Decadal variability in land carbon sink efficiency

Abstract Background The climate mitigation target of limiting the temperature increase below 2 °C above the pre-industrial levels requires the efforts from all countries. Tracking the trajectory of the land carbon sink efficiency is thus crucial to evaluate the nationally determined contributions (NDCs). Here, we define the instantaneous land sink efficiency as the ratio of natural land carbon sinks to emissions from fossil fuel and land-use and land-cover change with a value of 1 indicating carbon neutrality to track its temporal dynamics in the past decades. Results Land sink efficiency has been decreasing during 1957–1990 because of the increased emissions from fossil fuel. After the effect of the Mt. Pinatubo eruption diminished (after 1994), the land sink efficiency firstly increased before 2009 and then began to decrease again after 2009. This reversal around 2009 is mostly attributed to changes in land sinks in tropical regions in response to climate variations. Conclusions The decreasing trend of land sink efficiency in recent years reveals greater challenges in climate change mitigation, and that climate impacts on land carbon sinks must be accurately quantified to assess the effectiveness of regional scale climate mitigation policies.

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Decadal Variability in Land Carbon Sink Efficiency Reveals Apparent Trend Reversal After 2009

10.21203/rs.3.rs-101487/v1 ◽

2020 ◽

Author(s):

Lei Zhu ◽

Philippe Ciais ◽

Ana Bastos ◽

Ashley P. Ballantyne ◽

Frederic Chevallier ◽

...

Keyword(s):

Fossil Fuel ◽

Decadal Variability ◽

Temporal Dynamics ◽

Carbon Sink ◽

Climate Mitigation ◽

Carbon Sinks ◽

Carbon Neutrality ◽

A Value ◽

Natural Land ◽

Nationally Determined Contributions

Abstract Background: The climate mitigation target of limiting the temperature increase below 2 °C above the pre-industrial levels requires the efforts from all countries. Tracking the trajectory of the land carbon sink efficiency is thus crucial to evaluate the nationally determined contributions (NDCs). Here, we define the instantaneous land sink efficiency as the ratio of natural land carbon sinks to emissions from fossil fuel and land-use and land-cover change with a value of 1 indicating carbon neutrality to track its temporal dynamics in the past decades.Results: Land sink efficiency has been decreasing during 1957-1990 because of the increased emissions from fossil fuel. After the effect of the Pinatubo eruption diminished (after 1994), the land sink efficiency firstly increased before 2009 and then began to decrease again after 2009. This reversal around 2009 is mostly attributed to changes in land sinks in Latin America in response to climate variations.Conclusions: The decreasing trend of land sink efficiency in the recent years reveals greater challenges in climate change mitigation, and impacts of climate on land carbon sinks need to be accurately quantified to assess the implementation of climate mitigation policies.

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Estimating net climate impacts of timber production and utilization in fossil fuel intensive material and energy substitution

Canadian Journal of Forest Research ◽

10.1139/cjfr-2016-0525 ◽

2017 ◽

Vol 47 (8) ◽

pp. 1010-1020 ◽

Cited By ~ 3

Author(s):

Ashraful Alam ◽

Harri Strandman ◽

Seppo Kellomäki ◽

Antti Kilpeläinen

Keyword(s):

Forest Management ◽

Life Span ◽

Fossil Fuel ◽

Assessment Tool ◽

Forest Biomass ◽

Climate Impact ◽

Climate Impacts ◽

Mitigation Strategies ◽

Climate Mitigation ◽

Similar System

We utilized an ecosystem model and life cycle assessment tool for studying carbon flows between the ecosystem, technosystem, and atmosphere for scenarios utilizing forest biomass (biosystem) against fossil fuel intensive materials (fossil system). The net climate impacts were studied for a Norway spruce (Picea abies (L.) Karst.) stand over two consecutive rotation periods (2 × 80 years) in the boreal conditions in central Finland (62°N, 29°E). The effects of alternative forest management on the carbon dynamics in the biosystem were studied in comparison with the fossil system by using an unmanaged and baseline thinning regime. The results showed that the biosystem produced carbon benefits compared with the similar system with the use of fossil fuel intensive materials and energy. The unmanaged stand stored the highest amount of carbon and retained carbon the longest when solely the ecosystem was considered. Studying the ecosystem and the technosystem together, the biosystem was found effective in storing and increasing the residence of carbon with or without changing the life span of biomass-based products. We found that the increase of the life span of biomass-based products could reduce emissions up to 0.28 t CO2·ha−1·year−1 depending on the management regimes over the study period. The increased stocking regimes could increase negative net climate impact by 47% over the study period compared with the use of baseline thinning in the biosystem. The proper climate mitigation strategies should consider the benefits from forest management and forest biomass in storing carbon into both the ecosystem and technosystem.

