"Green Infrastructure for Climate Change Adaptation - the role of"
Green Infrastructure for Climate Change Adaptation - the role of spatial planning Dr Susannah Gill firstname.lastname@example.org 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