I really need your help. please! Can you tell me what are the mistakes in this paragraph?
Power stations, cars and factories produce carbon dioxide. Trees and plants change it back to oxygen, but we are cutting down trees in the Amazon rainforests, so the amount of carbon dioxide in the air ___*is rising*.___
The carbon dioxide allows radiation from the sun to enter the atmosphere but not to leave it. This __*is causing*__ the atmosphere to heat up.
Scientist think that the polar ice caps and glaciers around the world __*are melting*.__This is creating more water and the level of the sea __*is increasing*.__ In many parts of the world there is a possibility of floods on land near the coast. In general, the world´s climate __*is changing*.__
This means warm areas __*are having*__ colder winters, and previously cold areas __*are getting*__warmer.

Question

I really need your help. please!   Can you tell me what are the mistakes in this paragraph?
Power stations, cars and factories produce carbon dioxide. Trees and plants change it back to oxygen, but we are cutting down trees in the Amazon rainforests, so the amount of carbon dioxide in the air ___*is rising*.___
The carbon dioxide allows radiation from the sun to enter the atmosphere but not to leave it. This __*is causing*__ the atmosphere to heat up.
Scientist think that the polar ice caps and glaciers around the world __*are melting*.__This is creating more water and the level of the sea __*is increasing*.__ In many parts of the world there is a possibility of floods on land near the coast. In general, the world´s climate __*is changing*.__
This means warm areas __*are having*__ colder winters, and previously cold areas __*are getting*__warmer.

Answer

This was really good! Sounds like a native speaker. I don't know why your italki English rating is so low, unless you had a lot of help writing this/someone else wrote it, your English rating should be higher, in my opinion. Maybe speaker/comprehension are harder for you. I don't know, just my input. 
The only tiny little thing I would change is that when referring to sea levels the common word to use is "rise" instead of "increase." Increase makes perfect sense, and it would be okay if you said it, however "rise" is just the word that most common in this context. You will often hear people referring to "rising sea levels."