Moore has a history of exaggerating his plastic finds.
His original account:
"as I gazed from the deck at the surface of what ought to have been a pristine ocean, I was confronted, as far as the eye could see, with the sight of plastic.
It seemed unbelievable, but I never found a clear spot. In the week it took to cross the subtropical high, no matter what time of day I looked, plastic debris was floating everywhere: bottles, bottle caps, wrappers, fragments."
As someone who has picked up literally tons of plastic trash off Pacific beaches with my bare hands, let me be the first to say that you have no idea what you are talking about. Charles has consistently been on the forefront of discovery in environmental concerns and has been proven right over and over again, and you want to berate him for exaggerating. He's not exaggerating, he's just ahead of the curve.
Also, please don't conflate estimates with eye witness accounts. If you want to dispute his claims, use data from actual expeditions.
This article is from 2011. If you RTFA above, you'd have noticed that things have gotten significantly worse in just 6 years. What's changed since then? Organized, industrial scale dumping from eastern pacific countries (Indonesia in particular).
Garbage on beaches is by definition not garbage in the "patches." If you are picking up plastic with your bare hands, you're not picking up the microplastics which even Moore now describes as the problem with the garbage patches. At best you can say that plastic chunks you pick up are hopefully not going to end up as microplastic bits in the gyres.
"[for a week] plastic debris was floating everywhere: bottles, bottle caps, wrappers, fragments" -- Moore, 1998(?)
vs.
"It was and is a thin plastic soup, a soup lightly seasoned with plastic flakes, bulked out here and there with “dumplings”: buoys, net clumps, floats, crates, and other “macro debris.”" -- Moore 2011, in the slate article above
And regarding the "plastic soup", every eye witness account I've found except Moore's say it's visually just ocean water, and occasionally you find a chunk of junk. (e.g., https://www.scientificamerican.com/article/sea-unworthy-a-pe...) Another research group cited in the Slate article decided to phrase it as "plastic smog" rather than soup.
When I've found videos or pictures claiming to be from the garbage patch, they're either of garbage-clogged harbors, or of an item or tangle of debris surrounded by clear blue waters, or as you describe, beaches with garbage. Do you have other pictures?
Where Moore has historically over-sensationalized his descriptions, I find I take his sensational descriptions with a grain of salt.
This isn't to say plastic in the oceans isn't a concern, or isn't something we should work really hard to avoid, just that sensational claims, along with sensational estimates need critical examination, rather than simple acceptance.
"Bigger than Mexico!" What does that even mean? An area the size of Mexico has detectable bits of plastic? What's the density threshold that defines the area? And they made this size estimate based on a single traversal? This suggests the size estimate is based more on the area of currents rather than measurement of the particulate density.
If you have better documentation of the area claim or densities than was given or linked from R-ing-TFA above, I'd love to see it. Something more along the lines of that 2011 study you glibly dismiss: https://www.researchgate.net/publication/234157160_Plastic_p...
His original account:
"as I gazed from the deck at the surface of what ought to have been a pristine ocean, I was confronted, as far as the eye could see, with the sight of plastic.
It seemed unbelievable, but I never found a clear spot. In the week it took to cross the subtropical high, no matter what time of day I looked, plastic debris was floating everywhere: bottles, bottle caps, wrappers, fragments."
http://www.naturalhistorymag.com/features/172720/trash-revis...
This contrasts with other estimates of one to two bottle caps worth of plastic per 50 Olympic swimming pools worth of water.
A decade later he backed off those claims, emphasizing the micro particles.
amp.slate.com/articles/health_and_science/the_next_20/2016/09/the_great_pacific_garbage_patch_was_the_myth_we_needed_to_save_our_oceans.html
Other scientists say it is troubling, but exaggerated, and not getting worse in spite of increased production and use of plastic:
http://oregonstate.edu/ua/ncs/archives/2011/jan/oceanic-“gar...