Every net tow since 1972
Each dot is one sample: a fine net dragged along the surface, with its catch of small plastic weighed. Pick a decade to compare inside and outside the patch. Dots on the bottom row caught nothing.
Loading the tows…
| Decade | Tows inside | Typical inside | Tows outside | Typical outside |
|---|
Studies used different nets and routes, so single dots are noisy. Compare the typical values, and read the 1980s and 1990s loosely: very few tows were taken inside the patch then.
Why it keeps growing
Plastic keeps arriving from rivers, coasts and fishing fleets around the Pacific, and very little leaves. The currents of the North Pacific Gyre hold floating debris in the calm middle for years.
Plastic does not break down there either. Sunlight makes it brittle and waves crack it into smaller and smaller pieces, so a crate that drifted in decades ago becomes thousands of fragments. That is part of why the number of small pieces in the nets has climbed so steeply.
The tows only measure small plastic at the surface, so this chart is a trend, not a total. The patch's overall weight comes from the 2015–2016 survey; see how big it is and how the numbers were made.