Net carbon sink of China was overestimated by more than 35%

Abstract As a carbon source/sink of atmospheric carbon dioxide, the net regional carbon budget (NRCB) of terrestrial ecosystems is very important to effect global warming, especially China with the largest emissions at present. However, the carbon consumption is difficult to measure accurately, which is caused by the emissions of CH4 and CO, the utilization of agriculture, forestry and grass, and the emissions from rivers and other physical processes, such as forest fires. Therefore, the spatial patterns and driving factors of NRCB are not clear. Here, we used multi-source data to estimate the NRCB of 31 provincial administrative divisions of China and to develop NRCB datasets from 2000 to 2018. We found that the average of NRCB was 669 TgC yr−1, and it significantly decreased at a rate of 2.56 TgC yr−1. The relative contribution rates of fluxes of emissions from anthropogenic (FEAD), reactive carbon and creature ingestion (FERCCI), autotrophic respiration (Ra), heterotrophic respiration (Rh) and natural disturbances (FEND) were 35.17%, 26.09%, 19.68%, 17.38% and 1.68% respectively. In addition, NRCB datasets of the different administrative regions of China were mapped. These datasets will provide support for China's carbon neutrality and the study of the global carbon cycle.

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Soil nitrogen cycle unresponsive to decadal long climate change in a Tasmanian grassland

Biogeochemistry ◽

10.1007/s10533-019-00627-9 ◽

2019 ◽

Vol 147 (1) ◽

pp. 99-107 ◽

Cited By ~ 3

Author(s):

Tobias Rütting ◽

Mark J. Hovenden

Keyword(s):

Climate Change ◽

Atmospheric Carbon Dioxide ◽

Carbon Sink ◽

Vegetation Type ◽

Terrestrial Ecosystems ◽

Soil N ◽

Mineral N ◽

N Dynamics ◽

Terrestrial Carbon Sink ◽

Soil Nitrogen Cycle

AbstractIncreases in atmospheric carbon dioxide (CO2) and global air temperature affect all terrestrial ecosystems and often lead to enhanced ecosystem productivity, which in turn dampens the rise in atmospheric CO2 by removing CO2 from the atmosphere. As most terrestrial ecosystems are limited in their productivity by the availability of nitrogen (N), there is concern about the persistence of this terrestrial carbon sink, as these ecosystems might develop a progressive N limitation (PNL). An increase in the gross soil N turnover may alleviate PNL, as more mineral N is made available for plant uptake. So far, climate change experiments have mainly manipulated one climatic factor only, but there is evidence that single-factor experiments usually overestimate the effects of climate change on terrestrial ecosystems. In this study, we investigated how simultaneous, decadal-long increases in CO2 and temperature affect the soil gross N dynamics in a native Tasmanian grassland under C3 and C4 vegetation. Our laboratory 15N labeling experiment showed that average gross N mineralization ranged from 4.9 to 11.3 µg N g−1 day−1 across the treatment combinations, while gross nitrification was about ten-times lower. Considering all treatment combinations, no significant effect of climatic treatments or vegetation type (C3 versus C4 grasses) on soil N cycling was observed.

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The Missing Limb: Including Impacts of Biomass Extraction on Forest Carbon Stocks in GHG Balances of Wood Use

10.20944/preprints202112.0499.v1 ◽

2021 ◽

Author(s):

Horst Fehrenbach ◽

Mascha Bischoff ◽

Hannes Böttcher ◽

Judith Reise ◽

Klaus Josef Hennenberg

Keyword(s):

