Global Freshwater Use Research Articles

Optimizing crop production water footprints in the face of water scarcity: a combined experimental and simulation study of wheat in Zimbabwe

Abstract The optimization of water footprints in crop production is critical, given that agroecosystems currently account for more than 70% of global freshwater use. To achieve this, crop growth models provide insights into the impact of various crop and irrigation management strategies on both crop productivity and water use. This study evaluated the capability of the AquaCrop model in simulating wheat yields, crop water use, and water footprints in the Middle-Manyame Sub-Catchment, Zimbabwe. The model was calibrated and validated using experimental data collected from field experiments. Simulation experiments were conducted to assess the impact of early and late planting, drip and sprinkler irrigation techniques, and no mulch, organic mulch, and synthetic mulch options on the water footprint (WF). The AquaCrop model accurately simulated soil water content, crop water use, crop biomass, and grain yield. Simulation runs showed that early planting reduced WFblue and WFgreen by 25 and 4%, respectively. The lowest consumptive WF was observed with drip irrigation and synthetic mulching. The greatest decline in WFblue and WFgreen (52 and 11%) was simulated under early planting, using drip irrigation and synthetic mulching. Overall, the study highlights the importance of efficient crop and irrigation management practices to reduce water footprints in agroecosystems.

The Benefits and Burdens of Meat Consumption

The Benefits and Burdens of Meat Consumption

A shape-attention Pivot-Net for identifying central pivot irrigation systems from satellite images using a cloud computing platform: an application in the contiguous US

ABSTRACT Forty percent of global food production relies upon irrigation, which accounts for 70% of total global freshwater use. Thus, the mapping of cropland irrigation plays a significant role in agricultural water management and estimating food production. However, current spaceborne irrigated cropland mapping is highly reliant upon its spectral behavior, which often has high uncertainty and lacks information about the method of irrigation. Deep learning (DL) allows for the classification of irrigated cropland according to unique spatial patterns, such as the central pivot irrigation system (CPIS). But convolutional neural networks (CNNs) are usually biased toward color and texture features, a spatial transferable and accurate CPIS identification model is lacking owing to previous model seldom involves the round shapes of CPIS, which is usually key to distinguishing CPIS. To address this lack, we proposed a shape attention neural network by integrating spatial-attention gate, residual block, and multi-task learning, Pivot-Net, to incorporate shape information identify CPIS in satellite imagery. Specifically, we employed CPIS in Kansas to train our model using Sentinel-2 and Landsat-8 optical images. We found that Pivot-Net is superior to seven state-of-the-art semantic segmentation models on second-stage validation. We also evaluated the performance of Pivot-Net at three validation sites, which had an average F1-score and mean IOU of 90.68% and 90.45%, respectively, which further demonstrated the high accuracy of the proposed model. Moreover, to show that the proposed Pivot-Net can map CPIS at the country scale, we generated the first CPIS map at 30 m for the contiguous US using a cloud computing platform and our Pivot-Net model. The total CPIS area for the contiguous US was 61,094 km2 in 2018, which comprised 26.22% of all irrigated lands. Our results can be accessed at https://tianfyou.users.earthengine.app/view/cpisus. Therefore, the proposed shape-attention Pivot-Net demonstrates the ability to classify CPIS at large spatial scales and are feasible to map CPIS at national scales.

Growing Crops in Arid, Drought-Prone Environments: Adaptation and Mitigation

Drought poses significant risks to society, in particular irrigated-crop production, which accounts for a large share of global freshwater use. Given its key role in the production of food, feed and fiber crops, there exists a need for policy measures to prevent and mitigate the impacts of drought on irrigated agriculture. This paper proposes that the design of drought policy should take into account actual farmer behavior in response to water scarcity. To this end, we offer a detailed analysis of land allocation and crop-choice decisions over time in an irrigation district located in the dry plains of Northern Mexico. We find that farmers systematically change their crop mix in response to water availability. In particular, in times of drought, irrigation water flows to higher-yield and higher-price crops (which also require more intense irrigation) to the detriment of less water-demanding (but lower value) crops. Farmers use water with the goal of earning a living—economizing on water per se has no relevance in that context. Policies that do not explicitly recognize this may result in ineffective, inefficient and/or unfair outcomes.

