PCE warns cities will get warmer and wetter with climate change, urges housing intensification with more high rises not urban sprawl to save green spaces
Auckland has lost 30 per cent of its green space due, in part, to housing intensification. Photo /Sylvie Whinray
Auckland has lost 30 per cent of its green space due, in part, to housing intensification. Photo /Sylvie Whinray
The country’s environmental watchdog is urging cities to stop swallowing up green spaces and build up and not out, warning they could become less livable.
International research shows street trees and green spaces can cool air temperature by up to 4.5C, and also soak up stormwater - critical components amid a warming world and especially important after this year’s devastating cyclones and floods.
A study published today by Parliamentary Commissioner for the Environment Simon Upton calledAre we Building Harder, Hotter Cities? The Vital Importance of Urban Green Spacespresented new data on how public and private green spaces in Auckland, Hamilton and Greater Wellington had evolved over the decades.
Interactive maps can be viewed at the bottom of this article.
While it found New Zealand cities were “well-endowed with green space” the spread was disproportionate.
The data also showed urban green space has been declining. Between 1980 and 2016, green space per person fell at least 30 per cent in Auckland and at least 20 per cent in Hamilton. Nearly all of this loss occurred on private residential land.
Development in Epsom in 1942. Photo / PCE
Development in Epsom in 2016. Photo / PCE
Development in Epsom, Auckland, in 1942. Photo / PCE
Development in Epsom, Auckland, in 2016. Photo / PCE
The report found a key reason was infill development – the conversion of yards and sections into houses and driveways in existing urban areas. The second was a shift towards larger houses on smaller sections in new subdivisions.
Upton said planning for and providing urban green spaces of any description, public and private, should not be optional.
“The environmental services green spaces provide – such as temperature regulation, stormwater management, air filtration and habitat provision – don’t just benefit individuals.
“They benefit everyone around them. They are a form of infrastructure every bit as important as pipes and roads.
“The ability of our trees and parks to filter stormwater flows and cool their immediate surroundings can mitigate some of the heat and excess water that impervious surfaces generate.
“These services will be in even higher demand as our cities become hotter and more subject to extreme rain events in a changing climate.”
Data shows Auckland and Hamilton have become less green as they have grown. In Greater Wellington, green space has remained essentially constant. Photo / PCE
Upton said many councils were struggling to improve the quality and availability of public green spaces to compensate for the loss of private yards and gardens.
Greater Wellington was the exception as the proportion of urban green space remained the same as the city had grown.
Almost two-thirds of the urban area was green space and that figure increased if the outer green belt was included.
Upton said trends documented were already playing out before recent Government moves to promote further intensification, but these pressures would increase through the Medium Density Residential Standards.
This image, captured with an infrared camera, reveals the surface (not air) temperature on a sunny summer afternoon on a treelined street in central Wellington this summer. The yellow areas are hotter surfaces, and the blue/black areas are cooler. Photo / Dr Ashley Broadbent, Niwa
There were benefits to urban intensification, especially in addressing the housing shortage and reducing transport emissions.
“But not all intensification is the same, and the style of infill townhouse development that is currently happening within our cities comes with particular risks for the existing network of urban green space,” Upton said.
One solution was building high-rise apartments rather than low-rise infill development, which used urban land more efficiently and reduced pressure to develop green spaces elsewhere in the city.
Research suggests that a 10 per cent loss of green space (as a proportion of the total area) could add 0.3C of warming on top of the 0.5-1C already caused by climate change. Photo / PCE
More attention could also be given to counteracting the loss of private yards and gardens by improving nearby public green space.
That could include improving canopy cover in local parks, road reserves and other neglected corners of public land by planting trees, or repurposing impervious grey spaces such as carparks with some form of vegetation.
The difficulty of retrofitting green space into existing neighbourhoods highlights the importance of adequately providing it from the outset in new subdivisions on the city fringe.
Councils could take a more proactive approach to land acquisition for future parks and reserves to help achieve this.
“The changes we are making to the shape and form of our cities are largely irreversible.
