Population, Land Use, and Environment Research Directions (2005) / Chapter Skim
Currently Skimming:
1 The State of Knowledge
1 The State of Knowledge
Pages 7-30
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From page 7... ...
Analysis of populationenvironment relationships became broader in the second half of the twentieth century, when recognition became widespread that human activity posed major environmental threats not only through land use, which among other effects can degrade the food-producing capacity of lands, but also through pollution resulting from industrial activities that supported economic growth. Among the landmarks in this broadening of focus were the arguments raised in the early 1970s by Ehrlich and colleagues (Ehrlich and Ehrlich, 1970; Ehrlich and Holdren, 1971)
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From page 8... ...
Researchers' interests have focused increasingly on understanding the driving forces, including not only population, affluence, and technology, but also human values, social institutions, public policies, and more; their effects and interactions; the mechanisms by which they affect environmental outcomes; and feedbacks from environmental conditions to human activity. Just as demographic driving forces may lead to environmental outcomes in various ways, environmental conditions and changes may also influence population size, structure, and change.
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From page 9... ...
. Demographic factors, including population growth, density, fertility, mortality, and the age and sex composition of households, are known to be important influences on land use and land cover change.
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From page 10... ...
This volume 1One reason for limited research attention to processes linking demographic and other human variables to environmental consequences through production and consumption of industrial products has been the absence of targeted funding for this research in the United States. Industrial metabolism has become a focus of interest in the engineering field (see, e.g., Williams, Larson, and Ross, 1987; National Academy of Engineering, 1994; Graedel and Allenby, 1995; National Research Council, 2004b)
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From page 11... ...
For these reasons, we have looked closely at site-specific studies and also other studies that have tried to clarify the mechanisms linking demographic variables, land use change, and environmental outcomes. The notion of demographic factors as driving forces suggests one-way causation, and indeed the primary emphasis in many studies has been on the effects of human activities on environmental variables, including research undertaken as part of the Intergovernmental Panel on Climate Change (Fischer and O'Neill, Chapter 3)
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From page 12... ...
The other was for case studies that clearly analyze the roles of the various factors, such as property rights institutions, market conditions, and soil and climate characteristics, that condition populationland use relationships. It was expected that such studies could explain why population growth does not have uniform effects on the land and help develop a causal understanding of populationland use relationships.
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From page 13... ...
The former was a major focus of research for many years, in part due to high fertility in many parts of the world combined with dramatic decreases in death rates after World War II. Indeed, much of the early work was at the national level, where natural increase dominates as a component of population growth (e.g., Allen and Barnes, 1985)
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From page 14... ...
There is also the issue of possible environmental effects of policy-driven migrations, often aimed at replacing indigenous peoples, as in forced migrations or population dilutions of such peoples in North America in the nineteenth century and in the Soviet Union, Tibet, and elsewhere in the twentieth. These policy interventions tend to replace adapted indigenous land use systems with ones imported from other ecological zones.
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From page 15... ...
In much of the early research on population and land use, little attention was given to environmental outcomes beyond those involving land cover. Recent research is beginning to specify environmental variables in much more detail.
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From page 16... ...
They have carefully collected and analyzed multilevel, longitudinal, and spatially explicit data on population, land use, and environmental processes for specific localities, large and small (Galvin et al., 2002; Gutmann et al., Chapter 4; Matson et al., Chapter 10; Moran et al., 1994, 2003, Chapter 5; Walsh et al., Chapter 6; Redman, Chapter 7; Thornton et al., 2003; Turner, Geoghegan, and Foster, 2004)
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From page 17... ...
Studies of individuals or households typically cover relatively short temporal scales, often 5 or 10 years, at most 20 or 30 years. Studies of counties, states, or provinces may cover a century or more (Gutmann et al., Chapter 4)
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From page 18... ...
Spatial data may be analyzed at the observational levels of pixels and scenes; at ecological levels of plots, ecosystems, communities, and landscapes; by socially defined spatial units, such as field plots and village territories; or in environmentally defined units, such as watersheds and bioregions. Temporal analysis may involve observations daily, weekly, seasonally, annually, or at longer intervals.
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From page 19... ...
In this crossscale interaction, higher level social units form part of the context for decisions by lower units. When such phenomena exist, populationland use environment relationships that hold in a particular site may be conditional on the larger social (and environmental)
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From page 20... ...
. Linking Social and Environmental Data Research on populationland useenvironment relationships depends on integration of social and environmental features at the appropriate social, spatial, and temporal scales, and equally important, appropriate linkages of processes that cross sectoral components of the coupled human environment system.
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From page 21... ...
For example, decadal censuses provide valuable sources of information about population size and structure, but they are limited in important ways relevant to understanding populationland useenvironment interactions. One problem is the decadal level of temporal resolution: important population changes occur over much shorter intervals, as pointed out in several papers in this volume (e.g., Seto, Chapter 8; Matson et al., Chapter 10; Weeks et al., Chapter 11)
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From page 22... ...
. Another challenge is to make full use of the historical detail in time series available in remote images, which typically have much higher temporal resolution than censuses, land surveys, or social surveys.
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From page 23... ...
. In principle, such comparable data might come from space platforms, but these data must be analyzed in different ways to address different research questions and to fit the important land use and land cover changes under way in specific contexts.
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From page 24... ...
It also makes difficult any effort to address questions of scale dependence and cross-scale interaction. The growing number of detailed and sustained site-based studies represents an unparalleled collection of resources for better understanding population processes, land use change, and environmental determinants and consequences.
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From page 25... ...
Since then, three major kinds of research have been advancing the field in the direction of the needed causal understanding: detailed descriptive studies of change at specific sites, regression-based statistical analyses of change processes, and studies that emphasize mathematical modeling. Research has also begun to examine scale dependencies, crossscale interactions, thresholds, and feedbacks.
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From page 26... ...
Studies based on quantitative statistical analyses have so far stopped short of fully considering population-environment interactions as a complex system, and particularly the feedbacks from environment to population. Virtually always, population has been treated as exogenous to land use change and environmental impact.
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From page 27... ...
Fischer and O'Neill (Chapter 3) discuss the role of population in current global models of land use change and environment, with particular reference to the models used by the Intergovernmental Panel on Climate Change to produce scenarios of greenhouse gas emissions and those used to produce scenarios of changes in future ecosystem goods and services for the Millennium Ecosystem Assessment.
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From page 28... ...
Much of this research has necessarily been multidisciplinary or interdisciplinary, because the disciplines that study human population dynamics, land use change, and environmental change have not usually communicated much with each other. Projects funded by NICHD, other government agencies, and private foundations, focusing mainly on populationland use interactions, have made good progress in eliciting collaboration across the social sciences and between the social sciences and some natural science disciplines, notably those involved in interpreting remote observations of land use and land cover change.
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From page 29... ...
describe such an approach to the modeling of land use and land cover change in China. Mathematical modeling provides a common language that can enable researchers from different disciplines to communicate to each other certain aspects of their expertise that are critical to the complex system they are studying, even though they do not share disciplinary paradigms.
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From page 30... ...
Systematic in-depth and rigorous training in the full range of social and environmental sciences relevant to populationland useenvironment research is comparatively rare at the graduate level, compared with training in multiple disciplines in either the social or natural sciences.
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