1. How vulnerable is the Lower Niger Delta to inundation from Sea Level Rise? ZAHRAH N. MUSA, IOANA POPESCU, ARTHUR MYNETT UNESCO-IHE, Institute for Water Education Delft, The Netherlands 1

2. Focus on coastal areas 2 44% of world's population lives –UN within 150 km of the coast o high coastal population growth o high economic productivity o economic hubs of their countries (e.g. Rotterdam, Mumbai, Lagos, Guangzhou, etc)  Low elevation  Gentle slopes

3. Focus on coastal areas 3 Climate change o Rise in atmospheric temperature o Rise in sea surface temperature Consequences of climate change o Global warming o Change in precipitation patterns Increase/decrease o Increased frequency of floods o Rise in sea levels Increased frequency of storm surges Cyclones Flooding Intrusion of sea salts Inundation

4. Focus on coastal areas 4 o Loss of dry land o Loss of wetlands o Conversion of fresh water regimes to salt water regimes o Loss of natural biodiversity o creates a need for adaptation Dry land becomes a wetland, swamp or a part of a river, ocean /sea. Inundation from SLR  impeding drainage of river flood waters  inland movement of the shoreline  uplifting the groundwater table

5. The lower Niger delta 5  Area ~ 20,000 Km 2  450 km of coastline  Made up of nine states in the southern part of Nigeria  Nigeria’s economic hub  rich in oil and gas  main source of foreign exchange http://en.wikipedia.org/wiki/File:NigerDeltaStates.png http://www.marxist.com/nigeria-congress-2013.htm

6. The lower Niger delta 6 Environmental problems Natural o River flooding (Niger, Imo, Qua Iboe) o Erosion due to river and coastal flooding o Subsidence Man-made o Wood logging o deforestation o Oil spills o land loss o Contamination of surface water o Acid rain from gas flaring o corrodes roofing sheets o destroys biodiversity o Subsidence from oil and gas extraction http://www.nairaland.com/587622/niger-delta-pictures

7. The Lower Niger Delta 7 Hydrology: Rivers, Creeks, Lakes, Estuaries

8. Physical properties Low elevation Gentle slope Subsiding due to oil and gas exploration estimated at 25-125 mm/yr The Lower Niger Delta 8

9. 9 Vulnerability to inundation Method: Modified Bath Tub approach using GIS to map inundation from sea level rise  SRTM DEM  NigeriaSat1 image  tidal surface  projected SLR values Rahmstorf predicted values Tidal surface: the longitude, latitude and water levels of 15 tide gauges located in the Niger delta. o Interpolate a raster

10. Vulnerability to inundation 10 SLR inundation process Total surface area = 23,623.4 km 2 Subset from NigeriaSat 1 image SLR values 2030 = 0.12 m - 0.41 m 2050 = 0.23 m - 0.65 m Tidal surface+ SLR = new water level New water level – SRTM value = inundated area

11. Vulnerability to inundation 11 SLR only inundation extents 0.12 m by 2030 = 536.6 km 2 = 2.3% of the total surface area. 0.41 m by 2030 = 619.2 km 2 = 2.6% of the total surface area.

12. Vulnerability to inundation 12 SLR only inundation extents 0.23 m by 2050= 562.8 km 2 = 2.4% of the total surface area. 0.65 m by 2050= 763.6 km 2 = 3.2% of the total surface area.

13. Vulnerability to inundation 13 SLR plus Subsidence inundation extents Land subsidence value = 25 mm/yr 2030 =0.75 m, and 2050= 1.25 m Land subsidence value +SLR + surface grid = new water level New water level – SRTM = inundated area

14. Vulnerability to inundation 14 SLR plus Subsidence inundation extents SLR (0.12 m ) + subsidence (0.75 m ) by 2030 inundation extent = 791.8 km 2 = 3.4% of the total surface area. SLR (0.41 m ) + subsidence (0.75 m ) by 2030, inundation extent = 1090.3 km 2 4.6% of the total surface area.

15. Vulnerability to inundation 15 SLR plus Subsidence inundation extents SLR (0.23 m ) + subsidence (1.25 m ) by 2050 inundation extent = 1,511 km 2 = 6.4% of the total surface area. SLR (0.65 m ) + subsidence (1.25 m ) by 2050 inundation extent =1,759.5 km 2 = 7.5% of the total surface area.

16. Vulnerability to inundation 16 2.3 to 3.2% of the Niger delta could be inundated due to SLR by 2050. 3.4 to 7.5% of the Niger delta could be inundated due to SLR and land subsidence by 2050. Places affected… Implication

17. Vulnerability to inundation 17 Places affected….

18. Vulnerability to inundation 18 Population density…

19. Conclusion 19  The Niger delta is vulnerable to inundation by SLR o 2.3 to 3.2% could be inundated due to SLR by 2050.  Land subsidence will exacerbate the inundation effect of SLR on inland areas o 3.4 to 7.5% could be inundated due to SLR + land subsidence by 2050.  Based on projected population census data, 460,000 to 2.4 million people could be affected by SLR by the year 2050.

20. Thank you 20 Email: z.musa@unesco-ihe.org