Arguments
Greenland used to be green
What the science says...
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The Greenland ice sheet is at least 400,000 years old and warming was not global when Europeans settled in Greeland 1,000 years ago |
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Climate Myth...
Greenland was green
“CfA's Sallie Baliunas […] refers to the medieval Viking sagas as examples of unusual warming around 1003 A.D. ‘The Vikings established colonies in Greenland at the beginning of the second millennium, but they died out several hundred years later when the climate turned colder,’ she notes.” (William Cromie)
Greenland is a large area situated east of Canada, between the Arctic and Atlantic oceans. About 80% of the island is covered by the Greenland ice sheet. During the 980s, Scandinavian and Icelandic exporers established two or three settlements on the south-west coast of Greenland. So what were the conditions in Greenland like 1,000 years ago? More precisely, let's explore the three following questions:
- How old is the Greenland ice sheet?
- Is there evidence of global warming at that time?
- What factors cause climate change?
The Greenland ice sheet is at least 400,000 years old
Scientists have estimated that the Greenland ice sheet is between 400,000 and 800,000 years old. This means that the island today is unlikely to have been markedly different when Europeans settled there. However, there is evidence that the settled areas were warmer than today, with large birch woodlands providing both timber and fuel. This warmth coincided with the period known as the Medieval Climatic Anomaly, also known as the Medieval Warm Period, which we will discuss below.
So how did Greenland get its name? According to the Icelandic sagas, Erik the Red named it Greenland in an attempt to lure settlers in search of land and the promise of a better life. However, the age of the ice sheet, which is more than 3 kilometres thick in places and covers 80% of Greenland, proves that the opportunities to establish communities would have been limited to rather small areas.
Warming during the Medieval Climatic Anomaly was not global
During the Medieval Climatic Anomaly, some areas, most notably in the North Atlantic and parts of Europe, were at least as warm as today, if not warmer. However, other areas were colder, and overall evidence suggests that global temperatures during this period were similar to those at the beginning or middle of the 20th century, and colder than today. This period is explored in more depth here.
So not only was Greenland already mostly covered in ice when Europeans settled there, but also the relatively warm conditions during this period were not a global phenomenon. This contrasts with what we are seeing today, where warming is truly global. Figure 1 is a map showing reconstructions of temperature anomalies during the Medieval Warm Period. Blue colours show lower temperatures and warm colours show higher temperatures when compared to the 1961-1990 reference period.
Figure 1 - Reconstructed surface temperature anomalies for the Medieval Warm Period (950-1250) compared to a 1961-1990 reference period. (Source: Mann et al., 2009)
We can compare this with a similar reconstruction looking at surface temperature anomalies for the 1999 to 2008 period. This clearly shows the global nature of recent warming.
Figure 2 - Surface temperature anomaly for period 1999 to 2008, relative to the 1961– 1990 reference period. (Source: NOAA)
Natural versus man-made climate change
Warming can be the result of a number of factors, so that the cause of past climate change is not necessarily implicated in current climate change. For instance, the Medieval Climatic Anomaly was characterised by relatively high solar activity, low volcanic activity and possible changes in ocean circulation patterns. These factors can explain both the scale and pattern of warmth at that time. However, they cannot explain recent warming. More to the point, changes in natural factors would probably have led to cooling in the past few decades. This contrasts with the multiple lines of evidence pointing to the role played by humans in recent warming, as illustrated by the the graph below.
Conclusion
Greenland is unlikely to have been radically different 1,000 years ago since the ice sheet is at least 400,000 years old. So the evidence shows that not only was Greenland not green, the warmth was mainly a regional phenomenon caused by natural factors. Compare this with the unequivocal findings of the scientific community regarding ongoing warming: climate change now is global and in all likelihood driven primarily by human activities.
The key points can be summarised as follows:
- The Greenland ice sheet already covered large sections of Greenland when Europeans established communities there 1,000 years ago
- Warming was not global during the Medieval Climatic Anomaly; average global temperatures were lower than today
- Natural factors behind regional warming in medieval Greenland are probably not responsible for today's global warming
Basic rebuttal written by dana1981
Update July 2015:
Here is a related lecture-video from Denial101x - Making Sense of Climate Science Denial
Last updated on 15 May 2016 by pattimer. View Archives
AB: Radiocarbon dates of emergent organic remains along the western margin of Istorvet ice cap (70.8°N, 22.2°W) indicate a time when the ice cap was smaller than at present. This ice cap, similar to others in east Greenland, exhibits "historic" moraines ~1-2 km in front of the presently retreating ice margins....
