This year, I served on the judging panel for The Royal Statistical Society's (RSS) International Statistic of the Year.

This week, we announced the winner: 90.5 per cent, the amount of plastic that has never been recycled.

Why is that such a big deal?

Much like the Oxford English Dictionary's "Word of the Year" competition, the international statistic is meant to capture the zeitgeist of this year.


The judging panel accepted nominations from the statistical community and the public at large for a statistic that would shine a light on today's most pressing issues.

Last year's winner was 69, the annual number of Americans killed, on average, by lawn mowers — compared to two killed annually, on average, by immigrant jihadist terrorists and 11,737 killed annually by being shot by another American. That figure, first shared in The Huffington Post, was highlighted in a viral tweet by Kim Kardashian in response to the proposed migrant ban.

This year's statistic came into prominence from a United Nations report.

The chair of the judges and RSS president, Sir David Spiegelhalter, said: "It's really concerning that so little plastic has ever been recycled and, as a result, so much plastic waste has leached out into the world's environment. It's a great, growing and genuinely world problem."

Let's take a closer look at this year's winning statistic.

About 90.5 per cent of the 6.3 billion metric tonnes of plastic waste produced since mass production began about 60 years ago is now lying around our planet in landfills and oceans or has been incinerated. If we don't change our ways, by 2050, there will be about 12 billion metric tonnes of plastic waste.

When the panel first looked at this statistic, I didn't grasp what billions of tonnes of plastic meant. Based on a study from 2015 and some back-of-the-envelope calculations, that's the equivalent of 7.2 trillion grocery bags full of plastic as of 2018.

But again, I still didn't quite have a feel for how much that actually is. People tend to use distance measurements to compare numbers, so I tried that.


Assuming a grocery bag of plastic is about a foot high, if you stacked the grocery bags, you could go to the moon and back 5790 times. That started to feel a bit more real.

In fact, if you could monetise all of the plastic trash clogging up our environment — including the 12 per cent that is incinerated — you could buy some of the world's biggest businesses.

Assuming it costs US3.25c to produce a plastic bottle, we can estimate a grocery bag contains about US$1 ($1.46) of plastic material production. (I took one bag and filled it with 31 bottles.) So 7.2 trillion grocery bags is equivalent to US$7.2 trillion.

What can you buy with that? Apple, Amazon, Google, Microsoft, Walmart, Exxon, GM, AT&T, Facebook, Bank of America, Visa, Intel, Home Depot, HSBC, Boeing, Citigroup, Anheuser-Busch, all the NFL teams, MLB teams and Premier League football teams.

In other words, if someone could recycle all the unrecycled plastic, he or she would be the richest person on the planet.

A difficult aspect of statistics is putting numbers into a context we can wrap our heads around into a format that means something to us. All I can say is this speaks to me. It's time to clean up our act.


Liberty Vittert is a visiting assistant professor in statistics at Washington University in St Louis.

- The Conversation