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

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)

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

Average Summer Maximum Temperature Scenarios for the North West

Average Summer Precipitation Scenarios for the North West

Average Winter Precipitation Scenarios for the North West

Climate Change Management 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

Adaptation – the role of GI Changes over next 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

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 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

Maximum Surface Temperatures For a day occurring on average twice per summer

Residential ± 10% green cover

If grass does not evapotranspire… Maximum surface temperatures increase by – °C in high density residential areas – °C in schools Maximum surface temperatures increase by – °C in high density residential areas – °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’?

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 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 important role to play in climate change (especially adaptation) Functional importance of GI must be reflected in planning policy GI functions for climate change… MitigationAdaptation 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

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

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

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

Example policies… Sheffield City Council proposed green roof policy –Required on all medium and larger developments (more than 15 dwellings / over 1000 m 2 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

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