The Lorax

If you are looking for a good gift idea for a kid, think about the Lorax by Dr. Seuss. It talked about the environment, in a language that kids could understand, before it was cool and has had a resurgence in popularity:

Published in 1971, at a time when Earth Day and the ecology movement were gaining counterculture traction, "The Lorax" addressed then-unconventional issues such as deforestation, pollution and greed. It was "An Inconvenient Truth" for children ...

Plus, it's a book that's been in print for awhile and you should be able to pick it up used.

Just a few lines from the book:

Way back in the days when the grass was still green
and the pond was still wet
and the clouds were still clean ...

BUT...
business is business
And business must grow
regardless of crummies in tummies, you know.

I meant no harm.
I most truly did not.
But I had to grow bigger. So bigger I got.

I biggered my factory. I biggered my roads.
I biggered my wagons.
I biggered the loads of the Theends I shipped out ...

You're in charge of the last of the Truffula Seeds.
And Truffula Trees are what everyone needs.
Plant a new Truffula. Treat it with care.
Give it clean water. And feed it fresh air.
Grow a forest. Protect it from axes that hack.
Then the Lorax and all of his friends may come back."

All of the text of the book can be found here.