Carbon Storage ◽

Energy Use ◽

Carbon Sink ◽

Ghg Emissions ◽

Forest Carbon ◽

Wood Products ◽

Ghg Mitigation ◽

Carbon Neutrality ◽

Energy Wood ◽

Global Carbon

The global carbon neutrality challenge places a spotlight on forests as carbon sinks. However, greenhouse gas (GHG) balances of wood for material and energy use often reveal GHG emission savings in comparison with a non-wood reference. Is it thus better to increase wood production and use, or to conserve and expand the carbon stock in forests? GHG balances of wood products mostly ignore the dynamics of carbon storage in forests, which can be expressed as the carbon storage balance in forests (CSBF). For Germany, a CSBF of 0.25 to 1.15 t CO2/m³ wood can be assumed. When the CSBF is integrated into the GHG balance, GHG mitigation substantially deteriorates and wood products may even turn into a GHG source, e.g. in the case of energy wood. Here, building up the forest carbon sink would be the better option. We conclude that it is vital to include the CSBF in GHG balances of wood products if the wood is extracted from forests. Only then can GHG balances provide political decision-makers and stakeholders in the wood sector with a complete picture of GHG emissions.

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African tropical rainforest net carbon dioxide fluxes in the twentieth century

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0376 ◽

2013 ◽

Vol 368 (1625) ◽

pp. 20120376 ◽

Cited By ~ 37

Author(s):

Joshua B. Fisher ◽

Munish Sikka ◽

Stephen Sitch ◽

Philippe Ciais ◽

Benjamin Poulter ◽

...

Keyword(s):

Land Surface ◽

Tropical Rainforest ◽

Carbon Sink ◽

Past Century ◽

Carbon Dioxide Fluxes ◽

The Past ◽

Surface Models ◽

Model Variability ◽

Global Carbon ◽

Net Carbon Sink

The African humid tropical biome constitutes the second largest rainforest region, significantly impacts global carbon cycling and climate, and has undergone major changes in functioning owing to climate and land-use change over the past century. We assess changes and trends in CO 2 fluxes from 1901 to 2010 using nine land surface models forced with common driving data, and depict the inter-model variability as the uncertainty in fluxes. The biome is estimated to be a natural (no disturbance) net carbon sink (−0.02 kg C m −2 yr −1 or −0.04 Pg C yr −1 , p < 0.05) with increasing strength fourfold in the second half of the century. The models were in close agreement on net CO 2 flux at the beginning of the century ( σ 1901 = 0.02 kg C m −2 yr −1 ), but diverged exponentially throughout the century ( σ 2010 = 0.03 kg C m −2 yr −1 ). The increasing uncertainty is due to differences in sensitivity to increasing atmospheric CO 2 , but not increasing water stress, despite a decrease in precipitation and increase in air temperature. However, the largest uncertainties were associated with the most extreme drought events of the century. These results highlight the need to constrain modelled CO 2 fluxes with increasing atmospheric CO 2 concentrations and extreme climatic events, as the uncertainties will only amplify in the next century.

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Carbon storage estimation in a secondary tropical forest at CIEE Sustainability Center, Monteverde, Costa Rica

Scientific Reports ◽

10.1038/s41598-021-03004-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alexandra Paniagua-Ramirez ◽

Oliwia Krupinska ◽

Vicki Jagdeo ◽

William J. Cooper

Keyword(s):

Costa Rica ◽

Atmospheric Carbon Dioxide ◽

Carbon Sink ◽

Secondary Growth ◽

Total Surface Area ◽

International Educational Exchange ◽

Carbon Neutrality ◽

San Luis ◽

Camino Real ◽

Secondary Tropical Forest

AbstractSecondary growth tropical rainforests have the potential to sequester large amounts of atmospheric carbon dioxide and as such are an important carbon sink. To evaluate a local forest, a Carbon Neutrality Program was initiated at the Council on International Educational Exchange, San Luis Campus, Monteverde, Costa Rica. The study was conducted on 50 hectares of forest classified as Premontane Wet Forest. The forest, part of the Arenal-Monteverde Protected Zone, is estimated to be aproximately 50 years old and is in the upper regions of the San Luis valley at 1100 m elevation. Assessment of the carbon stock in trees was carried out in two permanent, 1 hectare plots, 100 m by 100 m, Camino Real and Zapote. The plots were divided into 25 subplots, 20 m by 20 m totaling 400 m2 per subplot. Ten subplots in each area were studied which represented 1.6% the total surface area of the forest. All of the trees were measured within the subplots that had a diameter at breast height ≥ 10 cm and the height of 10% of the trees measured. The estimated total CO2 sequestered by the campus forest was 18,210 ton (in 2019).

