If you like this story, I recommend reading How We Got to Now: Six Innovations That Made the Modern World. Its a quick read and very interesting. And, yes, "cold" is one of the six.
The book is based on a PBS/BBC TV show which is also excellent. It's on the Amazon, Google, and Microsoft video stores, and questionably legal copies are also on YouTube.
With the title "The far-reaching effects of air conditioning" I didn't immediately think "Yup ... that's handy: frozen peas" even though the technology underlying them is the same.
Refrigeration allows you to preserve any kind of food and eat it at any time of year. It allows food to be shipped in to remote locations, which is important.
Air conditioning directly lets people live where they otherwise couldn't; it doesn't seem obvious that refrigeration is larger-impact.