proxy Variables

Abstract. Human activities are significantly altering biogeochemical cycles at the global scale, and the scope of these activities will change with both future climate and socioeconomic decisions. This poses a significant challenge for Earth system models (ESMs), which can incorporate land use change as prescribed inputs but do not actively simulate the policy or economic forces that drive land use change. One option to address this problem is to couple an ESM with an economically oriented integrated assessment model, but this is challenging because of the radically different goals and underpinnings of each type of model. This study describes the development and testing of a coupling between the terrestrial carbon cycle of an ESM (CESM) and an integrated assessment (GCAM) model, focusing on how CESM climate effects on the carbon cycle could be shared with GCAM. We examine the best proxy variables to share between the models, and we quantify how carbon flux changes driven by climate, CO2 fertilization, and land use changes (e.g., deforestation) can be distinguished from each other by GCAM. The net primary production and heterotrophic respiration outputs of the Community Land Model (CLM), the land component of CESM, were found to be the most robust proxy variables by which to recalculate GCAM's assumptions of equilibrium ecosystem steady-state carbon. Carbon cycle effects of land use change are spatially limited relative to climate effects, and thus we were able to distinguish these effects successfully in the model coupling, passing only the latter to GCAM. This paper does not present results of a fully coupled simulation but shows, using a series of offline CLM simulations and an additional idealized Monte Carlo simulation, that our CESM–GCAM proxy variables reflect the phenomena that we intend and do not contain erroneous signals due to land use change. By allowing climate effects from a full ESM to dynamically modulate the economic and policy decisions of an integrated assessment model, this work will help link these models in a robust and flexible framework capable of examining two-way interactions between human and Earth system processes.

scholarly journals Coupling earth system and integrated assessment models: the problem of steady state

2014 ◽  
Vol 7 (1) ◽  
pp. 1499-1524 ◽  
Author(s):  
B. Bond-Lamberty ◽  
K. Calvin ◽  
A. D. Jones ◽  
J. Mao ◽  
P. Patel ◽  
...  
Keyword(s):  
Land Use ◽  
Steady State ◽  
Integrated Assessment ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
System Model ◽  
Earth System ◽  
Short Term ◽  
Proxy Variables

Abstract. Human activities are significantly altering biogeochemical cycles at the global scale, posing a significant problem for earth system models (ESMs), which may incorporate static land-use change inputs but do not actively simulate policy or economic forces. One option to address this problem is to couple an ESM with an economically oriented integrated assessment model. Here we have implemented and tested a coupling mechanism between the carbon cycles of an ESM (CESM, the Community Earth System Model) and an integrated assessment (GCAM) model, examining the best proxy variables to share between the models, and quantifying our ability to distinguish climate- and land-use-driven flux changes. The net primary production and heterotrophic respiration outputs of the Community Land Model (CLM), the land component of CESM, were found to be the most robust proxy variables by which to manipulate GCAM's assumptions of long-term ecosystem steady state carbon, with short-term forest production strongly correlated with long-term biomass changes in climate-change model runs. Carbon-cycle effects of anthropogenic land-use change are short-term and spatially limited relative to widely distributed climate effects, and as a result we were able to distinguish these effects successfully in the model coupling, passing only the latter to GCAM. By allowing climate effects from a full earth system model to dynamically modulate the economic and policy decisions of an integrated assessment model, this work provides a foundation for linking these models in a robust and flexible framework capable of examining two-way interactions between human and earth system processes.

scholarly journals From land use to land cover: restoring the afforestation signal in a coupled integrated assessment–earth system model and the implications for CMIP5 RCP simulations

2014 ◽  
Vol 11 (22) ◽  
pp. 6435-6450 ◽  
Author(s):  
A. V. Di Vittorio ◽  
L. P. Chini ◽  
B. Bond-Lamberty ◽  
J. Mao ◽  
X. Shi ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Integrated Assessment ◽  
Coupled Model ◽  
Assessment Model ◽  
Carbon Gain ◽  
Climate Projections ◽  
Full Potential ◽  
Earth System ◽  
Intergovernmental Panel

Abstract. Climate projections depend on scenarios of fossil fuel emissions and land use change, and the Intergovernmental Panel on Climate Change (IPCC) AR5 parallel process assumes consistent climate scenarios across integrated assessment and earth system models (IAMs and ESMs). The CMIP5 (Coupled Model Intercomparison Project Phase 5) project used a novel "land use harmonization" based on the Global Land use Model (GLM) to provide ESMs with consistent 1500–2100 land use trajectories generated by historical data and four IAMs. A direct coupling of the Global Change Assessment Model (GCAM), GLM, and the Community ESM (CESM) has allowed us to characterize and partially address a major gap in the CMIP5 land coupling design: the lack of a corresponding land cover harmonization. For RCP4.5, CESM global afforestation is only 22% of GCAM's 2005 to 2100 afforestation. Likewise, only 17% of GCAM's 2040 afforestation, and zero pasture loss, were transmitted to CESM within the directly coupled model. This is a problem because GCAM relied on afforestation to achieve RCP4.5 climate stabilization. GLM modifications and sharing forest area between GCAM and GLM within the directly coupled model did not increase CESM afforestation. Modifying the land use translator in addition to GLM, however, enabled CESM to include 66% of GCAM's afforestation in 2040, and 94% of GCAM's pasture loss as grassland and shrubland losses. This additional afforestation increases CESM vegetation carbon gain by 19 PgC and decreases atmospheric CO2 gain by 8 ppmv from 2005 to 2040, which demonstrates that CESM without additional afforestation simulates a different RCP4.5 scenario than prescribed by GCAM. Similar land cover inconsistencies exist in other CMIP5 model results, primarily because land cover information is not shared between models. Further work to harmonize land cover among models will be required to increase fidelity between IAM scenarios and ESM simulations and realize the full potential of scenario-based earth system simulations.

