Country-specific dietary shifts to mitigate climate and water crises     

《Global Environmental Change》2020

Undernutrition, obesity, climate change, and freshwater depletion share food and agricultural systems as an underlying driver. Efforts to more closely align dietary patterns with sustainability and health goals could be better informed with data covering the spectrum of countries characterized by over- and undernutrition. Here, we model the greenhouse gas (GHG) and water footprints of nine increasingly plant-forward diets, aligned with criteria for a healthy diet, specific to 140 countries. Results varied widely by country due to differences in: nutritional adjustments, baseline consumption patterns from which modeled diets were derived, import patterns, and the GHG- and water-intensities of foods by country of origin. Relative to exclusively plant-based (vegan) diets, diets comprised of plant foods with modest amounts of low-food chain animals (i.e., forage fish, bivalve mollusks, insects) had comparably small GHG and water footprints. In 95 percent of countries, diets that only included animal products for one meal per day were less GHG-intensive than lacto-ovo vegetarian diets (in which terrestrial and aquatic meats were eliminated entirely) in part due to the GHG-intensity of dairy foods. The relatively optimal choices among modeled diets otherwise varied across countries, in part due to contributions from deforestation (e.g., for feed production and grazing lands) and highly freshwater-intensive forms of aquaculture. Globally, modest plant-forward shifts (e.g., to low red meat diets) were offset by modeled increases in protein and caloric intake among undernourished populations, resulting in net increases in GHG and water footprints. These and other findings highlight the importance of trade, culture, and nutrition in diet footprint analyses. The country-specific results presented here could provide nutritionally-viable pathways for high-meat consuming countries as well as transitioning countries that might otherwise adopt the Western dietary pattern.  相似文献   

持续寡照对温室番茄开花座果、产量及果实品质的影响     

张继波  薛晓萍  李楠  李鸿怡  江梦圆 《气象与环境学报》2020,36(2):85-91

选取番茄品种“金冠5号”为试材,在日光温室中利用遮阳网设计不同寡照(光合有效辐射,PAR<200μmol·m^-2·s^-1)持续日数(0、1、3、5、7、9 d)及正常光照条件下的恢复试验,研究寡照胁迫对番茄开花座果、产量形成及果实品质的影响。结果表明:持续寡照胁迫造成番茄开花期推迟,开花数和单穗果实数减少,座果率降低,寡照胁迫7—9 d,番茄花期推迟一周左右;寡照胁迫还导致番茄单果重、单株产量、果实直径降低,非商品果率增加,寡照9 d处理番茄单果重、单株产量、果实直径分别较CK低0.04 kg、1.80 kg和1.10 cm,非商品果率较CK高3.1%;寡照胁迫下,番茄单株产量与植株叶片数,叶片气孔导度、蒸腾速率、光合速率等光合参数均呈显著正相关,而与叶片胞间CO 2浓度呈负相关;番茄果实维生素C含量、可溶性糖含量和可溶性蛋白含量随寡照胁迫持续时间增加而降低;而番茄果实抗坏血酸含量、有机酸含量和总酸度则相反,且寡照胁迫持续时间越长,番茄果实抗坏血酸含量、有机酸含量和总酸度越高。研究结论可为定量评估寡照灾害对设施番茄开花座果、产量及品质的影响提供一定依据。  相似文献   

It starts at home? Climate policies targeting household consumption and behavioral decisions are key to low-carbon futures     

