Multi-scale assessment of the environmental impact of refugee camps in the context of climatic variability

Transcription

1 Multi-scale assessment of the environmental impact of refugee camps in the context of climatic variability Olaf Kranz 1,2, Elisabeth Schoepfer 3, Kristin Spröhnle 3 & Stefan Lang 1 1 Interfaculty Department of Geoinformatics Z_GIS, University of Salzburg/Austria 2 Helmholtz Association Head Office, Research Section, Berlin/Germany 3 German Aerospace Center (DLR), German Remote Sensing Data Center (DFD), Oberpfaffenhofen/Germany GI_Forum Salzburg, 8 July 2015

2 51.2 million forcibly displaced worldwide Quelle: THW

3 approx. 17 million refugees approx. 33 million internally displaced persons approx. 1.2 million asylum-seekers Quelle: THW

4 Causes of flight and migration Wars and armed conflicts Violations Natural or man-made disasters Climate change / environmental change Population pressure Poverty etc. Quelle: THW

5 Impact of Refugees on the Environment Quelle: THW

6 Rainfall has Declined by 20 Percent Temperature Increases Intensify the Impact of Droughts Quelle: WWF

7 in the literature Chart 7

8 Multi-scale satellite image analysis approach Medium resolution (MR) monitoring of land cover changes High resolution (HR) detection of broad vegetation categories Very high resolution (VHR) separation of woody vegetation features Chart 8

9 Multi-scale satellite image analysis approach (MR) Data: Earth observation data, from MODIS VI (MOD13Q1), over one decade, 237 data sets Precipitation data, from Hydrological Data and Information System (HyDIS) Temperature data, from Berkeley Earth (2014) Population data, from HIC, UN OCHA, IRIN, UNEP, Sudan Tribune Methodology: Time series analysis, based on Seasonal Kendall (SK) test Results: Trend pattern showing trends in vegetation cover => significant land-cover changes Positive and negative trends => increase or decrease in vegetation Hotspots in areas with specific characteristics, i.e. near wadi banks or within the vicinity of settlements and IDP camps Indication for the influence of increasing population on natural resources => Correlation of these trend patterns with precipitation, temperature, and population data KRANZ, O., SACHS, A. & LANG, S. (2015), Assessment of environmental changes induced by internally displaced person (IDP) camps in the Darfur region, Sudan, based on multi-temporal MODIS data. Int. Journal of Remote Sensing, Vol. 36, No. 1, Chart 9

10 Multi-scale satellite image analysis approach (MR) Comparison of trend pattern resulting from the time series analysis with VHR satellite Imagery Red indicate negative change Green highlights increasing vegetation cover KRANZ, O., SACHS, A. & LANG, S. (2015), Assessment of environmental changes induced by internally displaced person (IDP) camps in the Darfur region, Sudan, based on multi-temporal MODIS data. Int. Journal of Remote Sensing, Vol. 36, No. 1, Chart 10

11 Multi-scale satellite image analysis approach (HR) Data: Earth observation data, from SPOT between 2003 and 2007 Precipitation data, from Hydrological Data and Information System (HyDIS) Population data, from UN OCHA, IRIN, UNEP, Sudan Tribune Methodology: Object-based image analysis Results: Trend pattern suggests negative and positive changes in woody vegetation Influence of the camps is not that obvious Precipitation data reveal that the change detection results are influenced by different precipitation and consequent phenological conditions at the time of data acquisition SPRÖHNLE, K., KRANZ, O., SCHÖPFER, S., VOIGT, S. & MÖLLER, M. (2015), Earth observation based multi-scale impact assessment of refugee camps on wood resources in Zalingei, Darfur. Geocarto International. SPRÖHNLE, K., KRANZ, O., & SCHÖPFER, S. (2010), Abschätzung der Umweltauswirkungen von Flüchtlingslagern mit Hilfe multitemporaler Fernerkundungsdaten am Beispiel des Camps Zalingei in Westdarfur. In: STROBL, J., BLASCHKE, T. & GRIESEBNER, G. (Eds.), Angewandte Geoinformatik Beiträge zum 22. AGIT Symposium, SPRÖHNLE, K. (2010): Earth Observation for Environmental Impact Assessment in the surroundings of Refugee Camps in Darfur. Unveröffentlichte Magisterarbeit, Bamberg, 105 S. Chart 11

