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1.
Sci Total Environ ; 792: 148161, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34465063

RESUMO

Paludiculture, the cultivation of crops on rewetted peatlands, is often proposed as a viable climate change mitigation option that reduces greenhouse gas emissions (GHGe), while simultaneously providing novel agricultural business options. In West Europe, experiments are ongoing in using the paludicrop cattail (Typha spp.) as feedstock for insulation panel material. Here, we use a Dutch case study to investigate the environmental potential and economic viability of shifting the use of peat soils from grassland (for dairy production) to Typha paludiculture (for cultivation and insulation panel production). Using a life cycle assessment and cost-benefit analysis, we compared the global warming potential (GWP), yearly revenues and calculated Net Present Value (NPV) of 1 ha Dutch peat soil used either for dairy production or for Typha paludiculture. We estimated that changing to Typha paludiculture leads to a GWP reduction of ~32% (16.4 t CO2-eq ha-1), mainly because of lower emissions from peat decomposition as a result of land-use management (-21.6 t CO2-eq ha-1). If biogenic carbon storage is excluded, the avoided impact of conventional insulation material is insufficient to compensate the impact of cultivating and processing Typha (9.7 t CO2-eq ha-1); however, this changes if biogenic carbon storage is included (following PAS2050 guidelines). Typha paludiculture is currently not competitive with dairy production, mainly due to high cultivation costs and low revenues, which are both uncertain, and will likely improve as the system develops. Its NPV is negative, mainly due to high investment costs. This can be improved by introducing carbon credits, with carbon prices for Typha paludiculture (30 years) comparable to EU-ETS prices. In conclusion, Dutch Typha paludiculture has a significant climate change mitigation potential by reducing emissions from deep drained peatlands. Nevertheless, attention is needed to increase its economic viability as this is a key aspect of the system change.


Assuntos
Gases de Efeito Estufa , Typhaceae , Agricultura , Dióxido de Carbono/análise , Gases de Efeito Estufa/análise , Solo , Áreas Alagadas
2.
Sci Total Environ ; 792: 148479, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34465066

RESUMO

This review paper aims to identify the main sources of carbon dioxide (CO2) emissions from wastewater treatment plants (WWTPs) and highlights the technologies developed for CO2 capture in this milieu. CO2 is emitted in all the operational units of conventional WWTPs and even after the disposal of treated effluents and sludges. CO2 emissions from wastewater can be captured or mitigated by several technologies such as the production of biochar from sludge, the application of constructed wetlands (CWs), the treatment of wastewater in microbial electrochemical processes (microbial electrosynthesis, MES; microbial electrolytic carbon capture, MECC; in microbial carbon capture, MCC), and via microalgal cultivation. Sludge-to-biochar and CW systems showed a high cost-effectiveness in the capture of CO2, while MES, MECC, MCC technologies, and microalgal cultivation offered efficient capture of CO2 with associate production of value-added by-products. At the state-of-the-art, these technologies, utilized for carbon capture and utilization from wastewater, require more research for further configuration, development and cost-effectiveness. Moreover, the integration of these technologies has a potential internal rate of return (IRR) that could equate the operation or provide additional revenue to wastewater management. In the context of circular economy, these carbon capture technologies will pave the way for new sustainable concepts of WWTPs, as an essential element for the mitigation of climate change fostering the transition to a decarbonised economy.


Assuntos
Gases de Efeito Estufa , Dióxido de Carbono/análise , Eletrólise , Gases de Efeito Estufa/análise , Águas Residuárias , Áreas Alagadas
3.
Science ; 373(6560): 1209-1210, 2021 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-34516807
4.
Chimia (Aarau) ; 75(9): 788-799, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34526185

