Do you believe that the medieval warm period is historical fact?

Question

If so, what was it caused by CO2? Why was it not reflected in the hockey stick graph?

How much warming would have had to occur to make Greenland farmable as is suggested by historical records?

Answer 1

Yes it was.  In Greenland there are uncovering settlements in what is now permafrost.

http://www.archaeology.org/online/featur...

The GRIP (Greenland) borehole temperature record is not a proxy, but a direct measure of temperature (Dahl-Jensen et al. 1998). It shows that current warmth is not unusual in the context of the last 2,000 years. A similar result for the last 1,000 years has also been obtained from borehole temperatures in the Ural Mountains, Russia (Demezhko and Shchapov, 2001).

Answer 2

It's certainly being researched and debated in the science community.

One recent paper (based on only 18 points around the globe) concluded it was about as warm as the average from the last 29 years:

"the MWP peak remains 0.07°C above the end of the 20th-century values, though the difference is not significant."

As the author hinself puts it, "It must be emphasized, of course, that this result is based on limited data."

Most scientific sources however conclude that it was not a warm period globally.

(Climate of the Last Millennium, by Raymond S. Bradley, Climate System Research Center, Dept. of Geosciences, University of Massachusetts, Amherst, IPCC Working Group 1 Report, Chapter 6, Figure 6.10 and Box 6.4, pages 467-469, Climate Over Past Millennia, by P.D. Jones and M.E. Mann, Medieval Warm Period and the Little Ice Age Myths)

I believe the hockey stick graph was based on global data, so it would not show regional anomalies if it was produced before the recent data set was developed.  

One theory that seems credible for why a regional warming might have occured is that ocean currents shifted temporarily to temporarily warm the climate of Europe.  We see that sort of thing happen periodically with the Arctic Oscillation.

Although some people seem to be lulled into a false sense of security by the PR slogan "the climate has changed naturally in the past", that temperatures can and do swing regionally due to currents indicates nothing about the capacity or tendency of carbon-based gases to change climate.  The evidence of past global climate change associated with CO2 increases, and the global consequences of that change (The Permian Triassic Extinction for example) confirms that we can't take the risk lightly.

"THOSE who deny our role in climate change claim that the existence of a medieval warm period 1000 years ago somehow undermines concerns about global warming. It puts them in perspective, for sure, but far from belittling them, it exposes humanity's vulnerability to the planetary thermostat, says Brian Fagan. The northern hemisphere warmed by about 1 °C - enough to nurture bumper harvests in Europe. That rise also brought mega-droughts to North America, and the collapse of both the Tang dynasty in China and the Mayan civilisation in central America."

http://www.newscientist.com/channel/opin...

One thing that no scientist is claiming is that the Medieval Warm Period was 6 degrees Celsius warmer than today, so what would its presence, or whether or not CO2 was involved, demonstrate?  Nothing.  

Whatever side of the MWP debate you choose to believe, it does not indicate that CO2 has stopped being a greenhouse gas, nor does its tiny rise in temperatures to today's levels show that humans can survive the changes that we're setting in motion due to the magnitude of the forecasted warming.

It's fascinating however to note that even illogical arguments can gain traction among people grasping for something reasonable-sounding to cling to to base their denial on, no matter how shallow the support and how faulty the reasoning is.

Answer 3

It was proved that even random data would cause the hockey stick graph.  This data was so flawed it had to be thrown out.

Only those who can't let go of the global warming myth still have faith in the hockey stick.

Answer 4

Yes it is fact.  In the tenth century Iceland was very prosperous and there was extensive farming in Greenland.  The remnants of these farms have been uncovered by archaeologists looking at areas uncovered by glaciers that are now receding.

There are at least two warm periods in recorded history, the Roman Warming approximately 2,000 years ago and the Medieval Warming that started c.900AD.  Both eras were characterized by increased crop yields, calmer weather and an improved standard of living.  By contrast, the Dark Ages (approximately 400AD to 900AD) were known for famine, disease and violent weather, and the same is also true of the Little Ice Age that ended 150 years ago.

As for the infamous "hockey stick" graph, that was exposed as a fraud a few years ago.  A couple of University of Toronto researchers took the software used to produce it, fed random numbers into it and got the same graph every time.

Answer 5

MABYE

Answer 6

Maybe a slight tilt in earth axis 5 degree tilt

Answer 7

I have never heard anyone deny the medieval warm period, no matter what their opinion is on global warming.

Answer 8

Yes it is a historical fact.

It was not caused by human CO2 emissions.

The hockey stick graph was designed to be misleading because it was trying to show a correlation between CO2 and warming when upon close scrutiny it shows no such thing.

It would have had to be much warmer than it is today to allow for farming in Greenland ( interesting name for a place covered by ice )

The AGW fruits will not let facts that do not support their agenda for control over our lives see the light of day if they can help it.

They have to rely on the gullible, the uninformed, emotional retoric or the politically motivated to support their master plan and they will use any strategy at their disposal to cloud the real data to achieve the goals of the AGW agenda.

Answer 9

"the MWP peak remains 0.07°C..."

JS, if reconstructed temperatures claiming tenths of a degree accuracy aren't silly enough, I guess we'll now claim hundredths of a degree accuracy.

Answer 10

OF COURSE THEY ARE PROVE (THERE'S A RESEACH IN WORLD SCIENCE MAGAZINE)

Answer 11

there was indeed a warm period in medieval europe, almost as warm as it is now.

it was a local effect, Europe and n America only, it did not affect the southern hemisphere, and the world average if anything was lower in this period.

we are now approaching the world average temperature of the Holocene climactic optimum

    http://www.globalwarmingart.com/wiki/Ima...

eric, did you actually read your link? skraelings, crippling church tithes, the trading ships from norway stopped coming, soil erosion and degradation, loss of vegitation from overgrazing and the smelting of bog iron, ......and then the weather got worse as well. and then;

"One Inuit story, recorded by Niels Egede, a Dane who grew up in Greenland during the eighteenth century when Denmark recolonized the island, lends some credence to the story of European raids. The narrator, whose ancestors had passed down the tale, recounts how three alien ships sailed in from the southwest "to plunder." In the ensuing fray, several of the Norsemen, to whom he refers as Norwegians, were killed. "But after the Norwegians had mastered them," he relates, "two of the ships had to sail away and the third they captured. The next year a whole fleet arrived and fought with the Norwegians, plundering and killing to obtain food. The survivors put out their vessels, loaded with what was left, and sailed away south, leaving some people behind. The next year the pirates came back again, and when we saw them we fled, taking some of the Norwegian women and children with us up the fjord, and left the others in the lurch. When we returned in the autumn hoping to find some people again, we saw to our horror that everything had been carried away, and houses and farms were burned down so that nothing was left."

Answer 12

idk i wouldn't know the answer,... (you must be wondering why I would answer fopr that reason) but there is always a starting point and ESPECIALLY in SCIENCE! there WAS a starting point in co2. historical records could help make predictions and theories and hypothesises (is that a word?) or guesses for the future but that's where it STARTS so they will have to look at their records to find that out =\

Answer 13

It doesn't show on any graph because it's way too small.  The Little Ice Age that followed barely shows.  I'm going by graphs I saw 30 years ago, not the hockey stick.  I don't think it would have to be very big to jibe with the records we have.  People want to make it gigantic, warmer than today, and that's silly.  I think a lot of people actually think the ice cap melted and reformed.  That stuff is not my problem.

Answer 14

it is reflected on the graph,  just that it was a TINY blimp on it.   the fact that that little bump caused such havock then, means houw "hockey stick" is going to SERIOUSLY kick our butts in a couple decades.   be prepared