Halfway between Hawaii and California, four ocean currents turn in a slow clockwise loop. Whatever floats into the loop drifts toward its calm centre and stays. This is a map of where that is, how much has piled up, and whose it is.
1.6Mkm²
of open ocean where floating plastic gathers. That is about three times the area of France. Inside it: at least 79,000 tonnes of plastic in 1.8 trillion pieces (Lebreton et al., 2018).
THE NORTH PACIFIC SUBTROPICAL GYRE · The Kuroshio, North Pacific, California and North Equatorial currents carry floating debris around the gyre. The shaded contours show where it concentrates; the darker the orange, the more plastic per km².
01 · Concentration
The patch has no shoreline
There is no island of trash. The patch is a gradient, and its edge is a line scientists chose: the contour where microplastic reaches 1 kg per km².
At sampling stations inside that line, the median was 1.8 kg/km². Outside it, the median was 0.3. Widen the boundary to the 0.1 kg/km² contour and the model puts more than 100,000 tonnes inside.
02 · Size classes
Most of the weight is in big pieces
Almost every piece out there is microplastic. Almost all the weight is not. More than three-quarters of the mass is debris larger than 5 cm.
Mass by size class · tonnes
Share of mass
8%
13%
25% macro
53% megaplastic — mostly nets
Share of pieces
94% microplastic
Microplastics are 8% of the mass but 94% of the 1.8 trillion pieces. Big objects such as nets, crates and buoys make up most of the tonnage, and over time they break down into more microplastic.
03 · Trend, 1970s → 2015
Rising faster inside than around it
Surface net tows inside the patch caught about three times as much microplastic per km² in 2015 as in the 1970s. Waters around the patch rose too, but more slowly.
04 · Counting
A bigger number came from a better count
The 2018 estimate was 4 to 16 times higher than earlier ones. Thirty vessels and two aircraft surveyed the area, which let researchers count the large objects that small surface nets miss.
05 · Origins
Not straws: nets, buoys and crates
Researchers sorted a 573 kg haul of hard plastic collected in 2019. Most of it traces back to fishing fleets, not beaches.
Country of origin · 232 identifiable objects (2019 haul)
46%
of the patch’s total mass is fishing nets.
LEBRETON ET AL. 2018
75–86%
of the floating hard plastic traces to fishing and aquaculture.
LEBRETON ET AL. 2022
1966
is the production date on the oldest object found, a buoy.
LEBRETON ET AL. 2022
What to notice on the map
Why it matters
The loop does the gathering. No one dumps trash at 32°N 145°W. The Kuroshio, North Pacific, California and North Equatorial currents turn clockwise, and floating debris drifts toward the calm centre.
It sits far from any coast. The centre lies about halfway between Honolulu and San Francisco, outside every country’s waters. Nobody is in charge of cleaning it up.
It moves. The study found the centre shifts with the seasons and swings north and south with El Niño and the Pacific Decadal Oscillation. Any outline on a map is a snapshot.
The source is on the water. If nets and fishing gear make up most of the mass, the most direct fix is at sea: gear marking, recovery and retrieval.