RESUMO

In today's societies, climate-damaging and finite fossil resources such as oil and natural gas serve a dual purpose as energy source and as carbon source for chemicals and plastics. To respond to the finite availability and to meet international climate goals, a change to a renewable energy and raw material basis is inevitable and represents a highly complex task. In this review, we assess possible technology paths for Switzerland to reach these goals. First, we provide an overview of Switzerland's current energy demand and discuss possible renewable technologies as well as proposed scenarios to defossilize the current energy system. In here, electric vehicles and heat pumps are key technologies, whereas mainly photovoltaics replace nuclear power to deliver clean electricity. The production of chemicals also consumes fossil resources and for Switzerland, the oil demand for imported domestically used chemicals and plastics corresponds to around 20% of the current energetic oil demand. Thus, we additionally summarize technologies and visions for a sustainable chemical sector based on the renewable carbon sources biomass, CO2 and recycled plastic. As biomass is the most versatile renewable energy and carbon source, although with a limited availability, aspects and proposed strategies for an optimal use are discussed.


Assuntos
Gases de Efeito Estufa , Dióxido de Carbono/análise , Eletricidade , Fontes Geradoras de Energia , Suíça
5.
Environ Monit Assess ; 193(10): 630, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34490554

RESUMO

Soil carbon dioxide emission is a major component of ecosystem respiration, responsible for organic carbon losses from the ecosystem. In Pinus roxburghii Sarg. plantations, higher CO2 emission coincided with maximum soil moisture and soil temperature during the rainy season (4.23 µmol CO2m-2 s-1) followed by summer season (1.69 µmol CO2m-2 s-1) and winter season (1.35 µmol CO2m-2 s-1). The soil CO2 emission rates recorded during the rainy season differed significantly from other seasons (p < 0.05). Multiple linear regression revealed that rainfall was the main dominant factor affecting the soil CO2 emission. A significant positive correlation with minimum air temperature and average air temperature during the lag period, i.e., preceding 15 days of data, was recorded. A significant positive correlation was also observed between annual soil CO2 emission rates with soil temperature, soil moisture, air temperature, and rainfall (p < 0.05). Vapor pressure and relative humidity at 14.19 h also emerged as additional scientific variables affecting soil CO2 emission with significant positive correlations. Annual soil CO2 emission rates and soil properties were not significantly correlated but were positively correlated with organic carbon, exchangeable potassium and negatively correlated with available nitrogen and phosphorous (p > 0.05). Higher annual average carbon stock, 95.05 t ha-1 in P. roxburghii plantations than the yearly soil CO2 emission, 33.23 t ha-1 indicates that plantations sequester more carbon than the emissions.


Assuntos
Pinus , Solo , Carbono , Dióxido de Carbono/análise , China , Ecossistema , Monitoramento Ambiental , Estações do Ano
6.
Artigo em Inglês | MEDLINE | ID: mdl-34444147

RESUMO

Meteorological variables have a noticeable impact on pollutant concentrations. Among these variables, wind speed is typically measured, although research into how pollutants respond to it can be improved. This study considers nine years of hourly CO2 and CH4 measurements at a rural site, where wind speed values were calculated by the METEX model. Nine wind speed intervals are proposed where concentrations, distribution functions, and daily as well as annual cycles are calculated. Contrasts between local and transported concentrations are around 5 and 0.03 ppm for CO2 and CH4, respectively. Seven skewed distributions are applied, and five efficiency criteria are considered to test the goodness of fit, with the modified Nash-Sutcliffe efficiency proving to be the most sensitive statistic. The Gumbel distribution is seen to be the most suitable for CO2, whereas the Weibull distribution is chosen for CH4, with the exponential function being the worst. Finally, daily and annual cycles are analysed, where a gradual decrease in amplitude is observed, particularly for the daily cycle. Parametric and nonparametric procedures are used to fit both cycles. The latter gave the best fits, with the agreement being higher for the daily cycle, where evolution is smoother than for the annual cycle.


