Causes of uncertainty in China's net primary production over the 21st century projected by the CMIP5 Earth system models

2015 ◽  
Vol 36 (5) ◽  
pp. 2323-2334 ◽  
Author(s):  
Tao Wang ◽  
Xin Lin ◽  
Yongwen Liu ◽  
Sarah Dantec-Nédélec ◽  
Catherine Ottlé
Keyword(s):  
Primary Production ◽  
21St Century ◽  
Net Primary Production ◽  
Earth System ◽  
System Models ◽  
Earth System Models

scholarly journals Continued increase in atmospheric CO<sub>2</sub> seasonal amplitude in the 21st century projected by the CMIP5 Earth System Models

2014 ◽  
Vol 5 (1) ◽  
pp. 779-807 ◽  
Author(s):  
F. Zhao ◽  
N. Zeng
Keyword(s):  
Primary Production ◽  
21St Century ◽  
Seasonal Cycle ◽  
Net Primary Production ◽  
Co2 Concentration ◽  
Carbon Uptake ◽  
Earth System ◽  
System Models ◽  
Amplitude Increase ◽  
Earth System Models

Abstract. Superimposed on the continued increase in the atmospheric CO2 concentration is a prominent seasonal cycle. Ground-based and aircraft-based observation records show that the amplitude of this seasonal cycle has increased. Will this trend continue into future? In this paper, we analyzed simulations for historical (1850–2005) and future (RCP8.5, 2006–2100) periods produced by 10 Earth System Models participating the Fifth Phase of the Coupled Model Intercomparison Project (CMIP5). Our results show a model consensus that the increase of CO2 seasonal amplitude continues throughout the 21st century. The seasonal amplitude of the multi-model global mean detrended CO2 increases from 1.6 ppm during 1961–1970 to 2.7 ppm during 2081–2090, and the mean relative amplitude increases by 62 ± 19%. This increase is dominated by a 68 ± 25% increase from Net Biosphere Production (NBP). We then show the increase of NBP amplitude mainly comes from enhanced ecosystem uptake during Northern Hemisphere growing season under future CO2 and temperature conditions. Separate analyses on net primary production and respiration reveal that enhanced ecosystem carbon uptake contributes to about 75% of the amplitude increase. Stimulated by higher CO2 concentration and high-latitude warming, enhanced net primary production likely outcompetes increased respiration at higher temperature. Zonal distribution and the spatial pattern of NBP change suggest that regions north of 45° N dominate the amplitude increase. We also found that changes of NBP and its seasonal amplitude are significantly (R = 0.73, p < 0.05) correlated – models that simulate a stronger carbon uptake tend to show a larger change of NBP seasonal amplitude.

scholarly journals Evaluating the ocean biogeochemical components of Earth system models using atmospheric potential oxygen and ocean color data

2015 ◽  
Vol 12 (1) ◽  
pp. 193-208 ◽  
Author(s):  
C. D. Nevison ◽  
M. Manizza ◽  
R. F. Keeling ◽  
M. Kahru ◽  
L. Bopp ◽  
...  
Keyword(s):  
Net Primary Production ◽  
Ocean Color ◽  
Seasonal Cycles ◽  
Geophysical Fluid Dynamics Laboratory ◽  
Earth System ◽  
System Models ◽  
Color Data ◽  
Ocean Biogeochemistry ◽  
Earth System Models ◽  
Potential Oxygen

Abstract. The observed seasonal cycles in atmospheric potential oxygen (APO) at a range of mid- to high-latitude surface monitoring sites are compared to those inferred from the output of six Earth system models (ESMs) participating in the fifth phase of the Coupled Model Intercomparison Project phase 5 (CMIP5). The simulated air–sea O2 fluxes are translated into APO seasonal cycles using a matrix method that takes into account atmospheric transport model (ATM) uncertainty among 13 different ATMs. Three of the ocean biogeochemistry models tested are able to reproduce the observed APO cycles at most sites, to within the large TransCom3-era ATM uncertainty used here, while the other three generally are not. Net primary production (NPP) and net community production (NCP), as estimated from satellite ocean color data, provide additional constraints, albeit more with respect to the seasonal phasing of ocean model productivity than overall magnitude. The present analysis suggests that, of the tested ocean biogeochemistry models, the community ecosystem model (CESM) and the Geophysical Fluid Dynamics Laboratory (GFDL) ESM2M are best able to capture the observed APO seasonal cycle at both northern and southern hemispheric sites. In most models, discrepancies with observed APO can be attributed to the underestimation of NPP, deep ventilation or both in the northern oceans.