Turning Food Protein Waste into Sustainable Technologies.

For each kilogram of food protein wasted, between 15 and 750 kg of CO2 end up in the atmosphere. With this alarming carbon footprint, food protein waste not only contributes to climate change but also significantly impacts other environmental boundaries, such as nitrogen and phosphorus cycles, global freshwater use, change in land composition, chemical pollution, and biodiversity loss. This contrasts sharply with both the high nutritional value of proteins, as well as their unique chemical and physical versatility, which enable their use in new materials and innovative technologies. In this review, we discuss how food protein waste can be efficiently valorized not only by reintroduction into the food chain supply but also as a template for the development of sustainable technologies by allowing it to exit the food-value chain, thus alleviating some of the most urgent global challenges. We showcase three technologies of immediate significance and environmental impact: biodegradable plastics, water purification, and renewable energy. We discuss, by carefully reviewing the current state of the art, how proteins extracted from food waste can be valorized into key players to facilitate these technologies. We furthermore support analysis of the extant literature by original life cycle assessment (LCA) examples run ad hoc on both plant and animal waste proteins in the context of the technologies considered, and against realistic benchmarks, to quantitatively demonstrate their efficacy and potential. We finally conclude the review with an outlook on how such a comprehensive management of food protein waste is anticipated to transform its carbon footprint from positive to negative and, more generally, have a favorable impact on several other important planetary boundaries.

Effect of Deficit Irrigation Practice on Nitrogen Mineralization and Nitrate Nitrogen Leaching under Semi-Arid Conditions

Agricultural sector acts as a major consumer of water which accounts for 70 percent of global freshwater use. Water scarcity acts as an imminent threat to agriculture, there is a need to use those irrigation and management practices that could overcome this overwhelming situation of water scarcity. Lab incubation study was designed to evaluate the effect of different moisture levels (50%, 60%, 70%, 80%, 90%, and 100% FC) on nitrogen mineralization rate. Net nitrogen mineralization was shown at 60% and 80% FC levels. Two optimized irrigation levels (I0.6 and I0.8) along with four levels of dairy manure (10, 15, 20, and 25 Mg ha-1) were used in a lysimetric trial. Nitrate-nitrogen was measured at four depths (D1: 30 cm, D2: 60 cm, D3: 90 cm, and D4: 120 cm). Results showed strong interaction of irrigation and dairy manure at all depths. Mean maximum nitrate-nitrogen concentration was shown under full irrigation at 120 cm soil depth with the application of DM ® 25 Mg ha-1. Under two levels of deficit irrigation, I0.8 has shown maximum nitrate-nitrogen concentration at 90 cm soil depth with the application of DM25, however, deficit irrigation level I0.6 restricted nitrate-nitrogen movement up to 60 cm soil depth, and high concentration was found at 30 cm soil depth. We concluded that deficit irrigation practice along with dairy manure resulted in more nitrate-nitrogen in the upper 60 cm layer of soil where it can be more available for the crops.

Water Policy for Sustainable Management: A Review

Water is essential for life and sustainable development. The demand for the world's increasingly scarce water supply is rising rapidly, challenging its availability for food production and putting global food security at risk. Managing water resource is essential for the international community to deliver the promise of the 2030 Agenda for Sustainable Development. Water is the foundation of sustainable development as it is the common denominator of all global challenges: energy, food, health, peace & security, and poverty eradication. This research review addresses the factors for increasing global fresh water use per year, global water policy for sustainable management, challenges, traits and opportunities with the conclusion of determining the best practice of water policy for the future generation. The world population increased from year to year due to increasing population, economic development and climate change. As a result, water resource policy which encompasses the policy-making processes that addresses provision, use, disposal and sustainability decisions, as well as, how policies created, executed, and amended by adopting set of best management practices to govern water management is the primary concern. Thus, to achieve sustainable water management; planning, development and management of water resources with best water policy that includes a multi-disciplinary and holistic approach in which technical, environmental, economic, landscape aesthetics, societal and cultural issues addressed. Keywords : Global freshwater use, Sustainable water management, Global Water policy, Water DOI: 10.7176/JRDM/72-03 Publication date: January 31 st 2021