Assuntos
Poluentes Atmosféricos , Vento , Poluentes Atmosféricos/análise , Dióxido de Carbono/análise , Monitoramento Ambiental , Humanos , População Rural
7.
Artigo em Inglês | MEDLINE | ID: mdl-34444204

RESUMO

This study investigates the linkage between tourism development, technological innovation, urbanization and environmental degradation across 30 provinces of China. Based on data from 2001 to 2018, the study used an advanced economic methodology for the long-run estimate, the Augmented Mean Group (AMG) estimator, which accounts for heterogeneity in slope parameters and dependencies across countries. The empirical results show that tourism development degrades environmental quality, while technological innovation mitigates carbon emissions. Further, findings show that urbanization increases carbon emissions, while an inverted U-shaped relationship exists between economic growth and environmental degradation, implying the existence of EKC in China. Further, the Dumitrescu-Hurlin panel causality test shows that any policy aimed at tourism development or technological innovation would substantially contribute to environmental degradation, but not the other way round.


Assuntos
Invenções , Urbanização , Dióxido de Carbono/análise , China , Análise de Dados , Desenvolvimento Econômico , Turismo
8.
Artigo em Inglês | MEDLINE | ID: mdl-34444252

RESUMO

To study the economic and environmental effects of human capital, previous studies measure human capital based on education; however, this approach has many shortcomings because not all educated people are innovative human capital. Hence, this study introduces the concept of innovative human capital by developing a new index that measures human capital based on the number of patents every one million R&D staff full-time equivalent. After this, this paper studies the impact of innovative human capital on CO2 emissions in China. The provincial panel data of 30 Chinese provinces from 2003 to 2017 is analyzed using the fixed effect, ordinary least squares, and the system generalized method of moments (SYS-GMM). The analysis revealed that innovative human capital alleviates environmental deterioration in China. The findings unfold the existence of the environmental Kuznets curve (EKC) considering innovative human capital in the model. It implies that Chinese economic development will eventually support environmental sustainability if China continues to develop its innovative human capital. Among the control variables, economic structure, population density, and energy intensity stimulate environmental degradation by increasing CO2 emissions. However, FDI has a negative relationship with CO2 emissions. Lastly, the study proposes comprehensive policies to increase innovative human capital for environmental sustainability.


Assuntos
Dióxido de Carbono , Desenvolvimento Econômico , Dióxido de Carbono/análise , China , Poluição Ambiental/análise , Humanos , Investimentos em Saúde
9.
Nat Commun ; 12(1): 4675, 2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34344875

RESUMO

Recent studies conclude that the global coronavirus (COVID-19) pandemic decreased power sector CO2 emissions globally and in the United States. In this paper, we analyze the statistical significance of CO2 emissions reductions in the U.S. power sector from March through December 2020. We use Gaussian process (GP) regression to assess whether CO2 emissions reductions would have occurred with reasonable probability in the absence of COVID-19 considering uncertainty due to factors unrelated to the pandemic and adjusting for weather, seasonality, and recent emissions trends. We find that monthly CO2 emissions reductions are only statistically significant in April and May 2020 considering hypothesis tests at 5% significance levels. Separately, we consider the potential impact of COVID-19 on coal-fired power plant retirements through 2022. We find that only a small percentage of U.S. coal power plants are at risk of retirement due to a possible COVID-19-related sustained reduction in electricity demand and prices. We observe and anticipate a return to pre-COVID-19 CO2 emissions in the U.S. power sector.


Assuntos
COVID-19/epidemiologia , Centrais Elétricas/estatística & dados numéricos , Poluentes Atmosféricos/análise , Dióxido de Carbono/análise , Clima , Carvão Mineral/análise , Carvão Mineral/economia , Eletricidade , Combustíveis Fósseis/análise , Humanos , Centrais Elétricas/economia , Centrais Elétricas/tendências , SARS-CoV-2 , Estados Unidos/epidemiologia
10.
Artigo em Inglês | MEDLINE | ID: mdl-34360165

