Jeffrey Sachs has a great article in Time called A Climate of Change. 

When climate-change skeptics mock the fear about a rise of a "few degrees" in temperature, we should remind them of how it feels to have a 103° fever. A few degrees above normal can mean the difference between life and death, species survival and extinction. And a few actions on our part could make the difference between a healthy planet and one that falls into an environmental tailspin. The time has come for action. The earth's future is in our hands.

  Read the whole article.