Green Infrastructure and Climate Change

1. Green Infrastructure and Climate Change Dr Susannah Gill The Mersey Forest susannahgill@merseyforest.org.uk

2. Overview • Green infrastructure • Climate change • Green infrastructure for adaptation in urban areas • Policy relevance in the UK • North West Climate Change Action Plan • Conclusions

3. Green Infrastructure • Life support system – the network of natural environmental components and green and blue spaces that lie within and between our cities, towns and villages and provide multiple social, economic and environmental benefits • http://www.greeninfrastructurenw.org.uk

4. Our Climate is Changing • Warming of the climate system is unequivocal • Coherent changes in many aspects of the climate system not just temperature (source: IPCC, 2007)

5. Changes go beyond natural variability Temperature change in last 50 years is very likely (>90% chance) due to increase in anthropogenic greenhouse gas concentrations (source: IPCC, 2007)

6. Global climate change projections (relative to 1980-99) (source: IPCC, 2007)

7. What does this mean for the UK? • UKCIP02 • 4 emissions scenarios • 3 time slices • 50 km outputs (some 5 km) • UKCIP08 • Probabilistic scenarios • 25 km output • Due October 2008

8. 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

9. Greater Manchester Average Maximum Summer Temperature Data from the UK Met Office and UKCIP02

10. Greater Manchester Summer Precipitation Data from the UK Met Office and UKCIP02

11. Greater Manchester Winter Precipitation Data from the UK Met Office and UKCIP02

12. Manchester (Mean Annual Temp) Baseline (1961-90) 2050s Low emissions 2050s High emissions 2080s High emissions Slide courtesy of Mark Broadmeadow

13. Baseline (1961-90) 2050s Low emissions 2050s High emissions 2080s High emissions Manchester (monthly mean temp, diurnal temp range & precipitation) Slide courtesy of Mark Broadmeadow

14. Matt Cardy/Getty Images Daniel Berehulak/Getty Images Kate Gillon/Getty Images Source: The Guardian website

15. June-Aug temp anomalies (relative to 1961-1990 mean) Source: Stott et al, 2004

16. Climate Change Management Smit et al (1999)

17. Mitigation Role of GI • Carbon sequestration & storage • Direct fossil fuel substitution • Material substitution • Local food production • Reducing need to travel

18. Adaptation Role of GI • Moderating temperature extremes • Decreasing rate and volume of rainwater runoff • Providing wildlife corridors • Providing recreation spaces e.g. high capacity, less sensitive landscapes

19. 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 http://www.k4cc.org/Members/Claire/BKCC-Results-Publication.pdf

20. ASCCUE Methodology • Two case study areas • Greater Manchester • Lewes, Sussex • Three exposure units • Integrity of the built environment • Human comfort • Urban greenspace

21. Urban Greenspace • Urbanisation alters • Micro-climate – increased temperatures • Hydrology – increased rate & volume of surface runoff • Climate change alters temperature & rainfall patterns • Urban greenspace can moderate ‘urban heat island’ effect and reduce rate & volume of runoff • Therefore urban greenspace has potential to adapt cities to climate change

22. Urban Morphology Types

23. Urban Characterisation

24. Greater Manchester Urban Morphology Types

25. UMT Surface Cover

26. ‘Evapotranspiring’ Surfaces

27. ‘Urban’ Tree Cover

28. Surface Cover and Residential Density

29. Modelling environmental functions • Use surface cover data as one input into surface temperature and runoff models • Series of model runs • Current urban form • Baseline and future climate • ‘Development scenarios’ • Baseline and future climate

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

31. Residential ± 10% green cover

32. 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)

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

34. 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

35. 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

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

37. Climatic adaptation via the green infrastructure Corridor Patch Matrix Functional importance of urban greenspace needs to be reflected in plans, policies, strategies

38. Summary of 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

39. Policy Implications • Work across administrative boundaries & disciplines • Protect critical environmental capital • No net loss of green cover • Creative greening • Take opportunities in new development / restructuring • Ensure water supply

40. Increasing Policy Relevance

41. NW Climate Change Action Plan • “Undertake scoping studies to assess future regional risks, opportunities and priorities for the potential for green infrastructure, including regional parks, to adapt and mitigate for climate change impacts and commence implementation of findings”

42. GI functions for climate change

43. Conclusion • Climate change mitigation role limited but important • Climate change adaptation role substantial • GI is a good adaptation strategy as it has other functions and benefits • To maximise this need strategic planning at all levels, with functionality in mind • Protect, create, enhance, and maintain