共查询到20条相似文献,搜索用时 547 毫秒
1.
Evaluation of carbon stock variation in Northern Italian soils over the last 70 years 总被引:1,自引:0,他引:1
Carbon (C) sequestration in soils is gaining increasing acceptance as a means of reducing net carbon dioxide (CO2) emissions to the atmosphere. Numerous studies on the global carbon budget suggest that terrestrial ecosystems in the mid-latitudes
of the Northern Hemisphere act as a large carbon sink of atmospheric CO2. However, most of the soils of North America, Australia, New Zealand, South Africa and Eastern Europe lost a great part of
their organic carbon pool on conversion from natural to agricultural ecosystems during the explosion of pioneer agriculture,
and in Western Europe the adoption of modern agriculture after the Second World War led to a drastic reduction in soil organic
carbon content. The depletion of organic matter is often indicated as one of the main effects on soil, and the storage of
organic carbon in the soil is a means of improve the quality of soils and mitigating the effects of greenhouse gas emission.
The soil organic carbon in an area of Northern Italy over the last 70 years has been assessed In this study. The variation
of top soil organic carbon (SOC) ranged from −60.3 to +6.7%; the average reduction of SOC, caused by agriculture intensification,
was 39.3%. This process was not uniform, but related to trends in land use and agriculture change. For the area studied (1,394 km2) there was an estimated release of 5 Tg CO2-C to the atmosphere from the upper 30 cm of soil in the period 1935–1990. 相似文献
2.
P. Smith J. U. Smith U. Franko K. Kuka V. A. Romanenkov L. K. Shevtsova M. Wattenbach P. Gottschalk O. D. Sirotenko D. I. Rukhovich P. V. Koroleva I. A. Romanenko N. V. Lisovoi 《Regional Environmental Change》2007,7(2):105-119
Three soil carbon models (RothC, CANDY and the Model of Humus Balance) were used to estimate the impacts of climate change
on agricultural mineral soil carbon stocks in European Russia and the Ukraine using detailed spatial data on land-use, future
land-use, cropping patterns, agricultural management, climate and soil type. Scenarios of climate were derived from the Hadley
Centre climate Version 3 (HadCM3) model; future yields were determined using the Soil–Climate–Yield model, and land use was
determined from regional agricultural and economic data and a model of agricultural economics. The models suggest that optimal
management, which entails the replacement of row crops with other crops, and the use of extra years of grass in the rotation
could reduce Soil organic carbon (SOC) loss in the croplands of European Russia and the Ukraine by 30–44% compared to the
business-as-usual management. The environmentally sustainable management scenario (SUS), though applied for a limited area
within the total region, suggests that much of this optimisation could be realised without damaging profitability for farmers. 相似文献
3.
V. A. Romanenkov J. U. Smith P. Smith O. D. Sirotenko D. I. Rukhovitch I. A. Romanenko 《Regional Environmental Change》2007,7(2):93-104
The Model of Humus Balance was used to estimate the influence of climate effects and changing agricultural practices on carbon
(C) levels in soddy–podzolic soils in the Russian Federation for the years 2000–2050. The model was linked with a spatial
database containing soil, climate and farming management layers for identification of spatial change of C sequestration potential.
Analysis of relationships between C, soil texture and climate indicated that compared with a business-as-usual scenario, adaptation
measures could increase the number of polygons storing soil organic carbon (SOC) by 2010–2020. The rate of possible C loss
is sensitive to the different climate scenarios, with a maximum potential for SOC accumulation expected in 2030–2040, thereafter
decreasing to 2050. The effect is most pronounced for the arid part of the study area under the emission scenario with the
highest rate of increase in atmospheric CO2 concentration, supporting findings from the dynamic SOC model, RothC. C sequestration during the study period was permanent
for clay and clay loam soils with a C content of more than 2%, suggesting that C sequestration should be focused on highly
fertile, fine-textured soils. We also show that spatial heterogeneity of soil texture can be a source of uncertainty for estimates
of SOC dynamics at the regional scale.
Figures in color are available at 相似文献
4.
