We all know how much NSIDC’s Dr. Mark Serreze has been touting the idea of the “Arctic death spiral“, and we’ve had predictions of ice free summers in 2008, 2013, 2015, 2020, 2030, 2040, 2050, 2060, 2070, and 2100 to name a few. Other forecasts don’t give specific dates but say things like within 5 years, 10 years, 20 years, 30 years, 100 years, decades, and sooner than expected. Such “all over the road forecast certainty” doesn’t really build any confidence that any of these climate soothsayers have any idea when or even if the Arctic will be “ice free” in the summer in the next 100 years.
Now, inconveniently, we have this new paper via ScienceDirect New insights on Arctic Quaternary climate variability from palaeo-records and numerical modelling which says that their studies show that the early Holocene might very well have had ice free summers. This is interesting, because as this generally well accepted graph shows, temperature was higher then. But there’s more.
From the description for this graphic: The main figure shows eight records of local temperature variability on multi-centennial scales throughout the course of the Holocene, and an average of these (thick dark line). (to 10000 BC-2000CE (from 0 — 12000 BP)) The records are plotted with respect to the mid 20th century average temperature, and the global average temperature in 2004 is indicated. An inset plot compares the most recent two millennia of the average to other recent reconstructions. At the far right of this plot it is possible to observe the emergence of climate from the last glacial period of the current ice age. During the Holocene itself, there is general scientific agreement that temperatures on the average have been quite stable compared to fluctuations during the preceding glacial period. The above average curve supports this belief. However, there is a slightly warmer period in the middle which might be identified with the proposed Holocene climatic optimum. The magnitude and nature of this warm event is disputed, and it may have been largely limited to high northern latitudes.
But, the other rub of the early Holocene is CO2 in the atmosphere. We know from ice core records that CO2 concentration has varied with ice ages. Coming out of the last ice age into the Holocene, we know that atmospheric CO2 concentrations rose as CO2 came out of the oceans as they warmed. This graph from the American Association for the Advancement of Science (AAAS) shows that the early Holocene (~10,000 years before present), had a rise coming out of the ice age and then had CO2 concentrations stabilize lower than that of today, about 260-270 ppm:
Figure 1. Top: One sigma-calibrated age ranges for the 14C control points 1, 2 and 6 as an indicator of the possible age range of the CO2 record reconstructed from stomatal frequency. The labels are the same as in Wagner et al. (1). Center and Bottom: Atmospheric CO2 concentration reconstructed from stomatal index (
) (1) and direct measurements of CO2 concentration of air enclosed in bubbles in the ice cores from Taylor Dome (
) (3, 4) and Vostok (
) (7, 8).
This new paper in the journal Quaternary Science Reviews throws a formidable monkey wrench into the the theory that CO2 induced warming is the cause of current Arctic ice loss. Because if we had ice free summers ten thousand years ago at ~ 260 ppm CO2, and we had warmer temperatures than today, we can’t then conclude that an additional 100 ppm of CO2 since then would be the cause of an ice free summer in the Arctic today. And ice free summer at lower CO2 and higher temperature is an incongruity with today’s theory of the “Arctic Death Spiral”.
Here’s the paper abstract:
New insights on Arctic Quaternary climate variability from palaeo-records and numerical modelling
Abstract
Terrestrial and marine geological archives in the Arctic contain information on environmental change through Quaternary interglacial–glacial cycles. The Arctic Palaeoclimate and its Extremes (APEX) scientific network aims to better understand the magnitude and frequency of past Arctic climate variability, with focus on the “extreme” versus the “normal” conditions of the climate system. One important motivation for studying the amplitude of past natural environmental changes in the Arctic is to better understand the role of this region in a global perspective and provide base-line conditions against which to explore potential future changes in Arctic climate under scenarios of global warming. In this review we identify several areas that are distinct to the present programme and highlight some recent advances presented in this special issue concerning Arctic palaeo-records and natural variability, including spatial and temporal variability of the Greenland Ice Sheet, Arctic Ocean sediment stratigraphy, past ice shelves and marginal marine ice sheets, and the Cenozoic history of Arctic Ocean sea ice in general and Holocene oscillations in sea ice concentrations in particular. The combined sea ice data suggest that the seasonal Arctic sea ice cover was strongly reduced during most of the early Holocene and there appear to have been periods of ice free summers in the central Arctic Ocean. This has important consequences for our understanding of the recent trend of declining sea ice, and calls for further research on causal links between Arctic climate and sea ice.
