Due to the combined effects of carbon emission and carbon sink, agriculture is acknowledged as an essential contributor to achieve the Chinese government's carbon neutrality goal of 2060, and carbon ...footprint (CF) and carbon footprint intensity are substantial indicators to reveal the carbon emission level. For these reasons, the Theil index technique and extended STIRPAT model were employed to evaluate their spatiotemporal heterogeneity and influencing factors using panel data from 31 provinces for the period 1997–2019. The findings revealed that the CF showed an increasing trend with an annual growth rate of 24.6 %. The carbon footprint intensity (CFI) indicated an evident spatiotemporal heterogeneity and transferred over time, with an average growth rate of 19.82 %. The CFI Theil index and its contribution rate both confirmed that intra-regional difference is the main source of the overall difference, among which, the CFI Theil index displayed the distribution feature of “western (11.50 %) > central (11.12 %) > eastern (10.56 %) > northeast (6.61 %). The contribution rate of CFI illustrated the spatial pattern of “eastern (33.74 %) > central (21.07 %) > western (19.87 %) > northeast (5.24 %). Furthermore, the influencing effects of GDP per capita, planting structure, population density and urbanization level on CF and CFI also demonstrate evident spatiotemporal heterogeneity.
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•Carbon sink is considered into the CF and CFI accounting system.•Theil index method and STIRPAT model are applied to conduct empirical analysis.•CF increased 24.6 % per year and demonstrates “central > northeast > eastern > western”.•CFI presented a spatiotemporal heterogeneity with an average growth rate of 19.82 %.•The influencing effect of CF and CFI indicates obvious spatiotemporal heterogeneity.
The long-term stressful utilization of forests and grasslands has led to ecosystem degradation and C loss. Since the late 1970s China has launched six key national ecological restoration projects to ...protect its environment and restore degraded ecosystems. Here, we conducted a large-scale field investigation and a literature survey of biomass and soil C in China’s forest, shrubland, and grassland ecosystems across the regions where the six projects were implemented (∼16% of the country’s land area). We investigated the changes in the C stocks of these ecosystems to evaluate the contributions of the projects to the country’s C sink between 2001 and 2010. Over this decade, we estimated that the total annual C sink in the project region was 132 Tg C per y (1 Tg = 1012 g), over half of which (74 Tg C per y, 56%) was attributed to the implementation of the projects. Our results demonstrate that these restoration projects have substantially contributed to CO₂ mitigation in China.
Hidden carbon sink beneath desert Li, Yan; Wang, Yu-Gang; Houghton, R. A. ...
Geophysical research letters,
28 July 2015, Volume:
42, Issue:
14
Journal Article
Peer reviewed
Open access
For decades, global carbon budget accounting has identified a “missing” or “residual” terrestrial sink; i.e., carbon dioxide (CO2) released by anthropogenic activities does not match changes observed ...in the atmosphere and ocean. We discovered a potentially large carbon sink in the most unlikely place on earth, irrigated saline/alkaline arid land. When cultivating and irrigating arid/saline lands in arid zones, salts are leached downward. Simultaneously, dissolved inorganic carbon is washed down into the huge saline aquifers underneath vast deserts, forming a large carbon sink or pool. This finding points to a direct, rapid link between the biological and geochemical carbon cycles in arid lands which may alter the overall spatial pattern of the global carbon budget.
Key Points
An active carbon sink results from irrigation of saline/alkaline soils in arid zones
A huge inorganic carbon pool has accumulated in the groundwater beneath deserts
Under the new vista of carbon neutrality, all industries in China face new challenges. As the pillar industry for fossil energy, the coal industry cannot blindly “de-coal”. It is necessary to combine ...the two-way force associated with abandoned mines to turn energy into resources and problems into solutions. Innovation that combines emission reduction and neutralization can overcome the bottlenecks in carbon neutralization in abandoned mines, and help achieve the national carbon peak in 2030 and carbon neutrality in 2060. This involves the entire life cycle of the mine, including the status quo of abandoned coal mines, and the development of downstream industries. The development mode of resource utilization in abandoned mines in accordance with the national situation was summarized, and the suggestion of carbon neutralization in abandoned mines was put forward, which involves three steps: (1) Define the value of abandoned mines, consolidate energy market share, enjoy the policy dividend, and realize carbon neutralization breakthrough; (2) list the development path of carbon neutralization in abandoned mines, utilize photosynthesis to sequester carbon, combine industrial advantages to promote the development of a new energy industry, promote the integration of carbon emission, gathering, sequestration and utilization, realize carbon sequestration and mineralization in terminals and participate in carbon sink market allocation; (3) promote multiple simultaneous measures to solve existing problems, develop abandoned mines, and implement carbon neutralization goals.
