Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Twitter Facebook YouTube Mastodon MeWe

RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Was Greenland really green in the past?

What the science says...

Select a level... Basic Intermediate

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

Climate Myth...

Was Greenland really green in the past?

“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)

At a glance

The past 2024 years - i.e. everything AD - are referred to by archaeologists as the Common Era (CE). Decades ago, long before the refinements and data-coverage of modern science, the CE was divided into a series of climate epochs. Among these were the 'Mediaeval Warm Period' (MWP), from around 800-1200 CE and the 'Little Ice-Age', from 1200-1850 CE.

Each of these epochs has the origin of its name in older paleoclimatic evidence from the Northern Hemisphere and particularly Europe. But things have moved on. We now know that unlike modern global warming, the MWP was regional in its nature. A particularly warm region was the Northern Atlantic, including southern Greenland.

Icelandic sagas tell how, in 982 CE, Erik the Red was sentenced to exile from Iceland for three years. He had been involved in an escalated dispute with a neighbour that had culminated in several deaths. With a band of fellow Vikings, he set sail towards Greenland. Erik's party landed and settled near the mouth of Tunulliarfik Fjord, which has the modern Innuit settlement of Narsarsuaq at its head. This part of Greenland is a largely ice-free enclave today, situated in the SW part of the island, some 200 km from its southern tip. Legend tells how Erik came up with the name, 'Greenland', in order to attract further settlers. Apparently the ploy worked.

With hundreds of settlers arriving in the SW of Greenland, a mixed economy developed. It was based on combined pastoral farming, hunting and fishing. Livestock were kept mostly for milk, cheese and butter. Meat instead came mostly from hunting, both locally and in seasonal expeditions further north. These longer forays visited areas in which walrus, narwhal and polar bears were abundant. Hides and ivory became export commodities, allowing maritime trade with the rest of Europe, in return for iron, timber and other essentials.

A few centuries into this colonisation, the regional climate deteriorated. Ice-sheets readvanced. Recent research has also shown that sea-levels rose, too. It may seem counter-intuitive, but when ice sheets grow, nearby coasts often drown. Two things work together to cause this: the larger gravitational pull of all the extra ice on the sea surface and the subsidence of Earth's crust due to the added weight of that ice. One recent study has suggested over 200 square kilometres of coastal land - where the settlers would have had many of their farms - were lost. Geophysics has detected remains of some of the settlements, now beneath the waves.

Progressive sea-level rise, likely in tandem with social and environmental factors such as famines, epidemics and harsher weather, took its toll. The Inuit, who had arrived in around 1200 CE, remained in Greenland through the severe cold of the Little Ice Age but by around 1500 CE, the Vikings had vanished for good. Climate change drove them out.

That's what happened to the Vikings. But regional and global climate change are different things. Regional historic change has little bearing on the global events that are happening right now.

Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!


Further details

Greenland, the large island situated to the east of Canada between the Arctic and Atlantic oceans, is only green in part. About 80% of the island is covered by the Greenland ice sheet, variably from 400,000 to 800,000 years old.

In the year 982 CE, Viking explorers, mostly operating out of Iceland, began to establish settlements along the south-west coast of Greenland. So what were the conditions like back then? There is evidence that the settled areas, at low levels proximal to fjords, were warmer than today. Driftwood and birch woodlands (Gauthier et al. 2010) provided both timber and fuel - at first. This warmth coincided with the period known as the Medieval Warm Epoch (Lamb 1965), also known as the Medieval Climatic Anomaly or the Medieval Warm Period (MWP), which we will discuss below.

According to the Icelandic sagas, Erik the Red gave Greenland its name, in an attempt to lure settlers in search of land and the promise of a better life. This early bit of estate-agency apparently worked. However, the opportunity may not have been as good as it sounded. The size and age of the ice sheet, which is more than 3 kilometres thick in places, dictates that settlements would have been limited to those relatively small areas in the southern part of the island, with proximity to the coast.

Warming during the MWP was not global

During the MWP, some regions, most notably in the North Atlantic and parts of Europe, were at least as warm as today. However, other regions were colder. Overall, the evidence indicates that global temperatures during this period were similar to those at the middle of the 20th century. The MWP is explored in more depth here.

Not only was Greenland mostly covered in ice when Vikings settled there, but also the relatively warm conditions at the time were not a global phenomenon (fig. 1). This strongly contrasts with what we see today, with observed warming that is truly global in nature.

Reconstructed surface temperature anomalies for the Medieval Warm 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 2022. This clearly shows the global nature of recent warming.

Surface temperature anomaly for 2022.

