scholarly journals Audit of the global carbon budget: estimate errors and their impact on uptake uncertainty

2015 ◽  
Vol 12 (8) ◽  
pp. 2565-2584 ◽  
Author(s):  
A. P. Ballantyne ◽  
R. Andres ◽  
R. Houghton ◽  
B. D. Stocker ◽  
R. Wanninkhof ◽  
...  
Keyword(s):  
Land Use ◽  
Growth Rate ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Global Carbon Budget ◽  
Novel Approach ◽  
Observation Network ◽  
C Cycle ◽  
The 1960S ◽  
Fossil Fuel Emissions

Abstract. Over the last 5 decades monitoring systems have been developed to detect changes in the accumulation of carbon (C) in the atmosphere and ocean; however, our ability to detect changes in the behavior of the global C cycle is still hindered by measurement and estimate errors. Here we present a rigorous and flexible framework for assessing the temporal and spatial components of estimate errors and their impact on uncertainty in net C uptake by the biosphere. We present a novel approach for incorporating temporally correlated random error into the error structure of emission estimates. Based on this approach, we conclude that the 2σ uncertainties of the atmospheric growth rate have decreased from 1.2 Pg C yr−1 in the 1960s to 0.3 Pg C yr−1 in the 2000s due to an expansion of the atmospheric observation network. The 2σ uncertainties in fossil fuel emissions have increased from 0.3 Pg C yr−1 in the 1960s to almost 1.0 Pg C yr−1 during the 2000s due to differences in national reporting errors and differences in energy inventories. Lastly, while land use emissions have remained fairly constant, their errors still remain high and thus their global C uptake uncertainty is not trivial. Currently, the absolute errors in fossil fuel emissions rival the total emissions from land use, highlighting the extent to which fossil fuels dominate the global C budget. Because errors in the atmospheric growth rate have decreased faster than errors in total emissions have increased, a ~20% reduction in the overall uncertainty of net C global uptake has occurred. Given all the major sources of error in the global C budget that we could identify, we are 93% confident that terrestrial C uptake has increased and 97% confident that ocean C uptake has increased over the last 5 decades. Thus, it is clear that arguably one of the most vital ecosystem services currently provided by the biosphere is the continued removal of approximately half of atmospheric CO2 emissions from the atmosphere, although there are certain environmental costs associated with this service, such as the acidification of ocean waters.

scholarly journals Audit of the global carbon budget: estimate errors and their impact on uptake uncertainty

2014 ◽  
Vol 11 (10) ◽  
pp. 14929-14979 ◽  
Author(s):  
A. P. Ballantyne ◽  
R. Andres ◽  
R. Houghton ◽  
B. D. Stocker ◽  
R. Wanninkhof ◽  
...  
Keyword(s):  
Land Use ◽  
Fossil Fuel ◽  
Reporting Practices ◽  
Global Carbon Budget ◽  
Novel Approach ◽  
C Cycle ◽  
Flexible Framework ◽  
The 1960S ◽  
Relative Errors ◽  
Fossil Fuel Emissions

Abstract. Over the last 5 decades monitoring systems have been developed to detect changes in the accumulation of C in the atmosphere, ocean, and land; however, our ability to detect changes in the behavior of the global C cycle is still hindered by measurement and estimate errors. Here we present a rigorous and flexible framework for assessing the temporal and spatial components of estimate error and their impact on uncertainty in net C uptake by the biosphere. We present a novel approach for incorporating temporally correlated random error into the error structure of emission estimates. Based on this approach, we conclude that the 2 σ error of the atmospheric growth rate has decreased from 1.2 Pg C yr−1 in the 1960s to 0.3 Pg C yr−1 in the 2000s, leading to a ~20% reduction in the over-all uncertainty of net global C uptake by the biosphere. While fossil fuel emissions have increased by a factor of 4 over the last 5 decades, 2 σ errors in fossil fuel emissions due to national reporting errors and differences in energy reporting practices have increased from 0.3 Pg C yr−1 in the 1960s to almost 1.0 Pg C yr−1 during the 2000s. At the same time land use emissions have declined slightly over the last 5 decades, but their relative errors remain high. Notably, errors associated with fossil fuel emissions have come to dominate uncertainty in the global C budget and are now comparable to the total emissions from land use, thus efforts to reduce errors in fossil fuel emissions are necessary. Given all the major sources of error in the global C budget that we could identify, we are 93% confident that C uptake has increased and 97% confident that C uptake by the terrestrial biosphere has increased over the last 5 decades. Although the persistence of future C sinks remains unknown and some ecosystem services may be compromised by this continued C uptake (e.g. ocean acidification), it is clear that arguably the greatest ecosystem service currently provided by the biosphere is the continued removal of approximately half of atmospheric CO2 emissions from the atmosphere.