Jason B. Fellman Eldon H. Franz Chelsea L. Crenshaw Denise Elston 《Environment, Development and Sustainability》2009,11(4):871-885
It has become increasingly well documented that human activities are enhancing the greenhouse effect and altering the global
climate. Identifying strategies to mitigate atmospheric carbon dioxide emissions on the national level are therefore critical.
Fossil fuel combustion is primarily responsible for the perturbation of the global carbon cycle, although the influence of
humans extends far beyond the combustion of fossil fuels. Changes in land use arising from human activities contribute substantially
to atmospheric carbon dioxide; however, land use changes can act as a carbon dioxide sink as well. A soil carbon model was
built using STELLA to explore how soil organic carbon sequestration (SOC) varies over a range of values for key parameters
and to estimate the amount of global soil carbon sequestration from livestock waste. To obtain soil carbon sequestration estimates,
model simulations occurred for 11 different livestock types and with data for eight regions around the world. The model predicted
that between 1980 and 1995, United States soils were responsible for the sequestration of 444–602 Tg C from livestock waste.
Model simulations further predicted that during the same period, global soil carbon sequestration from livestock waste was
2,810–4,218 Tg C. Our estimates for global SOC sequestration are modest in proportion to other terrestrial carbon sinks (i.e.
forest regrowth); however, livestock waste does represent a potential for long-term soil carbon gain. SOC generated from livestock
waste is another example of how human activities and land use changes are altering soil processes around the world.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
5.
The study was conducted to assess the potential of Norwegian agricultural ecosystems to sequester carbon (C) based on the data from some long-term agronomic and land use experiments. The total emission of CO2 in Norway in 1998 was 41.4 million metric ton (MMT), of which agriculture contributed only 0.157 MMT, or <0.4% of the total emissions. With regards to methane (CH4) and nitrous oxide (N2O) gases, however, agricultural activities contributed 32.5% and 51.3% of their respective emissions in Norway. The soil organic carbon (SOC) losses associated with accelerated soil erosion in Norway are estimated at 0.475 MMTC yr–1. Land use changes and soil/crop management practices with potential for SOC sequestration include conservation tillage methods, judicious use of fertilizers and manures, use of crop residues, diverse crop rotations, and erosion control measures. The potential for SOC sequestration is 0.146 MMTC yr–1 for adopting conservation tillage, 0.011–0.035 MMTC yr–1 for crop residue management, 0.026 MMTC yr–1 for judicious use of mineral fertilizer, 0.016–0.135 MMTC yr–1 for manure application, and 0.036 MMTC yr–1 for adopting crop rotations. The overall potential of these practices for SOC sequestration ranges from 0.591 to 1.022 MMTC yr–1 with an average value of 0.806 MMTC yr–1. Of the total potential, 59% is due to adoption of erosion control measures, 5.8% to restoration of peat lands, 21% to conversion to conservation tillage and residue management, and 14% to adoption of improved cropping systems. Enhancing SOC sequestration and improving soil quality, through adoption of judicious land use and improved system of soil and crop management, are prudent strategies for sustainable management of soil, water and environment resources.Readers should send their comments on this paper to:
bhaskarn ath@aol.com within 3 months of publication of this issue. 相似文献
6.
The Welsh Government is committed to reduce greenhouse gas (GHG) emissions from agricultural systems and combat the effects of future climate change. In this study, the ECOSSE model was applied spatially to estimate GHG and soil organic carbon (SOC) fluxes from three major land uses (grass, arable and forest) in Wales. The aims of the simulations were: (1) to estimate the annual net GHG balance for Wales; (2) to investigate the efficiency of the reduced nitrogen (N) fertilizer goal of the sustainable land management scheme (Glastir), through which the Welsh Government offers financial support to farmers and land managers on GHG flux reduction; and (3) to investigate the effects of future climate change on the emissions of GHG and plant net primary production (NPP). Three climate scenarios were studied: baseline (1961–1990) and low and high emission climate scenarios (2015–2050). Results reveal that grassland and cropland are the major nitrous oxide (N2O) emitters and consequently emit more GHG to the atmosphere than forests. The overall average simulated annual net GHG balance for Wales under baseline climate (1961–1990) is equivalent to 0.2 t CO2e ha?1 y?1 which gives an estimate of total annual net flux for Wales of 0.34 Mt CO2e y?1. Reducing N fertilizer by 20 and 40 % could reduce annual net GHG fluxes by 7 and 25 %, respectively. If the current N fertilizer application rate continues, predicted climate change by the year 2050 would not significantly affect GHG emissions or NPP from soils in Wales. 相似文献
7.
