Transcript (LE lecture) - Apr2008 (NXPowerLite)

Green Infrastructure
and Climate Change
Dr Susannah Gill
The Mersey Forest
[email protected]
www.merseyforest.org.uk
Overview
• Green infrastructure
• Climate change
• Green infrastructure for adaptation in
urban areas
• Policy relevance in the UK
• North West Climate Change Action Plan
• Conclusions
www.merseyforest.org.uk
Green Infrastructure
• Life support system – the network
of natural environmental
components and green and blue
spaces that lie within and between
our cities, towns and villages and
provide multiple social, economic
and environmental benefits
• http://www.greeninfrastructurenw.org.uk
www.merseyforest.org.uk
Our Climate is Changing
• Warming of the
climate system is
unequivocal
• Coherent
changes in many
aspects of the
climate system
not just
temperature
www.merseyforest.org.uk
(source: IPCC, 2007)
Changes go beyond natural variability
Temperature
change in last 50
years is very
likely (>90%
chance) due to
increase in
anthropogenic
greenhouse gas
concentrations
(source: IPCC, 2007)
www.merseyforest.org.uk
(relative to 1980-99)
Global climate change projections
www.merseyforest.org.uk
(source: IPCC, 2007)
What does this mean for the UK?
• UKCIP02
– 4 emissions scenarios
– 3 time slices
– 50 km outputs (some 5 km)
• UKCIP08
– Probabilistic scenarios
– 25 km output
– Due October 2008
www.merseyforest.org.uk
UK Climate Changes
•
•
•
•
•
•
•
•
•
•
•
Average temp increases
High temp extremes increase in frequency
Low temp extremes decrease in frequency
Sea-surface temp warms
Thermal growing season lengthens
Winter precipitation increases
Winter precipitation intensity increases
Greater contrast between summer & winter
Snowfall decreases
Summer soil moisture decreases
Sea-level rises
UKCIP02 High Confidence Levels
www.merseyforest.org.uk
Greater Manchester Average Maximum Summer Temperature
Data from the UK Met Office and UKCIP02
www.merseyforest.org.uk
Greater Manchester Summer Precipitation
Data from the UK Met Office and UKCIP02
www.merseyforest.org.uk
Greater Manchester Winter Precipitation
Data from the UK Met Office and UKCIP02
www.merseyforest.org.uk
Manchester
(Mean Annual Temp)
Baseline (1961-90)
2050s Low emissions
2050s High emissions
2080s High emissions
Slide courtesy of Mark Broadmeadow
Manchester
(monthly mean temp, diurnal temp range
& precipitation)
Baseline (1961-90)
2050s Low emissions
2050s High emissions
2080s High emissions
Slide courtesy of Mark Broadmeadow
Matt Cardy/Getty Images
Daniel Berehulak/Getty Images
Kate Gillon/Getty Images
Source: The Guardian website
June-Aug temp anomalies (relative to 1961-1990 mean)
Source: Stott et al, 2004
Climate Change Management
www.merseyforest.org.uk
Smit et al (1999)
Mitigation Role of GI
•
•
•
•
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Carbon sequestration & storage
Direct fossil fuel substitution
Material substitution
Local food production
Reducing need to travel
www.merseyforest.org.uk
Adaptation Role of GI
• Moderating temperature extremes
• Decreasing rate and volume of
rainwater runoff
• Providing wildlife corridors
• Providing recreation spaces e.g.