Water Policy for Sustainable Management: A Review

Water is a fundamental need for life and societal growth. It is essential to meet personal and household needs, as well as for energy and industrial development, as well as to preserve critical water-dependent habitats and ecological services. Demand for the world's highly limited water supply is quickly growing, posing a threat to global food security and limiting its availability for food production. This research review addresses the increasing of global water use per year, global water policy for sustainable management, challenges, traits and opportunities with the objective of determining the best practice of water policy for the future generation. The world population increased from 2.77 billion to 7.794 billion since 1955 till end of 2020 with the growth rate of 1.88% to 1.05% respectively. The World Gross domestic product from 1960-2019 increased from 1.36 $ trillion to 87.67 $ trillion. Due to increasing population, economic development and climate change the global freshwater use since 1900 by broad regional groupings indicate that: OECD nations (Organizations for Economic Cooperation and Development) uses approximately 20-25%, BRICS countries (Brazil, Russia, India, China and South Africa) use the largest share at approximately 45% and the Rest of the World nations (ROW) use at 30-33%. Thus, to achieve sustainable water management, best water policy should provide a multi-disciplinary and comprehensive approach that addresses scientific, environmental, economic, landscape aesthetics, societal, and cultural issues.

The water-scarcity footprint of Australian adult diets – evidence from a large population health survey

AbstractThe food system is responsible for around 70% of global freshwater use. Pathways toward responsible consumption and production of food are therefore critically needed to ensure the planetary boundary for freshwater use is not transgressed. There is also an uneven spatial distribution of freshwater resources and human water demands, meaning that water-scarcity is acute in some regions but a lesser concern in others. Quantifying the water-scarcity impacts associated with food consumption is therefore a complex challenge due to the diversity of individual eating patterns, the very large number of individual food products available, and the many different regions where food is grown or processed. To our knowledge, this is the first study to calculate water footprints for a large number of self-selected diets. Life cycle assessment was used to model the water-scarcity footprints of 9,341 individual Australian adult diets obtained through 24-hour recall as part of the most recent Australian Health Survey. Three water-scarcity indicators were used, including the AWARE model recently developed by a project group working under the auspices of the United Nations Environment Programme (UNEP) / Society of Environmental Toxicology and Chemistry (SETAC) Life Cycle Initiative (www.lifecycleinitiative.org). In addition, a diet quality score was calculated for each of these diets. Our objective was to identify pathways toward healthier diets with lower water-scarcity impacts. Dietary water-scarcity footprints averaged 362 L-eq person-1 day-1 and were highly variable (sd. 218 L-eq person-1 day-1), reflecting the diversity of eating habits in the general community. The largest water-scarcity impacts were related to the excessive consumption of discretionary foods (alcoholic beverages, processed meat products, dairy desserts, cream, butter, muesli bars, confectionery, chocolate, biscuits, cakes, waffles, fried potato and extruded snacks, etc.). The potential to reduce dietary water-scarcity impacts is large, although the opportunity to intervene through amended dietary guidelines is not straightforward due to the large variations in water-scarcity footprint intensity between individual foods within a food group, and the inability of consumers to identify lower water-scarcity footprint products without food labeling. Reductions in the water-scarcity footprint of Australian food consumption are likely best achieved through reductions in food waste, technological change to improve water-use efficiency in food production, as well as the implementation of product reformulation and procurement strategies in the food manufacturing sector to avoid higher water-scarcity footprint intensity ingredients.

