<論説>大戦間期イギリス帝国におけるグローバルな環境危機論の形成 (特集 : 環境)

Abstract

本稿の目的は、大戦間期イギリス帝国における自然災害の要因と対策をめぐる議論の分析から、植民地科学者／官僚の間でグローバルな環境危機論が形成されるプロセスを検証するとともに、その特質を明らかにすることである。主として「サハラ砂漠の拡大」をめぐる論争と、アメリカ中西部の広域砂塵被害「ダスト・ボウル」に関する議論を取り上げ、植民地科学者／宮僚の間で共有されていた環境認識を考察した。その結果、かれらの間では、一九三〇年代までに人間と自然との関係が問い直されるようになっていたことが示された。土壌浸食などの自然災害は人間の誤った活動によって引き起こされるという見方が普遍化され、被害は世界中に拡大して、世界の人口や文明を維持するための資源・食糧の供給が限界に達するという認識が広がったことが、グローバルな環境危機論の形成につながったと考えられるのである。

This study examines the way in which the discourse of global environmental crisis emerged and spread in the British Empire between the Wars, and also identifies the nature of this discourse. In the field of environmental history, the processes by which and how far environments have changed on a global basis has been a main concern. Most historians agree that the empire had a major impact on such environmental changes. Meanwhile, the questions how and why anxiety about the global environment were widespread have not yet been answered. In this article, I mainly deal with the arguments among colonial scientists of environmental degradation, such as soil erosion and desiccation, not only within the empire but also in the rest of the world. In the first part of this study, I observe the progression of desiccation theory. I use the term 'desiccation theory' to incorporate a large body of ideas centred on the connections between deforestation on the one hand, and increased erosion, flooding and overall aridity of land and climate on the other. This theory had been advocated mostly by the members of the Indian Forest Service since the late nineteenth century. They recognized desiccation as a phenomenon particular to tropical and subtropical conditions, but they began to understand that desiccation could happen anywhere in the world after the First World War. There follows an analysis of the discussion about 'the encroachment of the Sahara', which had effects on the discourse of global environmental crisis. Through this discussion, I explore how desiccation theory was interpreted by ecologists, geographers, agriculturalists, soil scientists and so on. At the same time, I seek to indicate that colonial scientists came to share ideas concerning the relationship between man and nature. They had realized that human agency rather than climate was the determining factor in the process of desiccation. This awareness led them to regard desiccation as a universal phenomenon. Then I shed light on the 'Dust Bowl', large-scale dust storms and soil erosion on the Great Plains, which had an exceptionally dire impact on the world in the 1930s. Most scientists in the United States considered the Dust Bowl Rot as a symptom of global environmental crisis but as a national disaster. However, colonial scientists in the British Empire took this disastrous case as an example of the same kind of problem that was widespread in the empire. They also used it to suggest that man could induce soil erosion in any part of the world. In this sense, they took a leading role in globalizing consciousness of the threat of desiccation. Finally, I elucidate the essential ideas that were embedded in the discourse of global environmental crisis. It was recognized that these areas suffered from artificially induced soil erosion and desiccation was expanding around the world. Additionally, it was realized that the loss of soil on a global scale resulted in damage to food production necessary to support an increasing population. We can find here that man's injurious effect on nature was generalized. Colonial scientists insisted that this relationship between man and nature should be revised in order to avoid the decline of civilization in the near future. This article points out the particular contribution of colonial scientists to the emergence of the discourse of global environmental crisis. In the present day, global environmental problems are one of the most urgent issues in international society. At the international agencies where global environmental matters are discussed, generalized environmentalism advocated by professional scientists has a strong influence on national and local policies, economy and culture. We often see that indigenous people were excluded from decision making on environmental programs, because they were seen as the very cause of environmental degradation, especially in developing countries. In the face of this problem, more and more work will be required to reveal process whereby global environmentalism was established and the engagement of colonial scientists in it.