The Urban Impact On Climate

Tuesday 21 December 2021, 9:34PM

By Garth Dawson


There no such thing as a free lunch with Intensification of the Urban landscape

Yes the CO2 levels are increasing. But we als also adding to global warming by the way we are living and changing our city scapes.

There is much talk abiut reducing our carbon footprint to reduce the impact of climate change. There is little or no talk about the impact of urbanisation and the reduction in matrue trees, the increase in hard surfaces (roofs as well as roads and paving), the increase in use of air-conditioners, and the general intensification of people (more CO2) in smaller areas.

Each of these add up to an increase in CO2 as well as heat. Yes heat. Heat being radiated back into the atmosphere. Take a walk down an urban street these days and you swelter. There is hardly a mature tree to be seen. Even less in the newer suburbs, with houses cheek by jowl. And if not separated, then rows of town houses.

Look at a typical city scape (urban as well as CBD), spot the mature tree. As we intensify housing, we cut down the mature urban forest. We also increase the area of hard surfaces - roofs and paving. Paving being both concrete and ashphalt. More roads to meet the every increasing population.

This paving also captures and re-radiates the heat back into the atmosphere.

Air-conditioners. Ahhh, the humble air-conditioner. How does that add to global warming? Quite simply by the way it works. To cool the inside of a house or building you have to remove heat. That heat has to go somewhere. That is the unit that sits outside your house or on the roof of an apartment or office. That heat is then radiated out into the atmosphere. Again, adding to the increase in global temperatures.

Ah, but you may say. it's only a little bit. Every little bit adds up. We are using air-conditioners more and more. The outside (and inside) temperature rises, we retreat indoors and turn on the air-conditioner.

The Healthy Homes Act has added to the number of air-conditioners overnight! More houses ae being build with air-conditioners. Everone of them adding their little bit of transferred heat to the atmosphere.

Removing the urban forest and having open space with trees planted sparsely around the edges is removing the natural cooling effect of trees. How many people have enjoyed sitting under the sade of a tree in summer, or walking along a tree lined path and enjoyed the coolness and shade the trees provide?

So it is time to stop just focusing on carbon emmsioins, but to start looking at all the elements that humanity are doing that is effecting the change in our climate and adding to the global warming.