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Recent pause in the growth rate of atmospheric CO2 due to enhanced terrestrial carbon uptake

Nature Communications ◽

10.1038/ncomms13428 ◽

2016 ◽

Vol 7 (1) ◽

Cited By ~ 130

Author(s):

Trevor F Keenan ◽

I. Colin Prentice ◽

Josep G Canadell ◽

Christopher A Williams ◽

Han Wang ◽

...

Keyword(s):

Growth Rate ◽

Carbon Sink ◽

Large Fraction ◽

Terrestrial Ecosystems ◽

Anthropogenic Emissions ◽

Terrestrial Carbon ◽

Vegetation Models ◽

Terrestrial Carbon Sink ◽

Global Vegetation ◽

Global Carbon

Abstract Terrestrial ecosystems play a significant role in the global carbon cycle and offset a large fraction of anthropogenic CO2 emissions. The terrestrial carbon sink is increasing, yet the mechanisms responsible for its enhancement, and implications for the growth rate of atmospheric CO2, remain unclear. Here using global carbon budget estimates, ground, atmospheric and satellite observations, and multiple global vegetation models, we report a recent pause in the growth rate of atmospheric CO2, and a decline in the fraction of anthropogenic emissions that remain in the atmosphere, despite increasing anthropogenic emissions. We attribute the observed decline to increases in the terrestrial sink during the past decade, associated with the effects of rising atmospheric CO2 on vegetation and the slowdown in the rate of warming on global respiration. The pause in the atmospheric CO2 growth rate provides further evidence of the roles of CO2 fertilization and warming-induced respiration, and highlights the need to protect both existing carbon stocks and regions, where the sink is growing rapidly.

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Enhanced Seasonal Exchange of CO2 by Northern Ecosystems Since 1960

Science ◽

10.1126/science.1239207 ◽

2013 ◽

Vol 341 (6150) ◽

pp. 1085-1089 ◽

Cited By ~ 221

Author(s):

H. D. Graven ◽

R. F. Keeling ◽

S. C. Piper ◽

P. K. Patra ◽

B. B. Stephens ◽

...

Keyword(s):

Boreal Forests ◽

Atmospheric Carbon Dioxide ◽

Ecosystem Models ◽

The North ◽

Ecological Changes ◽

Term Change ◽

Major Shift ◽

Underlying Mechanisms ◽

Global Carbon

Seasonal variations of atmospheric carbon dioxide (CO2) in the Northern Hemisphere have increased since the 1950s, but sparse observations have prevented a clear assessment of the patterns of long-term change and the underlying mechanisms. We compare recent aircraft-based observations of CO2 above the North Pacific and Arctic Oceans to earlier data from 1958 to 1961 and find that the seasonal amplitude at altitudes of 3 to 6 km increased by 50% for 45° to 90°N but by less than 25% for 10° to 45°N. An increase of 30 to 60% in the seasonal exchange of CO2 by northern extratropical land ecosystems, focused on boreal forests, is implicated, substantially more than simulated by current land ecosystem models. The observations appear to signal large ecological changes in northern forests and a major shift in the global carbon cycle.

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Amazonian Fire Events Disturbed the Global Carbon Cycle: A Study from 2019 Amazon Wildfire Using Google Earth Engine

Environmental Sciences Proceedings ◽

10.3390/iecf2020-08033 ◽

2020 ◽

Vol 3 (1) ◽

pp. 43

Author(s):

Subhajit Bandopadhyay ◽

Dany A. Cotrina Sánchez

Keyword(s):