I. A. Romanenko V. A. Romanenkov P. Smith J. U. Smith O. D. Sirotenko N. V. Lisovoi L. K. Shevtsova D. I. Rukhovich P. V. Koroleva 《Regional Environmental Change》2007,7(2):63-77
This study estimates the consequences of climate change on cropland with and without implementation of adaptation measures,
paying special attention to the maintenance of soil organic carbon (C) stocks. We examine the possibility for regional sustainable
agricultural management practice that combines both maintenance and gain in soil carbon level with profit maximization. Future
scenarios of Regional Agricultural Production Systems (RAPS) were constructed for 2000–2070 based on linking the effects of
global climate change, predicted change in productivity parameters for the main agricultural crops, land-use and soil database
parameters. The RAPS were used to examine profitability and feasibility of alternative agricultural scenarios, based on an
economic model. A number of recommendations for decision making were proposed based on an assessment of the efficiency of
adaptation in animal husbandry and in the crop production sector, after analysis of current percentage of perennial grass
in rotation in comparison with future economic scenarios.
Figures in color are available at 相似文献
8.
农田固碳措施对温室气体减排影响的研究进展 总被引:2,自引:0,他引:2
农田是CO2,CH4和N2O三种温室气体的重要排放源,在全球范围内农业生产活动贡献了约14%的人为温室气体排放量,以及58%的人为非CO2排放,不合理的农田管理措施强化了农田温室气体排放源特征,弱化了农田固碳作用。土壤碳库作为地球生态系统中最活跃的碳库之一,同时也是温室气体的重要源/汇。研究表明通过采取合理的农田管理措施,既可起到增加土壤碳库、减少温室气体排放的目的,又能提高土壤质量。农田土壤碳库除受温度、降水和植被类型的影响外,还在很大程度上受施肥量、肥料类型、秸秆还田量、耕作措施和灌溉等农田管理措施的影响。本文通过总结保护性耕作/免耕,秸秆还田,氮肥管理,水分管理,农学及土地利用变化等农田管理措施,探寻增强农田土壤固碳作用,减少农田温室气体排放的合理途径。农田碳库的稳定/增加,对于保证全球粮食安全与缓解气候变化趋势具有双重的积极意义。在我国许多有关土壤固碳与温室气体排放的研究尚不系统或仅限于短期研究,这也为正确评价各种固碳措施对温室气体排放的影响增加了不确定性。 相似文献
9.
Weisheng Zhou 《Sustainability Science》2006,1(1):115-122
It has been clearly recognized that future global climate change will limit the possibilities for sustainable development in China. To minimize these negative effects, as a practical strategy, we suggest that the Chinese government engage in international cooperation as a key contributor in the prevention of global warming. This suggestion results from numerical estimations of China’s greenhouse gas (GHG) emission trends accompanied with economic growth up to 2100. The results show that China’s gross domestic product (GDP), measured in terms of purchasing power parity (PPP), may overtake the sum of the GDPs of the United States and Canada in 2020. It is predicted that GDP per capita may reach US$20,000 and $80,000 in 2050 and 2100, respectively; meanwhile, CO2 emissions in China will increase from 6.6 billion tons (in carbon equivalent units) in 1990 to 54.6 billion tons in 2100. This means that the global peak concentration of GHG cannot be practically reduced without significant contributions from China. For international cooperation in mitigating global climate change, we introduce a new option, “per-capita emission restricted by assigned amount,” as an accounting rule for GHG reduction. This baseline classifies global CO2 reduction actions into three categories: compulsory reduction, self-imposed reduction, and voluntary reduction. We suggest that China contribute to world CO2 reduction according to the following timetable: voluntary reduction until 2012, self-imposed reduction until 2020, and compulsory reduction from 2020. The simulation results also indicate that China can benefit from this strategy in terms of improvements in its domestic economy and environment, for instance, by reducing fossil fuel consumption and the emission of pollutants.
