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.

Modelling species distributions using regression quantiles

Abstract: Species distribution modelling is an important and well-established tool for conservation planning and resource management. Modelling techniques based on central estimates of species responses to environmental factors do not always provide ecologically meaningful estimates of species -environment relationships and are being increasingly questioned. Regression quantiles (RQ) can be used to model the upper bounds of species -environment relationships and thus estimate how the environment is limiting the distribution of a species. The resulting models tend to describe potential rather than actual patterns of species distributions. Model selection based on null hypothesis testing and backward elimination, followed by validation procedures, are proposed here as a general approach for constructing RQ limiting effect models for multiple species. This approach was applied successfully to 16 of the most abundant marine fish and cephalopods in the eastern English Channel. Most models were validated successfully and null hypothesis testing for model selection proved effective for RQ modelling. "Synthesis and applications." Modelling the upper bounds of species-habitat relationships enables the detection of the effects of limiting factors on species' responses. Maps showing potential species distributions are also less likely to underestimate species responses' to the environment, and therefore have subsequent benefits for precautionary management.

The vulnerabilities of agricultural land and food production to future water scarcity

Abstract: Rapidly increasing populations coupled with increased food demand requires either an expansion of agricultural land or sufficient production gains from current resources. However, in a changing world, reduced water availability might undermine improvements in crop and grass productivity and may disproportionately affect different parts of the world. Using multi-model studies, the potential trends, risks and uncertainties to land use and land availability that may arise from reductions in water availability are examined here. In addition, the impacts of different policy interventions on pressures from emerging risks are examined. Results indicate that globally, approximately 11% and 10% of current crop- and grass-lands could be vulnerable to reduction in water availability and may lose some productive capacity, with Africa and the Middle East, China, Europe and Asia particularly at risk. While uncertainties remain, reduction in agricultural land area associated with dietary changes (reduction of food waste and decreased meat consumption) offers the greatest buffer against land loss and food insecurity.

Are adaptation studies effective, and what can enhance their practical impact?

Abstract: In this piece we explore the interface between adaptation research and adaptation policy, planning, and investment. We ask, ‘How is research on adaptation informing the nascent domain of adaptation policy and practice?’ To inform this discussion, we extract a few of the more salient lessons from four different domains of adaptation research: risk assessment and impact response, social vulnerability and adaptive capacity, resilience, and the science of decision making and policy implementation. Through a few select case studies of adaptation planning, we explore the extent to which we see these lessons taking hold in adaptation practice. The cases reviewed suggest that there may be significant differences in the type of research that informs planning in more industrial contexts compared to the developing world. Risk assessment and cost/benefit analysis appear to dominate adaptation planning in the industrialized world, while insights concerning governance, the social and economic constraints to adaptation, and building systemic resilience are featured more in planning documents from the developing world. The focus on risk assessment and associated technological interventions in the industrialized world illustrates the difficulty of addressing underlying structural and cognitive barriers to change, as well as the policy implications of conceptualizing adaptation as an outcome rather than a dynamic process. More broadly, the challenge of adaptation now offers an opportunity for innovative and collaborative research in which networks of academics, policy makers, at-risk populations, and other stakeholders actively participate in understanding the process of adaptation, experimenting in responses to change and learning from that process. WIREs Clim Change 2011 2 141–153 DOI: 10.1002/wcc.100 For further resources related to this article, please visit the WIREs website

The global cropland sparing potential of high-yield farming

Abstract: The global expansion of cropland exerts substantial pressure on natural ecosystems and is expected to continue with population growth and affluent demand. Yet earlier studies indicated that crop production could be more than doubled if attainable crop yields were achieved on present cropland. Here we show on the basis of crop modelling that closing current yield gaps by spatially optimizing fertilizer inputs and allocating 16 major crops across global cropland would allow reduction of the cropland area required to maintain present production volumes by nearly 50% of its current extent. Enforcing a scenario abandoning cropland in biodiversity hotspots and uniformly releasing 20% of cropland area for other landscape elements would still enable reducing the cropland requirement by almost 40%. As a co-benefit, greenhouse gas emissions from fertilizer and paddy rice, as well as irrigation water requirements, are likely to decrease with a reduced area of cultivated land, while global fertilizer input requirements remain unchanged. Spared cropland would provide space for substantial carbon sequestration in restored natural vegetation. Only targeted sparing of biodiversity hotspots supports species with small-range habitats, while biodiversity would hardly profit from a maximum land-sparing approach. Agriculture has a massive and growing footprint. This study finds that optimizing fertilizer and major crops globally could reduce by 50% needed global cropland, allowing restored vegetation on spared land to sequester carbon.