scholarly journals Re-evaluating the 1940s CO<sub>2</sub> plateau

2016 ◽  
Vol 13 (17) ◽  
pp. 4877-4897 ◽  
Author(s):  
Ana Bastos ◽  
Philippe Ciais ◽  
Jonathan Barichivich ◽  
Laurent Bopp ◽  
Victor Brovkin ◽  
...  
Keyword(s):  
Land Use ◽  
Growth Rate ◽  
El Niño ◽  
Carbon Budget ◽  
Fossil Fuel ◽  
El Nino ◽  
Carbon Sink ◽  
Atmospheric Co2 ◽  
Ocean Carbon ◽  
Fossil Fuel Emissions

Abstract. The high-resolution CO2 record from Law Dome ice core reveals that atmospheric CO2 concentration stalled during the 1940s (so-called CO2 plateau). Since the fossil-fuel emissions did not decrease during the period, this stalling implies the persistence of a strong sink, perhaps sustained for as long as a decade or more. Double-deconvolution analyses have attributed this sink to the ocean, conceivably as a response to the very strong El Niño event in 1940–1942. However, this explanation is questionable, as recent ocean CO2 data indicate that the range of variability in the ocean sink has been rather modest in recent decades, and El Niño events have generally led to higher growth rates of atmospheric CO2 due to the offsetting terrestrial response. Here, we use the most up-to-date information on the different terms of the carbon budget: fossil-fuel emissions, four estimates of land-use change (LUC) emissions, ocean uptake from two different reconstructions, and the terrestrial sink modelled by the TRENDY project to identify the most likely causes of the 1940s plateau. We find that they greatly overestimate atmospheric CO2 growth rate during the plateau period, as well as in the 1960s, in spite of giving a plausible explanation for most of the 20th century carbon budget, especially from 1970 onwards. The mismatch between reconstructions and observations during the CO2 plateau epoch of 1940–1950 ranges between 0.9 and 2.0 Pg C yr−1, depending on the LUC dataset considered. This mismatch may be explained by (i) decadal variability in the ocean carbon sink not accounted for in the reconstructions we used, (ii) a further terrestrial sink currently missing in the estimates by land-surface models, or (iii) LUC processes not included in the current datasets. Ocean carbon models from CMIP5 indicate that natural variability in the ocean carbon sink could explain an additional 0.5 Pg C yr−1 uptake, but it is unlikely to be higher. The impact of the 1940–1942 El Niño on the observed stabilization of atmospheric CO2 cannot be confirmed nor discarded, as TRENDY models do not reproduce the expected concurrent strong decrease in terrestrial uptake. Nevertheless, this would further increase the mismatch between observed and modelled CO2 growth rate during the CO2 plateau epoch. Tests performed using the OSCAR (v2.2) model indicate that changes in land use not correctly accounted for during the period (coinciding with drastic socioeconomic changes during the Second World War) could contribute to the additional sink required. Thus, the previously proposed ocean hypothesis for the 1940s plateau cannot be confirmed by independent data. Further efforts are required to reduce uncertainty in the different terms of the carbon budget during the first half of the 20th century and to better understand the long-term variability of the ocean and terrestrial CO2 sinks.

scholarly journals Re-evaluating the 1940s CO<sub>2</sub> plateau

2016 ◽  
Author(s):  
Ana Bastos ◽  
Philippe Ciais ◽  
Jonathan Barichivitch ◽  
Laurent Bopp ◽  
Victor Brovkin ◽  
...  
Keyword(s):  
Land Use ◽  
Growth Rate ◽  
El Niño ◽  
Carbon Budget ◽  
Fossil Fuel ◽  
El Nino ◽  
Carbon Sink ◽  
Atmospheric Co2 ◽  
Ocean Carbon ◽  
Fossil Fuel Emissions

