First, there is no giant carpet of items making its way across the ocean. Immediately after the disaster, there were large rafts of debris — roofs and lumber and upturned boats clustered together — but these rapidly broke up. . .

How much debris is still out there? Headlines about the “staggering mess” reported that 20 million tons of flotsam — a “garbage wave” — could wash up on Hawaii’s beaches. Other reports claimed 100 million tons of tsunami debris is on its way to the West Coast.

These numbers are vastly inflated. The Japanese government estimates that nearly 5 million tons of debris washed into the ocean during the tsunami. About 70% of that sank, according to NOAA. That left 1.5 million tons of floating items such as buoys, oil drums, lumber and boats. More than a year later, some of that debris has sunk or degraded.

It’s clear that the vast amount of debris generated by the Japanese tsunami is just a small fraction of the human detritus that already fouls the oceans. Our seas already hold more trash than would be produced by dozens, if not hundreds, of tsunamis. And more is added each day.