Turning crowded urban areas into a green oasis could help fight the impact of climate change, Australian experts believe.

Urban greening advocacy group 202020 Vision wants Australia's green urban areas increased by 20 per cent by 2020 for economic and social benefits, including cooling cities.

The group says reducing the impact of heat in cities could soon be crucial.

The year 2014 was the third hottest in Australia and the hottest globally since reliable climate records began.

A joint CSIRO/Bureau of Meteorology report on climate change, released in January, showed average temperatures in Australia could rise up to 1.3C by 2030 and at least 2.8C by 2090, with more frequent heat extremes.

A University of Sydney study this month said increased heat from global warming could disproportionately affect heavily built-up urban areas, trapping heat by day, re-radiating it at night and increasing heat stress for residents.

Dr Simon Divecha, a 202020 Vision spokesman from the University of Adelaide's Environment Institute, says urban greening shields cities from heat.

"If we shade the buildings, the walls, the roads, it stops that mass ... absorbing that heat during the day and radiating that heat at night," Dr Divecha said.

Air-conditioning can work more efficiently if combined with planting shade trees and wall vegetation or rooftop gardens and urban re-greening along watercourses.

New commercial buildings in France must now have solar panels or rooftop gardens, Dr Divecha said.

A green roof reduces stormwater runoff when it rains, reduces air pollution, shades and doesn't re-radiate heat like a concrete roof does, he said.

Although more work is needed, Dr Divecha said Australian councils are embracing change.

The Sydney City Council encourages roof gardens in new buildings, while the City of Adelaide seeks efficient building design and Melbourne city planners are developing new ways to add greenery to urban landscapes.

  • Greener cities advocate for a simple philosophy, " Going back to Nature". I f the garden of eden was to be presented to us now, we would be awed! Think of it this way: Zero emissions, transportation conservation,100% day-lighting and natural ventilation etc. it's easy to claim this was very rudimentary when compared to the post industrial revolution era. that is true, but the approach could have been pro ecological sensitivity both in policy and design.

  • Cities consume 70% global energy and generate 70% Co2. These are all due to travel and buildings within cities. If travel and buildings are rationalised surely we can make this world close to Garden of Heaven. This would require our understanding and appreciation of the the impact of our actions. So let us attempt to plan, design and operate cities in a manner they become compact and smart.

  • Green is important, for many reasons, heat, water, nature, economy. But still, only precisely dimensioned green 'building-blocks' will be payed for. In cities space is often narrow, many other items cry for space. Thus those who will have to pay for extra green building blocks will ask for technical reasonment. We create such reasonment in a large EU program. Functional green. It is a 4 year program. We also find in our daily work that green building blocks cann often be created, when direct benefits are harvested!