Australasian Science Magazine

By Peter Bowditch

Number abuse is rife in online forums and even science news websites.

I’ve written before about innumeracy, the inability to use numbers correctly. Recently I’ve been exposed to three cases of number abuse in different contexts. One of these involves people with an agenda using a very large and apparently frightening number that actually means nothing much at all; one is people with a different agenda treating a large number as if it is zero; and one is a scientific publication using a number that is obviously and ridiculously wrong.

Anyone who has spent any time with forums and publications from the anti-medicine or anti-science worlds will know that two of the most evil corporations in the world are Monsanto and Nestlé (if you ignore the pharmaceutical companies), Monsanto because it is trying to own and control the world’s agricultural production by patenting genetically modified plants, and Nestlé because of the harm it does by distributing milk formula in Third World countries.

California is currently in the grip of a severe drought, and as an Australian I am well aware of the threat caused by drought. There is a ghost town in Queensland that used to be the centre of a wool industry with 20 million sheep until a few consecutive years of drought wiped out the flock, the farmers and the town. A recent piece of hysteria in the US has focused on water extracted for bottling by Nestlé, which paid $542 for 27 million gallons of water.

That is a lot of water. To use the media’s standard unit of measurement it is about 36 Olympic swimming pools. It is also about 67.5 seconds of California’s average water consumption. That’s right, if Nestlé stopped extracting water, California’s drought would last for just over a minute less.

I live in a small country town (population about 2000) and the local dam supplying the town’s water can deliver about 190 million US gallons per day for all uses (domestic, agriculture, manufacturing and river quality). In times of flood, the spillway can release about 56,000 million gallons per day without water overtopping the dam wall. So 27 million gallons is not really a lot of water.

The next misuse of numbers is the assumption that the energy used by electric cars comes from nowhere. This seems to be a blind spot for those who think that all pollution from transportation will stop when everyone has a Tesla. (I’m mentioning Tesla specifically because there is almost a religious fervour about this particular car manufacturer. One ignored number related to Tesla is that Holden is closing its manufacturing in Australia because it is not economic to run a factory that produces twice as many cars each year as Tesla.)

The most recent figures say that the combined annual consumption of petrol and diesel in Australia for passenger and light commercial vehicles is 23,519 million litres. (I know people are talking about electric semi-trailers but right now it seems that the weight of batteries needed to tow 40 tonnes from Sydney to Melbourne might leave little over for the actual paying freight, so I’ll leave those out for the time being.)

Putting these numbers through a spreadsheet and mixing in the energy densities of the fuels shows that replacing them with electricity would require an additional 24,000 MW of generating capacity. That would require the building of more than 17 black coal power stations the size of Mount Piper in NSW, which supplies electricity to my town (and most of Sydney), or an additional 11 plants the size of Loy Yang in Victoria (Australia’s largest power station).

But what about wind power? Providing the additional electricity would require 7.5 times the currently installed wind generation capacity. These figures do not take into account losses through transmission or storage.

The short version is that we are a very long way from everyone driving electric cars.

The third abuse of numbers is sadder than the ones above because it comes from a website that purports to provide scientific news to the lay population. It promotes its publications heavily through social media and ran a story recently with the headline: “This giant floating farm could produce almost 10 tonnes of food each year” (http://tinyurl.com/p9ahqag). The subtitle was “Fruits, vegetables and fish!” and the first paragraph teaser said: “Architects in Spain have designed a three-storey floating farm that would help produce nearly 10 tonnes of extra food for Earth’s growing population each year, without taking up any land or fresh water”. You will notice that the figure “10 tonnes” appears twice so it’s not a typo.

Feeding the world’s increasing population is certainly a problem, but to put the “nearly 10 tonnes of extra food” into perspective, Australia currently produces about 24 million tonnes of wheat alone each year. We even make about 340,000 tonnes of powdered milk, and export about 20,000 tonnes of seafood.

Numbers. They mean something and should be used with care.

Peter Bowditch is a former President of Australian Skeptics Inc. (www.skeptics.com.au).