scholarly journals From land use to land cover: restoring the afforestation signal in a coupled integrated assessment – earth system model and the implications for CMIP5 RCP simulations

2014 ◽  
Vol 11 (5) ◽  
pp. 7151-7188 ◽  
Author(s):  
A. V. Di Vittorio ◽  
L. P. Chini ◽  
B. Bond-Lamberty ◽  
J. Mao ◽  
X. Shi ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Integrated Assessment ◽  
Coupled Model ◽  
Forest Growth ◽  
Assessment Model ◽  
Carbon Gain ◽  
Climate Projections ◽  
Earth System ◽  
Climate Scenarios

Abstract. Climate projections depend on scenarios of fossil fuel emissions and land use change, and the IPCC AR5 parallel process assumes consistent climate scenarios across Integrated Assessment and Earth System Models (IAMs and ESMs). The CMIP5 project used a novel "land use harmonization" based on the Global Land use Model (GLM) to provide ESMs with consistent 1500–2100 land use trajectories generated by historical data and four IAM projections. A direct coupling of the Global Change Assessment Model (GCAM), GLM, and the Community ESM (CESM) has allowed us to characterize and partially address a major gap in the CMIP5 land coupling design: the lack of a corresponding land cover harmonization. The CMIP5 CESM global afforestation is only 22% of GCAM's 2005 to 2100 RCP4.5 afforestation. Likewise, only 17% of GCAM's 2040 RCP4.5 afforestation, and zero pasture loss, were transmitted to CESM within the directly coupled model. This is a problem because afforestation was relied upon to achieve RCP4.5 climate stabilization. GLM modifications within the directly coupled model did not increase CESM afforestation. Modifying the land use translator in addition to GLM, however, enabled CESM to simulate 66% of GCAM's afforestation in 2040, and 94% of GCAM's pasture loss as grassland and shrubland losses. This additional afforestation increases vegetation carbon gain by 19 PgC and decreases atmospheric CO2 gain by 8 ppmv from 2005 to 2040, implying different RCP4.5 climate scenarios between CMIP5 GCAM and CESM. Although the IAMs and ESMs were not expected to have exactly the same climate forcing, due in part to different terrestrial carbon cycles and atmospheric radiation algorithms, the ESMs were expected to project climates representative of the RCP scenarios. Similar land cover inconsistencies exist in other CMIP5 model results, primarily because land cover information is not shared between models. High RCP4.5 afforestation might also contribute to inconsistencies as some ESMs might impose bioclimatic limits to potential forest area and have different rates of forest growth than projected by RCP4.5. Further work to harmonize land cover among models will be required to address this problem.

scholarly journals Carbon density and anthropogenic land-use influences on net land-use change emissions

2013 ◽  
Vol 10 (10) ◽  
pp. 6323-6337 ◽  
Author(s):  
S. J. Smith ◽  
A. Rothwell
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Secondary Forest ◽  
Land Use Changes ◽  
Forest Harvesting ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
Carbon Cycle Model ◽  
Land Use Scenario ◽  
The Impact

Abstract. We examine historical and future land-use emissions using a simple mechanistic carbon-cycle model with regional and ecosystem specific parameterizations. We use the latest gridded data for historical and future land-use changes, which includes estimates for the impact of forest harvesting and secondary forest regrowth. Our central estimate of net terrestrial land-use change emissions, exclusive of climate–carbon feedbacks, is 250 GtC over the last 300 yr. This estimate is most sensitive to assumptions for preindustrial forest and soil carbon densities. We also find that land-use change emissions estimates are sensitive to the treatment of crop and pasture lands. These sensitivities also translate into differences in future terrestrial uptake in the RCP (representative concentration pathway) 4.5 land-use scenario. The estimate of future uptake obtained here is smaller than the native values from the GCAM (Global Change Assessment Model) integrated assessment model result due to lower net reforestation in the RCP4.5 gridded land-use data product.

scholarly journals Bioenergy-induced land-use change emissions with sectorally fragmented policies

2021 ◽  
Author(s):  
Leon Merfort ◽  
Nico Bauer ◽  
Florian Humpenöder ◽  
David Klein ◽  
Jessica Strefler ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Co2 Emissions ◽  
Emission Factor ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
Policy Framework ◽  
Energy Unit ◽  
Emission Regulations ◽  
The Impact

