23 -- Medieval Warm Period -- fact vs. fiction
Channel: potholer54
Date: 2012-07-28

This video looks at the scientific research to answer three basic questions: 1) Was the Medieval Warm Period global? 2) Was it warmer than today? 3) And what does this all mean anyway? I examine the internet feud over the hockey stick and the various myths and misinterpretations about the Medieval Warm Period that seem to be rife on the Internet. My sources for the myths are blogs and videos; my sources for the facts are scientific papers. 

CORRECTION AT 5:51: The graph without recent temperatures is not the work of a blogger after all, it comes from the researchers themselves. This does not change the fact that this graph was used by the Daily Mail to incorrectly infer that the MWP was warmer than today, while the graph the researchers used to show recent temperatures was not shown.

It is worth noting that a recent study could not find any evidence that the Medieval Warm Period was global ("No evidence for globally coherent warm and cold periods over the preindustrial Common Era" -- Nature, July 2019.)

I am informed that 'Ljungqvist' is pronounced as "Jungqvist"

SOURCES

0:45 Christopher Monckton interview with Michael Coren

01:23 -- co2science.org/data/mwp/regions/northamerica.php
and 
http://scienceandpublicpolicy.org/ima...


02:18  Ibid

02:42 "Global-scale temperature patterns and climate forcing over the past six centuries" -- ----- Mann Bradley and Hughes, Nature 1998

02:50 "Northern Hemisphere Temperatures During the Past
Millennium: Inferences, Uncertainties, and Limitations" Mann Bradley and Hughes, American Geophysical Union. 1999

03:03 "Hockey sticks, principal components, and spurious significance" -- McIntyre and McKitrick, Geophysical Research Letters 2005

03:18  "Surface Temperature Reconstructions for the Last 2,000 years" National Academy of Sciences 

03:41 "Ad Hoc Committee Report on the 'Hockey Stick' Global [sic] Climate Reconstruction" -- Edward Wegman, published in Computational Statistics and Data Analysis 2008

"Climate study gets pulled after charges of plagiarism" http://www.usatoday.com/weather/clima...

04:21 "Proxy-based reconstructions of hemispheric and global surface temperature variations
over the past two millennia" Mann et al, PNAS 2008

05:10 "Orbital Forcing of Tree Ring Data" Esper et al, Nature Climate Change 2012

05:20 Daily Mail story: http://www.dailymail.co.uk/sciencetec...

06:23 "A NEW RECONSTRUCTION OF TEMPERATURE VARIABILITY IN THE EXTRA-TROPICAL NORTHERN HEMISPHERE DURING THE LAST TWO MILLENNIA" Lungqvist, Swedish Society for Anthropology and Geography 2010

07:00 "Catastrophe Denied" by Warren Myer

07:37 "Highly variable Northern Hemisphere temperatures reconstructed from
low- and high-resolution proxy data" -- Moberg, Nature 2005

08:21 "A 2000-YEAR GLOBAL TEMPERATURE RECONSTRUCTION
BASED ON NON-TREERING PROXIES" -- Loehle 2007

08:28 Joannenova.com

08:40 "Correction to: A 2000-YEAR GLOBAL TEMPERATURE
RECONSTRUCTION BASED ON NON-TREE RING PROXIES" Loehle 2008

08:50 Ibid

09:01 http://www.skepticalscience.com/new-r...

09:15 "The Great Global Warming Swindle" -- by Martin Durkin Channel 4

09:26 "Global Warming Sunspots Explained" by David Archibald

09:31 "Catastrophe Denied" by Warren Myer

09:35 "The Truth About Global Warming" by David Icke

09:48 IPCC report, Chapter 7, 1990
10:10 McIntyre

10:19 "High-resolution palaeoclimatology of the last millennium: a review of current
status and future prospects" Jones et al, The Holocene, 2009

11:40  Global Warming (or is it Global Cooling)' http://rogerfromnewzealand.wordpress....

14:59 Joannenova.com

17:24 "Unstoppable Solar Cycles"
http://www.youtube.com/watch?v=Cl4Pz1...


19:10 "Extra-tropical Northern Hemisphere land temperature variability over the past 1000 years" Cook et al., Quaternary Science Reviews 2004

19:24 "Long-Term Aridity Changes in the Western United States" -- Cook et al, Science 2004 
See also: "Drought Reconstructions for the Continental United States" -- Cook et al, Journal of Climate 2004

19:27  "The 'Mediaeval Warm Period' drought recorded in Lake Huguangyan, tropical
South China" -- Chu et al, The Holocene 2002

19:29 "Amazonia suffered immense drought between 700-800 AD and 1000-1100 AD"  (Fire, Climate Change and Biodiversity in Amazonia: a Late Holocene Perspective. M. Bush. Phil. Trans. Royal Society. 2008. Archaeological Evidence for the Impact of Mega-Nino Events on Amazonia during the past two Millennia. B. Meggers. Smithsonian. 1994.)

19:33 http://www.newscientist.com/movie/usmap

19:45 "Drought Under Global Warming: a review" -- Aiguo Dai, Wiley Interdisciplinary Reviews: Climate Change 2011
https://www2.ucar.edu/atmosnews/news/...