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Green Infrastructure


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Green Infrastructure

  1. 1. Green infrastructure for sustainability and climate change resilience Fisseha Asmelash Institute of Biodiversity ConservationA paper presented at the international workshop under the theme “Biodiversity Conservation and Ecosystem Services for Climate Change Mitigation and Sustainable Development” December 20-22, 2012 Haramaya University, Ethiopia
  2. 2. 1. IntroductionGI is defined as, parts of urban area with a mix ofstreet trees, parks, cultivated land, wetlands, lakes, andstreams that are interconnected.GI and urban forest are regarded as being similar landuse types/Trees are integral parts of green infrastructureGI make cities sustainable because they provideEnvironmental, social, and economic benefits. Andboth to the present and future communities (GIs aremainly plants, they live many years in perpetuity withlittle management cost) 2
  3. 3. 2. Green infrastructure and their environmental benefitsMicroclimate ameliorationCO2 mitigation removal from the atmosphereAir pollution reductionReduce water pollution & reduce floodingReduce sound pollutionBiodiversity conservationLatin American cities; Mexico City and Sao Paolointegrated trees and other vegetation as part of urbanenvironmental improvement programs, policies, andmeasures (Escobedo et al., 2008). 3
  4. 4. environmental benefits con’t…2.1. Microclimate amelioration:In urban areas there is higher temperature compared to thesurrounding sub urban or rural areas. This phenomenon is called urbanheat island(UHI)Shading surfaces and evapotranspiration lowers temperatureIn Sacramento County it was estimated that doubling the canopycover to five million trees would reduce summer temperatures by 3degrees (Bell and Wheeler, 2006). 4
  5. 5. environmental benefits con’t…2.2. CO2 removal from the atmosphereStorage, sequestration, fossil fuel replacement, andbuilding energy saving2.3. Air pollution reductionTroposphere Ozone or smogNOx + volatile organic compounds (VOCs) in thepresence of sunlight(high Temp) results in TroposphereOzoneActive air pollution removalLeaf stomata take in polluting gasses (CO, NOx, SOx,O3) which are then absorbed by water inside the leafParticle matters deposition/passive pollution removalLarge evergreen broad-leafed trees with dense foliagecollect the most particulate matter 5
  6. 6. Environmental cont’d…Table 1: Urban forest management strategies to help improve air quality include (Nowak and Stevens, 2006) Strategy Reason Increase the number of healthy trees Increase pollution removal Sustain existing tree cover Maintain pollution removal levels Maximize use of low VOC-emitting trees Reduces ozone and carbon monoxide formation Sustain large, healthy trees Large trees have greatest per-tree effects Use long-lived trees Reduce long-term pollutant emissions from planting and removal Use low maintenance trees Reduce pollutants emissions from maintenance activities Reduce fossil fuel use in maintaining vegetation Reduce pollutant emissions Plant trees in energy conserving locations Reduce pollutant emissions from power plants Plant trees to shade parked cars Reduce vehicular VOC emissions Supply ample water to vegetation Enhance pollution removal and temperature reduction Plant trees in polluted or heavily populated areas Maximizes tree air quality benefits Avoid pollutant-sensitive species Improve tree health 6 Utilize evergreen trees for particulate matter Year-round removal of particles
  7. 7. Environmental cont’d…Maintain water quality and reduce floodingThe increased permeability of soil due to root growth allows for pollutantsto infiltrate the soil and possibly be decomposed and/or absorbed by plantroots. can effectively trap and retain up to 99% of common pollutantsThe reduction of flow volume and rate decreases surface pollutant wash offreduces flooding hazards and.Reduce sound pollutionIt was estimated that a 4-5 m width tree belt with dense vegetation structurecould trim sound level by 5 dBA (Jim et al, 2008). 7
