Green Infrastructure to combat Climate Change

part of the North West Climate Change Action Plan

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Green Infrastructure Report to the Royal Commission on Environmental Pollution

Part of RCEP Urban Environment Report

Date: 2006

Evidence type: Research

Organisation: Royal Commission Environmental Pollution

Author(s): Goode, D.

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Description

This is one of two detailed reports commissioned during the 26th RCEP Report on the Urban Environment study. Understanding the environmental functions of the green infrastructure is particularly relevant to assessing climate change impacts in urban areas and developing adaptation strategies. The report focuses on multifunctional green space and the ecosystem services provided by green infrastructure including climate amelioration, water management, biodiversity and health; with recommendations for policy guidance.

Key Messages

The report advocates the benefits of SUDS.

SUDS provide more natural approaches to urban drainage and help to prevent both flooding and water pollution. They can also be designed to provide new wildlife habitats and attractive features within the urban environment.

Green infrastructure type

Non-specific green infrastructure

Climate change role/function

Non-specific adaptation role/function; Managing surface water; Helping other species to adapt

Studies have indicated that increasing tree cover by 25% can reduce afternoon air temperatures by between 6 to 10 degrees C, and simulations of a 30% vegetation cover reduced temperatures by as much as 6 degrees C.

Vegetation provides cooling through evapo-transpiration, and also adds humidity to what is frequently uncomfortably dry city air. At the local level the importance of street trees in ameliorating the local climate of urban areas needs to be more fully appreciated, and their value for shading buildings more fully understood, particularly in relation to future climate change.

Green infrastructure type

Trees

Climate change role/function

Managing high temperatures

It has been demonstrated that green roofs make buildings more thermally efficient, prolong the life of the roof, ameliorate extremes of temperature and humidity, moderate surface water run-off and help to reduce air and noise pollution. They also provide opportunities for wildlife in heavily built up areas and can provide space for habitats of special urban character to be maintained.

As well as providing increased thermal insulation on buildings it has been found that green roofs have an added advantage where photovoltaics are installed. This is because their efficiency can be reduced by high temperatures of normal roof materials during hot weather, and they work more efficiently on green roofs because of the cooling effect of the vegetation.

Green infrastructure type

Green roofs

Climate change role/function

Managing high temperatures; Managing surface water; Helping other species to adapt

Conservation of nature in UK towns and cities has become widely accepted over the past twenty years as part of urban planning and design. It has been recognised that a considerable variety of habitats occur in urban areas and that provision needs to be made for their protection and enhancement

One of the strengths of urban nature conservation lies in the emphasis on community involvement. Many of the programmes are led by urban wildlife groups with strong community links. In this respect support for nature conservation in urban areas has drawn on a wider social constituency than the science-based approach to key site protection which forms the basis of UK policy for nature conservation.

Green infrastructure type

Non-specific green infrastructure

Climate change role/function

Helping other species to adapt

In addition to enhancing visual amenity, private gardens have important environmental functions. They provide areas of permeable soil where rainwater can infiltrate into the ground rather than flowing into the urban drainage system. They have a significant role in providing a wide range of habitats for urban biodiversity and they also provide local climatic amelioration within the urban fabric.

As the trend for converting front gardens to hard surfaces continues it is likely to further exacerbate problems of localised flooding. It is recommended that planning guidance be amended to require permeable surfaces to be used for provision of car parking spaces in front gardens, and to encourage retention and enhancement of the green infrastructure wherever possible to maximise local climatic benefits and to provide for biodiversity.