music rec request

Does anyone know of any recent (by that I mean in the last 3 or four years) hit songs with an environmental theme? It has to appeal/hopefully be familiar to Japanese high schoolers but I have absolutely no idea what's been on the charts in the last few years. Cuteness would be a plus too, so singers/musos like Mariah Carey who is well known here, would be an added bonus.

I'd be really grateful for any suggestions ...

*choc chip cookies in advance*