相似文献
Weisheng ZhouEmail: Phone: +81-75-4663418Fax: +81-75-4663418 |
10.
Soil erosion and the global carbon budget 总被引:62,自引:0,他引:62
Lal R 《Environment international》2003,29(4):437-450
Soil erosion is the most widespread form of soil degradation. Land area globally affected by erosion is 1094 million ha (Mha) by water erosion, of which 751 Mha is severely affected, and 549 Mha by wind erosion, of which 296 Mha is severely affected. Whereas the effects of erosion on productivity and non-point source pollution are widely recognized, those on the C dynamics and attendant emission of greenhouse gases (GHGs) are not. Despite its global significance, erosion-induced carbon (C) emission into the atmosphere remains misunderstood and an unquantified component of the global carbon budget. Soil erosion is a four-stage process involving detachment, breakdown, transport/redistribution and deposition of sediments. The soil organic carbon (SOC) pool is influenced during all four stages. Being a selective process, erosion preferentially removes the light organic fraction of a low density of <1.8 Mg/m(3). A combination of mineralization and C export by erosion causes a severe depletion of the SOC pool on eroded compared with uneroded or slightly eroded soils. In addition, the SOC redistributed over the landscape or deposited in depressional sites may be prone to mineralization because of breakdown of aggregates leading to exposure of hitherto encapsulated C to microbial processes among other reasons. Depending on the delivery ratio or the fraction of the sediment delivered to the river system, gross erosion by water may be 75 billion Mg, of which 15-20 billion Mg are transported by the rivers into the aquatic ecosystems and eventually into the ocean. The amount of total C displaced by erosion on the earth, assuming a delivery ratio of 10% and SOC content of 2-3%, may be 4.0-6.0 Pg/year. With 20% emission due to mineralization of the displaced C, erosion-induced emission may be 0.8-1.2 Pg C/year on the earth. Thus, soil erosion has a strong impact on the global C cycle and this component must be considered while assessing the global C budget. Adoption of conservation-effective measures may reduce the risks of C emission and sequester C in soil and biota. 相似文献
11.
Keigo Akimoto Fuminori Sano Takashi Homma Kenichi Wada Miyuki Nagashima Junichiro Oda 《Sustainability Science》2012,7(2):157-168
This study focuses on analyses of greenhouse gas (GHG) emission reductions, from the perspective of interrelationships among
time points and countries, in order to seek effective reductions. We assessed GHG emission reduction potentials and costs
in 2020 and 2030 by country and sector, using a GHG emission reduction-assessment model of high resolution regarding region
and technology, and of high consistency with intertemporal, interregional, and intersectoral relationships. Global GHG emission
reduction potentials relative to baseline emissions in 2020 are 8.4, 14.7, and 18.9 GtCO2eq. at costs below 20, 50, and 100 $/tCO2eq., corresponding to +19, −2, and −7 %, respectively, relative to 2005. The emission reduction potential for 2030 is greater
than that for 2020, mainly because many energy supply and energy-intensive technologies have long lifetimes and more of the
current key facilities will be extant in 2020 than in 2030. The emission reduction potentials in 2030 are 12.6, 22.0, and
26.6 GtCO2eq. at costs below 20, 50, and 100 $/tCO2eq., corresponding to +19, −2, and −7 %, respectively, relative to 2005. The emission reduction potential for 2030 is greater
than that for 2020, mainly because many energy supply and energy-intensive technologies have long lifetimes and more of the
current key facilities will be extant in 2020 than in 2030. The emission reduction potentials in 2030 are 12.6, 22.0, and
26.6 GtCO2eq. at costs below 20, 50, and 100 /tCO2eq., corresponding to +33, +8, and −3 %, respectively, relative to 2005. Global emission reduction potentials at a cost below
50 $/tCO2eq. for nuclear power and carbon capture and storage are 2.3 and 2.2 GtCO2eq., respectively, relative to baseline emissions in 2030. Longer-term perspectives on GHG emission reductions toward 2030
will yield more cost-effective reduction scenarios for 2020 as well. 相似文献
12.
