Glaciers In Antarctica Advanced During Little Ice Age

By Paul Homewood

As we all know, Antarctica is melting, we’re all going to drown and its all your fault.

Well maybe not.

There is a growing body of evidence that the Little Ice Age affected the Antarctic just as much as the rest of the world, and as a result glaciers there expanded. It therefore follows that the retreat of the ice is simply a natural rebound from this.

1) The Little Ice Age on James Ross Island

This study by Carrivick et al has analysed six glaciers on the island and found

all six of the glaciers investigated have undergone significant decreases in glacier extent and elevation since their maximum (when they deposited these moraines).

There are no absolute dates available for the age of these moraines. Dating them is difficult due to the lack of organic matter for radiocarbon dating, and because of the difficulties in cosmogenic nuclide dating of basalt boulders of such a young age. However, the moraines are much younger and fresher than the moraine in Brandy Bay, dated to 4500 years old by radiocarbon dating. These moraines are most likely to date from a Neoglacial readvance 700-1000 years ago, broadly synchronous with the early stages of a Little Ice Age, which has been postulated but undated for James Ross Island and from around the Antarctic Peninsula.

Not only does this offer more evidence that the LIA was worldwide, but that the period before the neoglacial advance, i.e. the MWP was warmer.

http://www.antarcticglaciers.org/glacial-geology/glacial-landforms/the-little-ice-age/

2) Cold conditions in Antarctica during the Little Ice Age — Implications for abrupt climate change mechanisms

Bertler et al found:

The Little Ice Age (LIA) is one of the most prominent climate shifts in the past 5000 yrs. It has been suggested that the LIA might be the most recent of the Dansgaard–Oeschger events, which are better known as abrupt, large scale climate oscillations during the last glacial period. If the case, then according to Broecker (2000a, 2000b) Antarctica should have warmed during the LIA, when the Northern Hemisphere was cold. Here we present new data from the Ross Sea, Antarctica, that indicates surface temperatures were ~ 2 °C colder during the LIA, with colder sea surface temperatures in the Southern Ocean and/or increased sea-ice extent, stronger katabatic winds, and decreased snow accumulation. Whilst we find there was large spatial and temporal variability, overall Antarctica was cooler and stormier during the LIA. Although temperatures have warmed since the termination of the LIA, atmospheric circulation strength has remained at the same, elevated level. We conclude, that the LIA was either caused by alternative forcings, or that the sea-saw mechanism operates differently during warm periods.

http://www.sciencedirect.com/science/article/pii/S0012821X11002925

3) The Little Ice Age in East Antarctica

Li et al, 2009:

Li et al. (2009) conducted chemical analyses of a shallow (82.5-m) ice core they obtained from "a location [76°32.5’S, 77°01.5’E] in the essentially unexplored area of Princess Elizabeth Land, East Antarctica," which they used to construct "a continuous, high-resolution 780-year (AD 1207-1996) glaciochemical record."

Results indicate that "the period of AD 1450-1850 in this record is characterized by sharply reduced snow accumulation rates and decreased concentrations of several chemical species that suffer post-depositional losses linked to very low accumulation rates." In fact, they found that "the average accumulation rate between 1450 and 1810 is nearly 80% lower than the twentieth century average," noting that "such sharply reduced accumulation suggests that the climate conditions in this region during this period of 400 years were colder than the earlier and later periods." And they correctly state that "this period of unusually cold climate conditions in the eastern Indian Ocean sector in East Antarctica coincides with the time frame of the Little Ice Age, which has been found to be a common neoglacial episode in many Northern Hemisphere locations and in a few places in the Southern Hemisphere."

If there was a Little Ice Age in Antarctica that separated the Current Warm Period from something else, that "something else" must have been the Medieval Warm Period, which is thus demonstrated by the study of Li et al. to have occurred in Princess Elizabeth Land, where Roberts et al. (2001) also found evidence for it. In addition, Li et al. report that the Little Ice Age has been demonstrated to have made its presence felt at Antarctica’s Law Dome (Morgan and Van Ommen, 1997), Dronning Maud Land (Karlof et al., 2000), Northern Victoria Land (Stenni et al., 2002), and the Antarctic Peninsula (Fabres et al., 2000; Domack et al., 2001; Shevenell and Kennett, 2002). Hence, the Medieval Warm Period must have preceded the Little Ice Age at these locations as well, reconfirming the global presence of that earlier low-CO 2 high-temperature period that some are reticent to recognize, because of the implications it holds for the non-CO 2 -induced global warming of the 20th century.

http://www.nipccreport.org/articles/2011/sep/20sep2011a5.html

4) The Little Ice Age in West Antarctica

Orsi et al:

Introducing their study, Orsi et al. (2012) write that "the Northern Hemisphere experienced a widespread cooling from about 1400 to 1850 C.E., often referred to as the Little Ice Age (hereafter LIA)," which they describe as "the latest of a series of centennial scale oscillations in the climate," citing Wanner et al. (2011). However, they say "it is still unclear whether the Southern Hemisphere high latitudes had a temperature response synchronous to that of the Northern Hemisphere," noting that "changes in the solar forcing" – which many scientists believe were responsible for driving the sequential climatic progression from Roman Warm Period to Dark Ages Cold Period to Medieval Warm Period to Little Ice Age to Current Warm Period – "would call for hemispheric synchroneity."

Further investigating the subject and working at a 300-meter-deep air-filled hole that had been drilled on the West Antarctic Ice Sheet (WAIS) Divide (79°28’S, 112°05’W) in January 2005, Orsi et al. employed a single thermistor — which had been calibrated at Scripps Institution of Oceanography against a secondary reference standard that led to a relative uncertainty over the range of their measurements of 0.0023°C – to measure vertical profiles of temperature in January of both 2008 and 2009, which allowed them to develop a history of surface temperature at that location over the last thousand years.

The three researchers, all from the Scripps Institution of Oceanography, report that from this exercise they were able to determine that "the WAIS Divide was colder than the last 1000-year average from 1300 to 1800 C.E.," and they say that "the temperature in the time period 1400-1800 C.E." – which meshes well with the chronology of the LIA in the Northern Hemisphere – "was on average 0.52 ± 0.28°C colder than the last 100-year average." As a result, Orsi et al. feel confident in stating that their finding "is consistent with the idea that the LIA was a global event, probably caused by a change in solar and volcanic forcing, and was not simply a seesaw-type redistribution of heat between the hemispheres as would be predicted by some ocean-circulation hypotheses."

As with the Northern Hemisphere, at least part of the warming since the mid 19thC simply reflects a natural rebound from the depths of the Little Ice Age.