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Green Infrastructure for Climate Change Adaptation - the role of by puw61439

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




                          Dr Susannah Gill
               susannahgill@merseyforest.org.uk




www.merseyforest.org.uk
            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 (>90% chance) due to increase in
        anthropogenic greenhouse gas
        concentrations

                                       IPCC (2007)


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
Average Summer Maximum Temperature
     Scenarios for the North West




www.merseyforest.org.uk
        Average Summer Precipitation
         Scenarios for the North West




www.merseyforest.org.uk
          Average Winter Precipitation
          Scenarios for the North West




www.merseyforest.org.uk
       Climate Change Management




www.merseyforest.org.uk
                                   Smit et al (1999)
             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



www.merseyforest.org.uk
          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


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
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
Greater Manchester UMT Map
Evapotranspiring Surfaces
  ‘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
UMT




             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
Maximum Surface Temperatures
For a day occurring on
average twice per summer
             Residential ± 10% green cover

                                               High density residential

                        40
Max surface temp (°C)




                        35

                        30                                                              current form
                                                                                        -10% green
                        25                                                              +10% green

                        20

                        15
                             1970s   2020s   2020s    2050s    2050s    2080s   2080s
                                      Low     High     Low      High     Low     High
                                             Time period and scenario
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         (Manchester Evening News, 2006)


    schools
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’?
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
         The role of spatial planning
• GI planning has an      GI functions for climate change…
  important role to       Mitigation         Adaptation
  play in climate         Biofuels production   Shading from sun
  change (especially      Timber production     Evaporative cooling
  adaptation)             Food production       Water storage
                          Carbon storage        Water interception
• Functional              Recreation            Water infiltration
  importance of GI        Green travel routes   Soil stabilisation
  must be reflected       Shading from sun      Storm protection
  in planning policy      Evaporative cooling   Habitat for wildlife
                                                Corridor for wildlife
                                                Recreation


www.merseyforest.org.uk
        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


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




www.merseyforest.org.uk
                          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


www.merseyforest.org.uk
                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




www.merseyforest.org.uk
                          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


www.merseyforest.org.uk

								
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