Not very long back, environmental science was not even a valid subject. There would be some research on it here and there. But the very introduction of environmental science as a subject of school is a grave concern for the environment and humanity in general. It was done so that every school going student realizes the necessity of the environment and the needs for protecting the environment in which they live.
Since the concern is grave, you have every chance of coming out with a very powerful paper on the subject should you choose to do it. You will not be able to write a powerful paper just by reading some good papers on the web. You should also be able to understand the many different concepts available as well.
Unless you are able to come with the right topic for the paper, there are a few things that may not go well for you. Unless you are ready to make the difference between a good and a mediocre topic, you will be able to understand the role of a good topic. So whenever there is a chance, go for some reading. Read about the importance of the topic in academic papers.
Once you realize the importance of selecting the right topic in environmental science papers, you should read through some topics that are both important and contextually viable. Here are some sample topics for you.