scholarly journals Changes in interannual climate sensitivities of terrestrial carbon fluxes during the 21st century predicted by CMIP5 Earth System Models

2016 ◽  
Vol 121 (3) ◽  
pp. 903-918 ◽  
Author(s):  
Yongwen Liu ◽  
Tao Wang ◽  
Mengtian Huang ◽  
Yitong Yao ◽  
Philippe Ciais ◽  
...  
Keyword(s):  
21St Century ◽  
Carbon Fluxes ◽  
Earth System ◽  
Terrestrial Carbon ◽  
System Models ◽  
Earth System Models

scholarly journals Oceanic primary production decline halved in eddy-resolving simulations of global warming

2021 ◽  
Vol 18 (14) ◽  
pp. 4321-4349
Author(s):  
Damien Couespel ◽  
Marina Lévy ◽  
Laurent Bopp
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Primary Production ◽  
Nutrient Transport ◽  
Biogeochemical Model ◽  
Earth System ◽  
System Models ◽  
Marine Biomass ◽  
Fish Catch ◽  
Earth System Models

Abstract. The decline in ocean primary production is one of the most alarming consequences of anthropogenic climate change. This decline could indeed lead to a decrease in marine biomass and fish catch, as highlighted by recent policy-relevant reports. Because of computational constraints, current Earth system models used to project ocean primary production under global warming scenarios have to parameterize flows occurring below the resolution of their computational grid (typically 1∘). To overcome these computational constraints, we use an ocean biogeochemical model in an idealized configuration representing a mid-latitude double-gyre circulation and perform global warming simulations under an increasing horizontal resolution (from 1 to 1/27∘) and under a large range of parameter values for the eddy parameterization employed in the coarse-resolution configuration. In line with projections from Earth system models, all our simulations project a marked decline in net primary production in response to the global warming forcing. Whereas this decline is only weakly sensitive to the eddy parameters in the eddy-parameterized coarse 1∘ resolution simulations, the simulated decline in primary production in the subpolar gyre is halved at the finest eddy-resolving resolution (−12 % at 1/27∘ vs. −26 % at 1∘) at the end of the 70-year-long global warming simulations. This difference stems from the high sensitivity of the sub-surface nutrient transport to model resolution. Although being only one piece of a much broader and more complicated response of the ocean to climate change, our results call for improved representation of the role of eddies in nutrient transport below the seasonal mixed layer to better constrain the future evolution of marine biomass and fish catch potential.

scholarly journals Oceanic Primary production decline halved in eddy-resolving simulations of global warming

2021 ◽  
Author(s):  
Damien Couespel ◽  
Marina Lévy ◽  
Laurent Bopp
Keyword(s):  
Global Warming ◽  
Primary Production ◽  
Nutrient Transport ◽  
Biogeochemical Model ◽  
Earth System ◽  
System Models ◽  
Coarse Resolution ◽  
Marine Biomass ◽  
Fish Catch ◽  
Earth System Models

&lt;p&gt;The decline in ocean primary production is one of the most alarming consequences of anthropogenic climate change. This decline could indeed lead to a decrease in marine biomass and fish catch, as highlighted by recent policy-relevant reports. Because of computational constraints, current Earth System Models used to project ocean primary production under global warming scenarios have to parameterize flows occurring below the resolution of their computational grid (typically 1&amp;#176;). To overcome these computational constraints, we use an ocean biogeochemical model in an idealized configuration representing a mid-latitude double-gyre circulation, and perform global warming simulations under increasing horizontal resolution &amp;#160;(from 1&amp;#176; to 1/27&amp;#176;) and under a large range of parameter values for the eddy parameterization employed in the coarse resolution configuration. In line with projections from Earth System Models, all our simulations project a marked decline in net primary production in response to the global warming forcing. Whereas this decline is only weakly sensitive to the eddy parameters in the eddy-parametrized coarse resolution, the simulated decline in primary production is halved at the finest eddy-resolving resolution (-12% at 1/27&amp;#176; vs -26 at 1&amp;#176;). This difference stems from the high sensitivity of the subsurface nutrient transport to model resolution. Our results call for improved representation of the role of eddies on nutrient transport below the seasonal mixed-layer to better constrain the future evolution of marine biomass and fish catch potential for decision-making.&lt;/p&gt;

scholarly journals Evaluating the ocean biogeochemical components of earth system models using atmospheric potential oxygen (APO) and ocean color data

