Tuesday, 4 October 2011

growth rates vs consumption rates

Back when I was doing my Masters research I wanted to address the question (among others) of "as our population has expanded on the Gold Coast have we also consumed more water per person rather than just consuming more water?"

My research indicated that the increase was only marginal, which went against the accepted view in the community that we were using more water per person. The graph here shows population as series one and the water extracted divided among the population. Its irregularity is perhaps a source of research but I'm of the feeling that it would be explainable by the rubbery accuracy of data by GCW.

None the less I think this demonstrates that we are not actually consuming more water per person, although as the population goes up we are consuming more water as a community.

At the moment I would be interested to know however about the impact of the population growth on our use / need for energy? Is it like water or not? For instance. I find myself driving further and longer to get to work these days. I live in a city where there are essentially no meaningful jobs (the Gold Coast), and as a result commute to another city (Logan) for my work. Back in 2004 it used to be to Brisbane, so perhaps I'm not so badly off.

However I notice that more and more people are joining this same road so that it is now almost always totally at capacity.

Australia is rapidly urbanising, with this page suggesting that the urbanisation rate is 1.2% and that the population growth rates are about 2.1%.

I'm not sure if this results in more or less efficient use of energy. My gut feeling is that its more, but its a subject I would like to have time to research properly.

This page suggests that Australia has been growing its energy consumption rates at about 2.3% which is slightly higher than the population growth rate. The data however is only until 2005 so I'd be interested to learn what it is in the last 5 years.

I did some back of the envelope calculations the other day and came up with the figure that we use about half a million liters of petrol on the freeway between springwood and the northern end of the gold coast every day just for commuting to work.

So this has me wondering if we're ramping up or its just population growth. That quick back of the envelope mentioned above gave me a figure of around 5,300 cars traveling on the highway between my work and home, which is a scary number and WAY more than it was just 5 years ago. I looked up stats from data averaged over the period 2008 to 2010 and found that its actually less than my calculation but pretty close.

It gets mighty busy and fast from 5am and ramps back at 6pm. I can say from my personal experience that this isn't how it is now with it still being busy in the 8pm segment and way busier on the weekends till much later.

Either way I think its not a good sign.


Cameron Murray said...

Short answer - yes, per capita energy use goes up real GDP per capita goes up. In fact, some academics have argued that real GDP per capita is the BEST estimate of energy consumption. (Len Brookes first argued this in 1972).

The logic goes that we can only increase real GDP per capita by using MORE energy to produce things we couldn't with labour alone.

There is simply so substitute for energy in making us more productive.

obakesan said...

Cameron, thanks for the economists views on this. I guess that its sort of QED even from a physicist perspective that as more work is done that more energy is needed.

I wonder how the process of efficiency applies here? Meaning that if we are more efficient we can do more with less energy needs.

I think that increases in GDP without additional increases in efficiency are not desirable long term targets if we wish to be sustainable AND manage a growing population.

obakesan said...

I think that Cameron is refering to this interesting thesis:

His analysis showed that any economically justified improvements in energy efficiency would in fact stimulate economic growth and increase total energy use. For improvements in energy efficiency to contribute to a reduction in economy-wide energy consumption, the improvement must come at a greater economic cost. Commenting in regard to energy efficiency advocates, he concludes that, "the present high profile of the topic seems to owe more to the current tide of green fervor than to sober consideration of the facts, and the validity and cost of solutions."