Population, Environment and Health
This cluster seeks to improve understanding of the relationship between demographic changes and the environment as they impact on health of the population. As the amount of natural resources and food is limited, there might in the future be shortages as the Thai population continues to expand. The search for habitats and agricultural land by mobile populations also adversely impacts on the environment due to increased deforestation trends. Increased urbanisation is straining the ability of municipalities to provide basic infrastructural services and air and water pollution is worsening as a result of the greater density of people and motor vehicles.
The conceptual framework of this cluster covers both urban and rural studies. Urban population and environmental variables help explain changes and interactions affecting infrastructure, economy, society, culture, technology and pollution. The impact of these urban factors are linked to destructive use of energy. Dependence on motor vehicles exacerbates the challenges faced in an urban environment and depletes non-renewable energy resources. Solid waste management becomes more of a challenge particularly in densely-populated urban areas. Associated with these phenomena are increased prevalence of mental illnesses and stress.
In rural areas, population and environmental issues of interest to researchers include the changing environment and how this impacts on agricultural production and reduced food security for Thailand as a whole in the future. This research cluster is also interested in how the changing rural environment impacts on health of different sub-groups of the population by age, occupation and ethnicity. The data collected from these studies will increase the body of knowledge and help inform linkages with demographic developments and the overall health of the population.
Figure 1: Conceptual framework for studies of population, environment and health
Theoretical foundations for this conceptual framework can be traced to the Malthusian doctrine (circa 1798) that foresaw that resources and the environment expand geometrically while population increases exponentially. As a result, when population exceeds the food supply, famine results to restore balance. Malthus did not anticipate the advances in agricultural technology that would allow vast increases in the global population. Later, Boserup (1965) argued that technology could help maintain a balance between food supply and population. Nevertheless, with the improvements of technology also came expansion of industry which exceeded the limits of the carrying capacity of the land resulting in disasters such as flooding, drought, degraded natural resources, income disparities and increased poverty, landlessness in rural areas and pollution in urban areas. These problems will increase in a vicious cycle. Ehrlich and Holdren (1974) argued that the size of the population, the growth rate and density are related to other factors such as consumption and technology and impact on the environment. Their concept is summarized by the model I = P A T where I is the impact of the size of the population (P), multiplied by consumption (A) and technology (T). Later, Billsborrow (1992) argued that socio-cultural and economic factors served as intermediate variables which linked population and environment and that population alone would not impact directly on the environment in and of itself.
Studies in Thailand in the context of linkages between population and the environment as they impact on health are still few in number. Most studies so far have focused on conflicts between government staff and people in the use of resources and control of land usage. One study by the Thailand Development Research Institute (1989) found that the degradation of forests in the Northeast region of Thailand during 1960 to 1988 was attributable to increased population density. While the study exposed the relationship between population increase and deforestation, this study did undertake a detailed analysis of the statistical relationship between the variables. Later studies by Jermsak Pintong et al (1991) and Anand Kanchanpan et al (1992) found that economic prosperity and market expansion were important factors in increasing encroachment on forested lands to pursue agro-industrial ventures for crop export. In addition to deforestation, this expansion also increased the use of chemical fertilisers and pesticides and these actions in turn reduced the fertility of the soil and degraded the environment with clear consequences for the health of the population.