Sydney at four million inhabitants is a moderate sized city by modern standards. It is a similar size to Phoenix, half the size of Chennai, and a suburb compared to the 34 million inhabitants of Tokyo.

But Sydney is plenty big enough to have transport problems. The arterial roads that feed into the harborside CBD are mostly modern freeways, with tunnels and six lane bridges, but they just cannot handle peak flow. Smart commuters travel on the train.

One bonus of train travel is that on the days when you forget your ipod you get to hear people chat. A young couple sat ahead of me on one such day and discussed water.

“No we can’t.”

“Why not” said the husband.

“Those things just spray you with drips that don’t even get your hair wet. I need to get my hair wet.”

“What about the water crisis?”

“What about it?”

“Here, the dams at 39.2%”

It was true; there in the black and white of the morning paper ‘Dam levels at a record low’.

Sydney relies on water storage in a major dam, Warragamba, and the rain sometimes forgets to fall in its catchment in the Blue Mountains some 80km inland from the coast. The significant drought that began in 2006 and broke three years later forced water restrictions on all domestic use. To augment supply and reassure consumers there was drawdown of groundwater together with pumping from catchments further afield. And then, just to be absolutely sure, a desalination plant was commissioned and constructed.

The husband pressed his point.

“If only half the residents of Sydney took a shower this morning that’s two million showers,” he said.

“Ah, you want me to sit next to someone who hasn’t showered. Gross.”

“No, if they all showered for a minute less than usual they would save ten litres a minute, that’s 20 million litres saved.”

He said 20 million as though it was a large number and it certainly sounds impressive. The water from a minute of 2 million showers is 20 megalitres, enough to fill 30 Olympic sized swimming pools, provide 2 million toilet flushes or irrigate several hectares of winter wheat.

“I don’t care if it saves the planet I need a real shower.”

“It would help,” the young man said with hope in his voice.

It is easy to imagine a similar discussion over all sorts of conservation actions that can be done around the home. Recycling kitchen waste for example. All it requires is a sealable tub on the kitchen bench.

“But it smells and clutters up the place, get rid of it. And I hate those ants.”

Yet even in an average household it is easy to generate 10 litres of apple cores, vegetable peels and melon skins every week. Then if everyone in the street did it, say thirty homes, then we might see many tons of green stuff that the garbage men would not have to truck, saving fuel and space in the landfill for the garbage we cannot recycle.

There is a 60 litre black plastic bin in my garden that receives all the kitchen scraps. Every now and then there is a layer of brown leaves added and a bucket of water from the washing machine rinse cycle. All those apple cores and potato peelings decompose readily so that the bin is never full, even in winter. The magic of entropy facilitated by the military style operation conducted by decomposer organisms keeps the breakdown ahead of the household ability to generate waste. In spring the material under the bin is carbon rich compost ready to start off the vegetable patch.

If every second household in Sydney did this then, over a few years, millions of tons in greenhouse gas emissions would be avoided just by not having to shift the waste into landfill. There would be issues around nitrogen runoff into remnant vegetation patches from gardens now replete with green manure, but it is food for thought.

These sustainability actions are all good but surely we can do better. It would be great to do more than change the light bulbs, install a low-flow shower head, manage the compost to help build up the carbon in the stony garden soil, recycle the gray water, install solar panels, grow vegetables and any number of household behaviours for sustainability. Perhaps we could become self-sufficient.

The reality is that there is little prospect of genuine self-sufficiency for most of us. Even with half a hectare of yard and the compost going great guns, most of the vegetables I grow end up feeding the wildlife. There is greenery but not enough to provide for the family. The household members are also used to vigorous hot showers, power on demand, perfect fruit and veggies, the air conditioner in summer and the fireplace lit when it gets chilly.

No longer do we sit in front of smoky coal grates in high backed chairs with wings to keep the draft off our necks. We are acclimated to an even twenty something degrees wherever and whenever we happen to be. This level of comfort has sensitized us to the point where we really feel deviations from our comfort level, not that a few degrees colder or hotter would have any affect at all on our chance of survival.

We have climbed the hierarchy of needs yet, in our minds, we sit as though we are still at the basal level where deviations from what feels safe have the power to upset us.

Does this mean that westerners are desensitized to the problems we have in the environment? Not totally. The media runs stories of environmental challenges and energy saving bulbs are sold in supermarkets. There are energy use ratings on white goods and grants to install water saving devices or solar heating systems.

In Sydney, the Inconvenient Truth made it onto the most watched movie list for a few weeks despite being shown only in selected cinemas; school kids prepare assignments that help them learn about water, land and wildlife challenges; market surveys put the environment high on the list of issues that decide elections hot on the heels of taxes, education, health and the military. Yet whatever we say people still want their needs met. This is their priority.

What we must accept is that our living environment has changed. For better or worse we are sensitized human beings. Most of us really would struggle to survive in the wild and this puts very different parameters on sustainability. Now we must sustain conditions in narrow comfort bands, supply only certain food types and ensure a high level of creature comforts.

The exchange on the train said it all. Not in the words, but the incredulity in the woman’s voice and the despairing logic of her husband.

“Ah, you want me to sit next to someone who hasn’t showered. Gross.”