《Chemie der Erde / Geochemistry》2002

Through their consumption behavior, households are responsible for 72% of global greenhouse gas emissions. Thus, they are key actors in reaching the 1.5 °C goal under the Paris Agreement. However, the possible contribution and position of households in climate policies is neither well understood, nor do households receive sufficiently high priority in current climate policy strategies. This paper investigates how behavioral change can achieve a substantial reduction in greenhouse gas emissions in European high-income countries. It uses theoretical thinking and some core results from the HOPE research project, which investigated household preferences for reducing emissions in four European cities in France, Germany, Norway and Sweden. The paper makes five major points: First, car and plane mobility, meat and dairy consumption, as well as heating are the most dominant components of household footprints. Second, household living situations (demographics, size of home) greatly influence the household potential to reduce their footprint, even more than country or city location. Third, household decisions can be sequential and temporally dynamic, shifting through different phases such as childhood, adulthood, and illness. Fourth, short term voluntary efforts will not be sufficient by themselves to reach the drastic reductions needed to achieve the 1.5 °C goal; instead, households need a regulatory framework supporting their behavioral changes. Fifth, there is a mismatch between the roles and responsibilities conveyed by current climate policies and household perceptions of responsibility. We then conclude with further recommendations for research and policy.  相似文献   

Food choices,health and environment: Effects of cutting Europe's meat and dairy intake     

《Global Environmental Change》2014

Western diets are characterised by a high intake of meat, dairy products and eggs, causing an intake of saturated fat and red meat in quantities that exceed dietary recommendations. The associated livestock production requires large areas of land and lead to high nitrogen and greenhouse gas emission levels. Although several studies have examined the potential impact of dietary changes on greenhouse gas emissions and land use, those on health, the agricultural system and other environmental aspects (such as nitrogen emissions) have only been studied to a limited extent. By using biophysical models and methods, we examined the large-scale consequences in the European Union of replacing 25–50% of animal-derived foods with plant-based foods on a dietary energy basis, assuming corresponding changes in production. We tested the effects of these alternative diets and found that halving the consumption of meat, dairy products and eggs in the European Union would achieve a 40% reduction in nitrogen emissions, 25–40% reduction in greenhouse gas emissions and 23% per capita less use of cropland for food production. In addition, the dietary changes would also lower health risks. The European Union would become a net exporter of cereals, while the use of soymeal would be reduced by 75%. The nitrogen use efficiency (NUE) of the food system would increase from the current 18% to between 41% and 47%, depending on choices made regarding land use. As agriculture is the major source of nitrogen pollution, this is expected to result in a significant improvement in both air and water quality in the EU. The resulting 40% reduction in the intake of saturated fat would lead to a reduction in cardiovascular mortality. These diet-led changes in food production patterns would have a large economic impact on livestock farmers and associated supply-chain actors, such as the feed industry and meat-processing sector.  相似文献   

Origin of the hydrocarbon gases carbon dioxide and hydrogen sulfide in Dodan Field (SE-Turkey)     

《Marine and Petroleum Geology》2014

Gas occurrences consisting of carbon dioxide (CO₂), hydrogen sulfide (H₂S), and hydrocarbon (HC) gases and oil within the Dodan Field in southeastern Turkey are located in Cretaceous carbonate reservoir rocks in the Garzan and Mardin Formations. The aim of this study was to determine gas composition and to define the origin of gases in Dodan Field. For this purpose, gas samples were analyzed for their molecular and isotopic composition. The isotopic composition of CO₂, with values of −1.5‰ and −2.8‰, suggested abiogenic origin from limestone. δ³⁴S values of H₂S ranged from +11.9 to +13.4‰. H₂S is most likely formed from thermochemical sulfate reduction (TSR) and bacterial sulfate reduction (BSR) within the Bakuk Formation. The Bakuk Formation is composed of a dolomite dominated carbonate succession also containing anhydrite. TSR may occur within an evaporitic environment at temperatures of approximately 120–145 °C. Basin modeling revealed that these temperatures were reached within the Bakuk Formation at 10 Ma. Furthermore, sulfate reducing bacteria were found in oil–water phase samples from Dodan Field. As a result, the H₂S in Dodan Field can be considered to have formed by BSR and TSR.As indicated by their isotopic composition, HC gases are of thermogenic origin and were generated within the Upper Permian Kas and Gomaniibrik Formations. As indicated by the heavier isotopic composition of methane and ethane, HC gases were later altered by TSR. Based on our results, the Dodan gas field may have formed as a result of the interaction of the following processes during the last 7–8 Ma: 1) thermogenic gas generation in Permian source rocks, 2) the formation of thrust faults, 3) the lateral-up dip migration of HC-gases due to thrust faults from the Kas Formation into the Bakuk Formation, 4) the formation of H₂S and CO₂ by TSR within the Bakuk Formation, 5) the vertical migration of gases into reservoirs through the thrust fault, and 6) lateral-up dip migration within reservoir rocks toward the Dodan structure.  相似文献   

