New Study claiming global temps highest in 4000 years, contradicted by previous studies — Media touted study based on ‘reconstructed data’ from only 73 data sites

By: - Climate DepotMarch 8, 2013 8:44 AM

Global warming activists and media outlets are hyping a new study published in Science that claims the Earth is experiencing unprecedented temperatures. See: New York Times: Global Temperatures Highest in 4,000 Years & Associated Press: HEAT SPIKE UNLIKE ANYTHING IN 11,000 YEARS

But the new media touted study is “based on ‘reconstructed data’ from 73 data sites, pretended to cover space-time of 196 million sq. mi. and 11,300 years

Another way to view the same claims are as follows: Earth Cooler Today Than 28% of the Past 11,300 Years: ‘This is a paper that was bound to cause lurid headlines along lines that Earth is warming faster than at any time during past 11,000 years’

The new study is also counter to a preponderance of existing peer-reviewed studies showing the Medieval Warm Period and the Roman Warming were both as warm or warmer than today without benefit of modern emissions or SUVs.

Penn State Professor Michael Mann has made similar claims of modern temperatures being the warmest, but such “Hockey Stick” temperature claims have been demolished in the scientific literature.

The latest research clearly reveals that the Medieval Warm Period (used to be referred to as the Medieval Climate Optimum) has been verified and was in fact global, not just confined to the Northern Hemisphere. The Center for the Study of Carbon Dioxide and Global Change reported in 2009 that the “Medieval Warm Period was: (1) global in extent, (2) at least as warm as, but likely even warmer than, the Current Warm Period, and (3) of a duration significantly longer than that of the Current Warm Period to date.”

In addition, The Science and Public Policy Institute reported in May 2009: “More than 700 scientists from 400 institutions in 40 countries have contributed peer-reviewed papers providing evidence that the Medieval Warm Period (MWP) was real, global, and warmer than the present. And the numbers grow larger daily.”

Climate Depot has assembled a small sampling of peer-reviewed studies, data and analyses that refute Michael Mann’s Hockey Stick temperature claims of unprecedented 20th century warmth.

See: Medieval Warm Period Round Up of Peer-Reviewed Studies & analyses


A ‘simple visual comparison suggests that their ‘unprecedented’ claim for the 1500 years BP is unlikely to hold up when examined against other reconstructions’ — Analysis of new paper claiming ‘unprecedented’ modern temps: Marcott et al claim of ‘unprecedented’ warming compared to GISP ice core data

NSIDC: Arctic Was Ice Free In The Past — ‘The latest hockey stick shows that current warming is unprecedented. Dr. Walt Meier from NSIDC says something different’ — Dr. Walt Meier in 2008: ‘The current Greenland warming, while not yet quite matching the temperatures of 70 years ago’

Analysis: ‘The new hockey stick shows temperatures 10,000 years ago within 0.1C of the Holocene Maximum. This is nonsensical and impossible’

New 4,000-year temperature reconstruction debunked — ‘Check out the Greenland ice core for the relevant period of time’ — ‘As can be plainly seen, modern warming isn’t even close to the ‘highest’ in past 4,000 years’

Greenland ice core isotope past 4000 yrs


Below are excerpts from an analysis from the website Real Science:

The 1990 IPCC report showed the period 5,000 years ago to be about 1.5C warmer than the present, and it was almost 3C cooler 11,000 years ago

ScreenHunter_399 Mar. 08 00.22

First IPCC report

But that wasn’t going to scare anyone, so the team came up with a new hockey stick, which disappears the end of the ice age.





The next graph overlays the new hockey stick on top of the 1990 IPCC version. Note that they have completely obliterated the entire paleo record. Impressive work.

ScreenHunter_398 Mar. 08 00.16

It is trivial to demonstrate that this new hockey stick is complete, utter crap.

Sea level rose 40 metres from 10,000 to 8,000 years ago, indicating that a huge amount of ice melted – yet the new hockey stick shows no warming during that period. All that excess ice 10,000 years ago would have kept temperatures way down, as was shown in the 1990 IPCC graph. Half of Canada was still covered with ice 10,000 years ago, yet the new hockey stick shows that temperatures had already reached the Holocene Maximum. Impossible and absurd.

Most of the ice sheet was still present 11,000 years ago, yet the new hockey stick shows that temperatures were only 0.2C cooler than 1970. That would have been impossible with all that ice, which would have greatly suppressed temperatures – as was shown in the 1990 IPCC report.




Antarctic ice cores also show that temperatures were about 4C colder 11,000 years ago. The new hockey stick completely missed that, showing temperatures less than 1C cooler at that time.

ScreenHunter_401 Mar. 08 00.49

New Antarctic Ice Core Data

Until the ice sheet melted 6,000 years ago, it would have been impossible to reach the Holocene Maximum – yet the new graph shows the peak temperatures occurring starting 10,000 years ago. Perhaps the authors think that ice wasn’t cold and white at that time?

How does this kind of garbage make it through peer review? They have violated the most basic laws of physics.

End excerpt from Real Science.


Related link:


‘More than 700 scientists from 400 institutions in 40 countries have contributed peer-reviewed papers providing evidence that the Medieval Warm Period was real, global, & warmer than the present’ — Climate Depot’s Medieval Warm Period Round Up of Studies