Pharmaceuticals, herbicides, and disinfectants in agricultural water sources

Agricultural water withdrawals account for the largest proportion of global freshwater use. Increasing municipal water demands and droughts are straining agricultural water supplies. Therefore, alternative solutions to agricultural water crises are urgently needed, including the use of nontraditional water sources such as advanced treated wastewater or reclaimed water, brackish water, return flows, and effluent from produce processing facilities. However, it is critical to ensure that such usage does not compromise soil, crop, and public health. Here, we characterized five different nontraditional water types (n = 357 samples) for the presence of pharmaceuticals, herbicides, and disinfectants using ultra-high-pressure liquid chromatography tandem mass spectrometry based method (UPLC-MS/MS). We then evaluated whether the levels of these contaminants were influenced by season. The highest level of herbicides (atrazine) was detected in untreated pond water (median concentration 135.9 ng/L). Reclaimed water had the highest levels of antibiotics and stimulants including azithromycin (215 ng/L), sulfamethoxazole (232.1 ng/L), and caffeine (89.4 ng/L). Produce processing plant water also tended to have high levels of atrazine (102.7 ng/L) and ciprofloxacin (80.1 ng/L). In addition, we observed seasonal variability across water types, with the highest atrazine concentrations observed during summer months, while the highest median azithromycin concentrations were observed in reclaimed water during the winter season. Further studies are needed to evaluate if economically feasible on-farm water treatment technologies can effectively remove such contaminants from nontraditional irrigation water sources.

HESS Opinions: A planetary boundary on freshwater use is misleading

Abstract. In 2009, a group of prominent Earth scientists introduced the planetary boundaries (PB) framework: they suggested nine global control variables, and defined corresponding thresholds which, if crossed, could generate unacceptable environmental change. The concept builds on systems theory, and views Earth as a complex adaptive system in which anthropogenic disturbances may trigger non-linear, abrupt, and irreversible changes at the global scale, and push the Earth system outside the stable environmental state of the Holocene. While the idea has been remarkably successful in both science and policy circles, it has also raised fundamental concerns, as the majority of suggested processes and their corresponding planetary boundaries do not operate at the global scale, and thus apparently lack the potential to trigger abrupt planetary changes. This paper picks up the debate with specific regard to the planetary boundary on global freshwater use. While the bio-physical impacts of excessive water consumption are typically confined to the river basin scale, the PB proponents argue that water-induced environmental disasters could build up to planetary-scale feedbacks and system failures. So far, however, no evidence has been presented to corroborate that hypothesis. Furthermore, no coherent approach has been presented to what extent a planetary threshold value could reflect the risk of regional environmental disaster. To be sure, the PB framework was revised in 2015, extending the planetary freshwater boundary with a set of basin-level boundaries inferred from environmental water flow assumptions. Yet, no new evidence was presented, either with respect to the ability of those basin-level boundaries to reflect the risk of regional regime shifts or with respect to a potential mechanism linking river basins to the planetary scale. So while the idea of a planetary boundary on freshwater use appears intriguing, the line of arguments presented so far remains speculative and implicatory. As long as Earth system science does not present compelling evidence, the exercise of assigning actual numbers to such a boundary is arbitrary, premature, and misleading. Taken as a basis for water-related policy and management decisions, though, the idea transforms from misleading to dangerous, as it implies that we can globally offset water-related environmental impacts. A planetary boundary on freshwater use should thus be disapproved and actively refuted by the hydrological and water resources community.

GROUNDWATER QUALITY IN THE PROXIMITY OF A POLLUTED LAKE: A JOINT EXPERIMENTAL-MODELING STUDY

Ground water is an important source of clean water supply throughout the world. A growing literature on the management of groundwater which takes into account the interaction of groundwater with surface water resupply sources (e.g., streams or lakes) is driven by concerns of intensified global fresh-water use coupled with increasing industrial and agricultural pollution levels. Our joint laboratory and numerical experiments simulate water withdrawals via two pumping wells from an unconfined aquifer bounded by two surface water bodies (streams or lakes). The water table position in the experimental setup was visualized by eight piezometers and numerically computed using VISUAL MODFLOW PRO, for different pumping regimes and initial hydraulic slopes. We also analyze numerically pollutant transport from the aquifer s boundaries toward the pumping wells. We show that it is possible to minimize pollution in the wells downstream of a polluted lake by managing the relative pumping rates in the two wells and the overall water table slope in the aquifer. The goal of our research is to (a) observe the physical processes involved in water and conservative tracer flow in an aquifer system surrounded by two lakes (b) develop a joint laboratory-numerical modeling teaching tool for future research and classroom use and (c) provide a simple tool that can be further developed to assist in management decisions regarding water-flow and pollution levels in aquifers.

