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1.
Reducing carbon emissions from deforestation and degradation in developing countries is of the central importance in efforts to combat climate change. A study was conducted to measure carbon stocks in various land-use systems including forms and reliably estimates the impact of land use on carbon (C) stocks in the forest of Rajasthan, western India (23°3′–30°12′N longitude and 69°30′–78°17′E). 22.8% of India is forested and 0.04% is the deforestation rate of India. In Indian forest sector of western India of Aravally mountain range covered large area of deciduous forest and it’s very helpful in carbon sequestration at global level. The carbon stocks of forest, plantation (reforestation) and agricultural land in aboveground, soil organic and fine root within forest were estimated through field data collection. Results revealed that the amount of total carbon stock of forests (533.64?±?37.54 Mg·ha ?1, simplified expression of Mg (carbon) ·ha ?1) was significantly greater ( P?<?0.05) than the plantation (324.37?±?15.0 Mg·ha ?1) and the agricultural land (120.50?±?2.17 Mg·ha ?1). Soil organic carbon in the forests (172.84?±?3.78 Mg·ha ?1) was also significantly greater ( P?<?0.05) than the plantation (153.20?±?7.48 Mg·ha ?1) and the agricultural land (108.71?±?1.68 Mg·ha ?1). The differences in carbon stocks across land-use types are the primary consequence of variations in the vegetation biomass and the soil organic matter. Fine root carbon was a small fraction of carbon stocks in all land-use types. Most of the soil organic carbon and fine root carbon content was found in the upper 30-cm layer and decreased with soil depth. The aboveground carbon (ABGC): soil organic carbon (SOC): fine root carbon ratios (FRC), was 8:4:1, 4:5:1, and 3:37:1 for the forest, plantation and agricultural land, respectively. These results indicate that a relatively large proportion of the C loss is due to forest conversion to agricultural land. 相似文献
2.
Climate change objectives of mitigation and adaptation are being mainstreamed into many policies and strategies around the world. In Europe, this has included the Rural Development Programme, which aims to tackle multiple social, economic and environmental objectives in rural areas, and the integration of climate change objectives adds another strand of complexity to the decision making process. When formulating policies determining the likely effectiveness of any particular measure can be challenging, especially with respect to the spatial and temporal variability of greenhouse gas emissions. This is a challenge faced by all countries and regions around the world. This study uses Europe as an example to explore this issue. It highlights the variability in emissions from land use operations that may be encountered under different conditions and time horizons and considers this in the context of policy formulation. The Optimal Strategies for Climate change Action in Rural Areas software has been adapted to derive net greenhouse gas emissions for rural development operations for all regions in Europe. Operations have been classified into five categories based on their benefit/burden over different time horizons. The analysis shows that it is important to understand the time period over which benefits or burdens are realised and determine how this fits with policy instruments, such as land management agreements and the permanency of actions. It also shows that in some regions an operation can have benefits, but in other regions it has burdens; thus, location can be critical. Finally, in the context of developing operations to meet multiple social, economic and environmental objectives, it is important to acknowledge that seeking options that only reduce emissions may not always be practical or possible. In some instances, we may have to accept an increase in emissions in order to meet other objectives. It is important that we evaluate the net greenhouse gas emissions of all operations, not just those aimed at climate change mitigation. We can then select those with the least burden in the process of developing optimal solutions to meet multiple objectives. 相似文献
3.
The recent and upcoming reforms of the Common Agricultural Policies (CAPs) aim at strengthening the multifunctional role of agriculture, acknowledging the differences in economic, environmental and social potentials within European regions. This paper presents results from an integrated assessment of existing and future policies within the framework set up in the FP6 EU project MEA-Scope. Spatial explicit procedures allow for the MEA-Scope modelling tools to provide information related to regional, environmental and socio-economics settings. The impact of different policy scenarios on structural change, land abandonment and cropping pattern of typical farms has been assessed based on linked agent-based (ABM) and Linear Programming (LP) models at regional and farm scale for two study areas. For the German case study area Ostprignitz-Ruppin (OPR), the issue of policy targeting has been addressed by relating non-commodity outputs (NCOs) to soil quality and protection status. For the Italian case study area (Mugello), changes in landscape patterns in terms of increased fragmentation or homogeneity as affected by changes in agricultural intensity have been analysed using semivariance analysis. The spatial explicit approach highlighted the relevance of case study research in order to identifying response structures and explaining policy implementation patterns. 相似文献
5.
