Climate Change Trends Projections And Vulnerability Integration To Enhance Urban Resilience Planning The Case Of Addis Ababa City

Impacts of climate change continue to knock on the doors of different societies includingrnurban dwellers. The effect is more severe in towns of developing world like Addis Ababarnwhere level of mitigation and adaptation measures are low and detailed climate changerninformation is lacking. Many of existing studies give no consideration to the futurernclimatic conditions, spatial quantification and mapping of vulnerability hotspots andrnintegration of these all together for enhanced resilience planning. They mainly focusedrnon basic environmental plans, where most of them fail implementation due to low levelrnof law enforcements and unavailability of up to dated cadastral information system.rnTaking these points into considerations, this study focuses on analyzing climate changerntrends, downscaling projected results from general circulation models, analyzing landrnsurface temperature changes, quantifying and mapping climate change vulnerability atrnsub-city level to recommend better environmental planning options which could bernimplemented to minimize severe climate change risks at Addis Ababa city. To achievernthese, various methodological approaches were applied in a sequential order. UsingrnStatistical Downscaling Model (SDSM), downscaled daily maximum temperature,rnminimum temperature, and precipitation in 30 years intervals from the second generationrnof the Earth System Model (CanESM2) and Coupled Global Climate Model (CGCM3)rnivrnunder two Representative Concentration Pathways (RCP) Scenarios (RCP4.5 andrnRCP8.5) and two Special Report Emission Scenarios (SRES), A1B and A2, wererngenerated to examine future changes and their extremes. Two representativernmeteorological stations were selected for model calibration and validation in the SDSM.rnWith this, ten core temperature and precipitation indices were selected to assessrntemperature changes and precipitation extremes. Spatio-temporal Land SurfacernTemperature (LST) characteristics were analyzed using four Landsat satellite imagernseries with ten years interval from 1986 to 2017. Sub-city level Climate changernvulnerability analyses were undertaken by integrating the Sullivan and Meigh’s Model ofrncomposite climate change vulnerability index and the IPCC’s approach of vulnerabilityrnassessment which comprises exposure, sensitivity and adaptive capacity. Fifteenrnsubcomponents of vulnerability indicators were identified in ten sub-cities, and theirrnvalues were normalized to a number which ranges between 0 and 1, with unequalrnweighting system, indicating as the values increased to 1, vulnerability to climate changernincreases. The results were mapped using ArcGIS 10.2 package. In-depth empiricalrnfield work including a survey of 399 households in four sub-cities and key informantrninterviews were conducted and analyzed using descriptive statistics and Chi-squared testsrnwere used to summarize the findings in SPSS. Finally climate change resilience plansrnwere proposed for a sustainable environmental protection and to reduce the vulnerabilityrnthat could be induced by climate change. The results showed that maximum temperature,rnminimum temperature and mean temperature was increasing in the last 60 years. Thernsecond thirty years mean temperature average, was higher than the first thirty yearsrnaverage by 1.1 ºC within 1957-2016. The trend in precipitation shows only insignificantrnvrnrise wihin the last six decades. The projected maximum temperature, increases were inrnthe range of 0.9ºC (RCP4.5) in 2020 to 2.1ºC (CGCM3A2) in 2080 at Addis AbabarnObservatory. The minimum temperature is projected to increase by 0.3ºC (RCP4.5) inrn2020 and 1.0 ºC in 2080 (CGCM3A1B). While the changes in maximum temperature arernlower at Entoto station compared to Addis Ababa Observatory, the highest minimumrntemperature change is projected at Addis Ababa Observatory, which ranges from 0.25ºCrnin the 2020s to 1.04ºC in 2080 according to the CGCM3 model. Except for the coldestrnnights (TNn), the mean temperature and other temperature indices will continue tornincrease to the end of this century. The highest precipitation change is projected byrnCGCM3A2 and CanESM2 RCP8.5 at an increase of about 11.8% and 16.62% by 2080.rnThe highest total precipitation increase is 29% (RCP4.5) in winter and 20.9% (RCP8.5)rnin summer by 2080. The rise in temperature will exacerbate the urban heat highlandrneffects in warm seasons and an increase in precipitation is expected along with a possiblernrisk of flooding due to a low level of infrastructure development and a high rate ofrnurbanization. It is also found that land surface temperature was highly influenced by landrncover types. The highest LST was found in built-up areas and barren lands. 49% andrn47% of the study area had an LST range of 23°C - 27°C in 1986 and 1995 respectively.rnHowever, in 2007 and 2017, 41% and 59% of the study area had LST range of 27°C -rn31°C respectively. The ten sub-cities in Addis Ababa were found in different levels ofrnvulnerability to climate change with the highest exposure and sensitivity in AddisrnKetema, Arada, and Lideta while the adaptive capacity was highest in Gulelle, Bole, andrnArada sub-cities. The overall climate change vulnerability was highest in Arada, AddisrnKetema and Kirkos. The result also found that 69.2% and 60.2% of the respondentsrnvirnperceived that temperature and precipitation increased within the last one to three decadesrnrespectively. Flash flood during high precipitation is common along the main roads inrnKirkos, while river flooding is a major problem in summer for the residents living alongrnthe sides of Akaki River where the cost of damage is high sometimes to the loss of allrnproperty and life too. The study recommended city level and landscape level resiliencernplans within Addis Ababa and the surrounding mountainous landscapes.

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