中国贝类养殖对海洋碳循环的贡献评估     

李海晏  陈涛  张海燕  叶瑛  姚志通  夏枚生 《海洋科学》2014,(4)

造成全球暖化的主要原因是温室气体的过量排放,其中CO2的贡献率达60 %,贝类养殖具有碳沉积作用。依据农业部渔业局编制的《中国渔业统计年签》,以2001年到2010年的年平均产量计算贝类捕获和养殖的碳沉积能力,并评估其碳沉积潜力;计算牡蛎、蛤、扇贝与贻贝四种贝壳单位面积的碳沉积能力并与森林、珊瑚礁的碳沉积能力进行比较分析。本文对我国浅海贝类养殖所具有的碳沉积能力进行评估,以了解贝类养殖对海洋碳循环的贡献,可为争取国家碳份额的合法权益提供基础数据。分析表明我国近十年贝类总产量稳定在1100万吨以上,并有增加的趋势,其中海水养殖贝类约占87.34 %。贝类养殖和捕获总产量的碳沉积和海水养殖产量的碳沉积量分别为58.57、51.15万吨/年,碳沉积能力分别相当于122.28、106.78万公顷的造林,可分别减少大气CO2增加量的0.0125 %、0.0109 %。牡蛎、蛤、扇贝与贻贝的单位面积碳沉积速率分别为1.573、0.388、0.301、1.039吨碳/(公顷?年);牡蛎和贻贝高于森林的碳沉积能力0.479吨碳/(公顷?年);但低于珊瑚礁的碳沉积能力1.8吨碳/(公顷?年)。我国贝类淡、海水养殖产量可分别创造约268.4万元/年、12,711.2万元/年的碳权商机。  相似文献   

Impact of climate change on wetland ecosystems: A critical review of experimental wetlands     

《Chemie der Erde / Geochemistry》2014

Climate change is identified as a major threat to wetlands. Altered hydrology and rising temperature can change the biogeochemistry and function of a wetland to the degree that some important services might be turned into disservices. This means that they will, for example, no longer provide a water purification service and adversely they may start to decompose and release nutrients to the surface water. Moreover, a higher rate of decomposition than primary production (photosynthesis) may lead to a shift of their function from being a sink of carbon to a source. This review paper assesses the potential response of natural wetlands (peatlands) and constructed wetlands to climate change in terms of gas emission and nutrients release. In addition, the impact of key climatic factors such as temperature and water availability on wetlands has been reviewed. The authors identified the methodological gaps and weaknesses in the literature and then introduced a new framework for conducting a comprehensive mesocosm experiment to address the existing gaps in literature to support future climate change research on wetland ecosystems. In the future, higher temperatures resulting in drought might shift the role of both constructed wetland and peatland from a sink to a source of carbon. However, higher temperatures accompanied by more precipitation can promote photosynthesis to a degree that might exceed the respiration and maintain the carbon sink role of the wetland. There might be a critical water level at which the wetland can preserve most of its services. In order to find that level, a study of the key factors of climate change and their interactions using an appropriate experimental method is necessary. Some contradictory results of past experiments can be associated with different methodologies, designs, time periods, climates, and natural variability. Hence a long-term simulation of climate change for wetlands according to the proposed framework is recommended. This framework provides relatively more accurate and realistic simulations, valid comparative results, comprehensive understanding and supports coordination between researchers. This can help to find a sustainable management strategy for wetlands to be resilient to climate change.  相似文献   

