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

1. Green Infrastructure for Climate Change Adaptation- the role of spatial planning Dr Susannah Gill susannahgill@merseyforest.org.uk

2. 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)

3. 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

4. Average Summer Maximum TemperatureScenarios for the North West

5. Average Summer Precipitation Scenarios for the North West

6. Average Winter Precipitation Scenarios for the North West

7. Climate Change Management Smit et al (1999)

8. 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

9. 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

10. 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

11. 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

12. Greater Manchester UMT Map

13. Evapotranspiring Surfaces

14. ‘Urban’ Tree Cover

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

16. Residential ± 10% green cover

17. 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)

18. Occurrence of Drought for Grass Months/year when grass water stressed

19. 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

20. 56% more rain results in 82% more runoff Surface Runoff For a precipitation event occurring on average one day per winter, with normal antecedent moisture conditions

21. Infiltration Capacity A case for ‘Conservation Areas’?

22. 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

23. 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

24. 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

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

26. 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

27. 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

28. 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