scholarly journals The impact of nitrogen and phosphorous limitation on the estimated terrestrial carbon balance and warming of land use change over the last 156 yr

2013 ◽  
Vol 4 (1) ◽  
pp. 507-539 ◽  
Author(s):  
Q. Zhang ◽  
A. J. Pitman ◽  
Y. P. Wang ◽  
Y. Dai ◽  
P. J. Lawrence
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Nutrient Limitation ◽  
Co2 Emissions ◽  
Carbon Sink ◽  
Terrestrial Carbon ◽  
The Past ◽  
The Difference ◽  
Terrestrial Carbon Sink ◽  
The Impact

Abstract. We examine the impact of land use and land cover change (LULCC) over the period from 1850 to 2005 using an Earth System Model that incorporates nitrogen and phosphorous limitation on the terrestrial carbon cycle. We compare the estimated CO2 emissions and warming from land use change in a carbon only version of the model with those from simulations including nitrogen and phosphorous limitation. If we omit nutrients, our results suggest LULCC cools on the global average by about 0.1 °C. Including nutrients reduces this cooling to ~ 0.05 °C. Our results also suggest LULCC has a major impact on total land carbon over the period 1850–2005. In carbon only simulations, the inclusion of LULCC decreases the total additional land carbon stored in 2005 from around 210 Pg C to 85 Pg C. Including nitrogen and phosphorous limitation also decreases the scale of the terrestrial carbon sink to 80 Pg C. In particular, adding LULCC on top of the nutrient limited simulations changes the sign of the terrestrial carbon flux from a sink to a source (12 Pg C). The CO2 emission from LULCC from 1850 to 2005 is estimated to be 130 Pg C for carbon only simulation, or 97 Pg C if nutrient limitation is accounted for in our model. The difference between these two estimates of CO2 emissions from LULCC largely results from the weaker response of photosynthesis to increased CO2 and smaller carbon pool sizes, and therefore lower carbon loss from plant and wood product carbon pools under nutrient limitation. We suggest that nutrient limitation should be accounted in simulating the effects of LULCC on the past climate and on the past and future carbon budget.

scholarly journals The impact of nitrogen and phosphorous limitation on the estimated terrestrial carbon balance and warming of land use change over the last 156 yr

2013 ◽  
Vol 4 (2) ◽  
pp. 333-345 ◽  
Author(s):  
Q. Zhang ◽  
A. J. Pitman ◽  
Y. P. Wang ◽  
Y. J. Dai ◽  
P. J. Lawrence
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Nutrient Limitation ◽  
Co2 Emissions ◽  
Carbon Sink ◽  
Terrestrial Carbon ◽  
The Past ◽  
The Difference ◽  
Terrestrial Carbon Sink ◽  
The Impact

Abstract. We examine the impact of land use and land cover change (LULCC) over the period from 1850 to 2005 using an Earth system model that incorporates nitrogen and phosphorous limitation on the terrestrial carbon cycle. We compare the estimated CO2 emissions and warming from land use change in a carbon-only version of the model with those from simulations, including nitrogen and phosphorous limitation. If we omit nutrients, our results suggest LULCC cools on the global average by about 0.1 °C. Including nutrients reduces this cooling to ~ 0.05 °C. Our results also suggest LULCC has a major impact on total land carbon over the period 1850–2005. In carbon-only simulations, the inclusion of LULCC decreases the total additional land carbon stored in 2005 from around 210 Pg C to 85 Pg C. Including nitrogen and phosphorous limitation also decreases the scale of the terrestrial carbon sink to 80 Pg C. Shown as corresponding fluxes, adding LULCC on top of the nutrient-limited simulations changes the sign of the terrestrial carbon flux from a sink to a source (12 Pg C). The CO2 emission from LULCC from 1850 to 2005 is estimated to be 130 Pg C for carbon only simulation, or 97 Pg C if nutrient limitation is accounted for in our model. The difference between these two estimates of CO2 emissions from LULCC largely results from the weaker response of photosynthesis to increased CO2 and smaller carbon pool sizes, and therefore lower carbon loss from plant and wood product carbon pools under nutrient limitation. We suggest that nutrient limitation should be accounted for in simulating the effects of LULCC on the past climate and on the past and future carbon budget.

scholarly journals Sensitivity of Holocene atmospheric CO<sub>2</sub> and the modern carbon budget to early human land use: analyses with a process-based model

