I've come across a few climate articles reporting warm temperatures and high sea levels just few millennia ago. A long time to us, just a blink of the eye in the geologic timeframe. The most interesting reports come from the Swiss Alps, but reports from Greenland and Peru suggest that the glacial retreat was worldwide.

A common theme of these articles is to report how anomalous our current temperatures are compared to the past. (Warmest in 7,000 years! Disaster is near!) Surprisingly absent is speculation that there may be more botanical and archaeological remains to be found should glaciers retreat further. The report on glacial wood does point that out. It would be refreshing to read an article looking why it was so warm then. I haven't gone looking for any, I'm sure I'll find one soon enough.

• 2008 Oct 20: Less ice in the Arctic Ocean 6000-7000 years ago
  "Recent mapping of a number of raised beach ridges on the north coast of Greenland suggests that the ice cover in the Arctic Ocean was greatly reduced some 6000-7000 years ago. The Arctic Ocean may have been periodically ice free."

  This includes a ruined settlement left by the Independence I Culture in North Greenland abandoned at least 4,000 years ago.

• 2008 Dec 5: Shrinking Glaciers Reveal Hidden Forests And A Warmer Climate
  Uniquely old tree remains have recently been uncovered by the thawing of the rapidly shrinking Kårsa Glacier west of Abisko in Lapland, in northernmost Sweden. The finds show that in the last 7,000 years it has probably never been so warm as during the last century. "If the area hadn't been covered by a glacier all these thousands of years, these tree remnants would never have made it. The finds yield information indicating that the 20th century was probably the warmest century in 7,000 years. The fact that the climate is so unique during the last century means that we must question whether this could be 100 percent the result of natural mechanisms," says Leif Kullman, professor of physical geography, who is directing the project. Pines and birches grew on the site of the glacier during parts of or perhaps the entire period between 11,800 and 7,000 years ago. This is shown by carbon 14 dating of the remains of trees that have now been uncovered. During that period, the glacier did not continuously exist, and the climate was warmer than at any time afterward.

• 2008 Oct 12: Glacier melts are erasing climate record
  "The largest glacial ice cap in the tropics, Quelccaya, lies in Peru. As it's been retreating, it occasionally uncovers surprises that had been buried as the glacier grew. Melting recently uncovered one wetland region that had been buried under ice for more than 5,000 years, revealing some 50 different members of the botanical community that once thrived there."

• 2008: Holocene optimum events inferred from subglacial sediments at Tschierva Glacier, Eastern Swiss Alps
  The lead author of this article is Ulrich Joerin, a scientist studying wood that is being released by the glacier retreat in the Alps. Much of this wood has been transported downhill by the glaciers. This means that there used to be forests in areas that are now glaciated. In this paper he reports "Three periods of glacier recession were detected, which occurred around 9200 cal yr BP, from 7450 to 6650 cal yr BP and from 6200 to 5650 cal yr BP. These periods are called Holocene optimum events (HOE)."

• 2007 Nov 1: Western Canada's Glaciers Hit 7000-Year Low
  "Koch compared the kill dates of the trees in the southern and northern Coast Mountains of British Columbia and those in the mid- and southern Rocky Mountains in Canada to similar records from the Yukon Territory, the European Alps, New Zealand and South America. He also looked at the age of Oetzi, the prehistoric mummified alpine "Iceman" found at Niederjoch Glacier, and similarly well-preserved wood from glaciers and snowfields in Scandinavia.

  The radiocarbon dates seem to be the same around the world, according to Koch. It's important to note that there have been many advances and retreats of these glaciers over the past 7000 years, but no retreats that have pushed them back so far upstream as to expose these trees."

• 2007 Feb: Ice-borne prehistoric finds in the Swiss Alps reflect Holocene glacier fluctuations
  This paper reports on archaeological finds exposed in Switzerland dating as far back as 4,900 years ago. It also reports on object dating back to other more recent glacial retreats.

