linking various aspects of atmospheric change through a systems analysis of food

Although interdisciplinary collaboration to address a singleenvironmental problem is more common than in the past, all toooften the significant atmospheric problems of our day such asstratospheric ozone depletion, acidic deposition or climaticchange are addressed on a single issue basis. Systems analysis isa way of looking at a problem in a holistic, integrated fashionthrough including as many as practicable of the importantcomponents, and the linkages among them. Systems analysisoften begins with a conceptual model which, even if lackingquantification, is a useful means of changing ones thinking to amulti-issue approach. If possible, conceptual models areoperationalized by quantification (using the best availablescientific knowledge) of the stocks and flows of the relevantcomponents of the problem, and the processes that are involved.In this paper, a systems approach to food production is used tolink various atmospheric issues such as regional acidification andclimatic change. A spreadsheet model of food demand andproduction in various world regions examined the possible effectof atmospheric change on how much food we can grow, andwhether or not we may be able to meet the increased demand inthe year 2025. Using relatively modest changes in factors ofagricultural production, the spreadsheet model calculated globalshortfalls by the year 2025 of the order of 10 to 20% in someimportant agricultural crops, despite the improvements in cropproduction factors that are envisaged by the Food andAgricultural Organization from now until the year 2010, and thatwere extrapolated in this paper to 2025. The model alsocalculated that climatic change in combination with eithertropospheric ozone or increased UV-B radiation caused bydepletion of the stratospheric ozone layer may in general makethe situation worse than in the case of climatic change alone.Given the large uncertainties in the input data, the results in thispaper should not be viewed as predictions but rather as anexample of taking a relatively simple systems approach to foodproduction using a spreadsheet model, and calculating the effectsthat various aspects of atmospheric change might have upon it.Therefore, it is extremely important to know the effects uponcrop production factors of climatic change, tropospheric ozoneand increased UV-B radiation not only as individual issues, butalso of their combined effect since it is probable that in manyregions they will occur in combination.     

Exploration's Role in Iron and Aluminum Supply Since the Second World War

This paper analyses the role of exploration in the worldwide supply of iron and aluminum by (1) reviewing changes in the level and geographic distribution of exploration since 1945, (2) studying important discoveries, and (3) comparing exploration's role in iron and aluminum supply with its role in the supply of other metals. It finds that even though exploration and discovery of new deposits account for part of the tremendous postwar expansion in the level and geographic distribution of iron ore and bauxite production, most of the areas that became major producers were known to contain significant mineralization long before detailed evaluation, development, and mining occurred. These areas needed increased consumer demand, lower ocean freight costs, or improved processing techniques to become economically attractive. Iron and aluminum are easier-to-find yet harder-to-process, and compared with other metals, discovering a better deposit will not reduce overall costs to the same degree as other cost-reducing forms of investment.     

Joint Effects of Inbreeding and Local Adaptation on the Evolution of Genetic Load after Fragmentation

Abstract: Disruption of gene flow among demes after landscape fragmentation can facilitate local adaptation but increase the effect of genetic drift and inbreeding. The joint effects of these conflicting forces on the mean fitness of individuals in a population are unknown. Through simulations, we explored the effect of increased isolation on the evolution of genetic load over the short and long term when fitness depends in part on local adaptation. We ignored genetic effects on demography. We modeled complex genomes, where a subset of the loci were under divergent selection in different localities. When a fraction of the loci were under heterogeneous selection, isolation increased mean fitness in larger demes made up of hundreds of individuals because of improved local adaptation. In smaller demes of tens of individuals, increased isolation improved local adaptation very little and reduced overall fitness. Short‐term improvement of mean fitness after fragmentation may not be indicative of the long‐term evolution of fitness. Whatever the deme size and potential for local adaptation, migration of one or two individuals per generation minimized the genetic load in general. The slow dynamics of mean fitness following fragmentation suggests that conservation measures should be implemented before the consequences of isolation on the genetic load become of concern.     

INVESTMENT IN THE COPPER INDUSTRY: NEEDS AND POLICIES

Investment required in the copper industries of the market economies over the period 1977-90 is estimated. The estimation methodology involves projection of copper consumption in the developed market economies, developing economies, and centrally planned economies. For the market group as a whole, consumption projections lead to required incremental capacity estimates and finally to required investment figures. (Pollution abatement costs and exploration requirements are also included). The sensitivity of investment requirements to major determining factors is investigated. Finally, the broader question of appropriate intergovernmental policies to influence the geographic allocation of minerals investment - including copper investment - is considered.