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•Recognize the status of coal mines and achieve breakthroughs in carbon neutrality•Promote clean new energy construction and land restoration in the industry•Realize the integration of carbon emission-collection-storage-utilization•Participate in carbon sink market allocation and promote carbon neutrality•Put forward policy recommendations and get through the implementation blockages
The carbon burial and greenhouse gas emissions of lakes are pivotal in the global carbon cycle to offset or accelerate global warming. However, their balance or the magnitude of anthropogenic ...increase of carbon burial remains uncertain in global lakes. Here, we quantified the carbon sink dynamics and the sink-source balance in global lakes with effect-size metrics, that is, the log-response ratio of organic carbon burial between post-1950 and pre-1900 periods and the carbon balance ratio between carbon burial and greenhouse gas emissions, respectively. The organic carbon burial ratios revealed an average increase of 2.45 times in carbon burial rates during the Anthropocene, while the carbon balance ratios were negative in 82.68% of lakes, indicating that most lakes had lower burial rates than emission rates and acted as carbon sources rather than carbon sinks. The organic carbon burial ratios exhibited a significantly decreasing latitudinal trend and were mainly influenced by lake’s trophic state with the explained variation of 44.79%. They were also indirectly influenced by climate, lake morphometry, and catchment properties through their interactions with the lake’s trophic state. The carbon balance ratios, however, showed a nonsignificant latitudinal trend. They were primarily affected by lake catchment properties with the explained variation of 26.21% and were also indirectly affected by climate variables via the interactions with catchment properties. Overall, our study highlights that human activities such as lake eutrophication and catchment changes have altered the carbon sink and source in global lakes during the Anthropocene, and are essential drivers for future evaluations of lake carbon budgets.
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•NPP and carbon sink capacity showed an increasing trend.•NPP is more sensitive to precipitation than temperature in Shaanxi.•NPP shows a bimodal variation with elevation in Shaanxi.•NPP changes ...caused by land use are related to the structural differences and the transfer between different land use types.
Exploring the spatiotemporal variation in vegetation net primary productivity (NPP), analyzing the relationships between NPP and its influencing factors, and evaluating the vegetation carbon sink capacity are vital for ecological protection and restoration in Shaanxi Province, an area in China with a complex environment. In this study, the Mann-Kendall trend test, difference analysis, and variation stability analysis were used to analyze the spatiotemporal variation in NPP; partial correlation analysis and a land use change matrix were used to analyze the relationships between NPP and its influencing factors; and an estimation model of net ecosystem productivity (NEP) was used to evaluate the carbon sink capacity of vegetation based on the NPP product of the MOD17A3HGF dataset. The following results were obtained. (1) The average annual NPP in Shaanxi showed an increasing trend from 2000 to 2019, and its variation stability showed an increasing trend from the north to the south. (2) The average annual NPP in the south was higher than that in the north, but the increased amplitude of NPP was higher in the north and lower in the south. (3) The vegetation carbon sink capacity in Shaanxi showed an increasing trend from 2000 to 2019, and it was high in the south and low in the north. (4) NPP was more sensitive to precipitation than temperature in Shaanxi, and NPP showed a bimodal variation with elevation. The NPP changes caused by land use were related to the structural differences and the transfer between different land use types. This study provides a new perspective for the simultaneous study of spatiotemporal variation in NPP and carbon sink capacity under different natural conditions and the exploration of the factors influencing this variation. These findings are valuable for the scientific assessment of regional vegetation productivity and carbon sink capacity, as well as for the formulation of development strategies based on local realities. Our results indicate that the ecological environment in Shaanxi continuously improved in recent years, and further improvements to water resource conditions and ecological construction efforts are essential for improving the NPP and carbon sink capacity in Shaanxi.
•Global sensitivity of water use efficiency to increasing CO2 present a declining trend.•Increasing vapor pressure deficit is the main cause for the decreasing sensitivity.•CMIP6 models underestimate ...the decreasing water use efficiency sensitivity.