~~~~~~~~~~~~~~~~~~~~~~~~~~
Fig. 1. Map showing the locations of some of the studies included in the papers presented in this special issue. Numbers refer to Table 1, which contains the references to the respective study. Some of the papers on the Arctic Ocean involve sediment cores from a large spatial area; these are only plotted with boxes enclosing the areas of the studied cores. Furthermore, Cronin et al. (2010) analyzed sediment cores from virtually the entire central Arctic Ocean and, therefore, there is no number representing that study on the map. The maximum extensions of the Eurasian Ice Sheet during the late Quaternary compiled by the QUEEN project (Svendsen et al., 2004) are shown. LS: Late Saalian (>140 ka), EW: Early Weichselian (100–80 ka), MW: Middle Weichselian (60–50 ka), LGM: Late Weichselian (25–15 ka). The speculative extent of an MIS 6 ice shelf inferred by Jakobsson et al. (2010) is shown by the hatched area enclosed by a gray stippled line. The approximate spatial minimum cover of sea ice during 2007 is shown with a white shaded area enclosed by a black stippled line as a comparison to the median extension for the period 1979–2005 shown by a blue stippled line (Data is from National Snow and Ice Data Center). MJR: Morris Jesup Rise; YP: Yermak Plateau. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
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h/t to WUWT reader “josh”
Addendum: Some follow up graphic from comments, in my response to Richard Telford:
Here’s an interesting plot of solar insolation at 65 degrees north over time. To give readers an idea of this line, here is a map:
(Map from WikiMedia) Fairbanks, AK is at 64.5° N
The plot below shows how insolation varied with the Milankovitch cycles at 65° N. I’ve added the deltas comparing 10KYA to present.
The “Fermi Paradox” blogger who originally made the graph I annotated wrote: The graph shows the insolation in W/m^2 at 65 degrees norther latitude from 20ky before present to 10 ky in the future, calculated with the program insola from J. Laskar et al. The four plots are for the two months after the summer solstice and the two months before. It can be seen that the change in insolation over time is quite significant. Note though that this only applies at high latitudes – the global mean barely changes at all.
Note the magnitude of the change in insolation from 10K years ago to present, from 15 to 40 Watts/m2
Now look at this image from NOAA’ s Environmental Research Laboratory (ESRL):
CO2 accounts for 1.4 Watts/m2 of forcing in the last 150 years, so compared to the forcings of the Milankovitch cycles (at least at 65N) it is an order of magnitude lower. My point is that given the small impact of CO2 in forcings, it is not likely to be the driver of Arctic ice melt in the present, just like it wasn’t much of a significant factor 10K years ago.
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Mr. Watts:
The research study referred to above does not support a conclusion that increases in CO2 radiative forcing have not contributed to a decline in Arctic sea ice.
The abstract from the study states that it is to be used for comparison of “potential future changes in Arctic climate under scenarios of global warming”. The abstract does not say that CO2 does not contribute to current global warming or that current CO2 levels are not contributing to the recent multi-decade decline in Arctic sea ice. If the study makes such a claim, then please provide the direct quote and citation. The abstract stated:
“One important motivation for studying the amplitude of past natural environmental changes in the Arctic is to better understand the role of this region in a global perspective and provide base-line conditions against which to explore potential future changes in Arctic climate under scenarios of global warming.”
