There’s Rage-Inducing New Data On The Amount Of Plastic In The Ocean

Plastic pollution in the ocean frequently appears as seabird guts filled with cigarette lighters and bottle caps, marine mammals entangled in fishing gear and drifting plastic bags mimicking a gelatinous meal. Last year, a study estimated that around eight million metric tons of our plastic waste enter the oceans from land each year.

But where this plastic ends up and what form it takes is a mystery. Most of our waste consists of everyday items such as bottles, wrappers, straws or bags. Yet the vast majority of debris found floating far offshore is much smaller: it’s broken-down fragments smaller than your pinky fingernail, termed microplastic.

In a newly published study, we showed that this floating microplastic accounts for only about 1% of the plastic waste entering the ocean from land in a single year. To get this number – estimated to be between 93,000 and 236,000 metric tons – we used all available measurements of floating microplastic together with three different numerical ocean circulation models.

Getting a bead on microplastics

Our new estimate of floating microplastic is up to 37 times higher than previous estimates. That’s equivalent to the mass of more than 1,300 blue whales.

The increased estimate is due in part to the larger data set – we assembled more than 11,000 measurements of microplastics collected in plankton nets since the 1970s. In addition, the data were standardized to account for differences in sampling conditions.

For example, it has been shown that trawls carried out during strong winds tend to capture fewer floating microplastics than during calm conditions. That’s because winds blowing on the sea surface create turbulence that pushes plastics down to tens of meters depth, out of reach of surface-trawling nets. Our statistical model takes such differences into account.

The broad range in our estimates (93 to —> Read More