  8. 8. Environmental cont’d…Biodiversity conservationEl Niño resulted in die-off of mammals in the KumbhalgarhWildlife Sanctuary (KWS) in Rajasthan. These die-off coincidedwith the La Niña-induced drought of 2000, and two consecutivemonsoon failures. Indeed, Hanuman langurs (Semnopithecusentellus) suffered a population crash of nearly 50% from 1999 to2001 in KWS. But, langurs in Jodhpur city were bufferedagainst drought because of the availability of urban green habitatand food (Waite et al. 2007 in Singh et al., 2010).Even the trees in backyard provide the benefit of biodiversityconservation networks in urban ecosystems (Hillary et al. 2002in Singh et al., 2010).Increased habitat connectivity good for species to adapt to 8climate change by migration
  9. 9. Environmental cont’d…3. Green infrastructure social benefitstrees and natural environments improve psychological wellbeing over scenes of urban settings (Urlich et al., 1991).If urban forests do not actually protect you from gettingsick, research has shown “that recuperation was faster andmore complete” for patients viewing natural scenes comparedto urban surroundings (Urlich et al., 1991)Living and playing near trees and green space has positivebenefits for children, including decreased symptoms ofAttention Deficit and Hyperactivity Disorder (ADHD) andimproved development of cognitive skills and abilities (Tayloret al., 1998; 2001in UEI, 2008).The ability of urban trees to relieve extreme heat and reducenoise pollution has been linked to a decrease in violentbehavior (Kuo and Sullivan 2001 in UEI, 2008).Increase sense of community(gathering for holidays,planting trees together)Multiple studies by Frances E. Kuo suggest that tree-filledareas have relatively low rates of crime and domestic violencebecause trees relieve stress and promote a sense of safetyamong residents (UEI, 2008).Faster drivers and slower drivers both drove slower with thepresence of trees (Dixon and Wolf, 2007). 9
  10. 10. 4. Green infrastructure economic benefitsFuelwood, Food, Grazing for livestock, Timber and poles, Spices, fiber,medicines and other non-timber products (Carter, 1999).Trees also improve local business activity and increase property values.Shoppers are willing to make more frequent and longer shopping trips totree-lined commercial districts. Consumers have also been shown to spend upto 12% more when shopping in these districts (Wolf, 2003 in UEI, 2008).The sales price of residential property has been shown to increase at least 1%for each large front yard tree and up to 10% for large specimen trees (Andersonand Cordell 1985 in UEI, 2008).reduced cost from flood damage repair and flood controllow medical cost as a result of cleaner air and water by GI 10
  11. 11. 5. Green infrastructure, sustainability and climate change in Ethiopia; the case of Addis Ababa 5.1. Green infrastructure and sustainability: The fact that Addis Ababa is the capital of Ethiopia and Africa is attributed to urban forests. Without successful introduction of Eucalyptus under the reign of Emperor Menelik II, it is unlikely that Addis Ababa would have become the capital of Ethiopia and diplomatic center of Africa (Hancock 1995 in Horst, 2006). However, the green infrastructure of Addis Ababa is not developed and managed well to fulfill the environmental, social, and economic services. the urban forest in Addis Ababa has been transformed from once dense indigenous forest to degraded eucalyptus plantations (Horst, 2006).Fig. 1: Satellite imagery of Addis Ababa city and its surrounding in 1973 and 2005. Considerable size of green cover has vanished since 1973. The 2005 imagery also shows a drying polluted lake along the southern periphery. Source: United Nations Environment Program (UNEPin Dubbale Daniel et al.,2010) 11
  12. 12. AA sustainability con’t…Pollution of streams in Addis Ababa today is at alarming levels(BOD) and (COD) of the city’s streams stand at 56 and 59 timesmore than the acceptable amount (Dubbale Daniel et al.,2010).The Suspended solids in the city’s streams is 16 times more thanthe acceptable amount (Dubbale Daniel et al.,2010).The level of contamination by germs such as E. coli is 150-450times more than the acceptable amount (Dubbale Daniel etal.,2010).Reduction and pollution of ground water in AA 12
