Chapter 2: LAND AND WATER USE

Chapter 2 provides a comprehensive assessment of social science concepts on land and water use and explores their cause and effect relationship to climate change. A thematic overview of the chapter includes subsections devoted to: key concepts and empirical data on land and water use and transformation; a historical and contemporary environmental assessment of the state of these resources; the theoretical mechanisms and causal variables of land use that underlie greenhouse gas emissions; policy scenarios for emissions abatement; and feedback impacts of climate change on land and water.

Summary

The authors begin by examining the definitional parameters and distinctions between land use and land cover and classificatory features, illustrating how disciplinary biases (anthropocentric vs. ecocentric) shape the nature of problem definition, research methodology, and data analysis. Perhaps one of the most subtle but critical themes emerging from the chapter is the disparate, idiosyncratic, and often synchronic nature of social science research that makes objective, comparable analyses on a larger scale subject to much criticism. The authors conclude that ‘local data have not been generated in consistent, comparable, quantitative forms’(p. 84).

After attempting to tackle the conceptual quandaries of land and water use, the chapter traces land use conversion history from the dawn of agricultural civilization to the height of the industrial era. Summary data document the trajectory of greenhouse gas emissions, citing useful global and regional figures on land use transformation and conversion rates for agriculture, forestry, and related environmental sectors. In this discussion, and throughout the chapter, the authors point out important distinctions between the industrialized and developing nations, such as the heightened vulnerability of the latter -- owing largely to their greater population dependency on agriculture -- to climate change. A literature review and critique of key environmental phenomena such as desertification follows. Included in this section is the identification of causal features of land use such as deforestation, as key drivers of anthropogenic climate change. Land use-cover change processes including biomass burning, livestock production, rice paddy cultivation, landfill expansion, and inorganic fertilizer applications are quantitatively associated with their respective contributions to gas emissions. The impacts of land transformation on biodiversity loss conclude this section. As with other environmental measures of impact, the authors are quick to point out the difficulties inherent in quantifying species extinction.

A summary of water use history, current patterns, and consequences complements the land use section, although somewhat less exhaustive and detailed in its treatment. Useful data and primary sources of water withdrawal are linked to environmental impacts, such as the deleterious effects of irrigation on soils, water supply, and aquatic habitats, and water demands for energy use reducing groundwater supply. A salient figure given asserts that rates of water withdrawal have exceeded population growth by 35-fold since 1700.

The chapter then shifts to a contextual focus on the complex interplay of technology, geographical location, biophysical land features, and institutions as critical social, physical, and economic factors shaping land use. This section in particular underscores the complexity involved in assigning respective weights to biophysical and human processes as key factors shaping land use practice. Interesting international comparisons such as agricultural regimes in industrialized and developing countries focus on factor input availability in land, labor, and capital as the key determinants of environmental land use status. Institutional analysis is devoted largely to a discussion of resource ownership, exchange, and regulation of land tenure systems. A useful literature review of land tenure and water resources is linked to behavioral theory on resource use (profit maximization vs. risk aversion) and the role of domestic and international trade policy as key internal and external forces affecting their status.

A brief section is devoted to prescriptive strategies for land use emissions abatement, including ‘green’ energy sources (e.g., hydropower), afforestation, and agroecological and pastoral systems options. The authors are quick to point out the shortcomings, however, such as the problematic nature of standard benefit-cost analyses, the valuation of ecosystem diversity, and North-South equity concerns.

The chapter concludes with a review of key climate change impact studies as they affect land and water use. Impact is defined in terms of resource sensitivity and vulnerability. A broad assessment of vulnerability, incorporating societal and institutional dimensions as well as biophysical attributes, is presented. Three major climate change modeling studies (MINK, EPA, USDA Economic Research) are evaluated in terms of impact on world food supply. Results suggest that distributional impacts will be uneven, largely benefiting high latitude regions and disadvantaging low latitude areas, where water resource availability is expected to decline. Numerous limitations in these studies are noted, including spurious data quality, assumptions on land quality, and use of static, universal models of human behavior (e.g., profit-maximizing). Better assessment tools are called for in addressing human adaptation, particularly in the poorest nations where resilience to climate hazards is weakest. Analogues to past vulnerability, including societal coping mechanisms, are proposed as a tool to enhance assessment. The authors conclude by calling for better integrated models of land and water use that identify a broader range of driving forces and improve the integration of micro, meso, and macro scales of analysis.

Strengths

Land-water-climate interactions are inherently complex, defying narrow attempts at circumscription by purely quantitative means. Thus this chapter is effective in underscoring the broad dimensions of physical, societal, and institutional domains that must come into play in building appropriate explanatory models that explicitly link climate change to natural resource use. The contextual features of history and human agency, often marginalized or superceded by the hard science of climate change research, are given adequate weight and measure, thus illustrating the need for more holistic reflection and interdisciplinary coupling of biophysical and social science research. The ambitious inventorying of vast bodies of literature on land, water, and climate processes is admirably synthesized and cogently presented. The pitfalls of linear thinking and direct one-to-one associations of cause and effect are consistently refuted throughout this chapter.

Weaknesses

This chapter acknowledges the symptomatic shortcomings of social science research as non-systematized, idiosyncratic, and myopic in its modeling of scale. Nonetheless, this problem appears to remain unresolved at the conclusion of the chapter. An overt recognition of the problem is highlighted, but never really adequately attended to, thus perpetuating the stigma of non-utility and non-relevance among ardent climate change research scientists. The breadth of material covered is expansive, and occasionally discussion becomes unnecessarily mired in description or conceptual detail. Water, as a key natural resource in this chapter, generally is given short shrift to more elaborate analyses of land.


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