Medieval Cool Period

The "Medieval Cool Period," roughly from 1250 to 1500 CE, was a climate interval characterized by cooler temperatures in many parts of the world, though not a true ice age. During this time, mountain glaciers advanced in regions like the European Alps and New Zealand. Mean annual temperatures in the Northern Hemisphere dropped by about 0.6 °C (1.1 °F) compared to the 1000–2000 CE average.123

However, these cool periods did not occur simultaneously across all regions. Some areas experienced stable temperatures, while others, like parts of Europe and North America, faced increased dryness and prolonged droughts. The causes are thought to be a combination of factors, including reduced solar activity, volcanic eruptions, and shifts in atmospheric circulation patterns. This period preceded the current warming trend.1234