• 2006: On a bigger scale, a paper in The Holocene, Multicentury glacier fluctuations in the Swiss Alps during the Holocene by Ulrich E. Joerin, Thomas F. Stocker, and Christian Schluechter reports "A comparison with other archives and dated glacier advances suggests 12 major recession periods occurring at 9850- 9600, 9300-8650, 8550-8050, 7700-7550, 7450-6550, 6150-5950, 5700-5500, 5200-4400, 4300-3400, 2800-2700, 2150-1850, 1400-1200 cal. yr BP."

• 2005 Nov 18: Archaeological Finds in Retreating Swiss Glacier
  This is from Climate Audit, one of the more scientifically oriented skeptic blogs. This has earlier references to the paper above and other work.

• 2005 May 23: A New Alpine Melt Theory
  "The Alpine glaciers are shrinking, that much we know. But new research suggests that in the time of the Roman Empire, they were smaller than today. And 7,000 years ago they probably weren't around at all. A group of climatologists have come up with a controversial new theory on how the Alps must have looked over the ages."

  The central figure in this article is Ulrich Joerin, lead author of a 2008 paper above. A similar article is Green Alps instead of perpetual ice about work by Juerin collaborator Christian Schluechter.

• Oetzi, the glacier man
  Oetzi is the hunter found in 1991 when his final resting spot was exposed 5500 years after his death. This site has several pages with some of the most recent work on the body and its accoutrements.

• 2013 Mar 17: Peru: A failed prediction
  Glaciologist Lonnie Thompson, from Ohio State University, has long been sounding the alarm about disappearing glaciers. A 2007 article in Science Daily reported on

  his recent observations that suggest that the entire [Peruvian Qori Kalis] glacier [in the Quelccaya ice cap] may likely be gone within the next five years, providing possibly the clearest evidence so far of global climate change.

  Ancient plant beds have been newly uncovered as the ice retreats. The first were discovered in 2002, more are uncovered each year, and carbon dating indicates that most have been buried for at least 5,000 years.

  (See the 2008 Oct 12 entry above.)

  In late 2012, photos show little change, so perhaps the current retreat is slowing down. At any rate, the glacier "may likely" be there for several more decades.

• 2023 May 12: In one lake deep under Antarctica's ice, microbes feast on ancient carbon
  From the article:

  The lake's bacteria and other microbial inhabitants get by on carbon that seawater left behind thousands of years ago, researchers report in the April AGU Advances. The find adds to existing evidence that, during a period of warming about 6,000 years ago, the ice sheet in West Antarctica was smaller than it is today. That allowed seawater to deposit nutrients in what is now a lake bed buried under hundreds of meters of ice.

  This study is among the first to provide evidence from beneath the ice that the ice sheet was smaller in the not-so-distant past, geologically speaking, before growing back to its modern size, says Greg Balco, a geochemist at the Berkeley Geochronology Center in California.

• 2023 Nov 21: Melting ice reveals dozens of 7,000-year-old artifacts in Canada.
  This shows perishable objects made from things like birch bark and leather with references to artifacts 1,400 to 6,200 years old. From the article:

  "Most of the perishable artifacts were manufactured from wood, including birch bark containers, projectile shafts, and walking staffs," researchers said. Other artifacts were made "using animal remains include a stitched hide boot and carved antler and bone tools."

  The research area is Mount Edziza Provincial Park. Claims that the paper is open source appear wrong, but try Ice Patches and Obsidian Quarries...

Semi off topic links:

I hadn't looked hard, but I hadn't come across an information source for North American glaciers. I found Glacier Mass Balance in a blog entry. The site concentrates on the North America's North Cascades, but has links to mass balance information from wider areas. The data thins out going before 1980, so most of it covers the warming phase of a PDO cycle and no data is included from before 1890 or so. However it is a good source of modern glacier information.

A very good reference site for Swiss glaciers is maintained by the Swiss Federal Institute of Technology - Zurich. Its data goes back to the late 1800s when glacial flow first began to be studied.

Contact Ric Werme or return to his home page.

Last updated 2023 November 21, originally written 2008 December 6.