273 research outputs found
Implications of climate mitigation for future agricultural production
Climate change is projected to negatively impact biophysical agricultural productivity in much of the world. Actions taken to reduce greenhouse gas emissions and mitigate future climate changes, are thus of central importance for agricultural production. Climate impacts are, however, not unidirectional; some crops in some regions (primarily higher latitudes) are projected to benefit, particularly if increased atmospheric carbon dioxide is assumed to strongly increase crop productivity at large spatial and temporal scales. Climate mitigation measures that are implemented by reducing atmospheric carbon dioxide concentrations lead to reductions both in the strength of climate change and in the benefits of carbon dioxide fertilization. Consequently, analysis of the effects of climate mitigation on agricultural productivity must address not only regions for which mitigation is likely to reduce or even reverse climate damages. There are also regions that are likely to see increased crop yields due to climate change, which may lose these added potentials under mitigation action. Comparing data from the most comprehensive archive of crop yield projections publicly available, we find that climate mitigation leads to overall benefits from avoided damages at the global scale and especially in many regions that are already at risk of food insecurity today. Ignoring controversial carbon dioxide fertilization effects on crop productivity, we find that for the median projection aggressive mitigation could eliminate ~81% of the negative impacts of climate change on biophysical agricultural productivity globally by the end of the century. In this case, the benefits of mitigation typically extend well into temperate regions, but vary by crop and underlying climate model projections. Should large benefits to crop yields from carbon dioxide fertilization be realized, the effects of mitigation become much more mixed, though still positive globally and beneficial in many food insecure countries
Assessing opportunities to increase global food production within the safe operating space for human freshwater use
Die Landwirtschaft ist heute der wichtigste Treiber der globalen Degradation von Ökosystemen. Es existiert jedoch wenig konkretes Wissen, wie Ökosysteme zu schützen sind und gleichzeitig die Nahrungsproduktion für die wachsende Weltbevölkerung gesichert werden kann. In dieser Dissertation untersuche ich Optimierungsmöglichkeiten im landwirtschaftlichen Wassermanagement. Ich quantifiziere praxisorientierte Verbesserungen der Regenwassernutzung und Optimierungen von Bewässerungssystemen, unter Einhaltung der „environmental flow requirements“ (EFRs). Um diese komplexen Interaktionen zu untersuchen, entwickle ich ein agro-hydrologisches Modell auf Basis detaillierter, mechanistischer Prozessabbildung weiter. Erstens, 39% der derzeitigen Wasserentnahmen für Bewässerung sind nicht nachhaltig und somit auf Kosten der Ökosysteme. Zweitens, solche lokalen Wasserentnahmegrenzen legen nahe, dass die globale Grenze für den menschlichen Wasserverbrauch deutlich niedriger liegt, als bisher angenommen (2800 vs 4000 km3yr-1). Drittens, die Implementierung von EFRs würde die landwirtschaftliche Produktion erheblich beeinträchtigen, mit >20% in stark bewässerten Gebieten. Verbesserte Nutzung des Niederschlagswassers und die Optimierung von Bewässerungssystemen, können die weltweite Nahrungsmittelproduktion allerdings um rund 40% nachhaltig steigern - ausreichend, um die Nahrungsmittellücke der wachsenden Weltbevölkerung bis 2050 zu halbieren. Zusammenfassend stellt diese Arbeit die erste umfassende und systematische Einschätzung globaler Potentiale der nachhaltigen Intensivierung der Landwirtschaft aus der Wasserperspektive dar. Die in dieser Arbeit vorgebrachten innovativen und quantitativen Erkenntnisse legen nahe, dass das Potential der diskutierten Interventionen höhere politische Aufmerksamkeit erfahren sollte. Meine Ergebnisse können eine konkretere Diskussion zur Umsetzung der Sustainable Development Goals untermauern.Agriculture is today''s most important driver of ecosystem degradation across scales. However, there is little evidence on how to attain the historic twin-challenge of maintaining environmental integrity while producing enough food for a growing world population. In this thesis, I assess opportunities in agricultural water management to reconcile future food needs with environmental limits to water use. I explore solution-oriented ways to improve rainfed and irrigation systems alike, while safeguarding environmental flows (EFRs). To study complex interactions quantitatively, I advanced a state-of-the-art global modeling framework based on detailed, mechanistic process