The climate mitigation potential of tropical peatlands has gained increased attention as Southeast Asian peatlands are being deforested, drained and burned at very high rates, causing globally significant carbon dioxide (CO 2) emissions to the atmosphere. We used a process-based dynamic tropical peatland model to explore peat carbon (C) dynamics of several management scenarios within the context of simulated twenty-first century climate change. Simulations of all scenarios with land use, including restoration, indicated net C losses over the twenty-first century ranging from 10 to 100 % of pre-disturbance values. Fire can be the dominant C-loss pathway, particularly in the drier climate scenario we tested. Simulated 100 years of oil palm ( Elaeis guineensis) cultivation with an initial prescribed burn resulted in 2400–3000 Mg CO 2?ha ?1 total emissions. Simulated restoration following one 25-year oil palm rotation reduced total emissions to 440–1200 Mg CO 2?ha ?1, depending on climate. These results suggest that even under a very optimistic scenario of hydrological and forest restoration and the wettest climate regime, only about one third of the peat C lost to the atmosphere from 25 years of oil palm cultivation can be recovered in the following 75 years if the site is restored. Emissions from a simulated land degradation scenario were most sensitive to climate, with total emissions ranging from 230 to 10,600 Mg CO 2?ha ?1 over 100 years for the wettest and driest dry season scenarios, respectively. The large difference was driven by increased fire probability. Therefore, peat fire suppression is an effective management tool to maintain tropical peatland C stocks in the near term and should be a high priority for climate mitigation efforts. In total, we estimate emissions from current cleared peatlands and peatlands converted to oil palm in Southeast Asia to be 8.7 Gt CO 2 over 100 years with a moderate twenty-first century climate. These emissions could be minimized by effective fire suppression and hydrological restoration. 相似文献
6.
Sub-Saharan Africa is large and diverse with regions of food insecurity and high vulnerability to climate change. This project quantifies carbon stocks and fluxes in the humid forest zone of Ghana, as a part of an assessment in West Africa. The General Ensemble biogeochemical Modeling System (GEMS) was used to simulate the responses of natural and managed systems to projected scenarios of changes in climate, land use and cover, and nitrogen fertilization in the Assin district of Ghana. Model inputs included historical land use and cover data, historical climate records and projected climate changes, and national management inventories. Our results show that deforestation for crop production led to a loss of soil organic carbon (SOC) by 33% from 1900 to 2000. The results also show that the trend of carbon emissions from cropland in the 20th century will continue through the 21st century and will be increased under the projected warming and drying scenarios. Nitrogen (N) fertilization in agricultural systems could offset SOC loss by 6% with 30 kg N ha −1 year −1 and by 11% with 60 kg N ha −1 year −1. To increase N fertilizer input would be one of the vital adaptive measures to ensure food security and maintain agricultural sustainability through the 21st century. 相似文献
8.
Mitigation and Adaptation Strategies for Global Change - Climate change mitigation policies for the land use, land use change, and forestry (LULUCF) sector are commonly assessed based on marginal... 相似文献
9.
In the coming century, modern bioenergy crops have the potential to play a crucial role in the global energy mix, especially
under policies to reduce carbon dioxide emissions as proposed by many in the international community. Previous studies have
not fully addressed many of the dynamic interactions and effects of a policy-induced expansion of bioenergy crop production,
particularly on crop yields and human food demand. This study combines an updated agriculture and land use (AgLU) model with
a well-developed energy-economic model to provide an analysis of the effects of bioenergy crops on energy, agricultural and
land use systems. The results indicate that carbon dioxide mitigation policies can stimulate a large production of bioenergy
crops, dependent on the level of the policy. This production of bioenergy crops can lead to several impacts on the agriculture
and land use system: decreases in forestland and unmanaged land, decreases in the average yield of food crops, increases in
the prices of food crops, and decreases in the level of human demand of calories.
相似文献
10.