12 Multi-scale satellite image analysis approach (HR) SPRÖHNLE, K., KRANZ, O., & SCHÖPFER, S. (2010), Abschätzung der Umweltauswirkungen von Flüchtlingslagern mit Hilfe multitemporaler Fernerkundungsdaten am Beispiel des Camps Zalingei in Westdarfur. In: STROBL, J., BLASCHKE, T. & GRIESEBNER, G. (Eds.), Angewandte Geoinformatik Beiträge zum 22. AGIT Symposium, SPRÖHNLE, K. (2010): Earth Observation for Environmental Impact Assessment in the surroundings of Refugee Camps in Darfur. Unveröffentlichte Magisterarbeit, Bamberg, 105 S. Chart 12

13 Multi-scale satellite image analysis approach (VHR) Data: Earth observation data, from IKONOS and QUICKBIRD from 2004 and 2008 Precipitation data, from Hydrological Data and Information System (HyDIS) Population data, from UN OCHA, IRIN, UNEP, Sudan Tribune Methodology: Object-based image analysis Results: Land degradation becomes evident when comparing the VHR data of 2004 and 2008 Decline of woody vegetation in the surroundings of the IDP camps becomes obvious SPRÖHNLE, K., KRANZ, O., SCHÖPFER, S., VOIGT, S. & MÖLLER, M. (2015), Earth observation based multi-scale impact assessment of refugee camps on wood resources in Zalingei, Darfur. Geocarto International. SPRÖHNLE, K., KRANZ, O., & SCHÖPFER, S. (2010), Abschätzung der Umweltauswirkungen von Flüchtlingslagern mit Hilfe multitemporaler Fernerkundungsdaten am Beispiel des Camps Zalingei in Westdarfur. In: STROBL, J., BLASCHKE, T. & GRIESEBNER, G. (Eds.), Angewandte Geoinformatik Beiträge zum 22. AGIT Symposium, SPRÖHNLE, K. (2010): Earth Observation for Environmental Impact Assessment in the surroundings of Refugee Camps in Darfur. Unveröffentlichte Magisterarbeit, Bamberg, 105 S. Chart 13

14 Multi-scale satellite image analysis approach (VHR) SPRÖHNLE, K., KRANZ, O., & SCHÖPFER, S. (2010), Abschätzung der Umweltauswirkungen von Flüchtlingslagern mit Hilfe multitemporaler Fernerkundungsdaten am Beispiel des Camps Zalingei in Westdarfur. In: STROBL, J., BLASCHKE, T. & GRIESEBNER, G. (Eds.), Angewandte Geoinformatik Beiträge zum 22. AGIT Symposium, SPRÖHNLE, K. (2010): Earth Observation for Environmental Impact Assessment in the surroundings of Refugee Camps in Darfur. Unveröffentlichte Magisterarbeit, Bamberg, 105 S. Chart 14

15 The Context of Climatic Variability Chart 15

16 Population in Zalingei Chart 16

17 Discussion Why can decreases and increases in vegetation cover be detected at all scale? Generally, due a complex mix of interacting factors (e.g. human impact, groundwater availability as well as fluctuating climatic parameters) Positive trends: increasing fallow land indicating a recovery of vegetation in consequence of less pressure on shrubs and trees as well as grazing land intensification of agriculture and the recent greening of the Sahel Negative trends: decreasing precipitation and/or declining air temperatures (decreasing vegetation cover) dramatic increase in displaced persons in and around Zalingei until 2004 => increasing pressure on the limited natural resources Chart 17

18 Conclusions (1) the observed variability of climatic parameters is not strong enough for the pronounced land cover changes (2) decreases in vegetation cover are remarkably high in the vicinity of camps which is also underlined by other studies (3) the complete removal of trees and shrubs notably close to camps becomes obvious on the VHR images (4) if climatic parameters would be the main influencing factor one would expect a less pronounced decrease in vegetation cover around camps Thus, we assume that the climatic variability has significant impact but does not play the major role in the vicinity of camps Thank you for your attention! Chart 18