representation. First, a systematic upscaling of EFRs to global coverage indicates that 39% of current freshwater withdrawals for irrigation are unsustainable and occur at the cost of ecosystems. Second, accounting for EFRs indicates that the planetary boundary for freshwater use might be notably lower (2800 vs. 4000 km3yr-1) than expected. Third, maintaining EFRs would significantly affect food production, cutting >20% of total kcal production across intensely irrigated areas. Fourth, improving irrigation systems in combination with optimizing the use of precipitation water, provides effective and accessible measures to compensate for adverse impacts from protecting EFRs and climate change. Such integrated interventions could sustainably intensify global food production (+40% kcal) to the degree sufficient to halve the global food gap by 2050. In conclusion, this thesis provides the first comprehensive and systematic assessment of hitherto largely unquantified water opportunities in sustainable intensification of agriculture. While requiring corroboration by finer-scale research, the innovative quantitative foundation provided in this thesis suggests that farm water management merits a rise in political attention, and it can inform a more comprehensive discussion of related SDG target interactions
Efficacy of Risk Reducing Diversification Portfolio Strategies among Agro-Pastoralists in Semi-Arid Area: A Modern Portfolio Theory Approach
Agro-pastoralists in the tropical semi-arid dryland areas of sub-Saharan Africa are significantly affected by climate change and variability. The agro-pastoral families are coping with production-related climatic risks through livelihood diversification to ensure food security. Data were collected from a sample of 411 agro-pastoralists across five districts in the semi-arid northern and central regions of Tanzania through survey conducted between November 2017 and July 2018. Secondary data regarding crop yields and livestock populations for eight years from 2009 to 2017 were collected from the National Bureau of Statistics and the respective District offices. Results show that about three-quarters of the agro-pastoralists managed diversified crop and livestock portfolios with two or more crops and animal species. However, simulated crop yields reveal positive correlations. Construction of integrated portfolios that generate good returns at a modest risk can be achieved through strategic choices between high-return high-risk and low-return low-risk crop and livestock activities. Thus, the paper recommends for costly long-term breeding and genotype improvement programs, strategically changing the make-up of the current crop and livestock portfolios which appear to be an affordable and tailored solution for building risk resilience among agro-pastoral communities in the drylands
Desertification
IPCC SPECIAL REPORT ON CLIMATE CHANGE AND LAND (SRCCL)
Chapter 3: Climate Change and Land: An IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystem
Beyond intensification: landscapes and livelihoods in Mali’s Guinea Savannah
For more than a decade, sub-Saharan Africa has been the focus of calls for a new Green Revolution. Like its predecessor, the African Green Revolution aims to increase the productivity of smallholder farmers, improving their own food security and income as well as that of the continent as a whole. This is to be done with minimum environmental damage, through “sustainable intensification.” While sustainable intensification has shown potential in places where high population density precludes cropland expansion, evidence of its effectiveness in land-abundant, labor-limited areas is limited. One such land-abundant, labor-limited area is the Guinea Savannah region of West Africa, which the World Bank called a “Sleeping Giant” where agricultural development could drive economic growth both locally and at the national level. Within the Guinea Savannah region, we use southern Mali’s Bougouni district as a case study to explore potential futures for smallholder agriculture in the area. We explored the history of the area’s agriculture using a panel data set for three villages, as well as remote sensing analysis and census data. Over the period of the panel data (1994-2012), agricultural change was minor. Cultivated area per household was highly correlated with household size and the number of draft animals a household owned. This relationship remained constant over the full period, suggesting little change in labor productivity. Yields of major crops remained stagnant, even as fertilizer input increased. Cropland expansion occurred in parallel with population growth, but up to the present, over half the arable land in the study villages was not cultivated. Because uncultivated rangeland made up such a large percentage