2011 ◽  
Vol 8 (1) ◽  
pp. 69-88 ◽  
Author(s):  
B. D. Stocker ◽  
K. Strassmann ◽  
F. Joos
Keyword(s):  
Land Use ◽  
Late Holocene ◽  
Carbon Sink ◽  
Ice Cores ◽  
Atmospheric Co2 ◽  
Terrestrial Carbon ◽  
Dynamic Global Vegetation Model ◽  
Human Land Use ◽  
Terrestrial Carbon Sink ◽  
The Impact

Abstract. A Dynamic Global Vegetation model coupled to a simplified Earth system model is used to simulate the impact of anthropogenic land cover changes (ALCC) on Holocene atmospheric CO2 and the contemporary carbon cycle. The model results suggest that early agricultural activities cannot explain the mid to late Holocene CO2 rise of 20 ppm measured on ice cores and that proposed upward revisions of Holocene ALCC imply a smaller contemporary terrestrial carbon sink. A set of illustrative scenarios is applied to test the robustness of these conclusions and to address the large discrepancies between published ALCC reconstructions. Simulated changes in atmospheric CO2 due to ALCC are less than 1 ppm before 1000 AD and 30 ppm at 2004 AD when the HYDE 3.1 ALCC reconstruction is prescribed for the past 12 000 years. Cumulative emissions of 69 GtC at 1850 and 233 GtC at 2004 AD are comparable to earlier estimates. CO2 changes due to ALCC exceed the simulated natural interannual variability only after 1000 AD. To consider evidence that land area used per person was higher before than during early industrialisation, agricultural areas from HYDE 3.1 were increased by a factor of two prior to 1700 AD (scenario H2). For the H2 scenario, the contemporary terrestrial carbon sink required to close the atmospheric CO2 budget is reduced by 0.5 GtC yr−1. Simulated CO2 remains small even in scenarios where average land use per person is increased beyond the range of published estimates. Even extreme assumptions for preindustrial land conversion and high per-capita land use do not result in simulated CO2 emissions that are sufficient to explain the magnitude and the timing of the late Holocene CO2 increase.

scholarly journals Sensitivity of Holocene atmospheric CO<sub>2</sub> and the modern carbon budget to early human land use: analyses with a process-based model

2010 ◽  
Vol 7 (1) ◽  
pp. 921-952 ◽  
Author(s):  
B. Stocker ◽  
K. Strassmann ◽  
F. Joos
Keyword(s):  
Land Use ◽  
Late Holocene ◽  
Carbon Sink ◽  
Atmospheric Co2 ◽  
Ice Age ◽  
Terrestrial Carbon ◽  
Dynamic Global Vegetation Model ◽  
Human Land Use ◽  
Terrestrial Carbon Sink ◽  
The Impact

Abstract. A Dynamic Global Vegetation model is used as part of a simplified Earth system model to simulate the impact of human land use on Holocene atmospheric CO2 and the contemporary carbon cycle. We show that suggested upward revisions of Holocene land use reconstructions imply a smaller contemporary terrestrial carbon sink and that early agricultural activities did only marginally contribute to the late Holocene CO2 rise of 20 ppm measured on ice cores. Scenarios are used to test the robustness of the results. Simulated changes in atmospheric CO2 due to land use are less than 1 ppm before 0 AD and 22 ppm by 2004 AD when prescribing the HYDE 3.1 land use reconstruction over the past 12 000 years. Cumulative emissions are with 50 GtC by 1850 and 177 GtC by 2004 AD comparable to earlier estimates. In scenario H2, agricultural area from HYDE 3.1 is scaled by a factor of two before 1700 AD, thereby taking into account evidence that land area used per person was higher before than during early industrialisation. Then, the contemporary terrestrial carbon sink, required to close the atmospheric CO2 budget, is reduced by 0.5 GtC yr−1. CO2 changes due to land use change exceed natural interannual variability only after 1000 AD and are less than 4 ppmv until 1850 AD. Simulated CO2 change remains small even in scenarios where average land use per person is unrealistically increased by a factor of 4 to 8 above published estimates. Our results falsify the hypothesis that humans are responsible for the late Holocene CO2 increase and that anthropogenic land use prevented a new ice age.

