We have to clean it up because we have to protect our Earth.
Our Earth is dying because of global warming.
What is global warming?
Climate is changing because people are not being careful with trashing stuff and making the air bad.
Global warming is a change of climate.
Global warming is not only impacting the climate, it also kills a lot of animals. If the temperature of Earth goes up Earth might become desert, or get covered all over with sea water.
But it's just trash! Trash does not make heat.
So do you know why we should clean up the place?
If we leave the trash in nature it will take a really long time to break apart also during that process many other animals will eat it and die. If animals die they will make carbon dioxide which will make the atmosphere weaker, which can cause greenhouse effects. If the greenhouse effect starts, the ice in the North Pole and South Pole will melt, and it will affect the Earth.