• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer

RealClimate

Climate science from climate scientists...

  • Start here
  • Model-Observation Comparisons
  • Miscellaneous Climate Graphics
  • Surface temperature graphics
You are here: Home / Extras / Glossary / Hockey Stick

Hockey Stick

28 Nov 2004 by group

Instrumental data describing large-scale surface temperature changes are only available for roughly the past 150 years. Estimates of surface temperature changes further back in time must therefore make use of the few long available instrumental records and natural archives or ‘climate proxy’ indicators, such as tree rings, corals, ice cores and lake sediments, and historical documents, to reconstruct patterns of past surface temperature change. Due to the paucity of data in the Southern Hemisphere, recent studies have emphasized the reconstruction of Northern Hemisphere (NH) mean, rather than global mean temperatures over roughly the past 1000 years.

The term “Hockey Stick” was coined by the former head of NOAA’s Geophysical Fluid Dynamics Laboratory, Jerry Mahlman, to describe the pattern common to numerous proxy and model-based estimates of Northern Hemisphere mean temperature changes over the past millennium. This pattern includes a long-term cooling trend from the so-called “Medieval Warm Period” (broadly speaking, the 10th-mid 14th centuries) through the “Little Ice Age” (broadly speaking, the mid 15th-19th centuries), followed by a rapid warming during the 20th century that culminates in anomalous late 20th century warmth (Figure 1). Numerous myths regarding the “hockey stick” can be found on various non-peer reviewed websites and other non-scientific venues.

Filed Under: Glossary

Primary Sidebar

Search

Search for:

Email Notification

get new posts sent to you automatically (free)
Loading

Recent Posts

  • Unforced variations: Jun 2025
  • Predicted Arctic sea ice trends over time
  • The most recent climate status
  • Unforced variations: May 2025
  • Unforced Variations: Apr 2025
  • WMO: Update on 2023/4 Anomalies

Our Books

Book covers
This list of books since 2005 (in reverse chronological order) that we have been involved in, accompanied by the publisher’s official description, and some comments of independent reviewers of the work.
All Books >>

Recent Comments

  • William on Unforced variations: Jun 2025
  • David on Predicted Arctic sea ice trends over time
  • William on Unforced variations: Jun 2025
  • David on Predicted Arctic sea ice trends over time
  • nigelj on Predicted Arctic sea ice trends over time
  • nigelj on Unforced variations: Jun 2025
  • Steven Emmerson on Predicted Arctic sea ice trends over time
  • Tomáš Kalisz on Predicted Arctic sea ice trends over time
  • Kevin McKinney on Unforced variations: Jun 2025
  • Kevin McKinneuy on Unforced variations: Jun 2025
  • Tomáš Kalisz on Unforced variations: Jun 2025
  • Kevin McKinneuy on Unforced variations: Jun 2025
  • Paul Pukite (@whut) on Unforced variations: Jun 2025
  • Piotr on Unforced variations: Jun 2025
  • Barton Paul Levenson on Unforced variations: Jun 2025
  • Barton Paul Levenson on Unforced variations: Jun 2025
  • Barton Paul Levenson on Predicted Arctic sea ice trends over time
  • Pete Best on Unforced variations: Jun 2025
  • Piotr on Predicted Arctic sea ice trends over time
  • Adam Lea on Unforced variations: Jun 2025

Footer

ABOUT

  • About
  • Translations
  • Privacy Policy
  • Contact Page
  • Login

DATA AND GRAPHICS

  • Data Sources
  • Model-Observation Comparisons
  • Surface temperature graphics
  • Miscellaneous Climate Graphics

INDEX

  • Acronym index
  • Index
  • Archives
  • Contributors

Realclimate Stats

1,367 posts

11 pages

243,610 comments

Copyright © 2025 · RealClimate is a commentary site on climate science by working climate scientists for the interested public and journalists.