Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.


Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe

Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...

New? Register here
Forgot your password?

Latest Posts


Fact Brief - Was the Medieval Warm Period a global event?

Posted on 22 June 2024 by John Mason

FactBriefSkeptical Science is partnering with Gigafact to produce fact briefs — bite-sized fact checks of trending claims. This fact brief was written by John Mason in collaboration with members from the Gigafact team. You can submit claims you think need checking via the tipline.

Was the Medieval Warm Period a global event?

noThe Medieval Warm Period was regional, not global.

Between 950-1250 AD, temperatures as warm as those in the mid-20th century were isolated to parts of the Northern Hemisphere. Most of the planet was relatively cool.

The regional nature of the warming indicates that internal variability — how and where energy is moved about within the system — was the main cause. In addition, this was one of the quietest periods of the past 2000 years for volcanic eruptions. Fewer eruptions meant fewer sun-reflecting particles in the air.

The Medieval Warm Period’s warming was also short-lived. The Little Ice Age started soon after and continued until the Industrial Revolution, when our fossil fuel burning intensified.

All of Earth’s regions are now warming, and average global surface temperatures are about 1°C higher than during the Medieval Warm Period.

Current global warming will continue as long as humans keep emitting heat-trapping gases into the atmosphere.

Go to full rebuttal on Skeptical Science or to the fact brief on Gigafact

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


Science Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly (Sience)

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

Nature No evidence for globally coherent warm and cold periods over the preindustrial Common Era

Sage Journal The medieval quiet period.

University of Queensland - Medieval warm period

About fact briefs published on Gigafact

Fact briefs are short, credibly sourced summaries that offer “yes/no” answers in response to claims found online. They rely on publicly available, often primary source data and documents. Fact briefs are created by contributors to Gigafact — a nonprofit project looking to expand participation in fact-checking and protect the democratic process. See all of our published fact briefs here.

Gigafact Tipline

0 0

Printable Version  |  Link to this page


There have been no comments posted yet.

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

The Consensus Project Website


(free to republish)

© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us