全球变化知识资源中心

Large-scale water management systems were introduced to the Ganges-Brahmaputra and Mekong Deltas in the latter half of the twentieth century to manage extreme water hazards and increase food production. However, these systems significantly altered their respective hydrological regimes, often creating worse socio-ecological conditions and greater vulnerability to floods and seawater intrusion than existed previously. Despite this history of disaster experience, climate change adaptation measures in the Ganges-Brahmaputra and Mekong Deltas use contemporary socio-ecological conditions as the baseline for disaster mitigation efforts. Paradoxically relying on old approaches to address future climate threats, disaster planners overlook how current conditions in both deltas are unstable outcomes of historical processes. These cases illustrate that large-scale and capital-intensive climate responses may fail to measurably reduce disaster risk. The concept of shifting baselines, borrowed from fisheries science, becomes helpful for selecting more appropriate reference points for disaster mitigation than current conditions.