Green Infrastructure for Climate Change Adaptation - the role of spatial planning

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Green Infrastructure for Climate Change
Adaptation- the role of spatial planning

• Dr Susannah Gill
• susannahgill_at_merseyforest.org.uk

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Climate change context

• Our climate is changing
• Warming of the climate system is unequivocal
• Coherent changes in many aspects of the climate
  system not just temperature
• Changes go beyond natural variability
• Temperature change in last 50 years is very
  likely (gt90 chance) due to increase in
  anthropogenic greenhouse gas concentrations
• IPCC (2007)

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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

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Average Summer Maximum TemperatureScenarios for
the North West
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Average Summer Precipitation Scenarios for the
North West
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Average Winter Precipitation Scenarios for the
North West
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Climate Change Management
Smit et al (1999)
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Mitigation the role of GI

• Reducing greenhouse gas emissions and
  concentrations now impacts on the magnitude of
  future climate changes
• Limited but important role of GI
• Carbon sequestration storage
• Direct fossil fuel substitution
• Material substitution
• High quality landscapes near to where people live
  reducing, alternative routes to travel - reducing
  the need to travel by car

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Adaptation the role of GI

• Changes over next 30-40 years already determined
  by historic emissions
• Crucial role of GI
• Moderating temperature extremes, especially in
  urban areas
• Reducing volume and slowing rate of rainwater
  runoff
• Flood management
• Soil erosion
• Providing wildlife corridors
• Providing recreation spaces e.g. high capacity,
  less sensitive landscapes

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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
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Climate Change Impacts in the Built Environment

• Built environment is distinctive
• High building mass and low greenspace cover leads
  to urban heat island
• Surface sealing increases rate and volume of
  rainfall runoff
• Climate change strengthens this distinctiveness
• Urban greenspace helps to moderate these impacts
• BUT climate change will also impact on
  functionality of urban greenspace

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Greater Manchester UMT Map
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Evapotranspiring Surfaces
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Urban Tree Cover
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Maximum Surface Temperatures
For a day occurring on average twice per summer
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Residential 10 green cover
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If grass does not evapotranspire

• Maximum surface temperatures increase by
• 4.7-5.7C in high density residential areas
• 13.8-15.6C in schools

(Manchester Evening News, 2006)
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Occurrence of Drought for Grass
Months/year when grass water stressed
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Adaptation in the Public Realm
Surface temperature in tree shade here was 13C
cooler than in sun large mature tree canopies
provide more shade
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Surface Runoff
For a precipitation event occurring on average
one day per winter, with normal antecedent
moisture conditions
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Infiltration Capacity
A case for Conservation Areas?
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Summary of Research 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

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The role of spatial planning

• GI planning has an important role to play in
  climate change (especially adaptation)
• Functional importance of GI must be reflected in
  planning policy

GI functions for climate change 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
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All levels of spatial planning

• National PPS
• PPS1 supplement
• Climate Change Adaptation by Design (TCPA, 2007)
• Adapting to Climate Change a checklist for
  development (GLA, 2005)
• Guidance for Local Authorities on Implementing
  the Biodiversity Duty (Defra, 2007)
• Regional RSS
• Local LDF
• Also important Sub-Regional non-planning
  documents

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LDF

• GI Plan within LDF
• Climate change mitigation and adaptation
  functions a crucial part of this
• Developer contributions towards delivering GI Plan

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GI Plan

• What is there and what functions is it providing?
• Protect - Where it is critical environmental
  capital
• Urban centres, flood plains, private gardens on
  high infiltration soils
• Create - Where there is a need / functionality is
  lacking
• High density residential and built up areas, low
  green space cover with human vulnerability
• Enhance - Where management changes could improve
  functionality
• Water storage capacity, wildlife corridors, SuDS
• Maintain - So that it continues to provide that
  function
• Overall green space cover, times of water stress

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Example policies

• Sheffield City Council proposed green roof policy
• Required on all medium and larger developments
  (more than 15 dwellings / over 1000 m2 gross
  internal floor space)
• Encouraged on all other developments
• Must be compatible with other design and
  conservation considerations
• Must cover at least 80 of the total roof area
• Hull City Council proposing development control
  policies to reduce flooding impact flood-proof
  new development
• Remove permitted development rights to control
  loss of private gardens
• Lower development densities and higher green
  space public open space requirements
• Flood proofing built into any new development

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Conclusion

• Our climate is changing
• Need to mitigate and adapt
• Mitigation role of GI limited but important
• Adaptation role of GI substantial
• Spatial planning has an important role to play in
  climate change adaptation
• Planning policy must reflect the functional
  importance of GI at all levels
• Need to know what we have and how it functions in
  order to protect, create, enhance, and maintain