2014 ◽  
Vol 11 (6) ◽  
pp. 8485-8529
Author(s):  
C. D. Nevison ◽  
M. Manizza ◽  
R. F. Keeling ◽  
M. Kahru ◽  
L. Bopp ◽  
...  
Keyword(s):  
Transport Model ◽  
Net Primary Production ◽  
Ocean Color ◽  
Seasonal Cycles ◽  
Earth System ◽  
System Models ◽  
Color Data ◽  
Ocean Biogeochemistry ◽  
Earth System Models ◽  
Potential Oxygen

Abstract. The observed seasonal cycles in atmospheric potential oxygen (APO) at a range of mid to high latitude surface monitoring sites are compared to those inferred from the output of 6 Earth System Models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). The simulated air–sea O2 fluxes are translated into APO seasonal cycles using a matrix method that takes into account atmospheric transport model (ATM) uncertainty among 13 different ATMs. Half of the ocean biogeochemistry models tested are able to reproduce the observed APO cycles at most sites, to within the current large ATM uncertainty, while the other half generally are not. Net Primary Production (NPP) and net community production (NCP), as estimated from satellite ocean color data, provide additional constraints, albeit more with respect to the seasonal phasing of ocean model productivity than the overall magnitude. The present analysis suggests that, of the tested ocean biogeochemistry models, CESM and GFDL ESM2M are best able to capture the observed APO seasonal cycle at both Northern and Southern Hemisphere sites. In the northern oceans, the comparison to observed APO suggests that most models tend to underestimate NPP or deep ventilation or both.

scholarly journals Changes in soil organic carbon storage predicted by Earth system models during the 21st century

2013 ◽  
Vol 10 (12) ◽  
pp. 18969-19004 ◽  
Author(s):  
K. E. O. Todd-Brown ◽  
J. T. Randerson ◽  
F. Hopkins ◽  
V. Arora ◽  
T. Hajima ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
21St Century ◽  
Decomposition Rate ◽  
Radiative Forcing ◽  
Atmospheric Carbon Dioxide ◽  
Earth System ◽  
System Models ◽  
Organic Carbon Storage ◽  
Earth System Models

Abstract. Soil is currently thought to be a sink for carbon; however, the response of this sink to increasing levels of atmospheric carbon dioxide and climate change is uncertain. In this study, we analyzed soil organic carbon (SOC) changes from 11 Earth system models (ESMs) under the historical and high radiative forcing (RCP 8.5) scenarios between 1850 and 2100. We used a reduced complexity model based on temperature and moisture sensitivities to analyze the drivers of SOC losses. ESM estimates of SOC change over the 21st century (2090–2099 minus 1997–2006) ranged from a loss of 72 Pg C to a gain 253 Pg C with a multi-model mean gain of 63 Pg C. All ESMs showed cumulative increases in both NPP (15% to 59%) and decreases in SOC turnover times (15% to 28%) over the 21st century. Most of the model-to-model variation in SOC change was explained by initial SOC stocks combined with the relative changes in soil inputs and decomposition rates (R2 = 0.88, p<0.01). Between models, increases in decomposition rate were well explained by a combination of initial decomposition rate, ESM-specific Q10-factors, and changes in soil temperature (R2 = 0.80, p<0.01). All SOC changes depended on sustained increases in NPP with global change (primarily driven by increasing CO2) and conversion of additional plant inputs into SOC. Most ESMs omit potential constraints on SOC storage, such as priming effects, nutrient availability, mineral surface stabilization and aggregate formation. Future models that represent these constraints are likely to estimate smaller increases in SOC storage during the 21st century.

Long term trend of increasing iron stress in Southern Ocean phytoplankton

2021 ◽  
Author(s):  
Sandy Thomalla ◽  
Thomas Ryan-Keogh ◽  
Alessandro Tagliabue ◽  
Pedro Monteiro
Keyword(s):  
Southern Ocean ◽  
Primary Production ◽  
Net Primary Production ◽  
Earth System ◽  
Iron Stress ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Earth System Models

