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It’s been really hot in Melbourne recently. Today achieved the second highest recorded temperature in over 100 years (if I remember correctly) according to the news on TV - 45.1degrees. Being the geek that I am I’ve always had pale skin from too many days spent in dimly lit rooms in front of my computer, and heat wave has made me even more scared of leaving the comfort of my house.

Alarmingly the news (I think it was ABC, can’t be sure) also reported that the hot weather has meant hugely increased demand/usage of electricity (presumably from people turning on their airconditioning systems) on such a scale that demand is outstripping supply. Some homes around Victoria have been without power for three days. I find this a bit scary because to me it seems to imply a vicious circle: hot weather results in increased power usage, which means more greenhouse gases are released into the atmosphere, resulting in an increasing rate of global warming, in turn resulting in hotter weather, meaning more demand for power, meaning increased power usage etc. Of course one (long term) solution would be to invest in nuclear power plants for the future, but with such strong opposition to nuclear energy in Australia I can’t see anything like this happening within Kevin Rudd’s first term. For more info about nuclear power and other cool science-y topics from an Australian perspective see Physical Insights, a blog run by a friend of mine.

Similarly, the heat has resulted in people far exceeding the recommended daily water usage of 155litres per person per day. The news reported average water consumption per person had risen to 290litres per day. This was all to be expected of course. With everyone sweating buckets people are going to want to drink more. Oddly enough, last Saturday The Age ran an article about how the Opposition’s water spokesperson Louise Asher felt the target 155litres per person per day was too severe, claiming that forcing people to choose between having a shower and watering their garden was “demonstrably unfair”. Erm, what? Does she seriously not understand how this works? The amount of water in the dams can be treated as finite so long as water is being taken from the dams faster than the dams are filled (which is a fair assumption given The Age’s daily figures dam levels are consistently lower than dam levels last year). So using more water now will just mean we run out sooner and even more stringent targets must be put in place so that we have time to sort out some viable alternative water sources. If the daily per capita target was raised a few years from now people won’t be forced to choose between a shower and watering their garden, they’ll be choosing whether they or their garden will be able to have a drink (see the update below).

Today I asked the question on Twitter “does anyone else feel slightly guilty for leaving the airconditioning on most of the day?” One of my friends replied “was working (and sweating) all day - aircon on now and don’t feel guilty!” This is illustrative of how I think many people feel that they’re “entitled” to certain things, no matter the cost. This same attitude is surely evident by people who buy sports cars and other luxury items which have a negative impact on the world. They have worked hard each day and earned themselves a big pile of cash and paid the taxman and now they feel entitled to a slice of the good life, with no thought to the environmental impact. I’m not saying you’re an evil person if you have the aircon on during 40+degree heat (I know I had my aircon on), I’m just concerned about the disregard many people show towards the environment. I think there will come a time when all of these environmental effects will come to a head and people will be forced to pay attention because drastic action will need to be taken. As it is I don’t think the humanity is taking things seriously enough.

**UPDATE**

I decided to check out the Melbourne Water Website weekly report to get some solid numbers on water usage. Melbourne’s water storage facilities are currently at 33.1%, which is 4.2% less than the same time last year. This 33.1% water storage equates to 586.86 billion litres of water. Last week total water consumption averaged 1268 million litres per day. Keeping in mind that last week was one of the hottest weeks on record, if water consumption continued at the rate of 1268ML per day and without any replenishment, we would have 462.8 days until the water was entirely used up.

Now, given that the average residential water usage over last week was 207 litres per person per day, and assuming that the population of Melbourne is 3,806,092 (this is based on a 2007 figure, it’s probably closer to 3.9million now) that equates to a total residential water consumption of 787.86ML per day. This means that there’s 480.14ML of water per day used for non-residential purposes. Using the same population and non-residential water figures, if the residential population of Melbourne was to adhere to the 155L per person per day target, the total daily consumption for Melbourne would be 1070.08ML. If water consumption continued at the rate of 1070.08ML per day and without any replenishment, we would have 548.4 days until the water was entirely used up. Or to put it another way, for every 1L Melburnians save per day (ie. not consumed for residential purposes) the stored water will last another 9.46days.

Now, I wouldn’t take these figures as gospel, they are ballpark figures at best. Obviously I’m not taking into account the replenishment of the water storage facilities by rain/stream flow (according to the website, the rate at which Melbourne’s water is being replenished is well below average), and the non-residential water usage figure is slightly fudged because it’s based on the data from last week’s heatwave (so it’s probably safe to assume the non-residential water use is usually less than the figure I’ve used), and population figure used by the website would be different from the figure I used above (probably more recent).

However, I think the figures are enough to show that increasing the target per person per day water usage (which is presumably what Opposition water spokesperson Louise Asher would do because she feels it’s “demonstrably unfair” to force people to choose between showering and watering their garden) would have a profound effect on Melbourne’s water supply. To increase the target per person per day water usage would be irresponsible especially given the much lower than average rainfall and stream flow into Melbourne’s reservoirs and catchments.