Carbon and Noble Gas Isotopes in the Tengchong Volcanic Geothermal Area, Yunnan, Southwestern China   总被引：1，自引：0，他引：1  

Shun''ichi NAKAI  Hiroshi WAKITA 《《地质学报》英文版》2004,78(5):1122-1135

Carbon and noble gas isotope analyses are reported for bubbling gas samples from the Tengchong volcanic geothermal area near the Indo-Eurasian suture zone. All samples contain a resolvable component of mantle-derived 3He. Occurrence of mantle-derived 3He coincides with surface volcanism. However, 3He occurs over a larger geographic areathan do surface volcanics. δ13C values for CO2 and CH4 vary from -33.4‰ to 1.6 ‰ and from -52.8‰ to -2.8‰, respectively. He and C isotope systematics indicate that CO2 and CH4 in the CO2-rich gases originated predominantly from magmatic component mixed with crustal CO2 produced from carbonate. However, breakdown of organic matter and near-surface processes accounts for the CH4 and CO2 in N2-rich gases. 3He/4He ratio distribution pattern suggests that mantle-derived He and heat sources of high-temperature system in central Tengchong originate from a hidden magma reservoir at subsurface. CO2-rich gases with the highest 3He/4He ratio (5.2 Ra) may be representative of the  相似文献   

H₃ as a trap for noble gases: 1—The case of Argon     

F. Pauzat  Y. Ellinger 《Planetary and Space Science》2005,53(13):1389-1399

The possibility of H₃⁺ playing a role as a sink for noble gases has been investigated in the case of Argon. Elaborate quantum methods (ab initio Coupled Cluster and density functional BH&HLYP levels of theory) have been shown to reproduce the rotational constants within 0.3% together with the only known IR frequency on the test case of Ar…D₃⁺. Dissociation energies of (Ar)_n…H₃⁺ as a function of cluster size, i.e. 7.2 (n=1), 3.7 (n=2), 3.6 (n=3), 1.6 (n=4), 1.7 (n=5) kcal/mol, follow the pattern established experimentally for (Ar)_n…H₃⁺ and (H₂)_n…H₃⁺ series. Rotational constants and harmonic frequencies of (Ar)_n…H₃⁺ (n=1-3) are presented.  相似文献   

温室气体强迫与东亚亚热带季风演变耦合效应及动力机制研究     

侯立春  林振山  何亮 《地理科学》2018,38(1):151-160

基于主要温室气体（CO₂、CH₄和N₂O）强迫因子和石笋δ¹⁸О观测资料（1~2002 年）,分别利用关联性耦合模型和非线性统计-动力学方法,分析温室气体强迫与东亚亚热带季风演变耦合度的时序规律和定量反演模拟温室气体强迫对近2 000 a东亚亚热带季风演变影响的非线性趋势和相对贡献。研究发现：① 温室气体与季风演变耦合度的高低对应季风的强弱变化,即两者耦合作用越强,东亚亚热带季风越强;反之,两者耦合强度越小,东亚亚热带季风越弱;耦合度峰谷值对应季风极强降水和极端干旱时段。② 时序演变规律为：N₂O和CO₂相互作用与季风演变间耦合效应最强,成为东亚亚热带季风演变的主要驱动力。其次,N₂O一次项和CO₂非线性项对季风演变起主要的负反馈调节机制。③ 时序演变阶段上有所不同：1~180年,CH₄因子对季风演变主要起负反馈调节机制;180~1760年和1760~2002年,对季风演变起主要的驱动和调节机制分别为CO₂因子和N₂O因子;但1900年后N₂O和CO₂相互作用与季风演变的耦合驱动效应近百年来明显增强,耦合度在中等-较强（或极强）之间来回波动转换,耦合作用明显增强,在耦合度由较强（或极强）转弱至中等时,东亚亚热带季风也随之减弱。  相似文献