"Every little piece of plastic manufactured in the past 50 years that made it into the ocean is still out there somewhere,"

The Great Pacific Garbage Patch

An article about the giant soup of plastics floating in the Pacific. Apart from the intrinsic value of being informed about environmental problems, I am sure that, in one form or another, a question on this matter will  arise in the CAE exam. I am going to look for other environmentally based articles to give you ideas and vocabulary etc. Meanwhile read this article and the following article linked here.  They are both pretty easy to read and the second one is especially informative.
Below are some useful phrases for the first article:

growing at an alarming rate
debris / a vast expanse of debris:  detrito oceanic
flotsam: restos flotantes
a build up of plastics in the seas: a growth of plastics...
leash: una correa
to barf: American English to vomit.
to cut back on: a good phrasal verb meaning to reduce the amount of something.

Not all garbage ends up at the dump. A river, sewer or beach can't catch everything the rain washes away, either. In fact, Earth's largest landfill isn't on land at all.

"We need to turn off the taps at the source. We need to educate people on the proper disposal of things that do not break up, like plastics," she says. "Opportunities for recycling have to increase, but, you know, some people buy three bottles of water a day. As a society, we have to get better at reusing what we buy."

Useful phrases for the second article:
The second article is written in more of a chatty style to attract attention. It is very informative.  Read it carefully.

The floating junk yard sloshed into the public spotlight / slosh: the slap or splash of liquid
thanks to growing media coverage
despite the oft-cited claim that: despite the fact that it is often claimed that..
This is an example of using a noun phrase instead of a verb phrase, which I believe is valued in CAE writing.  It makes it sound more advanced.
ghost fishing: abandoned nets that float around and catch animals on their own
to entangle: enredardse
to mistake something for something or somebody for somebody else: confundir algo con algo
swallow plastic bags mistaking them for jelly fish
plentiful : abundante
wreak havoc: causar estragos
an increasingly evident link between plastic trash on land and plastic trash at sea