Figure 2 - Surface temperature anomaly for 2022, relative to the 1991-2020 mean. Source: NOAA.

Natural versus man-made climate change

Warming can be the result of a number of factors, so that causes of past climate change are not necessarily implicated in current climate change and vice-versa. For instance, the MWP 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, in the absence of our major carbon cycle perturbation, 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 set out by the graphic in Fig. 3 below.

Graph showing the human fingerprints on global warming

Fig. 3: evidence for anthropogenic global warming - staring us in the face everywhere we look.

What went wrong for the Vikings? Climate change.

Greenland is unlikely to have been radically different just over 1,000 years ago, since much of the ice sheet is at least 400,000 years old. The island was indeed locally green and supported agriculture for a few centuries in localised coastal regions. Nevertheless, around 80% of it would have been just as uninhabitable as it is today. The small area in the SW that was colonised did benefit from the MWP, a strictly regional climate phenomenon.

Ironically, it was climate change that degraded the settlements and had driven the last Vikings out by 1500 CE. The period leading up to this abandonment saw climatic deterioration, as evidenced by highly variable oxygen isotope ratios in local lake sediments (Lasher & Axford 2019). Oxygen isotope ratios are used as a reliable proxy for temperature. This instability marked the cooling into the Little Ice Age and expansion of the southern Greenland ice-sheet. There is evidence that the ice-expansion led to crustal subsidence in the settled area. Gravity-driven sea level rise would also have occurred along proximal coasts (Borreggine et al. 2023). Both phenomena would have caused the loss of good agricultural land. Drowned Viking settlements - or parts thereof - occur in places along the coastline.

The Little Ice Age was also a regional phenomenon. Such regional changes are often examples of internal climate variability, in which existing heat is moved from one part of the climate system to another. That differs from changes in external forcing - such as amounts of Solar irradiance or greenhouse gas levels - that instead change the total amount of heat in the whole system. Nevertheless, as evidenced by what happened to the Vikings, even internal variability can have its impacts.

Last updated on 12 February 2024 by John Mason. View Archives

Printable Version  |  Offline PDF Version  |  Link to this page

Argument Feedback

Please use this form to let us know about suggested updates to this rebuttal.

Comments

Prev  1  2  

Comments 26 to 34 out of 34:

  1. Thank you for posting.

    I agree with the topic, Greenland used to be green. When Greenland has discovered and named by Erik the Red about 1,000 years ago, it will be different from now. If there is no any evidence that show Greenland was green, he would not name this place as Greenland. The DNA is proof that sometime between 450,000 and 800,000 years ago, much of Greenland was especially green and covered in a boreal forest that was home to alder, spruce and pine trees, as well as insects such as butterflies and beetles (From: https://www.livescience.com/7331-ancient-greenland-green.html). And from the map, like Google map or map in Wikipedia we can see that the edge around Greenland is still green. Greenland ice sheets is between 400,000 and 800,000 years old. So, Greenland today will maybe different from the past. Because of the global warming. Global warming not just changing Greenland, but it affects all over the world. One of the main driven of global warming is from human activities. We have to cooperate together, help each other to reduce global warming before it too late. And I also have some questions. As you can see in the map that at the edge of Greenland is green, I want to know why it’s not cover of ice? And is it true that Greenland now is greener than in the past?

  2. randman, your comment doesn't make sense to me. The map comes from a peer-reviewed scientific paper by a team of 9 scientists. Are you accusing the scientists of fraud...? The paper says it used a "diverse multiproxy network" documented in Dataset S1 of the Materials and Methods supplement associated with the paper. That'll be the observations, or in other words, evidence, upon which the map is based.

  3. "Greenland used to be green. When Greenland has discovered and named by Erik the Red about 1,000 years ago, it will be different from now. If there is no any evidence that show Greenland was green, he would not name this place as Greenland"

    The climate was already cold in Greenland at that time. In fact, the climate was so inhospitable that the few survivors of the Viking settlements left rather than die there.

    The Vikings did farm, but they farmed in two settlements in limited coastal fringes, and it was worse-than-subsistence farming (because the farming and building eroded the fragile top-soil). The same sort of farming seems to have been possible for much of the intervening time, therefore the farming cannot be taken as direct evidence of warmer conditions. The Vikings did so well at farming that they died doing it while the local Inuits still thrive today.

    The Viking settlements did not get buried under glaciers (Google Hvalsey Church). One got buried under wind-blown sand. Thus the failure of the settlements cannot be taken as direct evidence of cooler conditions. The portions of Greenland not immediately adjacent to the ocean have been continuously covered in ice sheets for tens of thousands to hundreds of thousands to millions of years.

