The greenhouse gas （GHG） footprint of an agricultural system is a measure of the climate change impact potential （CCIP） exerted by the formation of its product（s）, its accurate quantification is essential for de...The greenhouse gas （GHG） footprint of an agricultural system is a measure of the climate change impact potential （CCIP） exerted by the formation of its product（s）, its accurate quantification is essential for determining the green value added tax of agricultural products for food markets, which in turn may drastically change the current patterns of food consumption and production towards a product life cycle oriented economy. This paper reviews the literature regarding GHG footprints of crop cultivation systems.The review concludes that few studies have fully considered the categories/ items of net GHG emissions from an investigated crop cultivation system, and thus probably led to biases in footprint estimation. Most studies to date have even neglected changes in the soil organic carbon stocks of ecosystems with annual crops, while process-oriented biogeochemical models so far have seldom been involved in GHG footprint quantification.To help with solving these problems or drawbacks, the authors propose a generic methodological framework for quantifying GHG footprints of crop cultivation systems free from grazing, which takes into account all direct/indirect GHG contributors within a ＇cradle-to-gate＇ life cycle. The authors then provide example values of some GHG emission factors, such as those from machinery operations and other agricultural inputs, extracted from the literature. In addition, direct measurements or model simulations of other major on-farm emission factors are emphasized. The need to further update this methodological framework in future studies, especially by adapting it to mixed crop-livestock production systems, is also indicated.展开更多
It is common to assume that structures are designed in view of 50 year life cycle as per Euro-Code 2 and other codes. In special cases, structures are designed in view of longer life cycle, such as bridges, important ...It is common to assume that structures are designed in view of 50 year life cycle as per Euro-Code 2 and other codes. In special cases, structures are designed in view of longer life cycle, such as bridges, important infrastructure facilities, important religious structures or in case of extended returning period of seismic event or floods. Beside issues of durability and maintenance aspects, this involves also the need to cover the probability of exceeding characteristic design live loads during the extended period, while keeping the same levels of the accepted risk that were assumed by the various codes, as good enough for the standard 50 year life cycle. Bearing in mind that design procedures, formulations, materials characteristic strengths and partial safety factors are used for these structures as per the existing codes, scaling of partial safety factors, or alternatively an additional ＂compensating＂ factor is required. A simplified approach and procedure to arrive at a reasonable calibration of the code safety factors based on 50 years to compensate for an extended life cycle, based upon structural reliability considerations, is proposed.展开更多
Exponential increase of anthropogenic impact （human population number, some technological parameters） becomes menacing for biosphere functioning. Anyway, we should be able to estimate quantitatively limits of our im...Exponential increase of anthropogenic impact （human population number, some technological parameters） becomes menacing for biosphere functioning. Anyway, we should be able to estimate quantitatively limits of our impact on functional parameters of the biosphere. Considering biosphere as a natural life-support system （LSS）, we can receive the helpful information for working out and creation of artificial LSS of various types. Big biotic cycle induced with flows of a solar energy, is a basis of functioning of the biosphere and its basic cells-ecosystems. It＇s possible to summarize briefly the main functional and structural properties of the biosphere： integrity, closure, substance cycling, steady state, energy dependence and biodiversity. These properties of the biosphere, as a LSS, ensure potentially everlasting life under the conditions of a limited quantity of substrate suitable for the life on the planet. Ecological Footprint （EF） as a quantitative measure of anthropogenic impact on biosphere functioning is discussed in the paper. The index of the ecological reliability （IER） is introduced as a quantitative ecological indicator of different territories. The comparative dynamics of the United Nations＇ Human Development Index （HDI） and EF is discussed. The vital goal of sustainable human development： all humans can have opportunity to fulfill their lives without degrading the biosphere. To support sustainability, we should try to develop each nation and the mankind as a whole with a high HDI and a low ecological footprint. It means to have high level of HDI at low level of EF. But current tendency of economical and social development shows that the higher HDI is, the bigger EF is. EF of mankind is growing menacingly. Now actual pressure of the human civilization of our planet （2010） upon 50% exceeds its potential possibilities biological capacity （BC）, measured on the area ＂global＂ green hectares）. It means that we need 1.5 planets of the Earth＇s type. It leads to ecological incident in the scale of biosphere. Our biosphere is the large, multilevel, hierarchically organized system, and our civilization is only a part of it. This part is not central; it can disappear for ever, if we do not cope to be included in the biosphere as a great system.展开更多
