Suchergebnisse

Racial separation may be the result of many factors: variation in income, occupational differences, and individual preference come to mind immediately. Indeed, Thomas Schelling argued in 1969 that even mild individual preference for like neighbors could produce dramatic segregation in neighborhoods. This paper examines the robustness of his conclusion in two slightly more realistic environments. One adds the complication of vacant lots and more diverse utility-based agents. Each of the cases simulated here produced equilibria with some degree of racial segregation. The results therefore sustained Schelling's conjecture that individual intent is not necessarily related to the collective result of neighborhood segregation. In all of the simulations, each individual would have been content with a local neighborhood in which approximately half of the residents were of the same race; but all individuals acting together with this motive seemed to produce segregated neighborhoods. The Schelling conjecture was undermined to some degree by inclusion of local public goods, but only if they were highly valued. In those cases, proximity to the public goods worked against the disutility of mixed neighborhood so integrated neighborhoods became more likely. If the public goods were not highly valued, though, the segregation persisted or unstable and chaotic neighborhoods persisted.

We study the effects of development and climate change on infectious diseases in Sub-Saharan Africa. Infant mortality and infectious disease are closely related, but there are better data for the former. In an international cross-section, per capita income, literacy, and absolute poverty significantly affect infant mortality. We use scenarios of these three determinants and of climate change to project the future incidence of malaria, assuming it to change proportionally to infant mortality. Malaria deaths will first increase, because of population growth and climate change, but then fall, because of development. This pattern is robust to the choice of scenario, parameters, and starting conditions; and it holds for diarrhoea, schistosomiasis, and dengue fever as well. However, the timing and level of the mortality peak is very sensitive to assumptions. Climate change is important in the medium term, but dominated in the long term by development. As climate can only be changed with a substantial delay, development is the preferred strategy to reduce infectious diseases even if they are exacerbated by climate change. Development can, in particular, support the needed strengthening of disease control programs in the short run and thereby increase the capacity to cope with projected increases in infectious diseases over the medium to long term. This conclusion must, however, be viewed with caution, because development, even of the sort envisioned in the underlying socio-economic scenarios, is by no means certain.

A space of "not-implausible" scenarios for Egypt's future under climate change is defined along two dimensions. One depicts representative climate change and climate variability scenarios that span the realm of possibility. Some would not be very threatening. Others portend dramatic reductions in average flows into Lake Nassar and associated increases in the likelihood of year to year shortfalls below critical coping thresholds; these would be extremely troublesome, especially if they were cast in the context of increased political instability across the entire Nile Basin. Still others depict futures along which relatively routine and relatively inexpensive adaptation might be anticipated. The ability to adapt to change and to cope with more severe extremes would, however, be linked inexorably to the second set of social–political–economic scenarios. The second dimension, defined as "anthropogenic" social/economic/political scenarios describe the holistic environment within which the determinants of adaptive capacity for water management, agriculture, and coastal zone management must be assessed.