This paper presents a framework that encompasses a full range of options for including land use, land-use change, and forestry (LULUCF) within future agreements under the United Nations Convention on Climate Change (UNFCCC). The intent is to provide options that can address the broad range of greenhouse gas (GHG) emissions and removals as well as to bring the broadest possible range of nations into undertaking mitigation efforts. We suggest that the approach taken for the Kyoto Protocol's first commitment period is only one within a much larger universe of possible approaches. This larger universe includes partially or completely “de-linking” LULUCF commitments from those in other sectors, and allowing commitments specified in terms other than tonnes of greenhouse gases. Such approaches may provide clarity and transparency concerning the role of the various sectors in the agreements and encourage participation in agreements by a more inclusive, diverse set of countries, resulting in a more effective use of LULUCF in addressing climate change. 相似文献
11.
根据2007年1~2月对黄东海大面调查的资料,分析研究了黄东海颗粒有机碳(POC)的时空分布特征。结果表明,冬季黄东海POC的浓度范围是2.49~1 658.96μg/L,平均浓度为125.88μg/L。在垂直方向上,POC由上而下随着水深的增加浓度逐渐降低,到底层后浓度又升高。在平面分布上,POC整体上呈现西部近岸浓度较高、东部离岸浓度较低的特点;POC的高值区集中在浙江近岸海区,特别是浙江舟山群岛南部近海,POC浓度非常高,这是受陆源输入和沉积物再悬浮的共同作用。在周日变化上,受潮汐作用和海区生物活动的影响,东海陆架中部海域除底层以外,其它各层POC在午后、傍晚、凌晨出现浓度的高峰值,而西南海域,除了底层外,其它各层均表现出全日周期变化。 相似文献
12.
This research provides a synthesis of soil organic carbon (SOC) densities in a range of Australian soils and land use types
to decrease uncertainties in agricultural soil carbon (C) sequestration investments. This work provides information on existing
Australian C soil stocks, the relationships between SOC with various agricultural and forestry land use changes, and options
available for agriculturalists to cultivate and safeguard their C stocks. This work also includes recent developments in C
rights, soil C monitoring, and verification technologies and procedures now in use for C stock inventories. This review has
a special focus on known changes in SOC stocks, technological and methodological developments in the agricultural region of
southern Western Australia (WA). 相似文献
13.
Light-absorbing carbonaceous aerosols including black carbon(BC) and brown carbon(BrC)play significant roles in atmospheric radiative properties. One-year measurements of aerosol light absorption at multi-wavelength were continuously conducted in Xiamen,southeast of China in 2014 to determine the light absorption properties including absorption coefficients(σabs) and absorption ?ngstr?m exponent(AAE) in the coastal city.Light absorptions of BC and BrC with their contributions to total light absorption were further quantified. Mean σabsat 370 nm and 880 nm were 56.6 ± 34.3 and 16.5 ± 11.2 Mm-1,respectively. σabspresented a double-peaks diurnal pattern with the maximum in the morning and the minimum in the afternoon. σabswas low in warm seasons and high in cold seasons. AAE ranged from 0.26 to 2.58 with the annual mean of 1.46, implying that both fossil fuel combustion and biomass burning influenced aerosol optical properties. σabsof BrC at 370 nm was 24.0 ± 5.7 Mm-1, contributing 42% to the total absorption. The highest AAE(1.52 ± 0.02) and largest BrC contributions(47% ± 4%) in winter suggested the significant influence of biomass burning on aerosol light absorption. Long-distance air masses passing through North China Plain and the Yangtze River Delta led to high AAE and BrC contributions. High AAE value of 1.46 in July indicated that long-range transport of the air pollutants from intense biomass burning in Southeast Asia would affect aerosol light absorption in Southeast China. The study will improve the understanding of light absorption properties of aerosols and the optical impacts of BrC in China. 相似文献
14.
