Laura Helmuth's article in Slate is linked below.
Slate: The Reasons Behind the Longer Lifespans
"The most important difference between the world today and 150 years ago isn’t airplane flight or nuclear weapons or the Internet. It’s lifespan. We used to live 35 or 40 years on average in the United States, but now we live almost 80. We used to get one life. Now we get two."
---Laura Helmuth, Slate