of the land, we characterized the productivity, management and use of these rangelands (Chapter 3). In two villages, we assessed biomass quantity and species composition at 2-month intervals, tracked a sample of village herds, and used remote sensing combined with regression analysis to map the productivity of herbaceous biomass in a woody savannah landscape. We found that rangelands produced a seasonal peak of 2-2.5 t/ha of herbaceous biomass, from a diverse mix of annual and perennial species, notably Andropogon gayanus and A. pseudapricus. Herds covered distances of 10-18 km each day, with distance and location variable based on the season. During most of the year, the forage supply far exceeded the demands of grazing herds, but in the late dry season forage becomes scarce and herders supplement grazing with cut tree fodders, or send herds on transhumance to the south. While rangelands are exploited for a variety of uses, local management has thus far maintained high levels of productivity and biodiversity. In order to evaluate the potential of sustainable intensification to meet its goals of reducing poverty and improving food security, we explored the solution space of possible gains from intensification for farm households in three villages. With yields equivalent to the best farmers yields in the area, over 90% of households can achieve food self-sufficiency, and most can raise income levels above the threshold for extreme poverty. Reaching attainable yield levels, equal to those obtained in on-station trials, improved the picture further. However, agriculture must compete with other income generating options, which can be considerably more profitable. The average annual income for a gold miner in the area was 1600 per capita. Scenarios where tractor rental was available but tree planting was minimal resulted in somewhat lower rates of land conversion, but converted land was planted to annual staple crops, while tractor rental without the introduction of cashew increased annual incomes to $400 per capita, still twice the initial value. It seems clear that cropland expansion is highly likely to occur in this area, and preventing expansion comes at a real cost to local farmers. Tractor availability and cashew planting both led to land conversion, but the environmental impacts of cashew, as a perennial tree crop, are likely to be lower than the impacts of annual staples. A holistic evaluation of sustainability that considers farmer livelihoods might therefore conclude that expansion is as sustainable as intensification. The process of developing agricultural technology innovations in sub-Saharan Africa is generally led by scientists, but has many commonalities with engineering and product design methodologies. Increased attention to the steps in this process, from problem definition to developing design specifications to testing possible solutions, could help research for development projects develop more relevant technical solutions for farmers.</p
Climate Smart Agriculture: Building Resilience to Climate Change
The book uses an economic lens to identify the main features of climate-smart agriculture (CSA), its likely impact, and the challenges associated with its implementation. Drawing upon theory and concepts from agricultural development, institutional, and resource economics, this book expands and formalizes the conceptual foundations of CSA. Focusing on the adaptation/resilience dimension of CSA, the text embraces a mixture of conceptual analyses, including theory, empirical and policy analysis, and case studies, to look at adaptation and resilience through three possible avenues: ex-ante reduction of vulnerability, increasing adaptive capacity, and ex-post risk coping. The book is divided into three sections. The first section provides conceptual framing, giving an overview of the CSA concept and grounding it in core economic principles. The second section is devoted to a set of case studies illustrating the economic basis of CSA in terms of reducing vulnerability, increasing adaptive capacity and ex-post risk coping. The final section addresses policy issues related to climate change. Providing information on this new and important field in an approachable way, this book helps make sense of CSA and fills intellectual and policy gaps by defining the concept and placing it within an economic decision-making framework. This book will be of interest to agricultural, environmental, and natural resource economists, development economists, and scholars of development studies, climate change, and agriculture. It will also appeal to policy-makers, development practitioners, and members of governmental and non-governmental organizations interested in agriculture, food security and climate change
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