Rapid changes in upland farming systems in Southeast Asia generated predominantly by increased population pressure and ‘market forces’ have resulted in widespread land degradation that has been well documented at the plot scale. Yet, the links between agricultural activities in the uplands and downstream off-site effects remain largely unknown because of the difficulties in transferring results from plots to a larger scale. Many authors have thus pointed out the need for long-term catchment studies. The objective of this paper is to summarize the results obtained by the Management of Soil Erosion Consortium (MSEC) over the last 5 years from 27 catchments in five countries (Indonesia, Laos, Philippines, Thailand, and Vietnam). The purpose of the study was to assess the impacts of cultivation practices on annual runoff and erosion rates. Initial surveys in each catchment included topography, soils and land use. Monitoring included climatic, hydrologic and erosion (total sediment yield including bed load and suspended sediment load) data, land use and crop yields, and farmers’ income. In addition, new land management options were introduced through consultations with farmers and evaluated in terms of runoff and erosion. These included tree plantations, fruit trees, improved fallow with legumes, maize intercropped with legumes, planted fodder, native grass strips and agro-ecological practices (direct sowing and mulch-based conservation agriculture). Regressions analyses showed that runoff during the rainy season, and normalized runoff flow coefficient based on erosive rainfall during the rainy season (rainfall with intensity exceeding 25 mm h −1) increase with the percentage of the catchment covered by maize. Both variables decrease with increasing soil depth, standard deviation of catchment slope (that reflects terrain roughness), and the percentages of the catchment covered by fallow (regular and improved), tree plantations and planted fodder. The best predictors of sediment yield were the surface percentages of maize, Job's tears, cassava and footpaths. The main conclusions generated from this study were: (i) soil erosion is predominantly influenced by land use rather than environmental characteristics not only at the plot scale but also at the catchment scale; (ii) slash-and-burn shifting cultivation with sufficiently long rotations (1 year of cultivation, 8 years of fallow) is too often unjustly blamed for degradation; (iii) in its place, continuous cropping of maize and cassava promotes high rates of soil erosion at the catchment scale; (iv) conservation technologies are efficient in reducing runoff and total sediment yield at the catchment scale; (v) the adoption of improved soil management technologies by upland farmers is not a function of the degree of intensification of their farming system and/or of their incomes. The results suggest that if expansion of maize and cassava into already degraded upland systems were to occur due to increased demand for biofuels, there is a risk of higher runoff and sediment generation. A failure to adopt appropriate land use management strategies will result in further rapid resource degradation with negative impacts to downstream communities. 相似文献
15.
Many pathways have been proposed for including land use in a post-2012 climate agreement. Several involve new accounting structures which are quite different from the rules established in the Marrakech Accords and related decisions. However, a mechanism based largely on the structure agreed for the first commitment period also has its benefits. This paper discusses the weaknesses of the current system of land use, land-use change and forestry (LULUCF) accounting in the Kyoto Protocol's first commitment period, and proposes a mechanism based on that existing structure, but with modifications to address the weaknesses. 相似文献
16.
Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for Japan's agriculture. In this context, changes in soil C stocks in northern Japan's arable farming area over the period of 1971-2010, specifically in the region's typical Andosol (volcanic ash-derived) and non-Andosol soils, were simulated using soil-type-specific versions of the Rothamsted carbon model (RothC). The models were then used to predict the effects, over the period of 2011-2050, of three potential management scenarios: (i) baseline: maintenance of present crop residue returns and green manure crops, as well as composted cattle manure C inputs (24-34 Mg ha −1 yr −1 applied on 3-55% of arable land according to crop), (ii) cattle manure: