Have you ever heard of the Great Pacific Garbage Patch? If not, here is a little bit of information about it.
Basically it a massive amount of plastic pollution floating around in the Northern Pacific Ocean circulating with the oceanic currents. Apparently it is quite large, between 0.41 & 8.5% of the Pacific Ocean. It is however difficult to gain a true estimation of its size because it isn't visible in satellite imagery as the material is suspended in the upper water column rather than directly on the surface and much of it is plastic particulates rather than entire plastic containers.
Its presence was originally hypothesized in a paper in 1988, but its presence was 'discovered' by a sailor in 1997 who brought its presence to the attention of the scientific community. It is thought that the patch has formed over time through the accumulation of marine (plastic) pollution collected in oceanic currents, with wind-surface currents retaining the pollution within the Pacific region.
If this was a visible feature on our coastlines I'm sure people would have paid attention to the issue more readily before now, but as it is out of sight, I guess it is also a little out of mind. My hope is that the dissemination of such information will bring about changes to people's habits, particularly in relation to consumption of products within plastic containers to start with (as it has to go somewhere once you're finished with the product) or alternatively just dispose of these items more appropriately. Reduce, reuse, recycle!