Rezwan wrote:

CO2 is the tip of the iceberg as regards environmental destruction going on right now … For instance the oceans are rapidly becoming full of tiny bits of plastic, dumped from Chinese factories, which are probably going to destroy marine ecosystems worldwide once they have been whittled small enough.

I don’t understand that. Why would small bits of plastic be a problem? They seem pretty benign. Do they react with anything? Isn’t there a lot of debris in nature? If an animal swallows a bit of plastic, wouldn’t they just poop it out?

I think plastic debris is more of an aesthetic annoyance – people see it, and it reminds them of other people – which we all tend to dislike a bit.

Check out “Life after people“. If people disappear – like the rapture comes or a unique to humans virus – and there’s no one around to maintain things, all our artifacts and impacts will just get swallowed back by nature. Most of this happens in 500 years, and, except for deserts where things don’t rot, by a few thousand years (which is NOTHING in geological time, or even natural history time) there won’t be a trace of us.

And then the sun will rise, and set, over and over, on the natural world, all those critters leading their short, intense, violent lives, escaping predators, competing for resources, eating and being eaten. Until asteroids hit or the sun blows up or whatever.

As chance would have it, the place where I read about the plastic particles was a book called “The World Without Us” !
http://www.worldwithoutus.com/about_book.html
I totally recommend this – it doesn’t say anything hectoring about how to save the environment, but it is terrifically interesting.
Sounds like the History Channel take on things was a lot more optimistic — maybe they sussed some of the things they didn’t mention but didn’t want to go through all the morbid stuff for an American audience?
The first thing he points out if the national grids all switched off, every fission plant would explode.
So yeah, the plastic particles thing: go here

http://www.worldwithoutus.com/excerpt.html

Not as benign as all that …

Thompson’s team realized that slow mechanical action—waves and tides that grind against shorelines, turning rocks into beaches—were now doing the same to plastics. The largest, most conspicuous items bobbing in the surf were slowly getting smaller. At the same time, there was no sign that any of the plastic was biodegrading, even when reduced to tiny fragments.

“We imagined it was being ground down smaller and smaller, into a kind of powder. And we realized that smaller and smaller could lead to bigger and bigger problems.”

He knew the terrible tales of sea otters choking on polyethylene rings from beer six-packs; of swans and gulls strangled by nylon nets and fishing lines; of a green sea turtle in Hawaii dead with a pocket comb, a foot of nylon rope, and a toy truck wheel lodged in its gut. His personal worst was a study on fulmar carcasses washed ashore on North Sea coastlines. Ninety-five percent had plastic in their stomachs—an average of 44 pieces per bird. A proportional amount in a human being would weigh nearly five pounds.

There was no way of knowing if the plastic had killed them, although it was a safe bet that, in many, chunks of indigestible plastic had blocked their intestines. Thompson reasoned that if larger plastic pieces were breaking down into smaller particles, smaller organisms would likely be consuming them. He devised an aquarium experiment, using bottom-feeding lugworms that live on organic sediments, barnacles that filter organic matter suspended in water, and sand fleas that eat beach detritus. In the experiment, plastic particles and fibers were provided in proportionately bite-size quantities. Each creature promptly ingested them.

When the particles lodged in their intestines, the resulting constipation was terminal. If they were small enough, they passed through the invertebrates’ digestive tracts and emerged, seemingly harmlessly, out the other end. Did that mean that plastics were so stable that they weren’t toxic? At what point would they start to naturally break down—and when they did, would they release some fearful chemicals that would endanger organisms sometime far in the future?

Richard Thompson didn’t know. Nobody did, because plastics haven’t been around long enough for us to know how long they’ll last or what happens to them. His team had identified nine different kinds in the sea so far, varieties of acrylic, nylon, polyester, polyethylene, polypropylene, and polyvinyl chloride. All he knew was that soon everything alive would be eating them.

“When they get as small as powder, even zooplankton will swallow them.”