  13. 13. Figer2: river bank slum (a) and garage wastes damped to rivers (b) 13
  14. 14. AA sustainability con’t…urban centers of Addis Ababa were 1.4-2.2°C warmer. And it is expected theUHI would become stronger affecting the living condition of the urban population(Bisrat Kifle).A study conducted in Sheger park and Ankorcha forest showed that from therecorded Lepidoptera family Noctuidae, Psychidae, Gracillariidae, Sesiidae, andTortricidae were found while none of butterfly families (e.g. Nymphalidae) wererecorded(Girma Negussie ,2009).butterflies, are mostly used as biodiversity indicators since they are highlysensitive to environmental instability, (Collinge et al., 2003 in Girma Negussie,2009).National figures show that these problems are leading causes of acuterespiratory infections, skin and parasitic diseases, resulting in mortality andmorbidity (Alebel Bayrau and Genanew Bekele,2007). 14
  15. 15. 5.2. Green infrastructure and climate change:In Addis the temperature is getting hotter and hotter and there has been frequent flooddamages in recent years (see figure below). •Fig3: Flood caused damage in Addis in 2010 15 Fig 4: City inhabitants around Ambassador theatre displaced by a heavy rain flood on Thursday August 18, 2012.(from fortune )
  16. 16. AA CC con’t…Based on the recorded data, the mean annual temperature has risen1.3°C or 0.028°C per year between 1960 and 2006 and the number of hotdays and hot nights has increased by 20% and 37.5% between 1960 and2003. Where, “hot” is defined as 10% higher than average temperaturefor that area and period (Daniel Elala, 2011).There is no empirical evidence in historical data of any change inannual rainfall, even with long term rainfall data at hand (Conway et al.2004 in Daniel Elala,2011) but NMA(2007), there is observed variabilityin rain fall distribution(wet and dry years).Studies made at NMA have shown that there is a link between ElNinoand LaNina Phenomena and Ethiopian rainfall (Haile, T., 1988, Korecha,D., and Barnston, A.G, 2007, Gissila, T. etal, 2004 in NMA,2007). 16
  17. 17. 5.3. Opportunities, challenges and limitations:Opportunities: The revised 2002 master plan, the climate resilient greeneconomy, the Ethiopian constitution Article 44(the right to live in cleanenvironment)and article 92(development should not damage environment),carbon trade are good opportunitiesChallenges: the gigantic nature of socio economic problems in AddisAccording to the study conducted by the Addis Ababa Water Supply Agency,82% of the population in the city lives in unplanned, high density and lowstandard housings (Alebel Bayrau and Genanew Bekele, 2007).Limitations: the tree ordinance is not ratified by the city cabinet, there is nocomplete inventory data and management plan 17
  18. 18. 6. ConclusionGreen infrastructure is now known to provide quantifiable Environmental benefits.For example Wisconsin’s Green Bay Metro urban forest was estimated to provide thefollowing benefits( cited on 12/12/12) $1.81 million per year in summer cooling and winter heating energy savings.$1.78 million per year in storm water management savings by interceptingapproximately 65 million gallons of storm water annually.$2.02 million per year increase in local property values.$296,206 per year in air quality improvement by mitigating harmful air pollutants.$233,998 per year in atmospheric carbon dioxide reduction.“Conectiv Electric Utility” negotiated to have a $1 million air pollution fine donatedto the New Jersey Tree Foundation for the air pollution it caused( cited on 12/12/12)developing and managing the city green infrastacture will only mean the Renaissanceof Addis Ababa.if the city’s green infrastructure is developed well, Addis Ababa will truly be “newflower” when celebrating its 150 year anniversaryother urban areas in Ethiopia should consider green infrastructures as the core oftheir engagement so that they can be sustainable and resilient to climate change. 18
  19. 19. I thank you! 19