scholarly journals Role of forest regrowth in global carbon sink dynamics

2019 ◽  
Vol 116 (10) ◽  
pp. 4382-4387 ◽  
Author(s):  
Thomas A. M. Pugh ◽  
Mats Lindeskog ◽  
Benjamin Smith ◽  
Benjamin Poulter ◽  
Almut Arneth ◽  
...  
Keyword(s):  
Land Use ◽  
Carbon Sink ◽  
Natural Disturbances ◽  
Terrestrial Carbon ◽  
Terrestrial Biosphere ◽  
Old Growth ◽  
Old Growth Forest ◽  
Forest Regrowth ◽  
Terrestrial Carbon Sink ◽  
Forest Demography

Although the existence of a large carbon sink in terrestrial ecosystems is well-established, the drivers of this sink remain uncertain. It has been suggested that perturbations to forest demography caused by past land-use change, management, and natural disturbances may be causing a large component of current carbon uptake. Here we use a global compilation of forest age observations, combined with a terrestrial biosphere model with explicit modeling of forest regrowth, to partition the global forest carbon sink between old-growth and regrowth stands over the period 1981–2010. For 2001–2010 we find a carbon sink of 0.85 (0.66–0.96) Pg year−1located in intact old-growth forest, primarily in the moist tropics and boreal Siberia, and 1.30 (1.03–1.96) Pg year−1located in stands regrowing after past disturbance. Approaching half of the sink in regrowth stands would have occurred from demographic changes alone, in the absence of other environmental changes. These age-constrained results show consistency with those simulated using an ensemble of demographically-enabled terrestrial biosphere models following an independent reconstruction of historical land use and management. We estimate that forests will accumulate an additional 69 (44–131) Pg C in live biomass from changes in demography alone if natural disturbances, wood harvest, and reforestation continue at rates comparable to those during 1981–2010. Our results confirm that it is not possible to understand the current global terrestrial carbon sink without accounting for the sizeable sink due to forest demography. They also imply that a large portion of the current terrestrial carbon sink is strictly transient in nature.

scholarly journals Biological control of the terrestrial carbon sink

2005 ◽  
Vol 2 (5) ◽  
pp. 1283-1329 ◽  
Author(s):  
E.-D. Schulze
Keyword(s):  
Biological Control ◽  
Carbon Sink ◽  
Carbon Fluxes ◽  
Biogeochemical Processes ◽  
Terrestrial Carbon ◽  
The Past ◽  
The Future ◽  
Terrestrial Carbon Sink ◽  
Biological Program ◽  
International Biological

Abstract. This is a summary of the Vernadsky medal lecture given at the Nice EGU meeting in 2004. The lecture reviews the past (since the International Biological Program) and the future of our understanding of terrestrial carbon fluxes with focus on photosynthesis, respiration, primary, ecosystem, and biome productivity. Consideration is given to the interactions between biodiversity and biogeochemical processes.

scholarly journals Erosion, deposition and replacement of soil organic carbon in Mediterranean catchments: a geomorphological, isotopic and land use change approach

2012 ◽  
Vol 9 (3) ◽  
pp. 1099-1111 ◽  
Author(s):  
E. Nadeu ◽  
A. A. Berhe ◽  
J. de Vente ◽  
C. Boix-Fayos
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Land Use Change ◽  
Soil Organic Carbon ◽  
Carbon Sink ◽  
Terrestrial Carbon ◽  
Change Analysis ◽  
Deep Soil ◽  
Erosion Processes ◽  
Carbon Dioxide Co2

Abstract. Determination of whether soil erosion can constitute a net terrestrial carbon dioxide (CO2) sink continues to suffer from lack of sufficient focused studies and field data. Two of the major gaps in our understanding of the erosion induced terrestrial carbon sink issue include rate of eroded soil organic carbon replacement by production of new photosynthate and stability of eroded organic carbon (OC) post deposition. Here we examined the effect of erosion processes and land use change on the stock, type, and stability of OC in two medium-sized subcatchments (18 and 50 ha in size) in SE Spain. We analysed soil samples from drainage areas and depositional settings for stock and isotopic composition of OC (14C and 13C), and particle size distribution. In addition, we conducted land use change analysis for the period 1956–2008 and a geomorphological survey of the current erosion processes taking place in the slope-streambed connections. Our findings demonstrate that land use change influenced the dominating erosion processes and, thus, the source of eroding sediments. Carbon isotopes used as tracers revealed that in one of the subcatchments the deposited sediments were derived from deep soil (average Δ14C of −271.5 ‰) through non-selective erosion processes and channel incision. In the other subcatchment, topsoil material was predominantly eroded and the average Δ14C in sediments was −64.2 ‰. Replacement of eroded soil OC was taking place in the analysed soil profiles in the slopes suggesting that erosion processes do not necessarily provoke a decrease in soil OC stock over time.

