What does it mean when climate models agree? A case for assessing independence among general circulation models

Climate modelers often use agreement among multiple general circulation models (GCMs) as a source of confidence in the accuracy of model projections. However, the significance of model agreement depends on how independent the models are from one another. The climate science literature does not address this. GCMs are independent of, and interdependent on one another, in different ways and degrees. Addressing the issue of model independence is crucial in explaining why agreement between models should boost confidence that their results have basis in reality.     

Why Economics Matters for Endangered Species Protection

Abstract: We offer three reasons why economics matters more to species protection than many people think and what this implies for the ongoing debate over the reauthorization of the Endangered Species Act of 1973. Economics matters because (1) human behavior generally, and economic parameters in particular, help determine the degree of risk to a species; (2) in a world of scarce resources, the opportunity cost of species protection—the costs of reduced resources for other worthwhile causes—must be taken into account in decision making; and (3) economic incentives are critical in shaping human behavior, and consequently the recovery of species. Endangered species protection that explicitly addresses these basic principles can avoid wasting valuable resources that yield no gain in species protection.     

Are savannas patch-dynamic systems? A landscape model

Savannas are ecosystems characterized by the coexistence of woody species (trees and bushes) and grasses. Given that savanna characteristics are mainly formed from competition, herbivory, fire, woodcutting, and patchy soil and precipitation characteristics, we propose a spatially explicit model to examine the effects of the above-mentioned parameters on savanna vegetation dynamics in space and time. Furthermore, we investigate the effects of the above-mentioned parameters on tree–bush–grass ratios, as well as the degrees of aggregation of tree–bush–grass biomass. We parameterized our model for an arid savanna with shallow soil depth as well as a mesic one with generally deeper and more variable soil depths. Our model was able to reproduce savanna vegetation characteristics for periods of time over 2000 years with daily updated time steps. According to our results, tree biomass was higher than bush biomass in the arid savanna but bush biomass exceeded tree and grass biomass in the simulated mesic savanna. Woody biomass increased in our simulations when the soil's porosity values were increased (mesic savanna), in combination with higher precipitation. Savanna vegetation varied from open savanna to woodland and back to open savanna again. Vegetation cycles varied over ∼300-year cycles in the arid and ∼220-year cycles in the mesic-simulated savanna. Autocorrelation values indicated that there are both temporal and spatial vegetation cycles. Our model indicated cycling savanna vegetation at the landscape scale, cycles in cells, and patchiness, i.e. patch dynamics.     

Modeling normativity in sustainability: a comparison of the sustainable development goals,the Paris agreement,and the papal encyclical

The idea of sustainability is intrinsically normative. Thus, understanding the role of normativity in sustainability discourses is crucial for further developing sustainability science. In this article, we analyze three important documents that aim to advance sustainability and explore how they organize norms in relation to sustainability. The three documents are: the Pope’s Encyclical Laudato Si’, the Sustainable Development Goals and the Paris Agreement. We show that understanding the role of different types of norms in the three documents can help understand normative features of both scientific and non-scientific sustainability discourses. We present the diverse system of norms in a model that interrelates three different levels: macro, meso, and micro. Our model highlights how several processes affect the normative orientation of nations and societies at the meso-level in different ways. For instance, individual ethical norms at the micro-level, such as personal responsibility, may help decelerate unsustainable consumerism at the aggregate meso-level. We also show that techno-scientific norms at the macro-level representing global indicators for sustainability may accelerate innovations. We suggest that our model can help better organize normative features of sustainability discourses and, therefore, to contribute to the further development of sustainability science.     

Erratum to: Addressing future trade-offs between biodiversity and cropland expansion to improve food security

Potential trade-offs between providing sufficient food for a growing human population in the future and sustaining ecosystems and their services are driven by various biophysical and socio-economic parameters at different scales. In this study, we investigate these trade-offs by using a three-step interdisciplinary approach. We examine (1) how the expected global cropland expansion might affect food security in terms of agricultural production and prices, (2) where natural conditions are suitable for cropland expansion under changing climate conditions, and (3) whether this potential conversion to cropland would affect areas of high biodiversity value or conservation importance. Our results show that on the one hand, allowing the expansion of cropland generally results in an improved food security not only in regions where crop production rises, but also in net importing countries such as India and China. On the other hand, the estimated cropland expansion could take place in many highly biodiverse regions, pointing out the need for spatially detailed and context-specific assessments to understand the possible outcomes of different food security strategies. Our multidisciplinary approach is relevant with respect to the Sustainable Development Goals for implementing and enforcing sustainable pathways for increasing agricultural production, and ensuring food security while conserving biodiversity and ecosystem services.

     

A study of total beta specification through symmetric regression: the case of the Johannesburg Stock Exchange

A topic of recent interest is risk management in equity investments from emerging markets. One traditional measure for systematic risk of an asset is beta, which is constructed through ordinary least squares (OLS) regression between historical returns on an individual asset and an index representing the overall market. OLS regression assumes all the error lies within the asset returns. Tofallis (Eur J Oper Res 187(3):1358–1367, 2008) made the case for constructing a systematic risk measure through symmetric regression, where error is assumed to be present in the returns of both the asset and the index. In this paper, we construct a systematic risk measure using symmetric regression for the case of the Johannesburg Stock Exchange (JSE). This paper makes the case that the so-called ‘total beta’ parameter provides a more realistic and stable estimator for market-related risk and return. The total beta estimate, explicitly allowing for error in both variables, is less likely to underestimate the magnitude of the beta parameter.     

A meta‐analytic investigation into the moderating effects of situational strength on the conscientiousness–performance relationship

Debates about the utility of conscientiousness as a predictor of job performance have focused primarily on mean effect size estimates, despite theoretical and empirical reasons to expect variability across situations. The present study meta‐analytically demonstrates that occupation‐level situational strength is one important source of this variability. Consistent with theory, predicted uncorrected conscientiousness–performance correlations ranged from r = .09 to .23 (overall performance) and r = .06 to .18 (task performance), with stronger correlations observed in weak occupations. These results highlight the need for continued inquiry into the nature of situational strength, its impact on other predictor–outcome relationships, and the implications of these issues vis‐à‐vis theory and practice. Copyright © 2009 John Wiley & Sons, Ltd.     

The influence of temperature on the deactivation of commercial Pd/Rh automotive catalysts

Automotive catalyst deactivation can be promoted by thermal and poisoning mechanisms. Catalyst efficiency is reduced by thermal degradation resulting in the agglomeration of precious metals and the reduction of the washcoat surface area. In this paper, the temperature influence on the commercial Pd/Rh-based automotive catalyst performance was studied. Textural and physicochemical characterisation techniques were employed, such as X-ray fluorescence (XRF), atomic absorption spectrometry (AAS), N₂ physisorption, X-ray diffraction (XRD), temperature programmed reduction (TPR) and scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM–EDX). The catalysts were evaluated for CO and propane oxidation with a stoichiometric gas mixture similar to engine exhaust gas. The results indicated the transformation of alumina into high temperature phases and the formation of new mixed oxide phases. Evidence of sintered particles and several spots of palladium agglomerates was seen by SEM–EDX analysis. The activity results showed the effects of thermal deactivation on the conversion of the pollutants. In spite of exposure to extreme temperature conditions (72 h at 1200 °C), significant activity was still observed for carbon monoxide and propane oxidation reactions.