Elin Röös Bojana Bajželj Pete Smith Mikaela Patel David Little Tara Garnett 《Regional Environmental Change》2017,17(2):367-377
Multiple production and demand side measures are needed to improve food system sustainability. This study quantified the theoretical minimum agricultural land requirements to supply Western Europe with food in 2050 from its own land base, together with GHG emissions arising. Assuming that crop yield gaps in agriculture are closed, livestock production efficiencies increased and waste at all stages reduced, a range of food consumption scenarios were modelled each based on different ‘protein futures’. The scenarios were as follows: intensive and efficient livestock production using today’s species mix; intensive efficient poultry–dairy production; intensive efficient aquaculture–dairy; artificial meat and dairy; livestock on ‘ecological leftovers’ (livestock reared only on land unsuited to cropping, agricultural residues and food waste, with consumption capped at that level of availability); and a ‘plant-based eating’ scenario. For each scenario, ‘projected diet’ and ‘healthy diet’ variants were modelled. Finally, we quantified the theoretical maximum carbon sequestration potential from afforestation of spared agricultural land. Results indicate that land use could be cut by 14–86 % and GHG emissions reduced by up to approximately 90 %. The yearly carbon storage potential arising from spared agricultural land ranged from 90 to 700 Mt CO2 in 2050. The artificial meat and plant-based scenarios achieved the greatest land use and GHG reductions and the greatest carbon sequestration potential. The ‘ecological leftover’ scenario required the least cropland as compared with the other meat-containing scenarios, but all available pasture was used, and GHG emissions were higher if meat consumption was not capped at healthy levels. 相似文献
13.
Wiebke Saathoff Christina von Haaren René Dechow Andrew Lovett 《Regional Environmental Change》2013,13(4):825-841
Greenhouse gases (GHG) emissions from agricultural farming practice contribute significantly to European GHG inventories. For example, CO2 is emitted when grassland is converted to cropland or when peatlands are drained and cultivated. N2O emissions result from fertilization. Enabling farmers to reduce their GHG emissions requires sufficient information about its pressure–impact relations as well as incentives, such as regulations and funding, that support climate-friendly agricultural management. This paper discusses potentials to improve the supply of information on: farm-specific climate services or impacts, present policy incentives in Germany and England that support climate-friendly farm management and related adaptation requirements. Tools which have been developed for a farm environmental management software (to be added after review because of potential identification) are presented. These tools assess CO2 emissions from grassland conversion to cropland and peatland cultivation, as well as N2O emissions from nitrogen fertilization. As input data, the CO2 tool requires a classification of soil types according to soil organic carbon storage. The input data based on soil profile samples was compared with reference data from the literature. The N2O tool relies on farm data concerning fertilization. These tools were tested on three farms in order to determine their viability with respect to the availability of required data and the differentiation of results, which determines how well site-specific conservation measures can be identified. Assessing CO2 retention function of grassland conservation to cropland on the test farms leads to spatially differentiated results (~100 to ~900 potentially mitigated t CO2 ha?1). Assessed N2O emissions varied from 0.41 to 1.1 t CO2eq. ha?1 a?1. The proposed methods support policies that promote a more differentiated funding of climate conservation measures. Conservation measures and areas can be selected so that they will have the greatest mitigation effects. However, even though present policy instruments in Germany and England, such as Cross Compliance and agri-environmental measures, have the potential to reduce agricultural GHG, they do not appear to guide measures effectively or site-specifically. In order to close this gap, agri-environmental measures with the potential to support climate protection should be spatially optimized. Additionally, the wetland restoration measures which are most effective in reducing GHG emissions should be included in funding schemes. 相似文献
14.