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Carbon Fluxes and Stocks by Mexican Tropical Forested Wetland Soils: A Critical Review of Its Role for Climate Change Mitigation

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17207372 ◽

2020 ◽

Vol 17 (20) ◽

pp. 7372

Author(s):

Sergio Zamora ◽

Luis Carlos Sandoval-Herazo ◽

Gastón Ballut-Dajud ◽

Oscar Andrés Del Ángel-Coronel ◽

Erick Arturo Betanzo-Torres ◽

...

Keyword(s):

Climate Change ◽

Soil Carbon ◽

Carbon Sink ◽

Carbon Stocks ◽

Response Strategy ◽

Forested Wetland ◽

Wetland Soils ◽

Carbon Sinks ◽

Tropical Regions ◽

Global Carbon

Wetland soils are important stores of soil carbon (C) in the biosphere, and play an important role in global carbon cycles in the response strategy to climate change. However, there areknowledge gaps in our understanding of the quantity and distribution in tropical regions. Specifically, Mexican wetlands have not been considered in global carbon budgets or carbon balances for a number of reasons, such as: (1) the lack of data, (2) Spanish publications have not been selected, or (3) because such balances are mainly made in the English language. This study analyzes the literature regarding carbon stocks, sequestration and fluxes in Mexican forested wetlands (Forest-W). Soil carbon stocks of 8, 24.5 and 40.1 kg cm−2 were detected for flooded palms, mangroves, and freshwater or swamps (FW) wetland soils, respectively, indicating that FW soils are the Forest-W with more potential for carbon sinks (p = 0.023), compared to mangroves and flooded palm soils. While these assessments of carbon sequestration were ranged from 36 to 920 g-C m−2 year−1, C emitted as methane was also tabulated (0.6–196 g-C m−2 year−1). Subtracting the C emitted of the C sequestered, 318.2 g-C m−2 year−1 were obtained. Such data revealed that Forest-W function is mainly as carbon sink, and not C source. This review can help to inform practitioners in future decisions regarding sustainable projects, restoration, conservation or creation of wetlands. Finally, it is concluded that Forest-W could be key ecosystems in strategies addressing the mitigation of climate change through carbon storage. However, new studies in this research line and public policies that protect these essential carbon sinks are necessary in order to, hopefully, elaborate global models to make more accurate predictions about future climate.

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Differences of the inverted terrestrial ecosystem carbon flux between using GOSAT and OCO-2 XCO<sub>2</sub> retrievals

10.5194/acp-2018-1175 ◽

2018 ◽

Cited By ~ 1

Author(s):

Hengmao Wang ◽

Fei Jiang ◽

Jun Wang ◽

Weimin Ju ◽

Jing M. Chen

Keyword(s):