    If you want further proof and readings about what the Viking settlements failed, read Jared Diamond's "Collapse". Diamond refers to several book-length accounts, but a shorter older account is Magnus Magnusson's "Vikings" (1980).

    Evidence exists of an ice sheet of at least some extent in a Greenland for at least 2.7 million years.

    Further, recent research confirms that the Vikings’ mysterious abandonment of Greenland was not due to climate change.

    And then there's this:

    "the Greenland Norse were "not a civilization stuck in their ways." To NABO archaeologist George Hambrecht of the University of Maryland in College Park, "The new story is that they adapted but they failed anyway.""

    And

    "Despite the signs of crisis at a few Western Settlement sites, those in the Eastern Settlement show no sign of a violent end. Instead, after farmhouses collapsed, remaining settlers scavenged the wood from them, suggesting a slow dwindling of population. The challenge for the average Greenlander to survive drove "a constant emigration" back to Iceland and Europe, Fitzhugh hypothesizes, "which could bring the Eastern [Settlement] to a close peacefully, without starvation or death by Inuit.""

    As for this question of yours:

    "is it true that Greenland now is greener than in the past"

    It is likely true that Greenland is now greener than it has been for some 4,000 years.  Because the warming of the past 100 years (driven by human activities) has erased a natural cooling of some 4,000+ years:

    NH Temperatures

    Legend

    Larger image here.

  4. In the Greenland section of Jared Diamond's book "Collapse", he describes the Norse settlements in Greenland as failing owing to cultural factors rather than climate.

    The rise & spread of Muslim power (in Africa and the Middle East) blocked or impeded the European import of elephant ivory.   Consequently the Norse Greenlanders initially became quite wealthy by harvesting and exporting walrus ivory to Western Europe.  But that trade later altered as "geopolitics" changed. 

    Some aspects of Norse farming methodology were not well suited to Greenland conditions, and there was necessarily a swing to more reliance on wildlife hunting and especially the harvesting of seals.

    The Norse despised the aboriginal Inuit as heathen & uncivilized.  Intermarriage with Inuit and prudent diplomatic relations with Inuit did not happen.  The reverse — there were increasing hostilities with the Inuit, skirmishes and even some pitched battles (casualty numbers small but of course higly significant for such a small population of Norse.   *IIRC*, Diamond equated the Norse warriors lost in the worst battle, as representing the U.S. Army losing 3 million men in a single battle).

    In short, the Norse failed to live with their Inuit neighbours and failed to make full use of the "technology" which had sustained the Inuit in Greenland over thousands of years.   A lesson for us all.

    Even today, the 60,000 Greenlander population is 90% Inuit — though the economy is supported by fishing using modern technology.   And, as in northern Canada, there is a high level of demoralization, suicide & alcoholism — a result of the social climate, not the physical climate.

  5. Daniel Bailey:

    "If you want further proof and readings about what the Viking settlements failed, read Jared Diamond's "Collapse"…"

    ...and Eclectic:

    "In the Greenland section of Jared Diamond's book "Collapse", he describes the Norse settlements in Greenland as failing owing to cultural factors rather than climate.

    The rise & spread of Muslim power (in Africa and the Middle East) blocked or impeded the European import of elephant ivory. Consequently the Norse Greenlanders initially became quite wealthy by harvesting and exporting walrus ivory to Western Europe. But that trade later altered as "geopolitics" changed.

    Some aspects of Norse farming methodology were not well suited to Greenland conditions, and there was necessarily a swing to more reliance on wildlife hunting and especially the harvesting of seals.

    The Norse despised the aboriginal Inuit as heathen & uncivilized. Intermarriage with Inuit and prudent diplomatic relations with Inuit did not happen. The reverse — there were increasing hostilities with the Inuit, skirmishes and even some pitched battles (casualty numbers small but of course higly significant for such a small population of Norse. *IIRC*, Diamond equated the Norse warriors lost in the worst battle, as representing the U.S. Army losing 3 million men in a single battle).

    In short, the Norse failed to live with their Inuit neighbours and failed to make full use of the "technology" which had sustained the Inuit in Greenland over thousands of years. A lesson for us all..."

    Using Daiamond's Collapse is problematic.

    1) Diamond's argument (actually, McGovern's, see "The Fate of Greenland's Vikings", Archaeology) that the Norse should have adopted the toggle harpoon for ring seal hunting ignores that fact that even the Inuit (Eskimos) couldn't make them work for coastal fishing during this time, since the ice wasn't thick enough (see Gad, History of Greenland, Vol. I, p. 166).