物种急剧丧失·生态严重超载·跨越“地球边界”·区域公平失衡·“一个地球”生活——《地球生命力报告2014》解读

PDF HTML阅读 XML下载 导出引用 引用提醒 物种急剧丧失·生态严重超载·跨越“地球边界”·区域公平失衡·“一个地球”生活——《地球生命力报告2014》解读 DOI: 10.5846/stxb201501250196 作者: 作者单位: 湖北师范学院城市与环境学院,湖北师范学院城市与环境学院,湖北师范学院城市与环境学院,湖北师范学院城市与环境学院 作者简介: 通讯作者: 中图分类号: Q149; F129.9 基金项目: 江苏省环境演变与生态建设重点实验室2014开放基金(201401);资源枯竭城市转型与发展研究中心开放基金(Kf2013y08)(湖北省人文社科重点研究基地) Rapid species loss, severe ecological overshoot, crossed planetary boundaries, unfair regional consumption, one planet living: Main results of the Living Planet Report 2014 Author: Affiliation: Hubei Normal University,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:2014年9月30日,世界自然基金会(WWF)、Zoological Society of London(ZSL)、Global Footprint Network、Water Footprint Network联合发布《地球生命力报告2014》,除了以前主要使用的地球生命力指数(Living Planet Index,LPI)、生态足迹(Ecological Footprint, EF)、水足迹(Water Footprint)等指标外,首次使用"地球边界"揭示地球面临的严峻挑战。报告显示:(1)LPI自1970年以来已下降52%,温带和热带地区分别下降36%、56%,陆生和海洋物种均下降39%,淡水物种减少76%;(2)1961年全球生态足迹76亿全球公顷(global hectare, ghm2)、生物承载力99亿ghm2、生态盈余23亿ghm2,2010年全球生态足迹为181亿ghm2、生物承载力120亿ghm2、生态赤字61亿ghm2,1961年碳足迹占人类总生态足迹的36%,2010年碳足迹占比为53%;(3)全球生产水足迹排名中,印度、美国、中国、巴西和俄罗斯以大量的绿水足迹位居前五名;全球200多个河流流域、26亿7千万人每年至少1个月严重缺水;(4)生物多样性丧失、气候变化和氮循环3个"地球边界"被打破,并且已经对人类健康及人类所需要的食物、水和能源产生明显影响;(5)高收入国家将生物多样性丧失及其影响转嫁给低收入国家,这是另一种资源进口方式;大多数高收入国家人均生态足迹均已超过地球上人均可获得的生物承载力,依靠进口其他国家的生物承载力弥补超载;低收入国家生态足迹最小,生态系统却遭受最大破坏,高收入国家较高的人类发展水平是以高生态足迹为代价。报告指出人类对生态系统和生态功能的过度索取,正在危害着人类未来的安康、经济、食物安全、社会稳定乃至生存,特别提到当前人类所作选择和所采取措施的重要性。确保有恢复力、健康的生态环境维持人类繁荣发展,比现在人口增长、资源消耗增加、气候变化和生态退化的警钟更具挑战性。整篇报告可以概括为5个主题:物种急剧丧失、生态严重超载、跨越"地球边界"、区域公平失衡、"一个地球"生活。 Abstract:Living Planet Report 2014 was issued in September 2014 by World Wide Fund for Nature, Zoological Society of London, Global Footprint Network and Water Footprint Network. The indicator of “planetary boundaries” is analyzed that we are in danger of crashing Earth’s life-support systems besides living planet index (LPI), ecological footprint and water footprint. The latest data available (for 2010) indicate that the LPI has declined by 52 per cent since 1970. The temperate LPI declined by 36 per cent, and the tropical LPI shows a 56 per cent reduction over the same period. The terrestrial LPI and marine LPI had declined by 39 per cent, and the LPI for freshwater species shows an average decline of 76 per cent between 1970 and 2010. In 1961, global ecological footprint was 7.6 billion global hectare (gha), earth’s total biocapacity 9.9 billion gha, and ecological reserve 2.3 billion gha. In 2010, global ecological footprint was 18.1 billion gha, earth’s total biocapacity 12 billion gha, ecological deficit 6.1 billion gha. In 1961, carbon was 36% of our total Footprint, but by 2010, it comprised 53%. The 5 largest water footprints of production for the countries in the world are India, USA, China, Brazil and Russia. Stress on blue water resources is calculated on a monthly basis with more than 200 river basins, home to some 2.67 billion people, already experiencing severe water scarcity for at least one month every year. The nine identified boundaries are climate change, ocean acidification, biodiversity loss, interference with the global nitrogen and phosphorus cycles, ozone depletion, global fresh water use, land system change, atmospheric aerosol loading, and chemical pollution. We have already overstepped three (biodiversity loss, climate change, and the nitrogen cycle) of the nine planetary boundaries. The LPI of high-income countries appear to show an increase, middle-income and low-income countries show marked decline. They may reflect the way these countries import resources-effectively outsourcing biodiversity loss and its impacts to lower-income countries. High-income countries often rely on the biocapacity of other nations or the global commons to meet their consumption demands. The high human development in developed countries has been achieved at the expense of a high ecological footprint. Low-income countries should to significantly increase their IHDI without significantly increasing their ecological footprint and for countries with high IHDI to reduce their footprints. Five topics can be concluded based on the Living Planet Report 2014.There are rapid species loss, severe ecological overshoot, crossed planetary boundaries, unfair regional consumption, and one planet living. 参考文献 相似文献 引证文献