Addressing food supply chain and consumption inefficiencies: potential for climate change mitigation
Globally, more than 30 % of all food that is produced is ultimately lost and/or wasted through inefficiencies in the food supply chain. In the developed world this wastage is centred on the last stage in the supply chain; the end-consumer throwing away food that is purchased but not eaten. In contrast, in the developing world the bulk of lost food occurs in the early stages of the supply chain (production, harvesting and distribution). Excess food consumption is a similarly inefficient use of global agricultural production; with almost 1 billion people now classed as obese, 842 million people are suffering from chronic hunger. Given the magnitude of greenhouse gas emissions from the agricultural sector, strategies that reduce food loss and wastage, or address excess caloric consumption, have great potential as effective tools in global climate change mitigation. Here, we examine the challenges of robust quantification of food wastage and consumption inefficiencies, and their associated greenhouse gas emissions, along the supply chain. We find that the quality and quantity of data are highly variable within and between geographical regions, with the greatest range tending to be associated with developing nations. Estimation of production-phase GHG emissions for food wastage and excess consumption is found to be similarly challenging on a global scale, with use of IPCC default (Tier 1) emission factors for food production being required in many regions. Where robust food waste data and production-phase emission factors do exist—such as for the UK—we find that avoiding consumer-phase food waste can deliver significant up-stream reductions in GHG emissions from the agricultural sector. Eliminating consumer milk waste in the UK alone could mitigate up to 200 Gg CO2e year?1; scaled up globally, we estimate mitigation potential of over 25,000 Gg CO2e year?1. 相似文献
15.
Tommaso Chiti Giacomo Certini Lucia Perugini Giovanni Mastrolonardo Dario Papale Riccardo Valentini 《Regional Environmental Change》2011,11(2):371-376
The purpose of the present work is to asses the possibility of detecting changes in soil organic carbon (SOC) at the end of
the 5-years of the first Commitment Period (CP) of the Kyoto Protocol of the United Nation’s Framework Convention on Climate
Change (1 January, 2008–31 December, 2012), by both direct measurement and the use of an opportunely evaluated SOC model,
CENTURY. The investigated soil is young, developed since 28 years on virtually C-free spoil banks and under the influence
of two managed forest stands, one a mix of English oak (Quercus robur L.) and Italian alder (Alnus cordata Loisel.) and the other pure English oak. The SOC stock of either stand was monitored since the time the stands were planted
in 1981, and it was used together with other parameters for the model evaluation, while the future projections for the end
of the first (2012) and second (2017) CP were made according to two extreme IPCC climatic scenarios: A1F1, the most dramatic,
and B2, among the less impacting. Direct SOC measurements performed at the beginning and at the end of a time frame equivalent
to a commitment period (2004–2008) had not shown significant variations in either stands. Compared to the 2008 SOC stock,
in both stands the model shows variations at the end of the first CP from 0.7 to 1.8 Mg C ha−1 for the A1F1 scenario and from 0.3 to 1.7 Mg C ha−1 for the B2. These variations are within the standard deviations of the C stocks measured in 2008. On the contrary, at the
end of the second CP, the modelled SOC increments range from 2.5 to 3.6 Mg C ha−1 (A1F1) or from 1.9 to 3.4 Mg C ha−1 (B2), indicating the possibility to detect the SOC changes by direct measurement, since the values well agree with the minimum
detectable variation estimated for both sites in 3.3–4.5 Mg C ha−1. This work shows that SOC stock changes measured directly in the field can be minimal at the end of both CPs, and that CENTURY
well simulates the SOC dynamics of the stands. The use of such a model, validated at long-term experimental sites, hence represents
an effective tool for estimating future changes in SOC amounts in support of direct measurements when a short period of time,
such as the CP, is considered. 相似文献
16.
