1. Green infrastructure for
sustainability and climate change
resilience
Fisseha Asmelash
Institute of Biodiversity Conservation
A 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. 1. Introduction
GI is defined as, parts of urban area with a mix of
street trees, parks, cultivated land, wetlands, lakes, and
streams that are interconnected.
GI and urban forest are regarded as being similar land
use types/Trees are integral parts of green infrastructure
GI make cities sustainable because they provide
Environmental, social, and economic benefits. And
both to the present and future communities (GIs are
mainly plants, they live many years in perpetuity with
little management cost)
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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 Paolo
integrated trees and other vegetation as part of urban
environmental improvement programs, policies, and
measures (Escobedo et al., 2008). 3

4. environmental benefits con’t…
2.1. Microclimate amelioration:
In urban areas there is higher temperature compared to the
surrounding sub urban or rural areas. This phenomenon is called urban
heat island(UHI)
Shading surfaces and evapotranspiration lowers temperature
In Sacramento County it was estimated that doubling the canopy
cover to five million trees would reduce summer temperatures by 3
degrees (Bell and Wheeler, 2006).
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5. environmental benefits con’t…
2.2. CO2 removal from the atmosphere
Storage, sequestration, fossil fuel replacement, and
building energy saving
2.3. Air pollution reduction
Troposphere Ozone or smog
NOx + volatile organic compounds (VOCs) in the
presence of sunlight(high Temp) results in Troposphere
Ozone
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 foliage
collect the most particulate matter 5

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
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Utilize evergreen trees for particulate matter Year-round removal of particles

7. Environmental cont’d…
Maintain water quality and reduce flooding
The increased permeability of soil due to root growth allows for pollutants
to infiltrate the soil and possibly be decomposed and/or absorbed by plant
roots.
 can effectively trap and retain up to 99% of common pollutants
The reduction of flow volume and rate decreases surface pollutant wash off
reduces flooding hazards and.
Reduce sound pollution
It was estimated that a 4-5 m width tree belt with dense vegetation structure
could trim sound level by 5 dBA (Jim et al, 2008).
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8. Environmental cont’d…
Biodiversity conservation
El Niño resulted in die-off of mammals in the Kumbhalgarh
Wildlife Sanctuary (KWS) in Rajasthan. These die-off coincided
with the La Niña-induced drought of 2000, and two consecutive
monsoon failures. Indeed, Hanuman langurs (Semnopithecus
entellus) suffered a population crash of nearly 50% from 1999 to
2001 in KWS. But, langurs in Jodhpur city were buffered
against drought because of the availability of urban green habitat
and food (Waite et al. 2007 in Singh et al., 2010).
Even the trees in backyard provide the benefit of biodiversity
conservation networks in urban ecosystems (Hillary et al. 2002
in Singh et al., 2010).
Increased habitat connectivity good for species to adapt to
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climate change by migration

9. Environmental cont’d…
3. Green infrastructure social benefits
trees and natural environments improve psychological well
being over scenes of urban settings (Urlich et al., 1991).
If urban forests do not actually protect you from getting
sick, research has shown “that recuperation was faster and
more complete” for patients viewing natural scenes compared
to urban surroundings (Urlich et al., 1991)
Living and playing near trees and green space has positive
benefits for children, including decreased symptoms of
Attention Deficit and Hyperactivity Disorder (ADHD) and
improved development of cognitive skills and abilities (Taylor
et al., 1998; 2001in UEI, 2008).
The ability of urban trees to relieve extreme heat and reduce
noise pollution has been linked to a decrease in violent
behavior (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-filled
areas have relatively low rates of crime and domestic violence
because trees relieve stress and promote a sense of safety
among residents (UEI, 2008).
Faster drivers and slower drivers both drove slower with the
presence of trees (Dixon and Wolf, 2007). 9

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 to
tree-lined commercial districts. Consumers have also been shown to spend up
to 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 (Anderson
and 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
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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)
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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 times
more than the acceptable amount (Dubbale Daniel et al.,2010).
The Suspended solids in the city’s streams is 16 times more than
the acceptable amount (Dubbale Daniel et al.,2010).
The level of contamination by germs such as E. coli is 150-450
times more than the acceptable amount (Dubbale Daniel et
al.,2010).
Reduction and pollution of ground water in AA
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13. Figer2: river bank slum (a) and garage wastes damped to rivers (b)
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14. AA sustainability con’t…
urban centers of Addis Ababa were 1.4-2.2°C warmer. And it is expected the
UHI 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 the
recorded Lepidoptera family Noctuidae, Psychidae, Gracillariidae, Sesiidae, and
Tortricidae were found while none of butterfly families (e.g. Nymphalidae) were
recorded(Girma Negussie ,2009).
butterflies, are mostly used as biodiversity indicators since they are highly
sensitive to environmental instability, (Collinge et al., 2003 in Girma Negussie
,2009).
National figures show that these problems are leading causes of acute
respiratory infections, skin and parasitic diseases, resulting in mortality and
morbidity (Alebel Bayrau and Genanew Bekele,2007).
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15. 5.2. Green infrastructure and climate change:
In Addis the temperature is getting hotter and hotter and there has been frequent flood
damages in recent years (see figure below).
•Fig3: Flood caused damage in Addis in 2010
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Fig 4: City inhabitants around Ambassador theatre displaced by a heavy rain flood on Thursday August 18, 2012.(from fortune )

16. AA CC con’t…
Based on the recorded data, the mean annual temperature has risen
1.3°C or 0.028°C per year between 1960 and 2006 and the number of hot
days and hot nights has increased by 20% and 37.5% between 1960 and
2003. Where, “hot” is defined as 10% higher than average temperature
for that area and period (Daniel Elala, 2011).
There is no empirical evidence in historical data of any change in
annual rainfall, even with long term rainfall data at hand (Conway et al.
2004 in Daniel Elala,2011) but NMA(2007), there is observed variability
in rain fall distribution(wet and dry years).
Studies made at NMA have shown that there is a link between ElNino
and LaNina Phenomena and Ethiopian rainfall (Haile, T., 1988, Korecha,
D., and Barnston, A.G, 2007, Gissila, T. etal, 2004 in NMA,2007).
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17. 5.3. Opportunities, challenges and limitations:
Opportunities: The revised 2002 master plan, the climate resilient green
economy, the Ethiopian constitution Article 44(the right to live in clean
environment)and article 92(development should not damage environment),
carbon trade are good opportunities
Challenges: 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 low
standard housings (Alebel Bayrau and Genanew Bekele, 2007).
Limitations: the tree ordinance is not ratified by the city cabinet, there is no
complete inventory data and management plan
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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 the
following benefits(http://www.itreetools.org/resources/projects.php 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 intercepting
approximately 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 donated
to the New Jersey Tree Foundation for the air pollution it caused
(www.na.fs.fed.us/urban/states2003/nj/nj.htm cited on 12/12/12)
developing and managing the city green infrastacture will only mean the Renaissance
of Addis Ababa.
if the city’s green infrastructure is developed well, Addis Ababa will truly be “new
flower” when celebrating its 150 year anniversary
other urban areas in Ethiopia should consider green infrastructures as the core of
their engagement so that they can be sustainable and resilient to climate change.
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19. I thank you!
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