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.

Long-term trend in the maturation reaction norm of two cod stocks

Abstract: Average age and size at maturation have decreased in many commercially exploited fish stocks during the last decades. This phenomenon could be either a direct phenotypic response to some environmental variation or the evolutionary consequence of some selective pressure. Traditionally used maturation indices, e.g., the age and size at which 50% of individuals are mature, are not appropriate to assess the causes of changes in maturation because they are influenced, in addition to maturation per se, by growth and survival. To make up for this shortcoming, we use a reaction-norm-based approach to disentangle evolutionary changes and phenotypic plasticity. A method is presented to es- timate the reaction norm for age and size at maturation from data commonly gathered for the management of fisheries. This method is applied to data on Georges Bank and Gulf of Maine stocks of Atlantic cod ( Gadus morhua). The results show that maturation reaction norms in these stocks have shifted significantly downward, resulting in a tendency to mature earlier at smaller size. These findings support the hypothesis that an evolutionary trend, probably caused by high fishing mortalities, is partially responsible for the observed de- crease in age and size at maturation in these cod stocks. Two independent reasons justify this interpretation. First, there is no corresponding trend in growth that would suggest that improved feeding conditions could have facilitated maturation. Second, the results are based on maturation reaction norms, from which the known confounding effects of the growth and mortality variation are removed. Consequences of fisheries-induced evolution for the sustainability of the fishery are discussed.

Lighting the World: the first application of an open source, spatial electrification tool (OnSSET) on Sub-Saharan Africa

Abstract: In September 2015, the United Nations General Assembly adopted Agenda 2030, which comprises a set of 17 Sustainable Development Goals (SDGs) defined by 169 targets. 'Ensuring access to affordable, reliable, sustainable and modern energy for all by 2030' is the seventh goal (SDG7). While access to energy refers to more than electricity, the latter is the central focus of this work. According to the World Bank's 2015 Global Tracking Framework, roughly 15% of the world's population (or 1.1 billion people) lack access to electricity, and many more rely on poor quality electricity services. The majority of those without access (87%) reside in rural areas. This paper presents results of a geographic information systems approach coupled with open access data. We present least-cost electrification strategies on a country-by-country basis for Sub-Saharan Africa. The electrification options include grid extension, mini-grid and stand-alone systems for rural, peri-urban, and urban contexts across the economy. At low levels of electricity demand there is a strong penetration of standalone technologies. However, higher electricity demand levels move the favourable electrification option from stand-alone systems to mini grid and to grid extensions.

Globally observed trends in mean and extreme river flow attributed to climate change

Abstract: Anthropogenic climate change is expected to affect global river flow Here, we analyze time series of low, mean, and high river flows from 7250 observatories around the world covering the years 1971 to 2010 We identify spatially complex trend patterns, where some regions are drying and others are wetting consistently across low, mean, and high flows Trends computed from state-of-the-art model simulations are consistent with the observations only if radiative forcing that accounts for anthropogenic climate change is considered Simulated effects of water and land management do not suffice to reproduce the observed trend pattern Thus, the analysis provides clear evidence for the role of externally forced climate change as a causal driver of recent trends in mean and extreme river flow at the global scale