Niels H. Batjes 《Environment, Development and Sustainability》2004,6(1-2):133-143
Many agro(eco)systems in Africa have been degraded as a result of past disturbances, including deforestation, overgrazing, and over exploitation. These systems can be managed to reduce carbon emissions and increase carbon sinks in vegetation and soil. The scope for soil organic carbon gains from improved management and restoration within degraded and non-degraded croplands and grasslands in Africa is estimated at 20–43 Tg C year?1, assuming that 'best' management practices can be introduced on 20% of croplands and 10% of grasslands. Under the assumption that new steady state levels will be reached after 25 years of sustained management, this would correspond with a mitigation potential of 4–9% of annual CO2 emissions in Africa. The mechanisms that are being put in place to implement the Kyoto Protocol - through C emission trading - and prevailing agricultural policies will largely determine whether farmers can engage in activities that enhance C sequestration in Africa. Mitigation of climate change by increased carbon sequestration in the soil appears particularly useful when addressed in combination with other pressing regional challenges that affect the livelihood of the people, such as combating land degradation and ensuring food security, while at the same time curtailing global anthropogenic emissions. 相似文献
17.
Z. J. U. Malley M. Taeb T. Matsumoto 《Environment, Development and Sustainability》2009,11(1):175-195
Sustainable agricultural development is a necessity for sustainable economic growth and social development in Africa. Sustainable
agriculture largely depends on how effective natural and environmental resources are managed and utilized; it also depends
on the security of continuous access to such resources. This research was aimed to look into trends in agricultural productivity,
examine the persistence of the environmental insecurity, analyze the relationship between the two, and explore their links
to the national development policies. The results are discussed in the context of relevance to national development policies
and their implications on the sustainability of agriculture and rural livelihoods security. Literature survey, records collection
from the stakeholders, village level participatory assessments (PAs), observations and questionnaire survey were tools used
for data collection. The study shows significant (P < 0.01) declines in cereal crop yields, cattle milk yield and cattle calving rate, and increasing cattle mortality rate.
Elements of environmental insecurity were found to account for decline in agricultural productivity; significant (P < 0.01) proportion (68%), of 266 households interviewed, reported land resources deterioration, declining soil fertility,
and increasing drought frequencies as the causes of their low productivity. Declined fertilizer consumption and increasing
variability in rainfall amount significantly (P < 0.01) accounted for 59% and 39%, respectively, of the variations observed in total annual production of rice and maize,
which are major cereals in the study area. This study recommends measures to improve soil productivity such as improved fertilizer
application and use of organic manures along with mineral fertilizers for maintaining soil productivity; education of farmers
on sustainable use and management of land resources; and pro-poor rural policies in agricultural development and environmental
governance.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
18.
R. Wassmann H.U. Neue J.K. Ladha M.S. Aulakh 《Environment, Development and Sustainability》2004,6(1-2):65-90
The rice-wheat belt comprises nearly 24–27 million ha in South and East Asia. Rice is generally grown in flooded fields whereas the ensuing wheat crop requires well-drained soil conditions. Consequently, both crops differ markedly in nature and intensity of greenhouse gas (GHG) fluxes, namely emission of (1) methane (CH4) and (2) nitrous oxide (N2O) as well as the sequestration of (3) carbon dioxide. Wetland rice emits large quantities of CH4; strategies to CH4 emissions include proper management of organic inputs, temporary (mid-season) field drainage and direct seeding. As for the wheat crop, the major GHG is N2O that is emitted in short-term pulses after fertilization, heavy rainfall and irrigation events. However, N2O is also emitted in larger quantities during fallow periods and during the rice crop as long as episodic irrigation or rainfall result in aerobic-anaerobic cycles. Wetland rice ensures a relatively high content of soil organic matter in the rice-wheat system as compared to permanent upland conditions. In terms of global warming potential, baseline emissions of the rice-wheat system primarily depend on the management practices during the rice crop while emissions from the wheat crop remain less sensitive to different management practices. The antagonism between CH4 and N2O emissions is a major impediment for devising effective mitigation strategies in rice-wheat system - measures to reduce the emission of one GHG often intensify the emission of the other GHG. 相似文献
19.
The developing countries i.e., the non-Annex-I countries (parties to the Kyoto Protocol but not responsible to any reduction
target yet) in the Kyoto Protocol whose economies are in transition are also allowed to reduce GHG emissions. Among these,
the countries that have accepted the Kyoto Protocol may be benefited from CDM projects to promote sustainable development.