RESUMO

Energy transition in the transport sector (TS) is important for the goals of achieving carbon peak by 2030 and carbon neutrality by 2060 in China. A number of scholars have conducted studies to identify the potential energy savings of the TS and to improve its energy efficiency. Most of them concentrate on the direct energy use (EU). The indirect EU along the supply chain of the TS is often neglected. In this paper, the direct and indirect energy use, i.e., the embodied EU, of China's TS is measured by applying a multi-regional input-output (MRIO) model, where they are investigated from both the provincial and sectoral perspectives. Results show that intermediate use is the major driving force for the TS's embodied EU in China. From the sectoral level, supply from sectors such as petroleum refining and coking and demand from the service sector are the main reasons of the TS's embodied EU. From the provincial perspective, the TS's embodied EU is driven by low transportation technologies in most provinces located in central and western China. By contrast, abundant economic and social activities are the primary reason for the TS's embodied EU in most provinces in eastern China. In the terms of interprovincial transfer, the energy embodied in the TS flows from resource-intensive provinces located in central and western China to resource-deficient provinces in eastern China. In addition, a close geographical connection exists in the transfer. Finally, several strategies from the sectoral and provincial levels are provided for policymakers.


Assuntos
Dióxido de Carbono , Carbono , Carbono/análise , Dióxido de Carbono/análise , China , Fenômenos Físicos
11.
Sci Total Environ ; 790: 148169, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34380249

RESUMO

Global land use changes that tend to satisfy the food needs of augmenting population is provoking agricultural soils to act as a carbon (C) source rather than sink. Agricultural management practices are crucial to offset the anthropogenic C emission; hence, Carbon sequestration (CS) in agriculture is a viable option for reversing this cycle, but it is based on hypotheses that must be questioned in order to contribute to the development of new agricultural techniques. This review summarizes a global perspective focusing on 5 developing countries (DC) (Bangladesh, Brazil, Argentina, Nigeria and Mexico) because of their importance on global C budget and on the agricultural sector as well as the impact produced by several global practices such as tillage, agroforestry systems, silvopasture, 4p1000 on CO2 sequestration. We also discussed about global policies regarding CS and tools available to measure CS. We found that among all practices agroforestry deemed to be the most promising approach and conversion from pasture to agroforestry will be favorable to both farmers and in changing climate, (e.g., agroforestry systems can generate 725 Euroeq C credit in EU) while some strategies (e.g. no-tillage) supposed to be less promising and over-hyped. In terms of conservative tillage (no-, reduced-, and minimal tillage systems), global and DC's land use increased. However, the impact of no-tillage is ambiguous since the beneficial impact is only limited to top soil (0-10 cm) as opposed to conventional mechanisms. Grasses, cereals and cover crops have higher potential of CS in their soils. While the 4p1000 initiative appears to be successful in certain areas, further research is needed to validate this possible mode of CS. Furthermore, for effective policy design and implementation to obtain more SOC stock, we strongly emphasize to include farmers globally as they are the one and only sustainable driver, hence, government and associated authorities should take initiatives (e.g., stimulus incentives, C credits) to form C market and promote C plantings. Otherwise, policy failure may occur. Moreover, to determine the true effect of these activities or regulations on CS, we must concurrently analyze SOC stock adjustments using models or direct measurements. Above all, SOC is the founding block of sustainable agriculture and inextricably linked with food security. Climate-smart managing of agriculture is very crucial for a massive SOC stock globally especially in DC's.


Assuntos
Dióxido de Carbono , Aquecimento Global , Agricultura , Carbono , Dióxido de Carbono/análise , Sequestro de Carbono , Países em Desenvolvimento , Solo
12.
J Environ Manage ; 297: 113420, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34333309

