Call Maia A, Gray Clark, Yunus Mohammad, Emch Michael
UNC Department of Geography, Carolina Hall, CB #3220, Chapel Hill, NC 27599-3220.
UNC Department of Geography, 308 Carolina Hall, CB #3220, Chapel Hill, NC 27599-3220.
Glob Environ Change. 2017 Sep;46:157-165. doi: 10.1016/j.gloenvcha.2017.08.008. Epub 2017 Sep 20.
Mass migration is one of the most concerning potential outcomes of global climate change. Recent research into environmentally induced migration suggests that relationship is much more complicated than originally posited by the 'environmental refugee' hypothesis. Climate change is likely to increase migration in some cases and reduce it in others, and these movements will more often be temporary and short term than permanent and long term. However, few large-sample studies have examined the evolution of temporary migration under changing environmental conditions. To address this gap, we measure the extent to which temperature, precipitation, and flooding can predict temporary migration in Matlab, Bangladesh. Our analysis incorporates high-frequency demographic surveillance data, a discrete time event history approach, and a range of sociodemographic and contextual controls. This approach reveals that migration declines immediately after flooding but quickly returns to normal. In contrast, optimal precipitation and high temperatures have sustained positive effects on temporary migration that persist over one to two year periods. Building on previous studies of long-term migration, these results challenge the common assumption that flooding, precipitation extremes and high temperatures will consistently increase temporary migration. Instead, our results are consistent with a livelihoods interpretation of environmental migration in which households draw on a range of strategies to cope with environmental variability.
大规模移民是全球气候变化最令人担忧的潜在后果之一。最近对环境引发的移民的研究表明,这种关系比“环境难民”假说最初设想的要复杂得多。气候变化在某些情况下可能会增加移民,而在其他情况下则会减少移民,而且这些迁移往往更多是暂时的和短期的,而非永久的和长期的。然而,很少有大样本研究考察在不断变化的环境条件下临时移民的演变情况。为了填补这一空白,我们衡量了温度、降水和洪水能够预测孟加拉国马特莱地区临时移民的程度。我们的分析纳入了高频人口监测数据、离散时间事件史方法以及一系列社会人口和背景控制因素。这种方法表明,洪水过后移民立即减少,但很快又恢复正常。相比之下,最佳降水量和高温对临时移民有持续的积极影响,这种影响会持续一到两年。基于之前对长期移民的研究,这些结果挑战了一种常见的假设,即洪水、极端降水和高温会持续增加临时移民。相反,我们的结果与对环境移民的生计解释一致,即家庭会采用一系列策略来应对环境变化。