For example, shading from strategically placed street trees can lower surrounding temperatures by up to 6℃, or up to 20℃ over roads. Green roofs and walls can naturally cool buildings, substantially lowering demand for air conditioning. Green infrastructure can also provide habitat for wildlife, recreational opportunities for people, better management of stormwater runoff and improved urban aesthetics.
Hard surfacing, including concrete, asphalt and stone, is common in cities. It can increase urban temperatures by absorbing heat and radiating it back into the air. Green infrastructure can minimise this difficulty as it better regulates ambient air temperatures. Foliage allows local cooling through evapotranspiration, where plants release water vapour into the surrounding atmosphere.
A number of cities have grasped the adaptive advantages of green roofs and have implemented standards which allow local planning regimes to ensure that urban development includes this technology. For example, due to new development standards recently introduced in Toronto, the planning system can now utilise the development control process to ensure that new buildings have between 25 and 50 per cent green roof cover, depending on type and use. The planning regimes of Chicago, Boston and Minneapolis have also implemented similar standards . These examples demonstrate that urban planning regimes can play an important role in delivering urban adaptation through the establishment of infrastructure and design standards relating to green roofs.