Last year Brisbane’s summer temperatures reached international heat wave conditions. Health authorities speculate that the intense conditions, experienced Australia-wide, actually contributed to the deaths of more than 370 people.
Under climate change, the frequency and severity of such extreme weather events is expected to increase. Development of an effective strategy is of particular importance to Brisbane, where the city is expected to receive some of the most extreme weather nation-wide.
One of the major issues in Brisbane is that our housing and infrastructure is not designed to cope with this heat. “From Brisbane to Belorussia, from Dublin to Dubai, cities the world over have acquired a certain sameness. Air conditioning has greatly facilitated the globalisation of architecture by effectively detaching it from place,” Professor de Dear of the Queensland University of Technology (QUT) suggests. “And unfortunately air conditioning requires prodigious inputs of energy. Per capita, Australians are responsible for more greenhouse gas emissions than any other nationality on the planet.”
In response, the State Government funded Centre for Subtropical Design (CSD) has compiled a series of management suggestions for the Brisbane City Council. “As we gear up to receive another million citizens and increasing numbers of days when heat and humidity are not comfortable, urban sustainability and liveability require deliberate attentions to ‘place-based’ planning and urban design,” Rosie Kennedy, director of the CSD says.
“People not just buildings and infrastructure, make a place and their comfort is important. If we aspire to a less car-dependant, walkable city, then shade and shelter for pedestrians is essential” Mrs Kennedy follows.
The CSD emphasis on ‘shade and shelter’ is reflected in Brisbane City Council’s global warming management plan. Council has focused on increasing the city’s vegetation as a way to minimise climate change impacts. The 2 Million Trees Project engages local councils and community groups in the planting of native vegetation across the city. It aims to establish 60% vegetation cover by 2026 and has numerous projected benefits.
Trees provide shade on the city streets and reduce in-building temperatures, cutting air conditioning use and therefore significant emissions. “As the housing density in Brisbane increases, we need to let vegetation back in the city to allow residents to breathe and enjoy their climate,” Architect Elizabeth Watson-Brown, affiliate of the CSD says. “Extensive street planting provides welcome shade and allows the city to offset its emission of carbon dioxide.”
The capacity of trees to remove carbon dioxide from the atmosphere should not be underestimated. Professor Peter Grace, Director of the Institute for Sustainable Resources, estimates that carbon storage in the earth’s plants “has the potential to reduce the world’s annual carbon dioxide emissions by 10 to 15 percent”. This is a beneficial side-effect of planting trees for lifestyle, ensuring that global warming effects are managed while offsetting contributing emissions.