The Role of the Tropics in the Global Carbon Budget: Impacts and Possible Developments

1992 ◽  
pp. 241-252 ◽  
Author(s):  
Gerd Esser
Keyword(s):  
Carbon Budget ◽  
Global Carbon Budget ◽  
The Tropics ◽  
Global Carbon

scholarly journals Global carbon budget of reservoirs is overturned by the quantification of drawdown areas

2021 ◽  
Author(s):  
Philipp S. Keller ◽  
Rafael Marcé ◽  
Biel Obrador ◽  
Matthias Koschorreck
Keyword(s):  
Carbon Emissions ◽  
Carbon Budget ◽  
Water Level Fluctuations ◽  
Emission Rates ◽  
Global Carbon Budget ◽  
Carbon Burial ◽  
Reservoir Drawdown ◽  
The Tropics ◽  
Global Carbon

AbstractReservoir drawdown areas—where sediment is exposed to the atmosphere due to water-level fluctuations—are hotspots for carbon dioxide (CO2) emissions. However, the global extent of drawdown areas is unknown, precluding an accurate assessment of the carbon budget of reservoirs. Here we show, on the basis of satellite observations of 6,794 reservoirs between 1985 and 2015, that 15% of the global reservoir area was dry. Exposure of drawdown areas was most pronounced in reservoirs close to the tropics and shows a complex dependence on climatic (precipitation, temperature) and anthropogenic (water use) drivers. We re-assessed the global carbon emissions from reservoirs by apportioning CO2 and methane emissions to water surfaces and drawdown areas using published areal emission rates. The new estimate assigns 26.2 (15–40) (95% confidence interval) TgCO2-C yr−1 to drawdown areas, and increases current global CO2 emissions from reservoirs by 53% (60.3 (43.2–79.5) TgCO2-C yr−1). Taking into account drawdown areas, the ratio between carbon emissions and carbon burial in sediments is 2.02 (1.04–4.26). This suggests that reservoirs emit more carbon than they bury, challenging the current understanding that reservoirs are net carbon sinks. Thus, consideration of drawdown areas overturns our conception of the role of reservoirs in the carbon cycle.

scholarly journals Dissolution of Carbonate Rocks in a Laboratory Setting: Rates and Textures

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 605
Author(s):  
Erik B. Larson ◽  
Ronald V. Emmons
Keyword(s):  
Carbonate Rocks ◽  
Carbon Budget ◽  
Dissolution Rates ◽  
Global Carbon Budget ◽  
Landscape Processes ◽  
The Matrix ◽  
Mechanical Weathering ◽  
Global Carbon ◽  
Scanning Electron

Determining the dissolution rates of carbonate rocks is vital to advancing our understanding of cave, karst, and landscape processes. Furthermore, the role of carbonate dissolution is important for the global carbon budget and climate change. A laboratory experiment was setup to calculate the dissolution rates of two whole rock carbonate samples with different petrographic makeup (ooids and brachiopods). The carbonate rock samples were also explored under a scanning electron microscope to evaluate the textures that developed after dissolution The oolitic limestone dissolved at a rate of 1579 cm yr−1, and the pentamerous limestone (dolostone) dissolved at a rate of 799 cm yr−1. Both rocks did not dissolve evenly across their surface as indicated by scanning electron microscopy, it appears the allochems dissolved preferentially to the matrix/cement of the rocks and that some mechanical weathering happened as well. This work reports that the petrography and mineralogy of carbonate rocks is important to consider when exploring the cave, karst, and landscape evolution and that attention should be paid to the petrography of carbonate rocks when considering the global carbon budget.