all arable fields receive 20 Mg ha −1 yr −1 of composted cattle manure, increased C inputs from crop residues and present C inputs from green manure are assumed, and (iii) minimum input: all above-ground crop residues removed, no green manure crop, no cattle manure applied. Above- and below-ground residue biomass C inputs contributed by 8 major crops, and oats employed as a green manure crop, were drawn from yield statistics recorded at the township level and crop-specific allometric relationships (e.g. ratio of above-ground residue biomass to harvested biomass on a dry weight basis). Estimated crop net primary production (NPP) ranged from 1.60 Mg C ha −1 yr −1 for adzuki bean to 8.75 Mg C ha −1 yr −1 for silage corn. For the whole region (143 × 10 3 ha), overall NPP was estimated at 952 ± 60 Gg C yr −1 (6.66 ± 0.42 Mg C ha −1 yr −1). Plant C inputs to the soil also varied widely amongst the crops, ranging from 0.50 Mg C ha −1 yr −1 for potato to 3.26 Mg C ha −1 yr −1 for winter wheat. Annual plant C inputs to the soil were estimated at 360 ± 45 Gg C yr −1 (2.52 ± 0.32 Mg C ha −1 yr −1), representing 38% of the cropland NPP. The RothC simulations suggest that the region's soil C stock (0-30 cm horizon), across all soils, has decreased from 13.96 Tg C (107.5 Mg C ha −1 yr −1) in 1970 to 12.46 Tg C (96.0 Mg C ha −1 yr −1) in 2010. For the baseline, cattle manure and minimum input scenarios, soil C stocks of 12.13, 13.27 and 9.82 Tg C, respectively, were projected for 2050. Over the period of 2011-2050, compared to the baseline scenario, soil C was sequestered (+0.219 Mg C ha −1 yr −1) by enhanced cattle manure application, but was lost (−0.445 Mg C ha −1 yr −1) under the minimum input scenario. The effect of variations of input data (monthly mean temperature, monthly precipitation, plant C inputs and cattle manure C inputs) on the uncertainty of model outputs for each scenario was assessed using a Monte Carlo approach. Taking into account the uncertainty (standard deviation as % of the mean) for the model's outputs for 2050 (5.1-6.1%), it is clear that the minimum input scenario would lead to a rapid decrease in soil C stocks for arable farmlands in northern Japan. 相似文献
17.
Land use strongly influences soil properties and unsuitable practices lead to degradation of soil and environmental quality. The aim of this study was to assess the impact of different land uses on some chemical properties of soils developed from Pliocene clays, within hilly environments of central and southern Italy. The areas investigated are located in Vicarello di Volterra (Pisa, Tuscany), S. Quirico d’Orcia (Siena, Tuscany) and Soveria Simeri (Catanzaro, Calabria). Within each area different land uses were compared, including a natural ecosystem (Mediterranean bush), a perennial grass or pasture and an intensive crop (wheat, as monoculture or in rotation). The soils were sampled at 0.0–0.1, 0.1–0.2 and 0.2–0.4 m depth and analysed for particle size, pH, bulk density, cation exchange capacity and exchangeable cations, total organic carbon (TOC) and humified carbon (HC) concentrations, organic carbon stock and total N. The stratification ratio of soil organic carbon was calculated to characterize soil organic carbon distribution with depth. At all sites, soil under Mediterranean bush contained the largest amounts of TOC (as both concentration and stock), HC, total N and exchangeable K, together with the highest cation exchange capacity and the lowest pH values. The decrease in soil OC stock with land use change from natural to agricultural ecosystem was 65–85% to 0.1 m depth, 55–82% to 0.2 m depth and 44–76% to 0.4 m depth, with the lowest decrements for perennial grass from S. Quirico and the highest decrement for continuous wheat from Soveria Simeri. Continuous wheat cropping, based on conventional tillage, proved to be the least sustainable land use. At Soveria Simeri, the organic carbon content under pasture was not significantly larger than under wheat cultivation, probably because of grazing mismanagement; however, organic carbon under pasture was more humified. At S. Quirico, the perennial grass resulted in a significant increase in soil organic carbon at the soil surface relative to the wheat cultivation, while at Vicarello no differences were observed between alfalfa/wheat rotation and perennial grass. Our results lead to the questioning of sustainability of intensive cereal farming and uncontrolled grazing in the considered environments, emphasizing the need for greater attention to conservative land managements. 相似文献
18.
