#greenroofsaus_#urban heat island_#urban flooding_#green cities

Posted on Sat, 2017-02-11 15:28 by matt

Perth / urban flooding. Sydney / urban flooding followed by heat wave. No surprises really because we all know that 'Climate Change' means more extreme rainfall and higher temperatures. This is no longer a forecast because it is happening globally, now. These events occur, they are reported in the news, emergency teams march into action, insurance companies and owners pay for damage, society is disrupted and political leaders sympathetically inspect the recovery operation.

GRA are about offering one solution to assist with these impacts on our environment and our society. The solutions will not be found in our current twentieth century planning paradigm for urban growth and building performance best practice. The Industrial Revolution was about concrete and steel, urban sprawl, cars and planes, coal energy, GHG emissions, pollution, species extinction and social inequality. There is an urgency to THINK AGAIN & ACT ASAP.

Presently, Australians are experiencing the impacts of climate variability, being, an increase in temperature and rainfall. Thermal imaging over Sydney or any other urban area during extreme temperatures will prove that building roof tops and walls are 'heat sinks' for storing radiant energy which contributes to the Urban Heat Island Effect (UHIE). This results in a dramatic increase in building energy use for cooling using HVAC units which creates an energy drain on supply which increases GHG emissions. In response, all tiers of government in Australia have been slow, short sighted and incompetant by not providing innovative solutions to reduce GHG emissions. The built environment is responsible for 40% of global emissions, due mainly to heating and cooling services. In Australia, the energy supply is reliant on coal which also adds to GHG emissions. The result is a disfunctional cycle of producing more emissions to provide human comfort and compounding the problem.

Roof tops alone account for 27% of the urban area. Today and yesterday, Sydney is 40 - 48 degrees C between 12:00 - 2:00pm with minimal wind velocity. A concrete or metal roof will be approx 80 - 95 degrees c which adds to the ambient temperature around this building requiring an increase in energy usage for cooling.. A green roof or living wall will be 30 - 40 degrees c. and does not add to the ambient temperature but rather provides insulation resulting on a cooler interior / less energy requirements / less GHG emissions. Widespread usage of green roofs & living walls will have a profound impact on stabilising urban heat and consequently, reducing GHG emissions.

In the space of three days over the past week, Sydney has experienced extreme rainfall (50mm over a 1 hour period) which lead to urban flooding infrastructure damage and extreme temperatures between 40 - 50 dgrees C. leading to spikes on energy demands. On the west coast Perth is experiencing urban floods. These extreme events are a result of climate change.  A green roof will absorb and detain stormwater which provides less flow into the aging storm water infrastructure system. Widespread green roofs across urban areas will reduce storm water flows during peak rain events and reduce subsequent flooding events.

Green roofs and living walls incorporated into the built environment can provide sustainable solutions to the impacts of urban flooding and extreme temperature rises but that will only become a reality when governments mandate their inclusion through strong policy, incentives, grants and legislation.The quantitative & qualitative data plus case studies on many global cities provide our leaders with proof to act quickly and responsibly.

The housing supply shortage in Australia is an excellent opportunity to change the existing policy paradigm supporting disfunctional urban planning and inefficient building performance. The lowest fruit on the tree is to redevelop existing buildings and develop new buildings which meet strict sustainable performance levels mandated by government policy.  Developers will not plan to reduce urban flooding or reduce the impacts of the UHIE. Developers will not incorporate high performance levels unless they are required to do so. Governments need to provide the mandate and developers will plan accordingly, no doubt, absorbing additional costs without significant financial impact on profits. Currently, Australian property prices are ranked in the top five globally however the quality of building design is not reflective.

Q: What benefits are the Australian housing boom providing society at large and the environment?