Abstract We assess the impact of different land-use emission policies within a broader climate policy framework on bioenergy production and associated land-use carbon emissions. We use the global Integrated Assessment Model REMIND-MAgPIE integrating the energy and land-use sectors and derive alternative climate change mitigation scenarios over the 21st century. If CO2 emissions are regulated consistently across sectors, land-use change emissions of biofuels are limited to 12 kgCO2/GJ. Without land-use emission regulations applied, bioenergy-induced emissions increase substantially and the emission factor per energy unit raises to levels slightly below diesel combustion (64 kg CO2/GJ). Pricing these emissions on the level of bioenergy consumption diminishes bioenergy deployment and the associated CO2 emissions, while failing to reduce the average emission factor. Despite effective reduction of land-use emissions, undifferentiated penalization of bioenergy use substantially increases mitigation costs. If supply side policies comprehensively regulate direct and indirect emissions, bioenergy can be produced much more sustainably.

scholarly journals Carbon density and anthropogenic land use influences on net land-use change emissions

2013 ◽  
Vol 10 (3) ◽  
pp. 4157-4191
Author(s):  
S. J. Smith ◽  
A. Rothwell
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
Climate Feedbacks ◽  
Carbon Density ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
Land Use Scenario ◽  
Anthropogenic Land Use

Abstract. We examine historical and future land-use emissions using a simple mechanistic carbon-cycle model with regional and ecosystem specific parameterizations. Our central estimate of net terrestrial land-use change emissions, exclusive of climate feedbacks, is 250 Gt C over the last three hundred years. This estimate is most sensitive to assumptions for pre-industrial forest and soil carbon densities. We also find that estimates are sensitive to the treatment of crop and pasture lands. These sensitivities also translate into differences in future terrestrial uptake in the RCP4.5 land-use scenario. This estimate of future uptake is lower than the native values from the GCAM integrated assessment model result due to lower net reforestation in the RCP4.5 gridded land-use data product.

scholarly journals Greenhouse Gas Policy Influences Climate via Direct Effects of Land-Use Change

2013 ◽  
Vol 26 (11) ◽  
pp. 3657-3670 ◽  
Author(s):  
Andrew D. Jones ◽  
William D. Collins ◽  
James Edmonds ◽  
Margaret S. Torn ◽  
Anthony Janetos ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Radiative Forcing ◽  
Climate Impacts ◽  
Earth System Model ◽  
Assessment Model ◽  
System Model ◽  
Earth System ◽  
Alternative Scenario

Abstract Proposed climate mitigation measures do not account for direct biophysical climate impacts of land-use change (LUC), nor do the stabilization targets modeled for phase 5 of the Coupled Model Intercomparison Project (CMIP5) representative concentration pathways (RCPs). To examine the significance of such effects on global and regional patterns of climate change, a baseline and an alternative scenario of future anthropogenic activity are simulated within the Integrated Earth System Model, which couples the Global Change Assessment Model, Global Land-Use Model, and Community Earth System Model. The alternative scenario has high biofuel utilization and approximately 50% less global forest cover than the baseline, standard RCP4.5 scenario. Both scenarios stabilize radiative forcing from atmospheric constituents at 4.5 W m−2 by 2100. Thus, differences between their climate predictions quantify the biophysical effects of LUC. Offline radiative transfer and land model simulations are also utilized to identify forcing and feedback mechanisms driving the coupled response. Boreal deforestation is found to strongly influence climate because of increased albedo coupled with a regional-scale water vapor feedback. Globally, the alternative scenario yields a twenty-first-century warming trend that is 0.5°C cooler than baseline, driven by a 1 W m−2 mean decrease in radiative forcing that is distributed unevenly around the globe. Some regions are cooler in the alternative scenario than in 2005. These results demonstrate that neither climate change nor actual radiative forcing is uniquely related to atmospheric forcing targets such as those found in the RCPs but rather depend on particulars of the socioeconomic pathways followed to meet each target.

scholarly journals The potential land requirements and related land use change emissions of solar energy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dirk-Jan van de Ven ◽  
Iñigo Capellan-Peréz ◽  
Iñaki Arto ◽  
Ignacio Cazcarro ◽  
Carlos de Castro ◽  
...  
Keyword(s):  
Land Use ◽  
Solar Energy ◽  
Land Use Change ◽  
Management Practices ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
Electricity Mix ◽  
Novel Method ◽  
Region Scale ◽  
Carbon Losses

AbstractAlthough the transition to renewable energies will intensify the global competition for land, the potential impacts driven by solar energy remain unexplored. In this work, the potential solar land requirements and related land use change emissions are computed for the EU, India, Japan and South Korea. A novel method is developed within an integrated assessment model which links socioeconomic, energy, land and climate systems. At 25–80% penetration in the electricity mix of those regions by 2050, we find that solar energy may occupy 0.5–5% of total land. The resulting land cover changes, including indirect effects, will likely cause a net release of carbon ranging from 0 to 50 gCO2/kWh, depending on the region, scale of expansion, solar technology efficiency and land management practices in solar parks. Hence, a coordinated planning and regulation of new solar energy infrastructures should be enforced to avoid a significant increase in their life cycle emissions through terrestrial carbon losses.

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