Carbon Cycle ◽

Carbon Sink ◽

Brazilian Amazon ◽

Global Carbon Cycle ◽

Forest Productivity ◽

Google Earth ◽

Comparative Approach ◽

Burned Area ◽

Google Earth Engine ◽

Global Carbon

An unprecedented number of wildfire events during 2019 throughout the Brazilian Amazon caught global attention, due to their massive extent and the associated loss in the Amazonian forest—an ecosystem on which the whole world depends. Such devastating wildfires in the Amazon has strongly hampered the global carbon cycle and significantly reduced forest productivity. In this study, we have quantified such loss of forest productivity in terms of gross primary productivity (GPP), applying a comparative approach using Google Earth Engine. A total of 12 wildfire spots have been identified based on the fire’s extension over the Brazilian Amazon, and we quantified the loss in productivity between 2018 and 2019. The Moderate Resolution Imaging Spectroradiometer (MODIS) GPP and MODIS burned area satellite imageries, with a revisit time of 8 days and 30 days, respectively, have been used for this study. We have observed that compared to 2018, the number of wildfire events increased during 2019. But such wildfire events did not hamper the natural annual trend of GPP of the Amazonian ecosystem. However, a significant drop in forest productivity in terms of GPP has been observed. Among all 11 observational sites were recorded with GPP loss, ranging from −18.88 gC m−2 yr−1 to −120.11 gC m−2 yr−1, except site number 3. Such drastic loss in GPP indicates that during 2019 fire events, all of these sites acted as carbon sources rather than carbon sink sites, which may hamper the global carbon cycle and terrestrial CO2 fluxes. Therefore, it is assumed that these findings will also fit for the other Amazonian wildfire sites, as well as for the tropical forest ecosystem as a whole. We hope this study will provide a significant contribution to global carbon cycle research, terrestrial ecosystem studies, sustainable forest management, and climate change in contemporary environmental sciences.

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Assessment of Impacts of Hurricane Katrina on Net Primary Productivity in Mississippi

Earth Interactions ◽

10.1175/2010ei292.1 ◽

2010 ◽

Vol 14 (14) ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Shrinidhi Ambinakudige ◽

Sami Khanal

Keyword(s):

Natural Disasters ◽

Hurricane Katrina ◽

Primary Productivity ◽

Atmospheric Carbon Dioxide ◽

Net Primary Productivity ◽

Gulf Coast ◽

Carbon Sink ◽

Anthropogenic Activities ◽

Remote Sensing Data ◽

The United States

Abstract Southern forests contribute significantly to the carbon sink for the atmospheric carbon dioxide (CO2) associated with the anthropogenic activities in the United States. Natural disasters like hurricanes are constantly threatening these forests. Hurricane winds can have a destructive impact on natural vegetation and can adversely impact net primary productivity (NPP). Hurricane Katrina (23–30 August 2005), one of the most destructive natural disasters in history, has affected the ecological balance of the Gulf Coast. This study analyzed the impacts of different categories of sustained winds of Hurricane Katrina on NPP in Mississippi. The study used the Carnegie–Ames–Stanford Approach (CASA) model to estimate NPP by using remote sensing data. The results indicated that NPP decreased by 14% in the areas hard hit by category 3 winds and by 1% in the areas hit by category 2 winds. However, there was an overall increase in NPP, from 2005 to 2006 by 0.60 Tg of carbon, in Mississippi. The authors found that Pearl River, Stone, Hancock, Jackson, and Harrison counties in Mississippi faced significant depletion of NPP because of Hurricane Katrina.

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A coupled multi-proxy and process modelling approach for extraction of quantitative terrestrial ecosystem information from speleothems

10.5194/egusphere-egu21-4761 ◽

2021 ◽

Author(s):

Franziska Lechleitner ◽

Christopher C. Day ◽

Oliver Kost ◽

Micah Wilhelm ◽

Negar Haghipour ◽

...

Keyword(s):