RESUMO

Environmental degradation is significantly studied both in the past and the current literature; however, steps towards reducing the environmental pollution in carbon emission and haze pollution like PM2.5 are not under rational attention. This study tries to cover this gap while considering the carbon emission and PM2.5 through observing the role of renewable energy, non-renewable energy, environmental taxes, and ecological innovation for the top Asian economies from 1990 to 2017. For analysis purposes, this research considers cross-sectional dependence analysis, unit root test with and without structural break (Pesaran, 2007), slope heterogeneity analysis, Westerlund and Edgerton (2008) panel cointegration analysis, Banerjee and Carrion-i-Silvestre (2017) cointegration analysis, long-short run CS-ARDL results, as well as AMG and CCEMG for robustness check. The empirical evidence in both the short- and long-run has confirmed the negative and significant effect of renewable energy sources, ecological innovation, and environmental taxes on carbon emissions and PM2.5. Whereas, non-renewable energy sources are causing environmental degradation in the targeted economies. Finally, various policy implications related to carbon emission and haze pollution like PM2.5 are also provided to control their harmful effect on the natural environment.


Assuntos
Poluição do Ar , Desenvolvimento Econômico , Poluição do Ar/prevenção & controle , Dióxido de Carbono/análise , Estudos Transversais , Energia Renovável , Impostos
13.
J Environ Manage ; 297: 113400, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34346397

RESUMO

Shelterbelts are rows of trees planted around farmyards and field for protection against soil erosion, promotion of biodiversity and wildlife habitat. Additionally, to carbon sequestration through growth in tree biomass and carbon sinks in agricultural soil. In recent years, removal of shelterbelts has become more common, as crop land is preferred under higher crop prices, resulting in increased GHG emissions and decreases in carbon sinks. It is likely that landowners are making decisions without the knowledge of carbon sequestered by these trees. In this study, the level of carbon sequestration for the six common shelterbelt tree species found in Saskatchewan (hybrid poplar, green ash, Manitoba maple, Scots pine, white spruce, and caragana) was estimated using a carbon - life cycle analysis method. Net amount of carbon sequestered was estimated for five sequestration/emission stages - 1) seedling production, 2) transportation of seedlings to farm, 3) planting, 4) maintenance, and 5) growth of shelterbelts on farm. Since some landowners are removing shelterbelts, a removal stage was also included. During removal of shelterbelts, CO2 emissions were produced through: (i) physical process of removing the trees and subsequent burning of the wood; and (ii) loss of soil carbon after the removal over a long period of time. The functional unit for the analysis was one linear kilometer of shelterbelt, the normal structure of shelterbelts on agricultural land. All emissions/sequestration levels were measured as carbon dioxide (CO2) by multiplying the molecular weight of carbon dioxide to that of carbon (44/12). Other than the growth stage of shelterbelts, all other stages contributed net greenhouse gas emissions, which offset by carbon sequestration during tree growth. Hybrid poplar is a rapidly growing tree and sequesters the most carbon of the six species in all soil zones. A one km long hybrid poplar shelterbelt sequestered upwards of 1923 t CO2 by age 60 years in the Brown soil zone, compared to 2086 t CO2 over the same period in the Black soil zone. In comparison, in the Brown soil zone, Manitoba maple and white spruce sequestered 756 and 732 t CO2, respectively over the same period. If a landowner decides to remove a 60-year-old shelterbelt, 1205 t CO2 is lost within a short period after removal, whereas 718 t of remaining CO2 is retained as dead organic matter, which is slowly released over a period. Although field shelterbelts may emit greenhouse gases in the earlier stages of development, overall, they are net sinks of carbon and can therefore play a significant role in Canada's plan to reduce GHG emissions from agriculture.