scholarly journals Terrestrial carbon sink observed from space: variation of growth rates and seasonal cycle amplitudes in response to interannual surface temperature variability

2014 ◽  
Vol 14 (1) ◽  
pp. 133-141 ◽  
Author(s):  
O. Schneising ◽  
M. Reuter ◽  
M. Buchwitz ◽  
J. Heymann ◽  
H. Bovensmann ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Growth Rates ◽  
Seasonal Cycle ◽  
Temperature Anomaly ◽  
Carbon Sink ◽  
Atmospheric Co2 ◽  
Climate Feedback ◽  
Terrestrial Carbon ◽  
Terrestrial Carbon Sink ◽  
The Impact

Abstract. The terrestrial biosphere is currently acting as a net carbon sink on the global scale, exhibiting significant interannual variability in strength. To reliably predict the future strength of the land sink and its role in atmospheric CO2 growth, the underlying biogeochemical processes and their response to a changing climate need to be well understood. In particular, better knowledge of the impact of key climate variables such as temperature or precipitation on the biospheric carbon reservoir is essential. It is demonstrated using nearly a decade of SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) nadir measurements that years with higher temperatures during the growing season can be robustly associated with larger growth rates in atmospheric CO2 and smaller seasonal cycle amplitudes for northern mid-latitudes. We find linear relationships between warming and CO2 growth as well as seasonal cycle amplitude at the 98% significance level. This suggests that the terrestrial carbon sink is less efficient at higher temperatures during the analysed time period. Unless the biosphere has the ability to adapt its carbon storage under warming conditions in the longer term, such a temperature response entails the risk of potential future sink saturation via a positive carbon-climate feedback. Quantitatively, the covariation between the annual CO2 growth rates derived from SCIAMACHY data and warm season surface temperature anomaly amounts to 1.25 ± 0.32 ppm yr−1 K−1 for the Northern Hemisphere, where the bulk of the terrestrial carbon sink is located. In comparison, this relationship is less pronounced in the Southern Hemisphere. The covariation of the seasonal cycle amplitudes retrieved from satellite measurements and temperature anomaly is −1.30 ± 0.31 ppm K−1 for the north temperate zone. These estimates are consistent with those from the CarbonTracker data assimilated CO2 data product, indicating that the temperature dependence of the model surface fluxes is realistic.

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 Erosion, deposition and replacement of soil organic carbon in Mediterranean catchments: a geomorphological, isotopic and land use change approach

2011 ◽  
Vol 8 (4) ◽  
pp. 8351-8382 ◽  
Author(s):  
E. Nadeu ◽  
A. A. Berhe ◽  
J. de Vente ◽  
C. Boix-Fayos
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Land Use Change ◽  
Soil Organic Carbon ◽  
Carbon Sink ◽  
Change Analysis ◽  
Deep Soil ◽  
Erosion Processes ◽  
Depositional Settings ◽  
Terrestrial Carbon Sink

Abstract. The assessment of the net effect of soil erosion on the global carbon budget is still incomplete because of lack of enough focused studies and field data. Two of the major gaps on our understanding of the erosion induced terrestrial carbon sink issue include rate of eroded soil organic carbon (OC) replacement by production of new photosynthate and stability of eroded OC post deposition. Here we examine the effect of erosion processes and land use change on the stock, type and stability of OC in two medium-sized subcatchments (18 and 50 ha in size) in SE Spain. We analysed soil samples from drainage areas and depositional settings for stock and isotopic composition of OC (14C and 13C) and particle size distribution. In addition, we conducted land use change analysis for the period 1956–2008 and a geomorphological survey of the current erosion processes taking place in the slope-streambed connections. Our findings demonstrate how land use change influenced the dominating erosion processes and, thus, the source of eroding sediments. Carbon isotopes used as tracers revealed that in one of the subcatchments the deposited sediments derived from deep soil (average Δ14C of −271.5 ‰) through non-selective erosion processes. In the other subcatchment, topsoil material was predominantly eroded and the average Δ14C in sediments was −64.2 ‰. Replacement of eroded soil OC was positive (4 and 11 times-fold losses by erosion) for the analyzed soil profiles in the slopes suggesting that erosion processes do not necessarily provoke a decrease in soil OC stock.

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