SUSTAINABILITY. Comment on "Planetary boundaries: Guiding human development on a changing planet".

Steffen et al. (Research Articles, 13 February 2015, p. 736) recently assessed current global freshwater use, finding it to be well below a corresponding planetary boundary. However, they ignored recent scientific advances implying that the global consumptive use of freshwater may have already crossed the associated planetary boundary.

Anthropocene Futures and Water Security

Abstract. A central claim about the Anthropocene is that this new epoch, in which people have become the primary geological force, raises profound questions about the sustainability of human development (Crutzen 2002). Human populations have grown dramatically, especially over the past two centuries; these people have grown on average wealthier, drawing on massively greater natural resources and environmental services, including water (Steffen et al. 2011). A number of ‘planetary boundaries' have been defined (Röckstrom et al. 2009), which point to the most urgent dimensions of the global sustainability problems that flow from the scale and scope of human appropriations and interventions in biophysical Earth Systems. These include by now familiar changes and impacts associated with climate change, ozone depletion, biodiversity loss and land-use change, as well as global freshwater use. Röckstrom et al. (2009) suggest using consumptive water run-off (or blue water use) as a proxy for global freshwater use. Assuming an upper limit of ~12 500–15 000 km3 year−1 of accessible blue water resources, they suggest that consumptive uses above a threshold of 4000–6000 km3 year-1 would represent a significant risk to ecosystems, moisture feedbacks and freshwater/ocean mixing. Given that consumptive use is now at about 2600 km3 year−1 the authors conclude that there appears to be some room for manoeuvre, although there continues to be a trend of rapidly growing consumptive water use at the global scale. In addition, a number of other problems associated with access to resources have been pointed to: peak oil; peak phosphorus; and the resilience of ecosystem services (Steffen 2011). Beyond this, there is the growing awareness of "systemic risks" to global economic, financial and political systems linked to the degradation, failure or transformation of key biophysical and ecological systems. Perhaps one of the most striking claims is that an epoch of relative stability in these systems (the Holocene) has been replaced by a new period of rapid change, instability and continuing transience, with growing risks of thresholds and tipping points (Lenton et al. 2008).