Assuntos
Gases de Efeito Estufa , Agricultura , Animais , Ciclo do Carbono , Dióxido de Carbono/análise , Sequestro de Carbono , Efeito Estufa , Gases de Efeito Estufa/análise , Estágios do Ciclo de Vida , Saskatchewan , Solo
14.
J Environ Manage ; 297: 113360, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34346402

RESUMO

The triple components of energy consumption, carbon dioxide emissions, and economic expansion are important to achieving sustained economic activity and sound ecological advancement. This study aims to estimate the impact of wide-ranging parameters on environmental circumstances in South Asian countries. This analysis required two approaches: 1)quantile autoregressive distributed lag (QARDL) as an econometric model, and 2) data envelopment analysis (DEA) non-parametric comparable composite index to examine concurrently South Asian nations' data for the 2000-2018 period. The underscored category of the parameters were grouped into four key indices, namely financial, fiscal, human, and energy. The DEA's mathematical composite findings reveal varied circumstances regarding environmental self-maintenance in South Asian nations. India and Pakistan are doing quite well; Afghanistan is abysmal. In addition, the QARDL approach findings reveal that energy use and fiscal indicators abate pollution. Furthermore, the correlation between fiscal decentralization and ecological attributes is strengthened by the excellent level of institutions and human capital progress. There is a unidirectional impact emanating from fiscal devolution, gross domestic product, human capital, eco-innovation, and institutional excellence on carbon dioxide pollution, although different from the other correlations obtained.


Assuntos
Dióxido de Carbono , Desenvolvimento Econômico , Dióxido de Carbono/análise , Poluição Ambiental , Produto Interno Bruto , Humanos , Modelos Econométricos
15.
J Environ Manage ; 297: 113419, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34378543

RESUMO

Since climate change mitigation is the central debate of modern literature, the realization of carbon neutrality in response to diversified macroeconomic variables is the most crucial concern of international economies. However, the critical role of trade and renewable electricity output in export diversification-environmental nexus is missing. Therefore, this study investigates the combined influence of trade openness, exports diversification, and renewable electricity output on carbon dioxide emissions (CO2) in China from 1989 through 2019. Applying novel time series econometric techniques robust to structural breaks, following new outcomes are obtained. Firstly, long-run equilibrium cointegration existed among the under-analysis variables. Secondly, export diversification and renewable electricity output are predicted to decelerate CO2, supporting carbon neutrality in the long run. Thirdly, trade openness and gross domestic product accelerated the CO2, delaying carbon neutrality accomplishment. Most importantly, significant structural break dummy interacting with trade openness implicated that during the post-2001 era, China's trade openness extensively deteriorated the environmental quality in the face of trade liberalization obtained after joining the World Trade Organization (WTO). Based on empirical results, export diversification and renewable electricity production policies should be mutually non-exclusive and closely coordinated. Further, to counter the carbon emission acceleration impact of trade openness, increasing the share of green tradable products is suggested. Finally, bilateral trade restructuring is recommended to realize the long-term dream of economic sustainability and carbon neutrality.


Assuntos
Dióxido de Carbono , Desenvolvimento Econômico , Dióxido de Carbono/análise , China , Eletricidade , Produto Interno Bruto , Energia Renovável
16.
J Environ Manage ; 297: 113350, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34400390

RESUMO

Using the data from GCC countries, this paper analyses the co-movement between oil price, EU carbon allowance prices, global clean energy index and equity index from three GCC counties, namely, Kuwait, Saudi Arabia and the United Arab Emirates. Almost no previous research has investigated the dynamic interrelations in the conventional energy markets, like those of the GCC countries, against the dramatic growth in clean energy production and the new emissions trading schemes. Employing three different multivariate GARCH models, we document the existence of volatility spillover effects and co-movement among global clean energy production, crude oil price, CO2 emission price and each of the three GCC energy stock markets. Furthermore, we found that the conditional variances of all return series are influenced by the shocks coming from the markets themselves. Volatilities in all the markets under consideration are highly persistent, and the long-run persistent volatilities are more pronounced especially for oil and CO2 emission prices. The forecasting exercise demonstrates the superior performance of the multivariate diagonal-BEKK GARCH models.