&lt;p&gt;Net primary production is a major contributor to carbon export in the Southern Ocean and supports rich marine ecosystems [Henley et al., 2020], driven in part by high macronutrient availability and summertime light levels, but ultimately constrained by seasonal changes in light and scarce supply of the essential micronutrient iron [Martin et al., 1990; Boyd, 2002; Tagliabue et al., 2016]. Although changing iron stress is a component of climate-driven trends in model projections of net primary production [Bopp et al., 2013; Laufkotter et al., 2015; Kwiatkowski et al., 2020], our confidence in the accuracy of their predictions is undermined by a lack of &lt;em&gt;in situ&lt;/em&gt; constraints at appropriate spatial and temporal scales [Tagliabue et al., 2016; Tagliabue et al., 2020]. Earth System Models tend to predict increased Southern Ocean net primary production by the end of the 21st century, but are characterized by significant inter-model disagreement [Bopp et al., 2013; Kwiatkowski et al., 2020 Biogeosciences].&amp;#160; We show a significant multi-decadal increase in &lt;em&gt;in situ&lt;/em&gt; iron stress from 1996 to 2020 that is positively correlated to the Southern Annular Mode and reflected by diminishing &lt;em&gt;in situ&lt;/em&gt; net primary production over the last five years. It is not possible to directly infer Fe stress from observed concentrations, which necessitate experimental approaches (&lt;em&gt;in situ&lt;/em&gt; open ocean fertilization / bottle nutrient addition experiments or proteomics). These experimental methods cannot be easily applied at appropriate spatial and temporal scales across the Southern Ocean that are required to assess trends in ecosystem status linked to climate drivers. Our novel proxy for &lt;em&gt;in situ&lt;/em&gt; iron stress is based on the degree of non-photochemical quenching in relation to available light as a measurable photophysiological response to iron availability [Alderkamp et al., 2019; Schuback &amp; Tortell, 2019; Schallenberg et al., 2020; Ryan-Keogh &amp; Thomalla, 2020]. The proxy was able to reproduce expected variations in iron stress that occur seasonally [Boyd, 2002] and from natural and artificial fertilization [Boyd et al., 2000; Coale et al., 2004; Blain et al., 2008]. A particular strength of this iron stress proxy is that it can be retrospectively applied to data from ships and autonomous platforms with coincident measurements of fluorescence, photosynthetically active radiation and backscatter or beam attenuation to deliver a long-term time series. An iron stress trend of this magnitude in the Southern Ocean, where the primary constraint on net primary production is known to be iron limitation, is likely to have significant implications for the effectiveness of the biological carbon pump globally and may impact the trajectory of climate. The progressive &lt;em&gt;in situ&lt;/em&gt; trend of increasing iron stress is however much stronger than net primary production trends from a suite of remote sensing and earth system models, indicating hitherto potential underestimation of ongoing Southern Ocean change.&lt;/p&gt;

scholarly journals Continued increase in atmospheric CO<sub>2</sub> seasonal amplitude in the 21st century projected by the CMIP5 Earth system models

2014 ◽  
Vol 5 (2) ◽  
pp. 423-439 ◽  
Author(s):  
F. Zhao ◽  
N. Zeng
Keyword(s):  
Northern Hemisphere ◽  
21St Century ◽  
Seasonal Cycle ◽  
Co2 Concentration ◽  
Growing Season ◽  
Carbon Uptake ◽  
Earth System ◽  
System Models ◽  
Amplitude Increase ◽  
Earth System Models

Abstract. In the Northern Hemisphere, atmospheric CO2 concentration declines in spring and summer, and rises in fall and winter. Ground-based and aircraft-based observation records indicate that the amplitude of this seasonal cycle has increased in the past. Will this trend continue in the future? In this paper, we analyzed simulations for historical (1850–2005) and future (RCP8.5, 2006–2100) periods produced by 10 Earth system models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Our results present a model consensus that the increase of CO2 seasonal amplitude continues throughout the 21st century. Multi-model ensemble relative amplitude of detrended global mean CO2 seasonal cycle increases by 62 ± 19% in 2081–2090, compared to 1961–1970. This amplitude increase corresponds to a 68 ± 25% increase in net biosphere production (NBP). The results show that the increase of NBP amplitude mainly comes from enhanced ecosystem uptake during Northern Hemisphere growing season under future CO2 and temperature conditions. Separate analyses on net primary production (NPP) and respiration reveal that enhanced ecosystem carbon uptake contributes about 75% of the amplitude increase. Stimulated by higher CO2 concentration and high-latitude warming, enhanced NPP likely outcompetes increased respiration at higher temperature, resulting in a higher net uptake during the northern growing season. The zonal distribution and spatial pattern of NBP change suggest that regions north of 45° N dominate the amplitude increase. Models that simulate a stronger carbon uptake also tend to show a larger increase of NBP seasonal amplitude, and the cross-model correlation is significant (R=0.73, p< 0.05).

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