"Mountain Climbers and Global Warming"

Here.

Excerpt:

The Medieval Warm Period around 1000 was warmer than today with wine grapes growing in Greenland and Britain (and Britain also in Roman times). From the late 17 century to the early 19 century, the Little Ice Age afflicted the planet and glaciers grew. We have been warming our way out of this period ever since. As 'greenhouse gases' from industrialization increased in the 1940s through the 1970s, the temperature of the earth dropped so much that new Ice Age warnings were sounded and a notorious Time magazine cover visualized this fear.