The study provides a basis for challenging assertions made by some AGW proponents that current Arctic sea ice extent does not have any comparable historical precedent during the Holocene. It also challenges assertions by some AGW proponents that there have never been periods of ice free summers in the central Arctic Ocean during the Holocene. Neither of these assertions are necessary to support the theory that CO2 and other anthropogenic radiative forcings are contributing to the current observed decline in Arctic sea ice.
That the Arctic could achieve higher temperatures than we are currently experiencing (through higher TSI radiative forcing or changes in cloud cover) without adding any CO2 to the atmosphere is “old news”.
While CO2 levels are not the focus of this study, there is a large body of literature that supports the theory that increases in CO2 radiative forcing and the other anthropogenic forcings have contributed to the current ice decline and will contribute to future declines in Arctic sea ice.
Any implication that this study “throws a formidable monkey wrench into the the theory that CO2 induced warming is the cause of current Arctic ice loss” is false. While it is appropriate to make fun of silly phrases such as “Arctic Death Spiral”, this does not require the use of false assertions or the poorly constructed logic used to support the “monkey wrench” conclusion. The data concerning prior conditions is a useful starting point to an analysis of current conditions. The prior conditions reflect changes to the Arctic caused by changes in TSI and other non-anthropogenic forces, such as changes in cloud cover. However, if the specific forces which created the prior condition or “natural variability” are not identified, it is unclear how this information can be used in understanding the impact of current forces on the Arctic sea ice.
Mr. Watts:
I have found a copy of the paper “History of sea ice in the Artic” and the assertion in the posting above that:
“This new paper in the journal Quaternary Science Reviews throws a formidable monkey wrench into the the theory that CO2 induced warming is the cause of current Arctic ice loss.”
is such a piece of disinformation that whoever wrote this line must not have read the paper or is deliberately distorting the information contained in the paper.
Contrary to the post, section 4.4 of the paper supports the theory that the increase in atmospheric green-house gas concentrations is a major contributer to current Arctic sea ice loss.
“4.4. Recent warming
Arctic paleoclimate proxies in lake and marine sediments, tree rings, and icecores indicate that from the mid-19th century the
Arctic not only warmed by more than 1 C average in comparison with the‘‘LittleIce Age’’(Overpecketal., 1997), but also reached the highest temperatures in at least the last two thousand years (Kaufman etal.,2009). This warming sharply reversed the long-term cooling trend that had likely been caused by the orbitally-driven decreasing summer insolation with the positive feedbacks from ice ands now albedo (e.g., Otto-Bliesneretal., 2006b). Subglacial material exposed by retreating glaciers in the Canadian Arctic corroborates that modern temperatures are higher than any time in at least the past1600 years (Anderson etal., 2008). An even longer perspective for the outstanding magnitude of the modern warming and related ice loss is provided by the history of ice shelves at the northern coast of Ellsemere Island,which are made of super- thickened landfast ice supported by packice in the adjacent Arctic Ocean. These ice shelves have been stable for most of the last 5.5kyr
based on drift wood ages (England etal.,2008), but declined by more than 90% during the 20th century and continue to break at a notable rate (Mueller etal., 2008).
An unraveled magnitude and duration of modern sea-ice retreat on a millennial background has been reported for the Nordic Seas based on combined ice core and tree-ring proxy data from Svalbard and Scandinavia (Macias-Fauriaetal., 2009). A comparison of this reconstruction with the Arctic-wide compilation of ice extent since the mid-19th century (Kinnardetal.,2008) shows a close match except for an obvious discrepancy in the early 20th century (Fig. 12). This discrepancy reflects the pronounced warming event in the Nordic Seas that was amplified by multidecadal variability of the North Atlantic circulation (Polyakovetal., 2009) and therefore affected primarily the Atlantic sector of the Arctic, somewhat similar to the15th-century warming anomaly(Crespinetal., 2009). In contrast, a very close match between the Nordic Seas and Arctic-wide records of ice extent during the recent decades emphasizes the pan-Arctic nature of the modern ice loss.