基金supported jointly by the National Key R&D Program project of China[grant number 2017YFF0211704]the National Natural Science Foundation of China[grant number41761144054]
文摘The greenhouse gas （GHG） footprint of an agricultural system is a measure of the climate change impact potential （CCIP） exerted by the formation of its product（s）, its accurate quantification is essential for determining the green value added tax of agricultural products for food markets, which in turn may drastically change the current patterns of food consumption and production towards a product life cycle oriented economy. This paper reviews the literature regarding GHG footprints of crop cultivation systems.The review concludes that few studies have fully considered the categories/ items of net GHG emissions from an investigated crop cultivation system, and thus probably led to biases in footprint estimation. Most studies to date have even neglected changes in the soil organic carbon stocks of ecosystems with annual crops, while process-oriented biogeochemical models so far have seldom been involved in GHG footprint quantification.To help with solving these problems or drawbacks, the authors propose a generic methodological framework for quantifying GHG footprints of crop cultivation systems free from grazing, which takes into account all direct/indirect GHG contributors within a ＇cradle-to-gate＇ life cycle. The authors then provide example values of some GHG emission factors, such as those from machinery operations and other agricultural inputs, extracted from the literature. In addition, direct measurements or model simulations of other major on-farm emission factors are emphasized. The need to further update this methodological framework in future studies, especially by adapting it to mixed crop-livestock production systems, is also indicated.
文摘It is common to assume that structures are designed in view of 50 year life cycle as per Euro-Code 2 and other codes. In special cases, structures are designed in view of longer life cycle, such as bridges, important infrastructure facilities, important religious structures or in case of extended returning period of seismic event or floods. Beside issues of durability and maintenance aspects, this involves also the need to cover the probability of exceeding characteristic design live loads during the extended period, while keeping the same levels of the accepted risk that were assumed by the various codes, as good enough for the standard 50 year life cycle. Bearing in mind that design procedures, formulations, materials characteristic strengths and partial safety factors are used for these structures as per the existing codes, scaling of partial safety factors, or alternatively an additional ＂compensating＂ factor is required. A simplified approach and procedure to arrive at a reasonable calibration of the code safety factors based on 50 years to compensate for an extended life cycle, based upon structural reliability considerations, is proposed.
文摘Exponential increase of anthropogenic impact （human population number, some technological parameters） becomes menacing for biosphere functioning. Anyway, we should be able to estimate quantitatively limits of our impact on functional parameters of the biosphere. Considering biosphere as a natural life-support system （LSS）, we can receive the helpful information for working out and creation of artificial LSS of various types. Big biotic cycle induced with flows of a solar energy, is a basis of functioning of the biosphere and its basic cells-ecosystems. It＇s possible to summarize briefly the main functional and structural properties of the biosphere： integrity, closure, substance cycling, steady state, energy dependence and biodiversity. These properties of the biosphere, as a LSS, ensure potentially everlasting life under the conditions of a limited quantity of substrate suitable for the life on the planet. Ecological Footprint （EF） as a quantitative measure of anthropogenic impact on biosphere functioning is discussed in the paper. The index of the ecological reliability （IER） is introduced as a quantitative ecological indicator of different territories. The comparative dynamics of the United Nations＇ Human Development Index （HDI） and EF is discussed. The vital goal of sustainable human development： all humans can have opportunity to fulfill their lives without degrading the biosphere. To support sustainability, we should try to develop each nation and the mankind as a whole with a high HDI and a low ecological footprint. It means to have high level of HDI at low level of EF. But current tendency of economical and social development shows that the higher HDI is, the bigger EF is. EF of mankind is growing menacingly. Now actual pressure of the human civilization of our planet （2010） upon 50% exceeds its potential possibilities biological capacity （BC）, measured on the area ＂global＂ green hectares）. It means that we need 1.5 planets of the Earth＇s type. It leads to ecological incident in the scale of biosphere. Our biosphere is the large, multilevel, hierarchically organized system, and our civilization is only a part of it. This part is not central; it can disappear for ever, if we do not cope to be included in the biosphere as a great system.
