Green infrastructure has been in decline since settlement of WA in 1829. Since then some 70% of green cover (trees, shrubs, groundcovers, grasses and hedges) has disappeared. Government estimates tell us that a further 3% of native green infrastructure will go under the developer's bulldozers by the year 2050, to make way for the predicted population of 3.5 million people. Planting trees and lawn is now recognised as the most cost effective way of combatting this lethal heat trap effect.
Recent research both in WA and overseas shows that the decline in 'green space' has a number of serious consequences for human health and wellbeing. Our vulnerability to excessive summer heat is a very real issue for both cities and suburbs. Built structures such as roads, footpaths, car parks, blue metal lined railway beds, concrete and brick structures including homes and commercial buildings; all absorb heat during the day and re-radiate it back into the atmosphere at night. The result is that our cities and suburbs are getting hotter and we are not able to cope, particularly when we become old or ill.
The lack of green infrastructure is also having health effects in our homes. 'Affordable housing' is driving the size of home blocks down and the footprint of the house is covering the block to an unprecedented proportion. In other words the space to play outdoor sport on the home block has disappeared. When the average block was a quarter acre (1000m2) we allocated 10% of land in a development to public open space.
Today the average house block is getting closer to 250m2 yet the 10% public open space still applies. So from both perspectives we are losing recreational opportunities.
This lack of recreational space is a factor in what I see as an emerging indoor lifestyle. Another is the use of small screen electronic equipment, phones, laptops and tablets. Our kids, or in my case grandkids, are spending more of their life indoors. During summer this means living in energy hungry air conditioned homes.
Australia holds the record for skin cancer occurrence and we developed a world's best "Slip-Slop-Slap" campaign to protect skin from sun exposure. Now in Australia we have a new issue emerging - declining Vitamin D as a result of a lack of exposure to sunlight. We are out of balance on the sunlight front and getting kids outdoors to play has become a critical element in their health.
The new Perth Metronet provides an opportunity to change this habit. The network of rail lines serving Perth and suburbs is today a pretty grey affair. The southern lines going to Armadale and Thornlie, are characterised more by graffiti then anything green. My dream is to use the railway reserve that follows the tracks to create a ribbon of green that connects suburbs and the city.
At the least, this can provide a planted green corridor that absorbs pollution and supplies fresh oxygenated air, and at best, linear parks for recreation in forms such as bicycle and walking tracks as well as wildlife refuges and corridors.Perth needs projects that work to reverse the decline in green infrastructure.
Our most innovative and committed local government councils have developed and implemented tree canopy initiatives. However even in these council areas we have not turned the corner from decline in canopy cover, to an increase.
This is why we need a visionary project to change the colour of our rail infrastructure from grey to green.