Abstract. The high-resolution CO2 record from Law Dome ice core reveals that atmospheric CO2 concentration stalled during the 1940s (so-called CO2 plateau). This stalling implies the persistence of a sink of the same magnitude as the concurrent fossil fuel emissions, perhaps sustained for as long as a decade or more. This sink has been previously attributed to the ocean, conceivably as a response to the very strong El Niño event in 1940–42. However, this explanation is questionable, as recent ocean CO2 data indicate that the range of variability in the ocean sink has been rather modest in recent decades, and El Niño events have generally led to higher growth-rates of atmospheric CO2 due to the offsetting terrestrial response. Here, we use the most up-to-date information on the different terms of the carbon budget: fossil fuel emissions, four estimates of land-use change (LUC) emissions, ocean uptake from two different reconstructions, and the terrestrial sink modelled by the TRENDY project. Evaluating whether these datasets provide further insight about the 1940s plateau and its causes, we find that, they give a plausible explanation for most of the 20th century carbon budget, especially from 1970 onwards, but they greatly overestimate atmospheric CO2 growth rate during the plateau period, as well as in the 1960s. The mismatch between reconstructions and observations during the CO2 plateau epoch of 1940–1950 ranges between 0.9–2.0 Pg C yr−1, depending on the LUC dataset considered. This mismatch may be explained by: i) decadal variability in the ocean carbon sink not accounted for in the reconstructions we used; ii) a further terrestrial sink currently missing in the estimates by land-surface models; iii) land-use change processes not included in the current datasets. Ocean carbon models from CMIP5 indicate that natural variability in the ocean carbon sink could explain an additional 0.5 Pg C yr−1 uptake, but it is unlikely to be higher. The impact of the 1940–42 El Niño on the observed stabilization of atmospheric CO2 cannot be confirmed nor discarded, as TRENDY models do not reproduce the expected concurrent strong decrease in terrestrial uptake. Nevertheless, this would further increase the mismatch between observed and modelled CO2 growth rate during the CO2 plateau epoch. Tests performed using the OSCAR (v2.2) model, indicate that changes in land use not correctly accounted for during the period (coinciding with drastic socioeconomic changes during WW2) could contribute to the additional sink required.Thus, the previously proposed ocean hypothesis for the 1940s plateau cannot be confirmed by independent data. Further efforts are required to reduce uncertainty in the different terms of the carbon budget during the first half of the 20th century, and to better understand the long-term variability of the ocean and terrestrial CO2 sinks.

scholarly journals Anthropogenic CO<sub>2</sub> emissions in Africa

2009 ◽  
Vol 6 (3) ◽  
pp. 463-468 ◽  
Author(s):  
J. G. Canadell ◽  
M. R. Raupach ◽  
R. A. Houghton
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Co2 Emissions ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Global Average ◽  
The World ◽  
Per Capita ◽  
Global Emissions ◽  
Fossil Fuel Emissions

Abstract. An understanding of the regional contributions and trends of anthropogenic carbon dioxide (CO2) emissions is critical to design mitigation strategies aimed at stabilizing atmospheric greenhouse gases. Here we report CO2 emissions from the combustion of fossil fuels and land use change in Africa for various time periods. Africa was responsible for an average of 500 Tg C y−1 for the period 2000–2005. These emissions resulted from the combustion of fossil fuels (260 Tg C y−1) and land use change (240 Tg C y−1). Over this period, the African share of global emissions from land use change was 17%. For 2005, the last year reported in this study, African fossil fuel emissions were 285 Tg C accounting for 3.7% of the global emissions. The 2000–2005 growth rate in African fossil fuel emissions was 3.2% y−1, very close to the global average. Fossil fuel emissions per capita in Africa are among the lowest in the world, at 0.32 t C y−1 compared to the global average of 1.2 t C y−1. The average amount of carbon (C) emitted as CO2 to produce 1 US{$} of Gross Domestic Product (GDP) in Africa was 187 g C/$ in 2005, close to the world average of 199 g C/$. With the fastest population growth in the world and rising per capita GDP, Africa is likely to increase its share of global emissions over the coming decades although emissions from Africa will remain low compared to other continents.

scholarly journals Anthropogenic CO<sub>2</sub> emissions in Africa

2008 ◽  
Vol 5 (6) ◽  
pp. 4395-4411 ◽  
Author(s):  
J. G. Canadell ◽  
M. R. Raupach ◽  
R. A. Houghton
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Co2 Emissions ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Global Average ◽  
The World ◽  
Per Capita ◽  
Global Emissions ◽  
Fossil Fuel Emissions

Abstract. An understanding of the regional contributions and trends of anthropogenic carbon dioxide (CO2) emissions is critical to design mitigation strategies aimed at stabilizing atmospheric greenhouse gases. Here we report CO2 emissions from the combustion of fossil fuels and land use change in Africa for various time periods. Africa was responsible for an average of 500 TgC y−1 for the period 2000–2005. These emissions resulted from the combustion of fossil fuels (260 TgC y−1) and land use change (240 TgC y−1). Over this period, the African share of global emissions from land use change was 17%. For 2005, the last year reported in this study, African fossil fuel emissions were 285 TgC accounting for 3.7% of the global emissions. The 2000–2005 growth rate in African fossil fuel emissions was 3.2% y−1, very close to the global average. Fossil fuel emissions per capita in Africa are among the lowest in the world, at 0.32 tC y−1 compared to the global average of 1.2 tC y−1. The average amount of carbon (C) emitted as CO2 to produce 1 US $ of Gross Domestic Product (GDP) in Africa in 2005 was 187 gC/$, close to the world average of 199 gC/$. With the fastest population growth in the world and rising per capita GDP, Africa is likely to increase its share of global emissions over the coming decades although emissions from Africa will remain low compared to other continents.

