International Institute for Applied Systems Analysis

About: International Institute for Applied Systems Analysis is a nonprofit organization based out in Laxenburg, Austria. It is known for research contribution in the topics: Population & Greenhouse gas. The organization has 1369 authors who have published 5075 publications receiving 280467 citations. The organization is also known as: IIASA.

Understanding the weather signal in national crop-yield variability

Abstract: Year-to-year variations in crop yields can have major impacts on the livelihoods of subsistence farmers and may trigger significant global price fluctuations, with severe consequences for people in developing countries Fluctuations can be induced by weather conditions, management decisions, weeds, diseases, and pests Although an explicit quantification and deeper understanding of weather-induced crop-yield variability is essential for adaptation strategies, so far it has only been addressed by empirical models Here, we provide conservative estimates of the fraction of reported national yield variabilities that can be attributed to weather by state-of-the-art, process-based crop model simulations We find that observed weather variations can explain more than 50% of the variability in wheat yields in Australia, Canada, Spain, Hungary, and Romania For maize, weather sensitivities exceed 50% in seven countries, including the United States The explained variance exceeds 50% for rice in Japan and South Korea and for soy in Argentina Avoiding water stress by simulating yields assuming full irrigation shows that water limitation is a major driver of the observed variations in most of these countries Identifying the mechanisms leading to crop-yield fluctuations is not only fundamental for dampening fluctuations, but is also important in the context of the debate on the attribution of loss and damage to climate change Since process-based crop models not only account for weather influences on crop yields, but also provide options to represent human-management measures, they could become essential tools for differentiating these drivers, and for exploring options to reduce future yield fluctuations

Synergy and group size in microbial cooperation.

Abstract: Microbes produce many molecules that are important for their growth and development, and the exploitation of these secretions by nonproducers has recently become an important paradigm in microbial social evolution. Although the production of these public-goods molecules has been studied intensely, little is known of how the benefits accrued and the costs incurred depend on the quantity of public-goods molecules produced. We focus here on the relationship between the shape of the benefit curve and cellular density, using a model assuming three types of benefit functions: diminishing, accelerating, and sigmoidal (accelerating and then diminishing). We classify the latter two as being synergistic and argue that sigmoidal curves are common in microbial systems. Synergistic benefit curves interact with group sizes to give very different expected evolutionary dynamics. In particular, we show that whether and to what extent microbes evolve to produce public goods depends strongly on group size. We show that synergy can create an "evolutionary trap" that can stymie the establishment and maintenance of cooperation. By allowing density-dependent regulation of production (quorum sensing), we show how this trap may be avoided. We discuss the implications of our results on experimental design.

Technical and economic potential of concentrating solar thermal power generation in India

Abstract: This study aims to assess the technical and economic potential of concentrating solar power (CSP) generation in India. The potential of CSP systems is estimated on the basis of a detailed solar radiation and land resource assessment in 591 districts across the country. The land suitability, favorable solar resource conditions and wind power density over the vicinity have been considered key parameters for potential estimation. On the basis of a district-wise solar and land resource assessment, the technical potential of CSP systems is estimated over 1500 GW at an annual direct normal irradiance (DNI) over 1800 kWh/m2 and wind power density (WPD) ≥150 W/m2 after taking into accounts the viability of different CSP technologies and land suitability criteria. The economic potential of CSP is estimated at 571 GW at an annual DNI over 2000 kWh/m2 and WPD≥150 W/m2 in India. The technical evaluation of CSP technologies over the potential locations have been carried through System Advisor Model (SAM) Software using the Typical Meteorological Year data of Meteonorm 7.0 weather database. In near future, it is anticipated that locations with DNI values ≥1600–1800 kWh/m2 could also become economically feasible with the development of new technologies, advancement of materials, efficient and cost-effective thermal energy storage, economy of scale, manufacturing capability along with the enhanced policy measures, etc. In the long-term, it is possible to exploit over 2700 GW solar power through CSP in India with an annual DNI ≥1600 kWh/m2 and WPD≥150 W/m2. The findings of this study can be used for identification of niche areas for CSP projects in India.