Offline: Progress towards planetary health

2014 was the world's hottest year since records began in 1880—0·69°C higher than the 20th-century average, and 0·04°C higher than previous peaks. NASA's Gavin Schmidt was reported last week as saying that these latest findings do “not bode well for a civilisation that is continuing to add greenhouse gases to the atmosphere”. The news came just as Johan Rockström's team at the Stockholm Resilience Centre updated their now famous idea of “planetary boundaries”. In 2009, Rockström proposed the notion of a safe operating space for humanity. A zone of sustainable life was surrounded by nine boundaries—climate change, ocean acidification, stratospheric ozone, nitrogen and phosphorous cycles (now called biogeochemical flows), global freshwater use, land-system change, biodiversity loss, atmospheric aerosol loading, and chemical pollution. As these boundaries were crossed, Rockström argued, the sustainability of our planet would become eroded, reducing the safe operating space we inhabit. The planetary boundary concept has become a powerful lever in debates about the meaning and measurement of sustainable development. In 2013, Rockström, together with Jeff Sachs and others, wrote an influential submission for the High-Level Panel on the Post-2015 Development Agenda. That paper concluded that, “The science of planetary boundaries makes clear that we are on an unsustainable trajectory…Planetary boundaries define a planetary playing field that guide humanity on how to avoid environmental changes on a global scale.” The latest iteration of the planetary boundary approach, published in Science, includes important modifications. First, two core boundaries are identified—climate change and biosphere integrity. Adverse movements towards either boundary would likely have the necessary force to take us out of the Earth's safe operating space. Second, boundaries are given regional context. The integrity of the biosphere, biogeochemical flows, land-system change, freshwater use, and atmospheric aerosol loading all have considerable sub-global heterogeneity. Third, progress towards protecting our safe operating space is described, incorporating regional as well as global metrics. Finally, the concept of planetary boundaries is refined. For example, a boundary is not a tipping point. Instead, the gap between the boundary and the true threshold for catastrophic change not only indicates uncertainty as to where that threshold actually lies, but also provides an opportunity for early warning and action to reduce the risk of irreversible transition. Revision of the planetary boundary approach will surely continue. Most importantly, they are not yet integrated into the practical politics of sustainable development, the SDGs, or post-2015 planning. They should be. But come back to Gavin Schmidt's word—civilisation. The history of civilisations (our societies and our cultures) tells us that what often seems secure in our lives can collapse and disappear surprisingly easily. There are many well-documented examples of civilisations that have been born, grow, thrive, and then die. The time course is long—over many hundreds of years. There is an abundance of evidence chronicling the precarity of human civilisations. It is not unreasonable to suggest that it is at best complacent and at worst dangerous to think that our societies and cultures are somehow different (better and smarter) today compared with the past—that we are now immune from the forces that challenged and overcame our ancestors. History and science, to the contrary, suggest that we should take our intrinsic fragility very seriously. The planetary boundaries approach is powerful. But it repeats the mistake of saying that it is something outside of us that should be the object of our concern—carbon dioxide, acidified oceans, and so on. Not so. The object of our concern should be us. The seeds of our vulnerability lie within ourselves, not the disturbed natural systems around us. Do we have the right governance, institutions, and decision-making processes to address the predicaments we face? There is reasonable evidence to suggest that we might not. If we accept that our civilisations are fragile and if we agree that the principal threats to our species are deficiencies in human political, economic, social, and knowledge systems, surely the conclusion is that we must redefine health. Health is not only the health of individuals and populations. It is also the health of our civilisations too—what we might come to call planetary health.

Exploring a safe operating approach to weighting in life cycle impact assessment – a case study of organic, conventional and integrated farming systems

Abstract Normalization and weighting steps used in life cycle impact assessment (LCIA) are often ignored as the weighting factors currently available are seen as being uncertain, subjective and unreliable. This article aims to contribute to the development of a new approach towards weighting, exploring the application of the concept of a planetary safe operating space for human welfare. Based on this approach, the boundaries included in this study relate to: climate change, rate of biodiversity loss, nitrogen cycle, phosphorus cycle, stratospheric ozone depletion, global freshwater use and change in land use. The weighting factors are then applied to a case study comparing environmental impacts of organic, conventional and integrated farming systems with alternative land uses. An integrated farming system that uses a part of the land for natural forest was found to have the lowest total impact score. Conventional farming systems with Miscanthus and managed forest had the highest total impact scores. The main source of uncertainty in the results arose from the wide range of assessments for the safe boundary of the biodiversity loss impact category. As the weighting factors proposed in this paper are not based on the common LCA impact categories, more work is needed to adjust the weighting factors to be suitable for use in LCA studies. More research is also needed for further defining the safe planetary boundaries.