Using remote sensing and land abandonment as a proxy for long-term human out-migration. A Case Study: Al-Hassakeh Governorate, Syria

英语. The topic of human migration and displacement has become more important in recent years and will continue to do so in the following decades. Voices become louder claiming that climate change is a driving factor for increased displacement and migration. Increasing unsuitable living conditions due to unpredictable weather patterns and increased number of extreme events are putting pressure on the socio-economic situation of countries. The Syrian war which started in 2011 has widely been discussed across governments, academia, NGO’s and civil society. Hy-potheses exist that climate change was a key driver, which led to the onset of the war. The de-bated drought of 2008 was said to have led to the displacement of 1000’s of people from the countryside to the cities. The sudden rise in population in the cities led to increasing unemploy-ment and dissatisfaction across the Syrian population. In this study, my aim was to use remote sensing and earth observation to assess whether migra-tion took place in the north-eastern governorate Al-Hassakeh before the war. I made use of veg-etation indices derived from satellite images to look at the trend of vegetation health. Moreover, I investigated land cover changes using a land cover data set comprised of four classes (Bare Soil Single Crop, Multi Crop, Other Vegetation). Finally, by combining the two, I have assessed whether long-term out-migration took place using land abandonment as a proxy indicator in Al-Hassakeh Governorate from 2000-2015. I found a decrease in vegetation health in two out of four sub-districts, namely Ras-Al-Ain and Al-Hassakeh. In the case of the former, the observed decreasing vegetation health was predomi-nantly centered in between ephemeral waterbodies, while in Al-Hassakeh, the decrease was lo-cated in the southern part of the sub-district. The land cover did not significantly change in aerial extent, but I found a gradual decrease in Multi Crop across the whole governorate. Furthermore, I found that overall, the Single Crop class extent shifted northwards and closer to ephemeral waterbodies. Based on my analysis, long-term out-migration has only occurred in the southern part of Al-Hassakeh Governorate and more frequently so before the drought in 2008. The results suggested that long-term out-migration did take place before the war. However, the highly debated ‘additional’ migration as a result of the drought in 2008 remains questionable. I argue that it is more likely that a combination of factors ranging from policy changes and deci-sions, a continuous lack of access to freshwater and groundwater depletion on top of the slow climatic changes resulted in the observed out-migration. This study confirmed that remote sens-ing and earth observation are useful tools to assess vegetation and land cover trends. I have shown that a combination of methods can further be utilized to model possible human out-migration. The findings of this study specifically related to migration, however, are yet to be confirmed with other data.

英语. The topic of human migration and displacement has become more important in recent years and will continue to do so in the following decades. Voices become louder claiming that climate change is a driving factor for increased displacement and migration. Increasing unsuitable living conditions due to unpredictable weather patterns and increased number of extreme events are putting pressure on the socio-economic situation of countries. The Syrian war which started in 2011 has widely been discussed across governments, academia, NGO’s and civil society. Hypotheses exist that climate change was a key driver, which led to the onset of the war. The debated drought of 2008 was said to have led to the displacement of 1000’s of people from the countryside to the cities. The sudden rise in population in the cities led to increasing unemployment and dissatisfaction across the Syrian population. Using satellite images and Geographic Information Systems (GIS) I wanted to combine human and physical geography and assess whether migration took place in the north-eastern governorate Al-Hassakeh before the war. By using a 3-step approach, I have tried to assess whether long-term out-migration took place in Al-Hassakeh Governorate from 2000-2015. First, I looked at how the vegetation productivity changed over the time period. Secondly, I looked at the overall land cover changes for the same area. Then finally at step number three I identified those areas, which experienced a significant decline in vegetation productivity and changed in land cover from cropland to bare soil. I found a decrease in vegetation productivity in two out of four sub-districts, namely Ras-Al-Ain and Al-Hassakeh. In Ras-Al-Ain productivity decreased around the seasonal waterbodies, while in Al-Hassakeh, the decrease was located in the southern part of the sub-district. The land cover did not significantly change in areal extent, but I found a gradual decrease in areas being harvested twice a year for the whole governorate. Furthermore, I found that overall, the extent for usual cropland shifted northwards and closer to ephemeral waterbodies. The results suggested that long-term out-migration did take place before the war. However, the highly debated ‘additional’ migration as a result of the drought in 2008 remains questionable. I argue that it is more likely that a combination of factors ranging from policy changes and decisions, a continuous lack of access to freshwater and groundwater depletion on top of the slow climatic changes resulted in the observed out-migration. This study confirmed that remote sensing and earth observation are useful tools to assess vegetation and land cover trends. I have shown that a combination of methods can further be utilized to model possible human out-migration. The findings of this study specifically related to migration, however, are yet to be confirmed with other data.