The world changes a little faster these days. As concentrations of carbon dioxide in the atmosphere tick up year over year, more and more of the sun's heat gets trapped. That heat affects the planet in a variety of ways: raising global average temperatures, melting ice, increasing downpours, lengthening droughts and more. And this global warming is already transforming some of the places humans hold most dear.

The United Nations Educational, Scientific and Cultural Organization keeps a list of what it deems world heritage sites: human-made or natural places of "outstanding universal value," from the Palace of Versailles in France to the Sundarbans mangrove forest in Bangladesh. There are more than 1,000 such places now—and many of them may be changed beyond recognition by global warming.