A first-order analysis of the potential role of CO2 fertilization to affect the global carbon budget: a comparison of four terrestrial biosphere models

Tellus B ◽  
1999 ◽  
Vol 51 (2) ◽  
pp. 343-366 ◽  
Author(s):  
DAVID W. KICKLIGHTER ◽  
MICHELE BRUNO ◽  
SILKE DONGES ◽  
GERD ESSER ◽  
MARTIN HEIMANN ◽  
...  
Keyword(s):  
Carbon Budget ◽  
Potential Role ◽  
Terrestrial Biosphere ◽  
Co2 Fertilization ◽  
Order Analysis ◽  
First Order ◽  
Global Carbon Budget ◽  
Global Carbon

scholarly journals A first-order analysis of the potential rôle of CO2 fertilization to affect the global carbon budget: a comparison of four terrestrial biosphere models

Tellus B ◽  
1999 ◽  
Vol 51 (2) ◽  
pp. 343-366 ◽  
Author(s):  
David W. Kicklighter ◽  
Michele Bruno ◽  
Silke DZönges ◽  
Gerd Esser ◽  
Martin Heimann ◽  
...  
Keyword(s):  
Carbon Budget ◽  
Potential Role ◽  
Terrestrial Biosphere ◽  
Co2 Fertilization ◽  
Order Analysis ◽  
First Order ◽  
Global Carbon Budget ◽  
Global Carbon

scholarly journals The global carbon budget: a conflicting claims problem

2016 ◽  
Vol 136 (3-4) ◽  
pp. 693-703 ◽  
Author(s):  
José-Manuel Giménez-Gómez ◽  
Jordi Teixidó-Figueras ◽  
Cori Vilella
Keyword(s):  
Carbon Budget ◽  
Global Carbon Budget ◽  
Claims Problem ◽  
Global Carbon

scholarly journals Global carbon budget 2014

2014 ◽  
Vol 7 (2) ◽  
pp. 521-610 ◽  
Author(s):  
C. Le Quéré ◽  
R. Moriarty ◽  
R. M. Andrew ◽  
G. P. Peters ◽  
P. Ciais ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Land Cover ◽  
Land Cover Change ◽  
Co2 Emissions ◽  
Carbon Budget ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Cement Production ◽  
Global Carbon Budget ◽  
Global Carbon

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe datasets and a methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates, consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuel combustion and cement production (EFF) are based on energy statistics and cement production data, respectively, while emissions from Land-Use Change (ELUC), mainly deforestation, are based on combined evidence from land-cover change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent Dynamic Global Vegetation Models forced by observed climate, CO2 and land cover change (some including nitrogen-carbon interactions). We compare the variability and mean land and ocean fluxes to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ±1σ, reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2004–2013), EFF was 8.9 ± 0.4 GtC yr−1, ELUC 0.9 ± 0.5 GtC yr−1, GATM 4.3 ± 0.1 GtC yr−1, SOCEAN 2.6 ± 0.5 GtC yr−1, and SLAND 2.9 ± 0.8 GtC yr−1. For year 2013 alone, EFF grew to 9.9 ± 0.5 GtC yr−1, 2.3% above 2012, contining the growth trend in these emissions. ELUC was 0.9 ± 0.5 GtC yr−1, GATM was 5.4 ± 0.2 GtC yr−1, SOCEAN was 2.9 ± 0.5 GtC yr−1 and SLAND was 2.5 ± 0.9 GtC yr−1. GATM was high in 2013 reflecting a steady increase in EFF and smaller and opposite changes between SOCEAN and SLAND compared to the past decade (2004–2013). The global atmospheric CO2 concentration reached 395.31 ± 0.10 ppm averaged over 2013. We estimate that EFF will increase by 2.5% (1.3–3.5%) to 10.1 ± 0.6 GtC in 2014 (37.0 ± 2.2 GtCO2 yr−1), 65% above emissions in 1990, based on projections of World Gross Domestic Product and recent changes in the carbon intensity of the economy. From this projection of EFF and assumed constant ELUC for 2014, cumulative emissions of CO2 will reach about 545 ± 55 GtC (2000 ± 200 GtCO2) for 1870–2014, about 75% from EFF and 25% from ELUC. This paper documents changes in the methods and datasets used in this new carbon budget compared with previous publications of this living dataset (Le Quéré et al., 2013, 2014). All observations presented here can be downloaded from the Carbon Dioxide Information Analysis Center (doi:10.3334/CDIAC/GCP_2014). Italic font highlights significant methodological changes and results compared to the Le Quéré et al. (2014) manuscript that accompanies the previous version of this living data.

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