This is great for an 8 year old, but please consider the facts. For your first paragraph, you wanted to stop producing gasoline cars. This is an good idea but what happens when solar cars become popular? The gasoline cars end up in a landfill, or the furnace. That's a waste of metal, and effort. Also, what happens to the gas stations? They will become bankrupt because no one wants to go there because all the cars are solar powered.
Your second paragraph was also good, but then an over dosage of carbon dioxide will harm the trees. And there isn't a point in doing this because at night the trees will breathe the carbon dioxide back out. And if the trees get harmed, what happens to the paper industry? The paper we use may become frail or even turn black.
Your third paragraph is great though. However, your idea is already in use. Some universities have a program where people plant trees, and some groups have been made to plant trees as well.
Your second paragraph was also good, but then an over dosage of carbon dioxide will harm the trees. And there isn't a point in doing this because at night the trees will breathe the carbon dioxide back out. And if the trees get harmed, what happens to the paper industry? The paper we use may become frail or even turn black.
Your third paragraph is great though. However, your idea is already in use. Some universities have a program where people plant trees, and some groups have been made to plant trees as well.