scholarly journals The Australian terrestrial carbon budget

2012 ◽  
Vol 9 (9) ◽  
pp. 12259-12308 ◽  
Author(s):  
V. Haverd ◽  
M. R. Raupach ◽  
P. R. Briggs ◽  
J. G. Canadell ◽  
S. J. Davis ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
Carbon Budget ◽  
Fossil Fuel ◽  
Net Primary Production ◽  
Total Carbon ◽  
Regional Studies ◽  
Australian Continent ◽  
The Mean ◽  
Riverine Export ◽  
Fossil Fuel Emissions

Abstract. This paper reports a study of the full carbon (C-CO2) budget of the Australian continent, focussing on 1990–2011 in the context of estimates over two centuries. The work is a contribution to the RECCAP (REgional Carbon Cycle Assessment and Processes) project, as one of numerous regional studies being synthesised in RECCAP. In constructing the budget, we estimate the following component carbon fluxes: Net Primary Production (NPP); Net Ecosystem Production (NEP); fire; Land Use Change (LUC); riverine export; dust export; harvest (wood, crop and livestock) and fossil fuel emissions (both territorial and non-territorial). The mean NEP reveals that climate variability and rising CO2 contributed 12 ± 29 (1σ error on mean) and 68 ± 35 Tg C yr−1 respectively. However these gains were partially offset by fire and LUC (along with other minor fluxes), which caused net losses of 31 ± 5 Tg C yr−1 and 18 ± 7 Tg C yr−1 respectively. The resultant Net Biome Production (NBP) of 31 ± 35 Tg C yr−1 offset fossil fuel emissions (95 ± 6 Tg C yr−1) by 32 ± 36%. The interannual variability (IAV) in the Australian carbon budget exceeds Australia's total carbon emissions by fossil fuel combustion and is dominated by IAV in NEP. Territorial fossil fuel emissions are significantly smaller than the rapidly growing fossil fuel exports: in 2009–2010, Australia exported 2.5 times more carbon in fossil fuels than it emitted by burning fossil fuels.

scholarly journals The 21st Century Coal Question: China, India, Development, and Climate Change

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 476
Author(s):  
Kevin J. Warner ◽  
Glenn A. Jones
Keyword(s):  
Climate Change ◽  
Renewable Energy ◽  
Population Growth ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Renewable Energy Sources ◽  
Community Based ◽  
China And India ◽  
Development Goals ◽  
Fossil Fuel Emissions

China and India are not only the two most populous nations on Earth, they are also two of the most rapidly growing economies. Historically, economic and social development have been subsidized by cheap and abundant fossil-fuels. Climate change from fossil-fuel emissions has resulted in the need to reduce fossil-fuel emissions in order to avoid catastrophic warming. If climate goals are achieved, China and India will have been the first major economies to develop via renewable energy sources. In this article, we examine the factors of projected population growth, available fossil-fuel reserves, and renewable energy installations required to develop scenarios in which both China and India may increase per capita energy consumption while remaining on trach to meet ambitious climate goals. Here, we show that China and India will have to expand their renewable energy infrastructure at unprecedented rates in order to support both population growth and development goals. In the larger scope of the literature, we recommend community-based approaches to microgrid and cookstove development in both China and India.

scholarly journals The impact of human and livestock respiration on CO2 emissions from 14 global cities

2020 ◽  
Author(s):  
Qixiang Cai ◽  
Ning Zeng ◽  
Fang Zhao ◽  
Pengfei Han ◽  
Di Liu ◽  
...  
Keyword(s):  
Urban Areas ◽  
Fossil Fuels ◽  
Carbon Budget ◽  
Fossil Fuel ◽  
Large City ◽  
Global Scale ◽  
Emissions Inventory ◽  
Budget Analysis ◽  
The Impact ◽  
Fossil Fuel Emissions