Moreover, it indicates warm conditons at this latitude at the time of Norse colonization of Greenland."
The reason I came here is to ask the question where do we look to see where the earth is today on all these reported orbital and processional cycles and where is the earth in these cycles during an ice age?
If it was a propaganda tool they would not have named iceland as such. We still can't locate vineland due to the cooling since the discovery.
Possibly because the places were named by different people, 100 years apart?
Possible but not probable. Vineland was named by the greenlanders of that time, we can't identify it to this day because the climate changed.
"What does The Milankovitch Theory say about future climate change?
Orbital changes occur over thousands of years, and the climate system may also take thousands of years to respond to orbital forcing. Theory suggests that the primary driver of ice ages is the total summer radiation received in northern latitude zones where major ice sheets have formed in the past, near 65 degrees north. Past ice ages correlate well to 65N summer insolation (Imbrie 1982). Astronomical calculations show that 65N summer insolation should increase gradually over the next 25,000 years, and that no 65N summer insolation declines sufficient to cause an ice age are expected in the next 50,000 - 100,000 years ( Hollan 2000, Berger 2002). "
Don't these "scientists" know the difference between an ice age and a glacation? We ARE in an ice age. So I guess they mean it will end in 50K years or will it reach another glacial maximum? - From the people that brought you AGW.
"Unstoppable global warming every 1500 years".
We are currently in another upswing in the solar cycle, which started about 1750, and which will probably rise about another 0.5-1 degree C over the next few hundred years. Current T to the 21st century is entirely in line with this solar cyle trend. C02 is irrelevant to this cycle,it has been traced 600 times over the last 1 million years in ice cores, and is a result of an overlap between the 87 and 210 year solar cycles.
It is well documented, world wide, and climatologists have conveniently forgotten about it (see reference given above).
Greenland was settled by vikings during the last solar warming period, which is also why they travelled so far in general during this time period-the northern world was warm.
Vinland has been found. It's Lanse Aux Meadows on the Northern Peninsula of Newfoundland where Norse settlements were discovered in the 60s.
The mistranslation of Vinland leads many like yourself to think that it means "wine" when in fact, it's a Norse word for "meadow."
Which is where Lanse Aux Meadows gets its name today.
Iceland was named that before they realized that naming something "Ice" land would deter settlers. Greenland was an attempt to correct that.
And, thingadonta, I suggest you check out the argument "it's the sun." Fred Singer is the last person on Earth that you should be listening to when it comes to climate change. He is the same Singer that was also a "expert" when it came to the tobacco industry and proclaimed that second-hand smoke was not harmful to our health.
Guess how that worked out?
You should get your facts from the climate scientists, not those paid by the energy sector to be experts in the field:
http://www.realclimate.org/index.php/archives/2006/11/avery-and-singer-unstoppable-hot-air/
I think you got it straight! What you describe with an example, certainly seems to be the way in which the advocates of AGW work, whether they are scientists loyal to IPCC, or just well-read opinion makers. They pick out the data that support the trend that they want to prove, and ignore the data that do not support it. Then they make impressive-looking graphs, where the proper 'corrections' are always added, so that the desired slope of the curve is achieved.
The uniformity, the flaw-less consensus, and the lack of debate within the group of AGW supporters, all just works together to make me more skeptical. It would be a healthy sign if they sometimes disagreed, if they ever showed doubt, or if they once in a while agreed that a skeptic arguments had some merit.
It seems to me that they make a strong case (but perhaps not completely airtight one?) for the assumption that a warmer Greenland was a local phenomenon. Its not just an empty claim, there are various data to back it up.
I have no idea about what you are hinting at with those Siberian trees, so I can't answer that.
Argus> You have a certain not too favourable impression of AGW supporters. I don't share your point of view, and for instance it is not my "impression" that AGW supposters on this site always agree on everything. However, it is very hard to answer such general claim except by similar but opposite generalizations.