Most impacts on ecosystem services (ESs) are related to land use changes that may cause ecosystem fragmentation and loss of ecosystem functions. Spatial planning focused on sustainable landscape development should consider the local potential for providing ESs as well as ecological conservation due to land use changes. To better address the issues that are related to ecological and the ecological and environmental conservation, ecological compensation could coordinate the development of the energy, the economy, and the environment by internalizing environmental externalities and adjusting for the relationships with stakeholders’ benefits. In this study, we developed a framework for analyzing the spatial characteristics of land uses and calculating ecological compensation based on pay for ecosystem services (PESs) from 1995 to 2010 in the upstream of Min River, China. In terms of lacunarity analysis, we firstly explored the spatial patterns of land uses in these two periods that occurred at different spatial characteristic scales. We also observed a strong relationship between lacunarity values and the different distribution patterns of land uses. We then investigated changes in ESs in response to land use change through the assignment of per unit area ecological service value (ESV) method. The total value of ESs dropped from 449.97 billion yuan in 1995 to 441.35 billion yuan in 2010, exhibiting decreasing rate, mainly due to the degradation of woodlands. Soil formation and retention, gas regulation, and biodiversity protection were the three largest ESs, contributing about 50% of the total ESV. Considering the changed relation between social and economic indicators and ESV based on spatial visualization and analysis, we finally constructed a quantitative estimate model for ecological compensation taking a village as study unit and determined standard value so as to evaluate ecological compensation from 1995 to 2010. Spatial differences of the ecological compensation were significant among all the villages and towns. The maximum ecological compensation account (ranged from 1.68 to 8.54 billion yuan) appeared in the villages approximated to Li County, Heishui County, and Songpan County, Sichuan, People’s Republic of China. This proposed framework provides a better understanding of spatial characteristic scales of land uses and enables evaluation of the ecological integrity of landscapes. It also fills up the gap in the field of quantitative evaluation of regional ecological compensation and provides a feasible way to reconcile the conflicts among benefits in the economic, social, and ecological sectors. 相似文献
19.
Tropical peat swamp forests, which are predominantly located in Southeast Asia (SEA) and play a prominent role as a global carbon store, are being intensively degraded and converted to agricultural lands and tree plantations. For national inventories, updated estimates of peat emissions of greenhouse gases (GHG) from land use (LU) and land-use change in the tropics are required. In this context, we reviewed the scientific literature and calculated emission factors of peat net emissions of carbon dioxide (CO 2), methane (CH 4) and nitrous oxide (N 2O) in seven representative LU categories for SEA i.e. intact peat swamp forest, degraded forest (logged, drained and affected by fire), mixed croplands and shrublands, rice fields, oil palm, Acacia crassicarpa and sago palm plantations. Peat net CO 2 uptake from or emissions to the atmosphere were assessed using a mass balance approach. The balance included main peat C inputs through litterfall and root mortality and outputs via organic matter mineralization and dissolved organic carbon. Peat net CO 2 loss rate from degraded forest, croplands and shrublands, rice fields, oil palm, A. crassicarpa and sago palm plantations amounted to 19.4?±?9.4, 41.0?±?6.7, 25.6?±?11.5, 29.9?±?10.6, 71.8?±?12.7 and 5.2?±?5.1 Mg CO 2 ha ?1 y ?1, respectively. Total peat GHG losses amounted to 20.9?±?9.4, 43.8?±?6.8, 36.1?±?12.9, 30.4?±?10.6, 72?±?12.8 and 8.6?±?5.3 Mg CO 2-equivalent ha ?1 y ?1 in the same LU categories, respectively. A single land-clearing fire would result in additional emissions of 493.6?±?156.0 Mg CO 2-equivalent ha ?1. 相似文献
20.
Rainwater harvesting (RWH) is practised to mitigate water shortages in both household chores and agricultural use. This paper
examines the relationship between adoption of household RWH technologies in rural Uganda (dependant variable), and the influence
of independent variables (household characteristics such as age or monthly cash income, household perception including attitude
or risk preference, and institutional and policy-assumed variables such as household’s contact with extension workers, RWH-subsidy
provision, information flow channels and local community financial sources) that potentially influence technological adoption.
Logistic regression techniques were used on a random sample of 224 respondents to ascertain the influence of variables on
adoption of household RWH technologies. Analyses of hypothesised relationships revealed that subsidy provision was statistically
significant for adoption of RWH technologies in rural Uganda. Overall, the paper suggests the consideration of household RWH
subsidies in form of hardware when promoting adoption of RWH technologies. Moreover, when subsidies in the form of RWH construction
materials are provided, the chances of having a RWH system installed seem more likely than when cash is provided owing to
the many options cash can be used to purchase. Furthermore, household subsidy provision will produce immediate improvement
in rural water supply, fostering the probability of adoption of rainwater technologies, a choice that can be made with regard
to the form or level of public subsidy received depending on institutional and policy interventions. 相似文献
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