Assuntos
Dióxido de Carbono , Petróleo , Carbono , Dióxido de Carbono/análise , Previsões , Energia Renovável
17.
Artigo em Inglês | MEDLINE | ID: mdl-34360511

RESUMO

Modern agriculture contributes significantly to greenhouse gas emissions, and agriculture has become the second biggest source of carbon emissions in China. In this context, it is necessary for China to study the nexus of agricultural economic growth and carbon emissions. Taking Jilin province as an example, this paper applied the environmental Kuznets curve (EKC) hypothesis and a decoupling analysis to examine the relationship between crop production and agricultural carbon emissions during 2000-2018, and it further provided a decomposition analysis of the changes in agricultural carbon emissions using the log mean Divisia index (LMDI) method. The results were as follows: (1) Based on the results of CO2 EKC estimation, an N-shaped EKC was found; in particular, the upward trend in agricultural carbon emissions has not changed recently. (2) According to the results of the decoupling analysis, expansive coupling occurred for 9 years, which was followed by weak decoupling for 5 years, and strong decoupling and strong coupling occurred for 2 years each. There was no stable evolutionary path from coupling to decoupling, and this has remained true recently. (3) We used the LMDI method to decompose the driving factors of agricultural carbon emissions into four factors: the agricultural carbon emission intensity effect, structure effect, economic effect, and labor force effect. From a policymaking perspective, we integrated the results of both the EKC and the decoupling analysis and conducted a detailed decomposition analysis, focusing on several key time points. Agricultural economic growth was found to have played a significant role on many occasions in the increase in agricultural carbon emissions, while agricultural carbon emission intensity was important to the decline in agricultural carbon emissions. Specifically, the four factors' driving direction in the context of agricultural carbon emissions was not stable. We also found that the change in agricultural carbon emissions was affected more by economic policy than by environmental policy. Finally, we put forward policy suggestions for low-carbon agricultural development in Jilin province.


Assuntos
Dióxido de Carbono , Carbono , Agricultura , Carbono/análise , Dióxido de Carbono/análise , China , Produção Agrícola , Desenvolvimento Econômico
18.
Medicine (Baltimore) ; 100(33): e26973, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34414969

RESUMO

ABSTRACT: So far, only a few studies have examined and confirmed the correlation between end-expiratory carbon dioxide partial pressure (PETCO2) and arterial carbon dioxide tension (PaCO2) during invasive mechanical ventilation in critically ill patients. This study aimed to observe the correlation between PaCO2 and PETCO2 in patients on invasive mechanical ventilation.This was a cross-sectional study of adult patients on invasive mechanical ventilation enrolled between June 2018 and March 2019. Patients requiring invasive mechanical ventilation underwent one of the following mechanical ventilation modes: assisted/controlled ventilation, synchronized intermittent mandatory ventilation, and spontaneous breathing. Subsequently, the difference and correlation between PETCO2 and PaCO2 were analyzed.A total of 184 patients with 298 pairs of PETCO2-PaCO2 data were included in the analysis. Without distinguishing the ventilator mode, there was significant positive correlation between PETCO2 and PaCO2. In different ventilator modes, the correlation coefficient was 0.81 for synchronized intermittent mandatory ventilation, 0.47 for assisted/controlled ventilation, and 0.55 for spontaneous breathing, respectively. In patients with chronic obstructive pulmonary disease (r = 0.80), multiple trauma (r = 0.64), severe pneumonia (r = 0.60), gastrointestinal surgery (r = 0.57), and cerebrovascular diseases (r = 0.53), PETCO2 and PaCO2 were positively correlated. For oxygenation index <200 mm Hg, correlation coefficient r = 0.69, P < .001; oxygenation index ≥200, r = 0.73, P < .001. Under different oxygenation indexes, there was no statistically significant difference between the 2 correlation coefficients. Among 116 pairs of data with oxygenation index <200 mm Hg, the difference of PaCO2-PETCO2 ≥10 mm Hg was found in 25 pairs (21.55%); in 182 pairs of data with oxygenation index ≥200 mm Hg, the difference of PaCO2-PETCO2 ≥10 mm Hg was found in 26 pairsIn patients on invasive mechanical ventilation, there was a good correlation between PETCO2 and PaCO2 in different ventilator modes, different disease types, and different oxygenation indexes, especially in synchronized intermittent mandatory ventilation mode and chronic obstructive pulmonary disease patients.


