If Only The Guardian Understood Numbers – Fat Chance


As we know the arts graduates that produce The Guardian don’t understand numbers in the slightest. That’s why we get the tosh from them that we do. An example today being the damage done to human welfare by plastics in the seas. This doesn’t even make sense in the numbers they themselves quote:

Plastic pollution in the world’s oceans costs society billions of dollars every year in damaged and lost resources, research has found. Fisheries, aquaculture, recreational activities and global wellbeing are all negatively affected by plastic pollution, with an estimated 1-5% decline in the benefit humans derive from oceans. The resulting cost in such benefits, known as marine ecosystem value, is up to $2.5bn (£1.9bn) a year, according to a study published this week in Marine Pollution Bulletin. Plastic waste is also believed to cost up to $33,000 per ton in reduced environmental value, the study found. An estimated 8m tons of plastic pollution enter the world’s oceans every year.

Think it through for a moment. If it is $2.5 billion then we’ve not got a problem. This is damage to us all at entirely trivial levels, rounding errors type numbers. The NHS blew four times that number just on trying to get digital medical records. We can therefore all carry on using plastic and dumping it into the ocean.

Or, we can try working through the numbers presented. 8 million tonnes a year, $33,000 a tonne, that’s, umm, $264,000,000,000 or $0.250 trillion. That’s a bit more of a problem. But, you know, trillion, billion, who is bothering to count?

We might even start to think a little about where these vast numbers are coming from. In the original paper:

In light of this evidence, it is considered reasonable to postulate a 1–5% reduction in marine ecosystem service delivery as a result of the stock of marine plastic in the oceans in 2011. Such a conjecture is conservative when compared to the reduction in terrestrial ecosystem services due to anthropogenic disturbances available in the literature, e.g. a 11–28% decline of global terrestrial ecosystem services (by value) arising from land use changes between 1997 and 2011 (Constanza et al., 2014), and a reduction of up to 31% (by value) due to urbanisation in China (Su et al., 2014; Su et al., 2012). On a global scale, it has been estimated that for 2011 marine ecosystem services provided benefits to society approximating $49.7 trillion1 per year (Constanza et al., 2014).

That is:

This 1–5% decline in marine ecosystem service delivery equates to an annual loss of $500–$2500 billion in the value of benefits derived from marine ecosystem services.

The actual damage is up to $2.5 trillion.

Not that this is all that believable. Marine benefits to humanity of $50 trillion a year when the global economy back in that year was about $70 trillion? We probably shouldn’t believe it anyway but it would help if the Guardian knew numbers well enough to get within an order or two of magnitude of the right number, no?