Read the paragraph.

Global warming resulting from greenhouse gases is a serious issue that demands immediate action. Throughout the world, we can already see the significant effects of global warming on people and natural habitats.

What would make the best conclusion?

If we do not take action now, our world will undergo drastic changes that will negatively affect our environment for thousands of years.
I’ve seen temperatures rise over my lifetime, and I hate to think of them rising further.
Scientists will lead the way with new evidence, but we all must join together to take effective action against this impending issue.
More and more, our ice caps will melt and our weather will change, and only those of us who are insightful will take a stand.