FACT BRIEF

Was the Medieval Warm Period as warm as today?

Sunday, April 11, 2021

By Dana Nuccitelli

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Between 950 C.E. and 1250 C.E., temperatures in the North Atlantic were as warm as those in the mid-20th century. However, temperatures in the majority of Earth’s other regions were relatively cooler. The warming was also short-lived: soon after, the Little Ice Age occurred, beginning a downward temperature trend that lasted until the Industrial Revolution.

Once humanity started burning fossil fuels, the Little Ice Age ended and a warming trend began. This time, all of Earth’s regions are warming, and average global temperatures are about 1°C higher than during the Medieval Warm Period.

As long as humans keep emitting CO2, Earth will keep warming. In contrast, the modest Medieval warming naturally ceased in accordance with sun cycles and fluctuations in volcanic activity and ocean cycles.

See a full discussion of this at Skeptical Science

This fact brief is responsive to conversations such as this one.

Sources

Penn State Science: Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly

Nature Consistent multidecadal variability in global temperature reconstructions and simulations over the Common Era

UQx Denial101x Making Sense of Climate Science Denial Medieval warm period

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Skeptical Science is a non-profit science education organization. Our goal is to remove a roadblock to climate action by building public resilience against climate misinformation. We achieve this by publishing debunking of climate myths as well as providing resources for educators, communicators, scientists, and the general public. Skeptical Science was founded and is led by John Cook, a Senior Research Fellow with the Melbourne Centre for Behaviour Change at the University of Melbourne.

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