The developed countries i.e., the Annex-I countries (that have signed the Kyoto Protocol & are responsible to have specific
GHG emission reduction target) or the investing countries, in return, have privilege to purchase CER credits (in units equivalent
to one tonne of CO2 gas emission reduction) to meet the emission target as specified in the Kyoto Protocol. The key step in understanding about
CDM is to grasp the concept of “baseline” and “additionality”. The “Baseline” is the emissions level that would have existed if a CDM project had not happened. The feature of an approved CDM project
is that the planned reductions would not occur without the additional incentive provided by emission reduction credits; this
concept is known as “Additionality”. According to environmental additionality concept, baseline emission minus project emission is equal to emissions reduction.
“Investment Additionality,” ultimately rejected during negotiation of the “Marrakech Accords” and “Financial Additionality,” are the two important concepts. The concept of trading of CER matches to the idea of Pigovian tax (equal to the negative externality and which is considered one of the “traditional” means of bringing a modicum of market
forces) in Economics, making pollution more costly to the polluter, as the polluters have negative cost since they save money
by polluting; hence, there are supposed negative externalities associated with the market activity. Economic theory predicts
that in an economy where the cost of reaching mutual agreement between parties is high and where pollution is diffuse, Pigovian
tax will be an efficient way to promote the public interest and will lead to an improvement of the quality of life measured
by the Genuine Progress Indicator and other human economic indicators, as well as higher gross domestic product growth. We
can seek a level of pollution such that the marginal savings (MS) to one polluting unit from pollution (−MC) is equal to marginal
damage (MD) from pollution over the entire population, since pollution is a public bad i.e., MS (x*) = ∑MDi (x*) where ∑Di (x) is the total damage. Though the responsibility of reduction in emission does not lie on the non-Annex-I countries, still
effort of maintaining global emission balance can be expected equally from developed and developing countries. The responsibilities
of Kyoto Protocol are (a) to reduce global GHG emissions, (b) to bring about sustainable development in the developing countries
lie on above two groups since its effect on February 16, 2005. Different polluters have different costs of pollution control.
The least costly way of controlling pollution from various sources that reflects different costs of pollution control making
the set of environmental regulations to achieve the emission target at the lowest cost makes the regulation cost-effective.
Though efficiency is not attainable for many regulations, cost-effectiveness is attainable. 相似文献
20.
In this article we examine the technological feasibility of the global target of reducing GHG emissions to 50 % of the 1990 level by the year 2050. We also perform a detailed analysis of the contribution of low-carbon technologies to GHG emission reduction over mid- and long-term timeframes, and evaluate the required technological cost. For the analysis we use AIM/Enduse[Global], a techno-economic model for climate change mitigation policy assessment. The results show that a 50 % GHG emission reduction target is technically achievable. Yet achieving the target will require substantial emission mitigation efforts. The GHG emission reduction rate from the reference scenario stands at 23 % in 2020 and 73 % in 2050. The marginal abatement cost to achieve these emission reductions reaches 150/tCO < sub > 2 < /sub > -eq in 2020 and150/tCO2-eq in 2020 and 600/tCO2-eq in 2050. Renewable energy, fuel switching, and efficiency improvement in power generation account for 45 % of the total GHG emission reduction in 2020. Non-energy sectors, namely, fugitive emission, waste management, agriculture, and F-gases, account for 25 % of the total GHG emission reduction in 2020. CCS, solar power generation, wind power generation, biomass power generation, and biofuel together account for 64 % of the total GHG emission reduction in 2050. Additional investment in GHG abatement technologies for achieving the target reaches US6.0 trillion by 2020 and US 6.0 trillion by 2020 and US 73 trillion by 2050. This corresponds to 0.7 and 1.8 % of the world GDP, respectively, in the same periods. Non-Annex I regions account for 55 % of the total additional investment by 2050. In a sectoral breakdown, the power generation and transport sectors account for 56 and 30 % of the total additional investment by 2050, respectively. 相似文献