Ecosystem water use efficiency (WUE), which measures the ratio of carbon gain to water loss, is crucial to the global water, energy, and carbon cycles. It is an important metric in understanding how efficiently an ecosystem uses water to assimilate carbon and is affected by various environmental factors, including CO2 levels. However, the temporal dynamics of CO2-induced changes in WUE (CO2_WUE) remain uncertain. After isolating CO2_WUE from total changes in WUE, we assessed historical changes in global CO2_WUE and future projected trends. We found that the increasing atmospheric CO2 concentration enhanced global WUE by 5.65 ± 1.14 % 100 ppm−1 during 1982–2015. However, CO2-driven gains in WUE exhibit a significant declining trend across most of the Earth’s land surface during 1982–2015 (−1.38 ± 0.19 % 100 ppm−1 yr−1). This widespread CO2_WUE decline is projected to continue throughout the remainder of the 21st century. The decline in CO2_WUE implies that the global land surface is likely to witness a higher water cost to maintain the land carbon sink. This finding suggests a heightened difficulty of mitigating global warming and an elevated risk of global water scarcity. The global CO2_WUE decline is primarily driven by rising vapor pressure deficit (VPD) reducing photosynthesis and increasing total evaporation. Our findings highlight the key role of VPD in the coupling of global water and carbon cycles and reveal a continuous increase in the water cost of the global land carbon sink.
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•CaCO3 hemisphere arrays self form and organize on the solution surface without external interventions.•CaCO3 hemisphere arrays serve as templates in colloidal lithography to replace ...PS spheres.•High-performance Cu mesh TCFs are successfully prepared via the improved method.•The improved method not only saves costs but also benefits the environment.
Our works focused on the improvements of colloidal lithography applied in preparing Cu mesh transparent conductive film (TCF), a promising material for the flexible and wearable electronic devices of the next generation. By substituting polystyrene (PS) microspheres with microsized CaCO3 hemispheres in the template array and significantly improving the corresponding technology, no petrochemicals and relating manufacture equipments were involved in the proposed method. A well performed Cu mesh TCF, its light transmittance and sheet resistance were 81.0 % and 20.9 Ω/sq, respectively, could be easily and economically prepared based on the improvements. The usual etching treatment to the PS microspheres for reducing their diameters was no longer needed because of this template material related substitution. As the carbonate part of the CaCO3 hemisphere was directly taken from the CO2 in the surrounding air, our improvements not only eliminated involving any petrochemical in the template preparation, but created a real carbon sink to the environment, therefore highly consisted with green chemistry requirements and showed great industrial potentials.
In the study of global climate change, a major focus of research into the carbon cycle is to determine the fate of missing carbon sinks. Carbonate weathering-related carbon sinks as a result of ...water‑carbonate-CO2-aquatic phototroph interactions may make a major contribution. Establishing optimal land uses, which determine soil CO2 concentrations and water supplies for carbonate dissolution, may be a feasible and effective way to increase the sink potential. Elucidating both the hydrological and the hydrochemical behavior under different land uses is critical for rational planning of land use changes to increase the carbon sink. Given the complexity within natural karst catchments, the Shawan Simulation Test Site was established at Puding, Southwest China, to simulate the influence of land uses with controlled carbonate test beds - bare rock, bare soil, crop land, grass land, shrub land. Soil CO2 concentrations, hydrochemical parameters (pH, major ion concentrations) and the ‘spring’ (artificial drain) discharge were intensively measured from Sept. 1, 2015 to Aug. 31, 2016 to investigate the carbon and water responses to different land uses in different seasons. In the vegetated land uses (crop, grass or shrub), DIC increased due to the increase of soil CO2 resulting from stronger microbial activities and root respiration in summer and autumn growing seasons. In the bare rock and soil cases, there was also an increase in DIC in summer and autumn, due to decomposition of prior organic matter within soils and/or rock pores. The average DIC concentration ranking, high to low, was grass land, shrub land, crop land, bare soil, bare rock. Soil CO2 concentration was thus the dominant of DIC concentration, which is a key multiplier of carbon sink fluxes (CSF=0.5∗DIC∗RD, where RD is depth of runoff, DIC is DIC concentration, and 0.5 because in carbonate dissolution, only half of the HCO3− is of atmospheric carbon origin). However, runoff depth ranked almost in reverse order, i.e., from high to low, bare rock, bare soil, crop land, shrub land, grass land. The CSF ranking, from high to low, was grass, crop, shrub, bare rock, bare soil. A new parameter, LCIC (Land use Change Impact on CSF) is defined to compare the impacts of land use change on DIC and RD, and evaluate their combined effects on CSF. Compared to bare rock, the absolute values of LCIC (|LCIC|s) were >1, and CSFs were larger for the three tanks with vegetation cover; CSF is smaller for bare soil, |LCIC|<1. Finally, it was found that grass land may constitute an optimal land-use for increasing the carbonate weathering-related carbon sink that is critical for carbon management to counter global warming.
•Shawan Simulation Test Site was established to simulate varied land uses in karst.•Land uses determined soil CO2 and water supplies for carbonate dissolution.•A new parameter, LCIC (Land use Change Impact on CO2 flux), was proposed.•LCIC calculates the impact of land use change on CO2 flux.•Carbonate weathering-related carbon sink may be regulated by changing land uses.
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