Growth Rate ◽

Carbon Flux ◽

Carbon Sink ◽

Terrestrial Ecosystem ◽

Carbon Fluxes ◽

Carbon Sinks ◽

Tropical Regions ◽

Mixing Ratios ◽

Ecosystem Carbon ◽

Spatial Coverage

Abstract. In this study, both the Greenhouse Gases Observing Satellite (GOSAT) and the Orbiting Carbon Observatory 2 (OCO-2) XCO2 retrievals are assimilated within the GEOS-Chem 4D-Var assimilation framework to constrain the terrestrial ecosystem carbon flux during Jul 1, 2014 to Dec 31, 2015. The inverted global and regional carbon fluxes during Jan 1 to Dec 31, 2015 are shown and discussed. Surface CO2 mixing ratios from 47 surface flask sites and XCO2 measurements from 13 TCCON sites are used to evaluate the simulated concentrations with the posteriori carbon fluxes. The results show that globally, the terrestrial ecosystem carbon sink (excluding biomass burning emissions) estimated from GOSAT data is stronger than that inferred from OCO-2 data, and the annual atmospheric CO2 growth rate estimated from GOSAT data is more consistent with the estimate of GCP 2017. Regionally, in most regions, the land sinks inferred from GOSAT data are also stronger than those from OCO-2 data. Compared with the prior fluxes, the carbon fluxes in northern temperate regions change most, followed by tropical and southern temperate regions, and the smallest changes occur in boreal regions. Basically, in temperate regions, the inferred land sinks are significantly increased, while those in tropical regions are decreased. The different changes in different regions are mainly related to the spatial coverage and the amount of XCO2 data in these regions. Compared with CT2016, the inferred carbon sinks are comparable in most temperate regions, but much weaker in boreal and tropical regions. Evaluations using flask and TCCON observations suggest that GOSAT and OCO-2 data, can effectively improve the carbon flux estimates in the northern hemisphere, while in the southern hemisphere the optimized carbon sinks may be overestimated, especially for GOSAT data.

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The Method of Measuring Carbon Sinks Based on the Changes of oxygen concentration in Forest Canopy

10.21203/rs.3.rs-1141066/v1 ◽

2021 ◽

Author(s):

CHANGSHAN XING ◽

JIANG LV ◽

YUN SHI

Keyword(s):

Carbon Dioxide ◽

Carbon Sequestration ◽

Oxygen Concentration ◽

Forest Canopy ◽

Carbon Sink ◽

Accurate Method ◽

Growth Cycle ◽

Forest Carbon ◽

Carbon Sinks ◽

Carbon Neutrality

Abstract Measuring Forest Carbon Sinks is becoming a popular topic as the need of many countries’ carbon neutrality plans. We demonstrate a simple and accurate method of Forest Carbon Sinks measurement. By observing the daily average oxygen concentration in the canopy, we found it presented a parabolic distribution from Spring to Fall in a year. The forest finished the cycle from releasing oxygen and sequestrating carbon dioxide to using oxygen and releasing carbon dioxide in this period. We calculated the carbon sequestration of the forest was 101.39t/hm2/y, the Carbon Sink was 15.09t/hm2/y by calculating the changes of oxygen concentration in a growth cycle, the Carbon Sink is 16.29% of the carbon sequestration.

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A multiresolution spatial parameterization for the estimation of fossil-fuel carbon dioxide emissions via atmospheric inversions

Geoscientific Model Development ◽

10.5194/gmd-7-1901-2014 ◽

2014 ◽

Vol 7 (5) ◽

pp. 1901-1918 ◽

Cited By ~ 5

Author(s):

J. Ray ◽

V. Yadav ◽

A. M. Michalak ◽

B. van Bloemen Waanders ◽

S. A. McKenna

Keyword(s):

Spatial Variability ◽

Carbon Dioxide Emissions ◽

Fossil Fuel ◽

Matching Pursuit ◽

Regional Scale ◽

Reconstruction Algorithm ◽

Spatiotemporal Variability ◽

Realistic Representation ◽

Non Gaussian ◽

Low Dimensional

Abstract. The characterization of fossil-fuel CO2 (ffCO2) emissions is paramount to carbon cycle studies, but the use of atmospheric inverse modeling approaches for this purpose has been limited by the highly heterogeneous and non-Gaussian spatiotemporal variability of emissions. Here we explore the feasibility of capturing this variability using a low-dimensional parameterization that can be implemented within the context of atmospheric CO2 inverse problems aimed at constraining regional-scale emissions. We construct a multiresolution (i.e., wavelet-based) spatial parameterization for ffCO2 emissions using the Vulcan inventory, and examine whether such a~parameterization can capture a realistic representation of the expected spatial variability of actual emissions. We then explore whether sub-selecting wavelets using two easily available proxies of human activity (images of lights at night and maps of built-up areas) yields a low-dimensional alternative. We finally implement this low-dimensional parameterization within an idealized inversion, where a sparse reconstruction algorithm, an extension of stagewise orthogonal matching pursuit (StOMP), is used to identify the wavelet coefficients. We find that (i) the spatial variability of fossil-fuel emission can indeed be represented using a low-dimensional wavelet-based parameterization, (ii) that images of lights at night can be used as a proxy for sub-selecting wavelets for such analysis, and (iii) that implementing this parameterization within the described inversion framework makes it possible to quantify fossil-fuel emissions at regional scales if fossil-fuel-only CO2 observations are available.

