If saving trees isn't enough to get you to stop using plastic bags, the fact that there is a toxic plastic gathering — twice the size of Texas in the Pacific Ocean — should probably do the trick. This isn't just about saving the environment. This is about saving ourselves.
"Plastic Ocean" by Susan Casey (in the February issue of Best Life) tells the story of Capt. Charles Moore, who found this strange no-man's land in August of 1997, and has been studying it ever since. This accumulation of junk is not here by accident, but because of currents. This area is known as the North Pacific Subtropical Gyre, a becalmed area where currents gather.
Not only are there ubiquitous plastic bags, there are also less usual things, such as tires, traffic cones and bath toys. Unless you burn it and release harmful chemicals into the air, plastic stays around. Most of it is not recyclable, and the types that are can only be recycled partially.