    2) Diamond's (and McGovern's) claim that Greenland Norse didn't fish is ridiculous. When asked by a journalist, the archaeologist Jette Arneborg literally laughed (see Brown, The Far Traveler, 153). If Diamond had properly studied the Farm Beneath the Sands study, he would have realized that the reason so few fish bones were found is that they are very fragile, so the archaeologists weren't even looking for them at first. Once they started, despite the inherent difficulty, they found them (Enghoff, 7, 19, 48, 88). They also ignore Greenland Norse fishing gear, and the Norse accounts of fishing.

    3) Diamond claims that the Norse over-forested and -grazed Greenland. Georg Nyegaard studied a Norse farm, and found it had minimal effect (see his talk with Brown in The Far Traveller, 159-160). It certainly wasn't bad enough to drive the Norse to starvation. Even Diamond admits that there is evidence for only one Greenland Norseman who may possibly have starved to death (Collapse, 267), even as he describes the easily found evidence for entire families of the supposedly well adapted Inuit starving to death in their igloos (264, 273). Apparently, the guys who weren't starving to death in droves were supposed to take tips from the guys who were.

  6. Part II...

    4) As for Norse relations with the Inuit, we have the Inuits' recollections (see Rink's Tales and Traditions of the Eskimo). The Inuit themselves paint a mixed picture of relations with the Norse, sometimes friendly, sometimes hostile. It probably varied from tribe to tribe and time to time. They certainly didn't think of the Norse as maladapted. Diamond also mischaracterizes a case of an Inuit, who was found mortally wounded after a raid on a Norse settlement, as the victim of some Mengele-like medical experiment (see Gad).

    As for why the Norse settlement failed, the arrival of the Little Ice Age didn't help, nor did occasional fighting with the Inuit (and possibly the Basque), but there were other factors. The Norwegian government placed high taxes on trade with Greenland, and required visiting traders to buy Greenlandic goods, which hardly helped. The biggest factor was the competition for walrus ivory with elephant ivory during the 14th Century. Greenland simply went bust, like many a boom economy.

  7. JDG @31 ,

    I certainly agree with your last paragraph.  (But not so much your final sentence ~ "boom and bust" sounds like a business sector.  The Greenland Viking saga was closer to "extinction event". )

    From a climate point of view, it was a rather small decline in temperatures from the Medieval Warm Period . . . and it should not have been enough to extinguish the Viking colonies.

    As you have noted, it was a combination of factors (including a failure of appropriate adaptation) which caused the collapse.  I used the word "geopolitical" as an umbrella term for the various events: an increasing southward push by the Inuit; taxational pressure from Copenhagen; increased competition from Russian suppliers of walrus ivory & renewed elephant ivory supplies from Africa.   Including a societal change in Europe ~ there was a gradual fall-off in demand for ivory as a luxury good.

    Like the average plane crash: a number of adverse circumstances came together.  

    The climate Take-Home Message is that the decline of the MWP was too trivial a matter to finish off the Greenland Vikings.

  8. I was just looking around for some discussion around the topic of origin of the name Greenland and it's striking to me that people uncritically use the

     

    "Because," said he, "men will desire much the more to go there if the land has a good name."

     

    as any argument. It's a huge jump to conclusions.

     

    If a company releases a product named "ecofleebus" trying to market it as a very ecological fleebus how can one hop to conclusion that this fleebus has no ecological design aspects to it at all? Quite the opposite - for marketing to work, it has to be very believable. Marketing is more about exagerating, over-selling, etc. and rarely about calling black color white.

     

    Men will desire to go somewhere if it has an appealing name. No duh. Doesn't mean such appealing name is complete lie.

     

    So while it's still a huge guesswork, I think it's far more likely to assume that Greenland was "green enough" to try to "(over-)sell it".

  9. dpc @33,

    The original name for Greenland was Inuit Nunaat meaning 'country of human beings'. So perhaps there was once a burgeoning population living there. Or perhaps such names are poor descriptors which would be why, apparently, "people often say that Iceland and Greenland should switch names since Iceland is green and Greenland is so icy."

  10. Please note: the basic version of this rebuttal has been updated on February 11, 2024 and now includes an "at a glance“ section at the top. To learn more about these updates and how you can help with evaluating their effectiveness, please check out the accompanying blog post @ https://sks.to/at-a-glance

Prev  1  2  

Post a Comment

Political, off-topic or ad hominem comments will be deleted. Comments Policy...

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

Link to this page



The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us