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Investigating the Spatio-Temporal Variation of Soil Moisture and Agricultural Drought towards Supporting Water Resources Management in the Red River Basin of Vietnam

Sustainability ◽

10.3390/su13094926 ◽

2021 ◽

Vol 13 (9) ◽

pp. 4926

Author(s):

Nguyen Duc Luong ◽

Nguyen Hoang Hiep ◽

Thi Hieu Bui

Keyword(s):

Soil Moisture ◽

River Basin ◽

Temporal Dynamics ◽

Regional Scale ◽

Dry Season ◽

Red River ◽

Agricultural Drought ◽

Severe Drought ◽

Red River Basin ◽

Spatio Temporal

The increasing serious droughts recently might have significant impacts on socioeconomic development in the Red River basin (RRB). This study applied the variable infiltration capacity (VIC) model to investigate spatio-temporal dynamics of soil moisture in the northeast, northwest, and Red River Delta (RRD) regions of the RRB part belongs to territory of Vietnam. The soil moisture dataset simulated for 10 years (2005–2014) was utilized to establish the soil moisture anomaly percentage index (SMAPI) for assessing intensity of agricultural drought. Soil moisture appeared to co-vary with precipitation, air temperature, evapotranspiration, and various features of land cover, topography, and soil type in three regions of the RRB. SMAPI analysis revealed that more areas in the northeast experienced severe droughts compared to those in other regions, especially in the dry season and transitional months. Meanwhile, the northwest mainly suffered from mild drought and a slightly wet condition during the dry season. Different from that, the RRD mainly had moderately to very wet conditions throughout the year. The areas of both agricultural and forested lands associated with severe drought in the dry season were larger than those in the wet season. Generally, VIC-based soil moisture approach offered a feasible solution for improving soil moisture and agricultural drought monitoring capabilities at the regional scale.

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Pathways of China's PM2.5 air quality 2015–2060 in the context of carbon neutrality

National Science Review ◽

10.1093/nsr/nwab078 ◽

2021 ◽

Author(s):

Jing Cheng ◽

Dan Tong ◽

Qiang Zhang ◽

Yang Liu ◽

Yu Lei ◽

...

Keyword(s):

Air Pollution ◽

Air Quality ◽

Critical Role ◽

Climate Mitigation ◽

Air Pollution Control ◽

Carbon Neutrality ◽

Climate Action ◽

Clean Air ◽

Near Term ◽

Who Guideline

ABSTRACT Clean air policies in China have substantially reduced PM2.5 air pollution in recent years, primarily by curbing end-of-pipe emissions. However, further reaching the WHO guideline may instead depend upon the air quality co-benefits of ambitious climate action. Here, we assess pathways of Chinese PM2.5 air quality from 2015 to 2060 under a combination of scenarios which link Global and China's climate mitigation pathways (i.e. global 2°C- and 1.5°C-pathways, NDC pledges, and carbon neutrality goals) to local clean air policies. We find that China can achieve both its near-term climate goals (peak emissions) and PM2.5 air quality annual standard (35 μg/m3) by 2030 by fulfilling its NDC pledges and continuing air pollution control policies. However, the benefits of end-of-pipe control reductions are mostly exhausted by 2030, and reducing PM2.5 exposure of the majority of the Chinese population to below 10 μg/m3 by 2060 will likely require more ambitious climate mitigation efforts such as China's carbon neutrality goals and global 1.5°C-pathways. Our results thus highlight that China's carbon neutrality goals will play a critical role in reducing air pollution exposure to the WHO guideline and protecting public health.