high capacity, less sensitive
landscapes
www.merseyforest.org.uk
Key Stakeholders
Town & Country Planning Association (Chair)
Association of British Insurers
Environment Agency
North West Climate Group
Office of the Deputy Prime Minister
Royal Town Planning Institute
South East Climate Group
http://www.k4cc.org/Members/Claire/BKCC-Results-Publication.pdf
ASCCUE Methodology
• Two case study areas
– Greater Manchester
– Lewes, Sussex
• Three exposure units
– Integrity of the built
environment
– Human comfort
– Urban greenspace
Urban Greenspace
• Urbanisation alters
– Micro-climate – increased temperatures
– Hydrology – increased rate & volume of surface
runoff
• Climate change alters temperature & rainfall
patterns
• Urban greenspace can moderate ‘urban heat
island’ effect and reduce rate & volume of
runoff
• Therefore urban greenspace has potential to
adapt cities to climate change
Urban Morphology Types
Urban Characterisation
Greater Manchester Urban
Morphology Types
UMT
UMT Surface Cover
remnant countryside
disused & derelict land
distribution & storage
offices
manufacturing
town centre
retail
hospitals
schools
low density residential
med density residential
high density residential
cemeteries & crematoria
refuse disposal
water storage & treatment
energy production & distribution
river, canal
rail
airports
major roads
allotments
informal open space
formal open space
formal recreation
mineral workings & quarries
woodland
unimproved farmland
improved farmland
building
other impervious
tree
shrub
mown grass
rough grass
cultivated
water
bare soil / gravel
0.0
0.1
0.2
0.3 0.4 0.5 0.6 0.7
Proportional cover
0.8
0.9
1.0
‘Evapotranspiring’ Surfaces
UMT
‘Urban’ Tree Cover
remnant countryside
disused & derelict land
distribution & storage
offices
manufacturing
town centre
retail
hospitals
schools
low density residential
medium density residential
high density residential
cemeteries & crematoria
refuse disposal
water storage & treatment
energy production & distribution
river, canal
rail
airports
major roads
allotments
informal open space
formal open space
formal recreation
mineral workings & quarries
woodland
0
2
4
6
8
10 12 14 16 18 20 22 24 26 28 30
Percentage of all 'urban' tree cover
Surface Cover and Residential Density
Modelling environmental functions
• Use surface cover data as one input
into surface temperature and runoff
models
• Series of model runs
– Current urban form
• Baseline and future climate
– ‘Development scenarios’
• Baseline and future climate
Maximum Surface Temperatures
For a day occurring on
average twice per summer
Residential ± 10% green cover
High density residential
Max surface temp (°C)
40
35
current form
30
-10% green
25
+10% green
20
15
1970s
2020s
Low
2020s
High
2050s
Low
2050s
High
Time period and scenario
2080s
Low
2080s
High
If grass does not evapotranspire…
• Maximum surface
temperatures
increase by
– 4.7-5.7°C in high
density residential
areas
– 13.8-15.6°C in
schools
(Manchester Evening News, 2006)
Occurrence of Drought for Grass
Months/year when grass water
stressed
Adaptation in the Public Realm
Surface temperature in tree shade here was 13°C cooler
than in sun – large mature tree canopies provide more shade
Surface Runoff
56% more rain
results in 82% more
runoff
For a precipitation event occurring on average one day
per winter, with normal antecedent moisture conditions
Infiltration Capacity
A case for
‘Conservation
Areas’?
Climatic adaptation via the green
infrastructure
Corridor
Corridor
Patch
Matrix
•••
••
•
Infiltration
capacity
•
••
•••
Evaporative
cooling
•
•••
••
Shading
•
••
•••
Flood
storage
Patch
Matrix
Functional importance of urban
greenspace needs to be
reflected in plans, policies,
strategies
Summary of Findings
• Greenspace moderates temperatures
through evaporative cooling & shading
– Mature trees critical for shading
• Most effective in regulating surface
runoff on high infiltration soils
• Increase rainwater storage
• Opportunity to use for irrigation in
times of drought
Policy Implications
• Work across administrative boundaries
& disciplines
• Protect critical environmental capital
• No net loss of green cover
• Creative greening
• Take opportunities in new development /
restructuring
• Ensure water supply
Increasing Policy Relevance
www.merseyforest.org.uk
NW Climate Change Action Plan
• “Undertake scoping studies
to assess future regional
risks, opportunities and
priorities for the potential for
green infrastructure,
including regional parks, to
adapt and mitigate for
climate change impacts and
commence implementation
of findings”
www.merseyforest.org.uk
GI functions for climate change
Mitigation
Adaptation
Biofuels production
Timber production
Food production
Carbon storage
Recreation
Green travel routes
Shading from sun
Evaporative cooling
Shading from sun
Evaporative cooling
Water storage
Water interception
Water infiltration
Soil stabilisation
Storm protection
Habitat for wildlife
Corridor for wildlife
Recreation
www.merseyforest.org.uk
Conclusion
• Climate change mitigation role limited
but important
• Climate change adaptation role
substantial
• GI is a good adaptation strategy as it
has other functions and benefits
• To maximise this need strategic
planning at all levels, with functionality in
mind
• Protect, create, enhance, and maintain
www.merseyforest.org.uk