Maybe you could be more precise about who it is that in your opinion ignores data etc., and give some precise references. Then we could examine the situation together.
Argus, I do not believe your description of "AGW supporters" are reasonable, particularly if you include in that group the IPCC, which has staked out a very middle-of-the-road territory, avoiding extreme claims on either side.
For example, from time to time people make claims that climate sensitivity is > 6C per doubling of CO2, but those are generally rejected by mainstream climate scientists. Although the IPCC offers support for a range of 2.0 - 4.5 C, most people seem willing to settle on a probable 3C, in the middle of that range.
As for claims that supporters of AGW "never disagree" ... they generally agree on the big picture, but there is lots of disagreement (sometimes vehement!) over the details.
(Nor would the Vikings have been unfamiliar with the idea of inland glaciers, or thought them remarkable, as both Norway and Iceland have plenty of them.)
There are a lot of theories as to why the Greenland settlements failed. "Climate change" is only one, and in my (non-professional) opinion, at best at minor contributing factor. More likely is that the colonies were just too small to be self-sustaining, so that when regular European trade stopped, they dwindled and failed.
More information on past & present Greenland can be found here: http://www.greenland-guide.gl/
Grayman... Your comments about it being warmer in the past based on Greenland once being green are inaccurate. Please look at the website of Dr Jason Box and you can see what the modern temperature record is for Greenland. I would also highly suggest you read two papers on Greenland:
Miller 2010... Temperature and precipitation history of the Arctic
Alley 2010... History of the Greenland Ice Sheet: paleoclimatic insights
I think you'll find the issue is vastly more complex that Vikings living in Greenland.
original source:
Þat sumar fór Eiríkr at byggja land þat, er hann hafði fundit ok hann kallaði Grænland, því at hann kvað menn þat mjök mundu fýsa þangat, ef landit héti vel.
1880 translation:
In the summer Eirik went to live in the land which he had discovered, and which he called Greenland, "Because," said he, "men will desire much the more to go there if the land has a good name.
http://green-agenda.com/greenland.html
http://mclean.ch/climate/Arctic_1920_40.htm
By the way, I don't seem to hear about volcanic activity in the Arctic & Antarctica areas but you won't hear about that in the mainstream green media. There was an underwater active volcano found in the Sandwich Islands near Antarctica. There was a volcano that went off in Iceland; has any of the data mentioned that? Theres bound to be some volcanic activity going on and thats usually hot. Another thing the Arctic & Antarctica use to be semi tropical. Things change[DB] You already posted on these off-topic issues here. You were responded to immediately afterwards. Please read those responses. If you have any questions on those responses, place those questions there, not here.
Off-topic struck out.
Big deal. It's a load of rubbish. Did you actually read the article above, and pursue scientific studies? Or do you subscribe to the theory that if you read it on the Internet, it must be true?
Example... from your page:
And yet from this page:So the claim that it was so warm that there were vinyards in England, but not today, is specious.
Don't be so gullible.
Use the search box in the upper left hand corner. Type in volcano, read and learn.
All of this stuff has been covered over and over again. It only takes a moment to read and learn, rather than throwing out questions and comments and links that really just help to make other people as confused as you are.
Also note that there is a strict comments policy. Comments are expected to stay on topic. If you have a comment about another topic, find a relevant thread and post your comment there.
Off topic comments will be deleted.
The Saga of Erik the Red - Icelandic Saga Database
1880, English, transl. J. Sephton, from the original 'Eiríks saga rauða'.
Now, afterwards, during the summer, he proceeded to Iceland, and came to Breidafjordr (Broadfirth). This winter he was with Ingolf, at Holmlatr (Island-litter). During the spring, Thorgest and he fought, and Eirik met with defeat. After that they were reconciled. In the summer Eirik went to live in the land which he had discovered, and which he called Greenland, "Because," said he, "men will desire much the more to go there if the land has a good name."
MWP was global. Handwaiving it away and reconstructing a map in an effort to show it was not global isn't evidence. I will grant that, although there is evidence it was global, perhaps that's open to investigation; hence my first adament comment it was global should be rephrased.
Of course, so should all claims it was not global as well...:)