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Modelling Tree Growth in Monospecific Forests from Forest Inventory Data

Forests ◽

10.3390/f12060753 ◽

2021 ◽

Vol 12 (6) ◽

pp. 753

Author(s):

Guadalupe Sáez-Cano ◽

Marcos Marvá ◽

Paloma Ruiz-Benito ◽

Miguel A. Zavala

Keyword(s):

Tree Growth ◽

Large Scale ◽

Temporal Dynamics ◽

Carbon Sink ◽

Size Variation ◽

Biotic Interactions ◽

Richards Equation ◽

Tree Level ◽

Forest Inventories ◽

Large Scale Data

The prediction of tree growth is key to further understand the carbon sink role of forests and the short-term forest capacity on climate change mitigation. In this work, we used large-scale data available from three consecutive forest inventories in a Euro-Mediterranean region and the Bertalanffy–Chapman–Richards equation to model up to a decade’s tree size variation in monospecific forests in the growing stages. We showed that a tree-level fitting with ordinary differential equations can be used to forecast tree diameter growth across time and space as function of environmental characteristics and initial size. This modelling approximation was applied at different aggregation levels to monospecific regions with forest inventories to predict trends in aboveground tree biomass stocks. Furthermore, we showed that this model accurately forecasts tree growth temporal dynamics as a function of size and environmental conditions. Further research to provide longer term prediction forest stock dynamics in a wide variety of forests should model regeneration and mortality processes and biotic interactions.

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Large but decreasing effect of ozone on the European carbon sink

Biogeosciences ◽

10.5194/bg-15-4245-2018 ◽

2018 ◽

Vol 15 (13) ◽

pp. 4245-4269 ◽

Cited By ~ 14

Author(s):

Rebecca J. Oliver ◽

Lina M. Mercado ◽

Stephen Sitch ◽

David Simpson ◽

Belinda E. Medlyn ◽

...

Keyword(s):

Carbon Storage ◽

Primary Productivity ◽

Carbon Sink ◽

Spatial Scales ◽

Stomatal Closure ◽

Regional Scale ◽

Surface Model ◽

Background Concentrations ◽

Tropospheric O3 ◽

The Impact

Abstract. The capacity of the terrestrial biosphere to sequester carbon and mitigate climate change is governed by the ability of vegetation to remove emissions of CO2 through photosynthesis. Tropospheric O3, a globally abundant and potent greenhouse gas, is, however, known to damage plants, causing reductions in primary productivity. Despite emission control policies across Europe, background concentrations of tropospheric O3 have risen significantly over the last decades due to hemispheric-scale increases in O3 and its precursors. Therefore, plants are exposed to increasing background concentrations, at levels currently causing chronic damage. Studying the impact of O3 on European vegetation at the regional scale is important for gaining greater understanding of the impact of O3 on the land carbon sink at large spatial scales. In this work we take a regional approach and update the JULES land surface model using new measurements specifically for European vegetation. Given the importance of stomatal conductance in determining the flux of O3 into plants, we implement an alternative stomatal closure parameterisation and account for diurnal variations in O3 concentration in our simulations. We conduct our analysis specifically for the European region to quantify the impact of the interactive effects of tropospheric O3 and CO2 on gross primary productivity (GPP) and land carbon storage across Europe. A factorial set of model experiments showed that tropospheric O3 can suppress terrestrial carbon uptake across Europe over the period 1901 to 2050. By 2050, simulated GPP was reduced by 4 to 9 % due to plant O3 damage and land carbon storage was reduced by 3 to 7 %. The combined physiological effects of elevated future CO2 (acting to reduce stomatal opening) and reductions in O3 concentrations resulted in reduced O3 damage in the future. This alleviation of O3 damage by CO2-induced stomatal closure was around 1 to 2 % for both land carbon and GPP, depending on plant sensitivity to O3. Reduced land carbon storage resulted from diminished soil carbon stocks consistent with the reduction in GPP. Regional variations are identified with larger impacts shown for temperate Europe (GPP reduced by 10 to 20 %) compared to boreal regions (GPP reduced by 2 to 8 %). These results highlight that O3 damage needs to be considered when predicting GPP and land carbon, and that the effects of O3 on plant physiology need to be considered in regional land carbon cycle assessments.

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