Is Hot Topic wrong about this too?

In one of their current fluff pieces, commenter scaddenp – a GNS geologist if memory serves me correctly – makes the bold assertion that the Medieval Warm Period was regional, not global:

"That [the] MWP was regional event is well established. For starters look at Antarctic ice core. Excellent time resolution into MWP period, best temperature proxy possible. And yes, you see LIA, MWP type periods – just not at the same time!

(Though I have seen denialist web sites gloss over that by assuming that readers dont know the actual dates for MWP from NH records).

In Air Con I quoted a number of peer reviewed scientific studies suggesting MWP was global in effect. Others have collated similar data:

MWP a regional (not global) phenomenon? Really?

Asia: Evidence for the Existence of the Medieval Warm Period in China. Abstract: "it can be estimated that the annual mean temperature in south Henan Province in the thirteenth century was 0.9–1.0°C higher than at present." http://www.springerlink.com/content/gh98230822m7g01l/

 

Australasia: Evidence for a 'Medieval Warm Period' in a 1,100 year tree-ring reconstruction of summer temperatures in New Zealand. Abstract: "This record is the longest yet produced for New Zealand and shows clear evidence for persistent above-average temperatures within the interval commonly assigned to the MWP." http://www.agu.org/pubs/crossref/2002/2001GL014580.shtml

 

Arctic: Environmental change in eastern Greenland during the last 1300 years – evidence from foraminifera and lithofacies in Nansen Fjord. Abstract: "The evidence suggests that the climate in the region of Nansen Fjord was warmer and more stable than today during a 'Medieval Warm Period'" http://hol.sagepub.com/cgi/content/abstract/6/2/179

 

South Africa: Using thermal and hydrological demand for crops crown by the first agropastoralists, Huffman (1996) constructed a climate history of the region based on evidence acquired from various Iron Age settlements. Relic evidence of the presence of cultivated sorghum and millets proved that the climate of the subcontinent-wide region must have been warmer and wetter than it is today from approximately AD 900-1300 – indeed these crops cannot be grown in that part of southern Africa under current climatic conditions, which are far too cool and dry. Support for this result came from Tyson et. al. (2000), who obtained a quasi-decadal record of oxygen and carbon-stable isotope data from a well-dated stalagmite of Cold Air Cave in the Makapansgat Valley (30 km southwest of Pietersburg, South Africa). See also Holmgren et. al. (2001 & 2003) also Lamb et. al. (2003).

N America: Arseneault and Payette (1997) analysed tree ring and growth-form series in Quebec to produce a climate record for this region between 690 and 1591 AD – revealing a MWP. The scientists concluded that the Medieval Warm Period there was approximately 1°C warmer than the 20th century. Same continent but over a bit, Calkin et al. (2001) assessed 'the most current and comprehensive research of Holocene glaciation' along the Gulf of Alaska between the Kenai Peninsula and Yakutat Bay, where they detected a Medieval Warm Period that lasted for "at least a few centuries prior to A.D. 1200."

South America: Cioccale, M.A., Climatic fluctuations in the Central Region of Argentina in the last 1000 years. Quaternary International 62: 35-47 (1999) and Jenny, B., Valero-Garces, B.L., Urrutia, R., Kelts, K., Veit, H., Appleby, P.G. and Geyh M. 2002. Moisture changes and fluctuations of the Westerlies in Mediterranean Central Chile during the last 2000 years: The Laguna Aculeo record, Quaternary International 87: 3-18 (2002) the latter being a fine example of archaeolimnology

Europe: MWP evidence for MWP in Russia from Hiller et al. (2001), Norway from Hiller et al. (2001), Scotland from Brooks and Birks (2001), Switzerland from Filippi et al. (1999), Germany from Niggemann et al. (2003) and

Antarctic: an ice core from the eastern Bransfield Basin, Antarctic Peninsula, clearly identifies the Medieval Warm Period.

SST (Sea Surface Temperature): Keigwin (1996)

I devoted a substantial chunk of Air Con to this, and here's just a snippet to blow ScaddenP back under his rock:

In Antarctica, the poster child for global warming believers, sediment samples from the Antarctic Peninsula reveal the MWP temperature was substantially higher than the current warm period, even allowing for recent warm spells there.103

Not content with ice core samples, American Antarctic researchers went looking for the remains of old seal breeding sites and radiocarbon dated the remains they found. What they discovered was that elephant seal breeding colonies were well south (further inland) from their current locations because the Medieval Warm Period had substantially retreated the ice sheets inland.

This extended "summer of seals" began around 600 BC and ended at 1400 AD, "broadly contemporaneous with the onset of Little Ice Age climatic conditions in the Northern Hemisphere and with glacier advance near [Victoria Land's] Terra Nova Bay."104 Their study indicated "warmer-than-present climate conditions" over a long period of time, and they said that "if, as proposed in the literature, the [Ross] ice shelf survived this period, it would have been exposed to environments substantially warmer than present."105

I'm sure you're starting to get the picture. Synopses of these and many other studies can be found on the website CO2Science,106 and they make interesting reading in light of the claims that appear to dominate the news media.

The numbers are, of course, footnote references. So if the MWP was a minor regional event confined to Europe, why is there evidence of it all over the world at time frames broadly contemporaneous? And do you still believe young Scadden?

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