Degrade

I always find it difficult to justify the Plastic Bag Tax.

No, I should say I find it difficult to justify restricting the use of plastic bags - from the point of view of environment protection, we may actually encourage their usage.

Let's think of it: Why are people against using plastic bags ?

The answer is all too familiar, "Because it is not biodegradable and would therefore do harm to the environment !"

Alas, may I ask, "So, we accept paper bags or wooden box because they are biodegradable ?"

I could see you nod.

"How are papers and wood degrade, and what do they become ?"

Don't pretend you don't know the answers; they are plain obvious. Bacteria did the job, and those cellulose fibers become carbon dioxide.

Greenhouse gas !

(Meticulous earth science specialist would actually point out, depending on the exact species of bacteria and the condition of fermentation, the breakdown of cellulose fibers may be incomplete, resulting in the generation of carbon monoxide, methane, and a few other gaseous compounds that have a greater greenhouse effect than your good old carbon dioxide.)

Of course, you may argue the carbon dioxide could be re-cycled. There is re-uptake by plant for photosynthesis. But, look, the good is done by the plants but not paper bags. If we do not use paper and have the same amount of photosynthesis going around, we could actually reduce the amount of carbon dioxide in the atmosphere.