Assuntos
Dióxido de Carbono/sangue , Estado Terminal , Respiração Artificial , Idoso , Testes Respiratórios , Dióxido de Carbono/análise , Estado Terminal/terapia , Estudos Transversais , Feminino , Humanos , Masculino , Oxigênio/sangue , Pressão Parcial
19.
Proc Biol Sci ; 288(1954): 20210475, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34229493

RESUMO

Negative interactions among species are a major force shaping natural communities and are predicted to strengthen as climate change intensifies. Similarly, positive interactions are anticipated to intensify and could buffer the consequences of climate-driven disturbances. We used in situ experiments at volcanic CO2 vents within a temperate rocky reef to show that ocean acidification can drive community reorganization through indirect and direct positive pathways. A keystone species, the algal-farming damselfish Parma alboscapularis, enhanced primary productivity through its weeding of algae whose productivity was also boosted by elevated CO2. The accelerated primary productivity was associated with increased densities of primary consumers (herbivorous invertebrates), which indirectly supported increased secondary consumers densities (predatory fish) (i.e. strengthening of bottom-up fuelling). However, this keystone species also reduced predatory fish densities through behavioural interference, releasing invertebrate prey from predation pressure and enabling a further boost in prey densities (i.e. weakening of top-down control). We uncover a novel mechanism where a keystone herbivore mediates bottom-up and top-down processes simultaneously to boost populations of a coexisting herbivore, resulting in altered food web interactions and predator populations under future ocean acidification.


Assuntos
Dióxido de Carbono , Água do Mar , Animais , Dióxido de Carbono/análise , Cadeia Alimentar , Concentração de Íons de Hidrogênio , Oceanos e Mares , Comportamento Predatório
20.
J Environ Manage ; 295: 113141, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34198176

RESUMO

Urban ecosystems, the heterogeneous and rapidly changing landscape, showed a considerable impact on the global C cycle. However, studies encompassing the spatial differences in urban land uses on soil C dynamics are limited in tropical ecosystems. In this study, seasonal and temporal variability in soil CO2 efflux (SCE) and its regulatory physicochemical variables under five urban land use classes viz., Bare (BAR), Agriculture (AGR), Plantation (PLT), Grassland (GRA) and Lawns (LAW) were assessed from 2014 to 2016. Bare land use was considered as the reference for observing the variation for different land uses. Seasonal measurements of SCE, soil temperature, moisture content, pH, ammonium-N, nitrate-N and microbial biomass C (MBC) were performed whereas soil organic C (SOC), soil N, and soil physical properties were measured annually. Our results showed a significant (P < 0.01) increase in SCE by 89%, 117%, 132% and 166% for land use types from BAR to AGR, PLT, GRA and LAW, respectively. The results revealed a two-fold increase in SCE from anthropogenically managed urban lawns as compared to bare soil. PLT and LAW land use classes showed higher SOC and N contents. SCE was found positively correlated with temperature, moisture, SOC, soil N and MBC whereas negatively correlated with ammonium-N and nitrate-N (at P < 0.05) for the overall dataset. Soil moisture, temperature, SOC, porosity and pH were identified as the major determinant of urban SCE by explaining 63% of the variability in overall SCE. Further, temperature for BAR and LAW; moisture for PLT; ammonium-N for GRA; and nitrate-N for AGR were identified as the major regulators of SCE for different land use classes. The findings revealed that the interaction of soil temperature and moisture with nutrient availability regulates overall and seasonal variability in SCE in an urban ecosystem. Since these variables are highly affected by climate change, thus, the soil C source-sink relationships in tropical urban ecosystems may further change and induce a positive global warming potential from urban ecosystems.


Assuntos
Ecossistema , Solo , Agricultura , Biomassa , Carbono , Dióxido de Carbono/análise
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