Thanks for

more or less. If you have listened to this week's Radio 4

podcast, then you may have heard both items previously.

Hello and welcome to more or less on the BBC World Service.

We're your weekly guide to the numbers all around us in the news and in life,

and I'm Tim Harford.

It was widely reported recently that by 2050 there'll be more plastic in the oceans than fish.

A remarkable statistic but also a puzzling one. So we're now joined in the studio by our fish correspondent Leo Hornock.

Hello Leo.

Hello Tim, how's things? They're great. Thank you apart from the devastation of our oceans

So how seriously should I take this number where's this number come from? Well the Ellen MacArthur Foundation, the World Economic Forum, produced this report, it's called

the New Plastic Economy, and it's quite scary when you read it.

And the headline figure there was that in 2050 there will be as much or more plastic in the ocean

by tonnage than fish. I imagine it's quite difficult to count how much plastic.

We forget the forecast just right now to figure out how much plastic there is in the ocean

because the ocean is a big place and indeed it's probably even difficult to figure out

how many fish there are in the ocean or what's the way to fish so

have they got about doing that? The original version of the report did a couple of things to look into this question.

They refer back to a study led by an academic called Jenna Jambek, which was published last year and which attempts to do a sort of global census of plastic pollution.

And that study looks at estimates for total waste produced in

all countries that aren't landlocked. And that study only goes up to 2025. And what

the Ella MacArthur Foundation's report has done is taken that work and

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