Climate Change ◽

Soil Respiration ◽

Western Europe ◽

Global Climate ◽

Terrestrial Ecosystem ◽

Terrestrial Ecosystems ◽

Clear Correlation ◽

Northern Spain ◽

Regional Temperature ◽

Global Carbon

Terrestrial ecosystems are intimately linked with the global climate system, but their response to ongoing and future anthropogenic climate change remains poorly understood. Reconstructing the response of terrestrial ecosystem processes over past periods of rapid and substantial climate change can serve as a tool to better constrain the sensitivity in the ecosystem-climate response.In this talk, we will present a new reconstruction of soil respiration in the temperate region of Western Europe based on speleothem carbon isotopes (&#948;13C). Soil respiration remains poorly constrained over past climatic transitions, but is critical for understanding the global carbon cycle and its response to ongoing anthropogenic warming. Our study builds upon two decades of speleothem research in Western Europe, which has shown clear correlation between &#948;13C and regional temperature reconstructions during the last glacial and the deglaciation, with exceptional regional coherency in timing, amplitude, and absolute &#948;13C variation. By combining innovative multi-proxy geochemical analysis (&#948;13C, Ca isotopes, and radiocarbon) on three speleothems from Northern Spain, and quantitative forward modelling of processes in soil, karst, and cave, we show how deglacial variability in speleothem &#948;13C is best explained by increasing soil respiration. Our study is the first to quantify and remove the effects of prior calcite precipitation (PCP, using Ca isotopes) and bedrock dissolution (open vs closed system, using the radiocarbon reservoir effect) from the speleothem &#948;13C signal to derive changes in respired &#948;13C over time. Our approach allows us to estimate the temperature sensitivity of soil respiration (Q10), which is higher than current measurements, suggesting that part of the speleothem signal may be related to a change in the composition of the soil respired &#948;13C. This is likely related to changing substrate through increasing contribution from vegetation biomass with the onset of the Holocene.These results highlight the exciting possibilities speleothems offer as a coupled archive for quantitative proxy-based reconstructions of climate and ecosystem conditions.

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Using airborne HIAPER Pole-to-Pole Observations (HIPPO) to evaluate model and remote sensing estimates of atmospheric carbon dioxide

10.5194/acp-2015-961 ◽

2016 ◽

Cited By ~ 1

Author(s):

C. Frankenberg ◽

S. S. Kulawik ◽

S. Wofsy ◽

F. Chevallier ◽

B. Daube ◽

...

Keyword(s):

Carbon Dioxide ◽

Atmospheric Carbon Dioxide ◽

Correlation Coefficients ◽

Added Value ◽

Total Carbon ◽

Accuracy And Precision ◽

Atmospheric Carbon ◽

Carbon Dioxide Co2 ◽

Global Carbon ◽

Comparable Quality

Abstract. In recent years, space-borne observations of atmospheric carbon-dioxide (CO2) have become increasingly used in global carbon-cycle studies. In order to obtain added value from space-borne measurements, they have to suffice stringent accuracy and precision requirements, with the latter being less crucial as it can be reduced by just enhanced sample size. Validation of CO2 column averaged dry air mole fractions (XCO2) heavily relies on measurements of the Total Carbon Column Observing Network TCCON. Owing to the sparseness of the network and the requirements imposed on space-based measurements, independent additional validation is highly valuable. Here, we use observations from the HIAPER Pole-to-Pole Observations (HIPPO) flights from January 2009 through September 2011 to validate CO2 measurements from satellites (GOSAT, TES, AIRS) and atmospheric inversion models (CarbonTracker CT2013B, MACC v13r1). We find that the atmospheric models capture the XCO2 variability observed in HIPPO flights very well, with correlation coefficients (r2) of 0.93 and 0.95 for CT2013B and MACC, respectively. Some larger discrepancies can be observed in profile comparisons at higher latitudes, esp. at 300 hPa during the peaks of either carbon uptake or release. These deviations can be up to 4 ppm and hint at misrepresentation of vertical transport. Comparisons with the GOSAT satellite are of comparable quality, with an r2 of 0.85, a mean bias μ of −0.06 ppm and a standard deviation σ of 0.45 ppm. TES exhibits an r2 of 0.75, μ of 0.34 ppm and σ of 1.13 ppm. For AIRS, we find an r2 of 0.37, μ of 1.11 ppm and σ of 1.46 ppm, with latitude-dependent biases. For these comparisons at least 6, 20 and 50 atmospheric soundings have been averaged for GOSAT, TES and AIRS, respectively. Overall, we find that GOSAT soundings over the remote pacific ocean mostly meet the stringent accuracy requirements of about 0.5 ppm for space-based CO2 observations.

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