Abstract BackgroundThe CO2 released by humans and livestock through digestion and decomposition is an important part of the urban carbon cycle. But this part is reraly condidarded in the stuties of city carbon budget since its annual magnitude is lower than that of fossil fuel emissions within the boundaries of cities. However, human and livestock respiration may be substantial compared to fossil fuel emissions in areas with high population density such as Manhattan or Beijing. High-resolution datasets of CO2 release from respiration also have rarely been reported on a global scale or in cities globally. Here, we estimate the CO2 released by human and livestock respiration at global and large city scales and then compare it with the carbon emissions inventory from fossil fuels in 14 cities worldwide.ResultsThe results show that the total human and livestock respiration is up to 38.1% of fossil fuel emissions for Delhi among the studied cities. The proportion could be larger than 10% in cities of Sao Paulo, Cape Town and Tokyo. In other cities, it is raletivily small with a proportion around 5%, while Washington DC has the least proportion in 2.8%. In addition, almost 90% of respiratory carbon comes from urban areas in most cities, while up to one-third comes from suburban areas in Beijing on account of the siginificant livestock production.ConclusionThe results suggest that the respiration of humans and livestock represents a significant CO2 source in some cities and is nonnegligible for city carbon budget analysis and carbon monitoring.

Engineering and Economic Models of Vertical Axis Wind Turbines

2017 ◽  
Author(s):  
Elhadji Alpha A. Bah ◽  
Lakshmi N. Sankar ◽  
Jechiel I. Jagoda
Keyword(s):  
Wind Turbines ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Vertical Axis ◽  
Dynamic Stall ◽  
Economic Viability ◽  
Vertical Axis Wind Turbines ◽  
Many Sources ◽  
A Site ◽  
Fossil Fuel Emissions

The interest in sustainable forms of energy is being driven by the anticipated scarcity of traditional fossil fuels over the coming decades. There is also a growing concern about the effects of fossil fuel emissions on human health and the environment. Many sources of renewable energy are being researched and implemented for power production. In particular, wind power generation by vertical-axis wind turbines is one of the option often considered. This option offers a robust design because of the relative simplicity of its technology. However, it also presents challenges that are inherent to its very concept. These systems suffer from dynamic stall, noticeably one of the main causes of the loss of performance. A dual-element concept is proposed as a way of alleviating the losses due to the dynamic stall. An economic analysis is done to establish the economic viability of the model. The Great Coast of Senegal is selected as a site of operation in this study.

scholarly journals Bio-energy and CO2 emission reductions: an integrated land-use and energy sector perspective

2020 ◽  
Vol 163 (3) ◽  
pp. 1675-1693 ◽  
Author(s):  
Nico Bauer ◽  
David Klein ◽  
Florian Humpenöder ◽  
Elmar Kriegler ◽  
Gunnar Luderer ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Climate Change Mitigation ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Energy Sector ◽  
Emission Mitigation ◽  
Model Framework ◽  
Context Variables ◽  
Change Mitigation

AbstractBiomass feedstocks can be used to substitute fossil fuels and effectively remove carbon from the atmosphere to offset residual CO2 emissions from fossil fuel combustion and other sectors. Both features make biomass valuable for climate change mitigation; therefore, CO2 emission mitigation leads to complex and dynamic interactions between the energy and the land-use sector via emission pricing policies and bioenergy markets. Projected bioenergy deployment depends on climate target stringency as well as assumptions about context variables such as technology development, energy and land markets as well as policies. This study investigates the intra- and intersectorial effects on physical quantities and prices by coupling models of the energy (REMIND) and land-use sector (MAgPIE) using an iterative soft-link approach. The model framework is used to investigate variations of a broad set of context variables, including the harmonized variations on bioenergy technologies of the 33rd model comparison study of the Stanford Energy Modeling Forum (EMF-33) on climate change mitigation and large scale bioenergy deployment. Results indicate that CO2 emission mitigation triggers strong decline of fossil fuel use and rapid growth of bioenergy deployment around midcentury (~ 150 EJ/year) reaching saturation towards end-of-century. Varying context variables leads to diverse changes on mid-century bioenergy markets and carbon pricing. For example, reducing the ability to exploit the carbon value of bioenergy increases bioenergy use to substitute fossil fuels, whereas limitations on bioenergy supply shift bioenergy use to conversion alternatives featuring higher carbon capture rates. Radical variations, like fully excluding all technologies that combine bioenergy use with carbon removal, lead to substantial intersectorial effects by increasing bioenergy demand and increased economic pressure on both sectors. More gradual variations like selective exclusion of advanced bioliquid technologies in the energy sector or changes in diets mostly lead to substantial intrasectorial reallocation effects. The results deepen our understanding of the land-energy nexus, and we discuss the importance of carefully choosing variations in sensitivity analyses to provide a balanced assessment.

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