A climatic simulation by Sedla´cˇek and Mysak (in press) suggests that after about 1900 AD the slow increase in atmospheric green-house gas concentrations was the main driver of sea-ice changes in the Northern Hemisphere, while other forcings such as volcanic activity were mostly responsible for the thermodynamically produced changes in sea ice area and volume during the preceding four centuries. The remarkable modern warming and associated reduction in sea-ice extent are especially anomalous because orbitally-driven summer insolation in the Arctic has been decreasing steadily since its maximum at 11ka, and is now near its minimum in the precession cycle (Bergerand Loutre, 2004)”
The final paragraph of the paper concludes that the current Arctic ice decline is different from other declines that occurred during the Holocene:
“On suborbital timescales, ice distributions varied in the Holo-cene, but no evidence exists for large, pan-Arctic fluctuations.
Historical records indicate that Arctic sea-ice extent has been declining since the late 19th century. Although this decline was
accompanied by multidecadal oscillations, the accelerated ice loss during the last several decades lead to conditions not documented in at least the last few thousand years. Taking together the magnitude, wide geographic distribution, and abruptness of this ice loss, it appears to be anomalous in comparison with climatic and hydrographic variability observed on submillennial time scales and longer-term insolation changes.”
L. Polyaketal./QuaternaryScienceReviews29(2010)1757–1778 1772
For a summary of the paper, I refer you to the following link which was posted on September 8, 2010, which includes this statement from one of the authors of the paper:
When asked, “when was the last time the Arctic was ice free”, the lead author, Leonid Polyak, of Ohio State’s Byrd Polar Research Center, replied:
“The paleo data we have so far is very scant, so we can’t know for sure when the Arctic was ice free in the summer last time. To be conservative, the closest candidate is the early Holocene (roughly ~10 kyr ago), when the insolation in the Arctic was high due to the beneficial orbital configuration; however, the more data I see, the stronger is my impression that there was not that little ice at that time. The next best (actually, better) candidate is the Last Interglacial, about 125kyr ago, again due to orbitally-driven high insolation: the ice was likely very low, but we can’t say whether it was completely ice free in summer or not. There are also a few other major interglacials, which may have had a similar picture, in particular Marine Isotopic Stage 11, about 450 kyr ago. In any case we are talking about very rare events controlled by a forcing very different from today. If none of those intervals was really ice free, then a million year assessment would be correct.”
The final paragraph of the review anticipated the assertion so misleadingly made in the post above, when it stated:
“So the next time some anti-science disinformer — or more likely, one of the doubters who has been duped by them — says past warmth undermines our understanding of human-caused warming, tell them, quite the reverse is true. The paleoclimate record provides us more cause to be worried, not less. We know natural forcings led to warming in the past, but human emissions of greenhouse gases are overwhelming the climate now, and threatening catastrophic levels of warming if we stay on our current emissions path.”
http://climateprogress.org/2010/09/08/arctic-sea-ice-history-paleoclimate-polar-amplification/
While it is fair to disagree over whether the warming will actually be “catastrophic” and the extent to which AGW is “overwhelming the climate now” (please note, these hyperboles are also not supported by the paper), there is no need to fabricate an assertion concerning the paper which is so clearly contrary to the conclusions reached in the paper.
You may want to consider updating the posting referencing this paper.
Sorry about the reference to a different paper in Quarternary Science Reviews than the one cited in the post, but the general comment that the cited study providing data that “there appear to have been periods of ice free summers in the central Arctic Ocean” in the early Holocene, about 10-11,000 years ago and that this somehow throws a “monkey wrench into the the theory that CO2 induced warming is the cause of current Arctic ice loss” is not supported by other research in the same journal.