The most well-known ocean garbage patch sits in the North Pacific Ocean, roughly halfway between Hawaii and California. Its center hovers around 32°N latitude and 145°W longitude, placing it over a thousand miles from the nearest coastline. But it’s not the only one. Five major garbage patches exist across the world’s oceans, each formed inside a rotating current system called a gyre.
The Great Pacific Garbage Patch
The Great Pacific Garbage Patch occupies a massive stretch of the North Pacific, spanning an area of roughly 1.6 million square kilometers (about 618,000 square miles). That’s roughly twice the size of Texas or three times the size of France. It sits within a zone that extends from about 120°W to 160°W longitude and 20°N to 45°N latitude, though the densest concentration of debris is more centrally located.
The patch doesn’t stay perfectly still. Its center shifts east and west with the seasons, and its north-south position can swing between 26°N and 32°N depending on ocean currents and wind patterns. This movement means the boundaries are always approximate, not fixed lines on a map. A sailor named Charles Moore first stumbled across it in 1997 while sailing from Hawaii to California and noticed plastic debris scattered across the water for days.
What It Actually Looks Like
If you flew over the Great Pacific Garbage Patch, you wouldn’t see it. NOAA confirms the area can’t be spotted from space or even from an aircraft. The term “garbage patch” is misleading because it conjures images of a solid floating island of bottles and tires. In reality, most of the debris consists of tiny plastic fragments spread thinly across an enormous area, often invisible to the naked eye.
The plastic extends from the surface down to the ocean floor, not just across the top of the water. Research in the North Sea found microplastic particles at every depth tested, from surface waters down to the deep ocean, with no clear drop-off in concentration. Surface waters contained a median of 40 particles per cubic meter, while deeper waters held a median of 34 particles per cubic meter. The plastic isn’t concentrated in one layer; it’s distributed throughout the water column.
What’s Floating in It
A 2018 study published in Scientific Reports estimated the patch contains at least 79,000 tonnes of plastic and approximately 1.8 trillion individual pieces. The breakdown is striking: over three-quarters of the total mass comes from debris larger than 5 centimeters, and at least 46% of the weight is abandoned fishing nets (sometimes called ghost nets). These large items dominate by weight but not by count.
Microplastics, pieces smaller than 5 millimeters, account for just 8% of the total mass but make up 94% of the estimated 1.8 trillion pieces. So the patch is mostly tiny fragments by number but mostly large debris by weight. The most common plastic types at all depths are polyester, polypropylene, polyethylene, and polystyrene, the same materials found in clothing fibers, food packaging, and disposable containers. About 94% of the fragments measured between 11 and 300 micrometers, small enough to be swallowed by plankton and small fish.
The Other Four Garbage Patches
The North Pacific gets the most attention, but garbage patches form in all five of the world’s major ocean gyres. These rotating current systems act like slow-moving whirlpools, trapping floating debris that drifts in from coastlines, rivers, and ships.
- North Pacific Gyre: Home to the Great Pacific Garbage Patch between Hawaii and California. The largest and most studied.
- South Pacific Gyre: Located off the west coast of South America, in a remote stretch of the South Pacific. Less studied but confirmed to contain significant plastic concentrations.
- North Atlantic Gyre: Centered in the Sargasso Sea, east of Bermuda. Research there has found plastic-to-plankton ratios as high as one plastic particle per individual organism in surface waters, with ratios climbing dramatically when counting the smallest microplastics.
- South Atlantic Gyre: Positioned between South America and Africa, roughly between Brazil and Angola.
- Indian Ocean Gyre: Sits in the southern Indian Ocean, roughly between Africa, Australia, and Antarctica.
Each of these patches varies in size and density, and none of them are as well-mapped as the North Pacific accumulation zone. All five share the same basic mechanism: circular ocean currents concentrate buoyant debris toward the center of the gyre, where it collects over years and decades.
Why the Plastic Stays There
Ocean gyres are driven by a combination of wind patterns, the Earth’s rotation, and differences in water temperature and salinity. In the North Pacific, four major currents form a clockwise loop: the North Pacific Current to the north, the California Current along the U.S. West Coast, the North Equatorial Current to the south, and the Kuroshio Current along East Asia. Anything that enters this loop and floats gets gradually pushed toward the calm, relatively still center.
Once debris reaches the center of a gyre, there’s very little current to push it back out. Plastic is durable enough to persist for decades, slowly breaking into smaller and smaller fragments under UV light and wave action but never fully disappearing. The patch is also growing. The 2018 estimate of 79,000 tonnes was four to sixteen times higher than previous measurements, suggesting the accumulation rate is increasing rather than stabilizing.
How Plastic Gets to the Middle of the Ocean
Most of the plastic in these patches originates on land. Rain washes litter into storm drains, which flow into rivers, which empty into the ocean. Once in the water, currents carry lightweight plastic hundreds or thousands of miles over months and years. A piece of packaging that enters the Pacific from the coast of Japan or California can reach the center of the gyre within a few years.
A significant portion also comes directly from the fishing industry. With nearly half the Great Pacific Garbage Patch’s mass consisting of fishing nets, lines, and traps, the ocean itself is a major source of its own pollution. These items are lost, abandoned, or discarded during commercial fishing operations and are particularly harmful because they continue to trap marine life long after being lost, a process called ghost fishing.