I'm struggling to write about coffee, the environment, convenience's costs, and simple solutions. Since I've made a mess of it, but want you to know one idea, I'm just saying it here in big blue letters:
Carry a ceramic mug and stop using disposable paper coffee cups.
How difficult is that really?
There's no good reason to ever use a disposable coffee cup. No matter what you want to believe, they're likely not recyclable, so just stop. I'm sure you're smart enough to figure out another way. Get to it.
I'm going back to writing. I've got good coffee in my ceramic mug and eventually I'll clean up the mess I've made. Maybe we all will.