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Maybe the stupidest article title ever: "The Arctic has not been so heat in three million years" … AEUHHH ???

Guest "You Can't Fix Stupid" by David Middleton

The sad thing is that apparently this was written by two geoscience professors.

The Arctic has not been so warm in 3 million years – and that suggests major changes for the rest of the planet
September 30, 2020

Every year sea ice cover in the Arctic Ocean shrinks to a low point in mid-September. This year it measures just 3.74 million square miles (3.74 million square kilometers) – the second lowest value in the 42 years since satellite measurements began. The ice now covers only 50% of the area it covered 40 years ago in late summer.

As the Intergovernmental Panel on Climate Change (IPCC) has shown, carbon dioxide levels in the atmosphere are higher than ever before in human history. The last time atmospheric CO2 concentrations reached today's levels – around 412 ppm – was 3 million years ago during the Pliocene. That means the Arctic hasn't been this warm in 3 million years.

(…)

Julie Brigham-Grette
Professor of Earth Sciences, University of Massachusetts Amherst

Steve Petsch
Associate Professor of Earth Sciences, University of Massachusetts Amherst

The conversation

"The Arctic has not been so warm in 3 million years"

In many ways, the article isn't that bad. It's all about atmospheric CO2, not arctic temperatures. The authors provide a nice discussion of the Pliocene-era paleoclimate and an explanation of the weathering cycle of the rock (carbonate-silicate) which is said to control atmospheric CO2 over geological time. But the title of the article is absolutely stupid.

The article links atmospheric CO2 with temperature. While there is a subtle relationship between atmospheric CO2 and temperature, they are not interchangeable. It is entirely possible that atmospheric CO2 has not been as high since the Pliocene. It is also possible that it could have been almost as high for a short time in the early Holocene, perhaps even during the late Pleistocene Bølling – Allerød interstadial. However, this is one of the stupidest things ever written:

"The Arctic has not been so warm in 3 million years."

The Arctic was much warmer ~ 130,000 years ago in the last interglacial stage of the Pleistocene (Eemian / Sangamonian), with a CO2 content of probably only about 300 ppm.

Figure 1. “The oxygen isotopes in the ice indicate that the climate was stable during the last interglacial period and temperatures were 5 ° C warmer than today.” Members of the North Greenland Ice Core Project, 2004

Despite the warmth of the Eemians, the Arctic was not free of ice.

The last time temperatures in the Arctic were significantly higher than today was the early Holocene thermal maximum9, 10. However, the Holocene is an as yet unfinished interglacial cycle. This certainly justifies climatic assessments of older, completed warm interglacial cycles like the last interglacial (LIG), i.e. the Marine Isotope Stage (MIS) 5e (Eemian), which last between 130 and 115 ka and is often suggested as a possible analog for our in the nearer Future climatic conditions on earth11, 12. Based on proxy records from ice, land and sea archives, the LIG is characterized by an atmospheric CO2 concentration of around 290 ppm, ie similar to the pre-industrial (PI) value13 air temperatures in northeast Siberia , which were about 9 ° C higher than today14, air temperatures above the Greenland NEEM ice core location of about 8 ± 4 ° C above the mean value of the past millennium15, North Atlantic sea surface temperatures of about 2 ° C higher than modern (PI) temperatures12, 16 and a global sea level 5–9 m above the current sea level17. In the Nordic seas, on the other hand, the Eemian may have been cooler than the Holocene, as the flow of Atlantic surface water northwards towards the Fram Strait and Arctic Ocean was less, indicating the complexity of the interglacial climate system and its development in the northern high latitudes12, 18, 19. Stein et al., 2017

Stein et al., 2017

Figure 2. “Simulation of the Arctic sea ice cover of the last interglacial and the pre-industrial climate. The last interglacial (LIG) conditions were simulated for three time slices: LIG-130 (130 ka), LIG-125 (125 ka) and LIG-120 (120 ka). White circles indicate the positions of the four examined sediment cores. Stein et al., 2017

Most of the Arctic has been "as warm" or warmer for the past 10,000 years …

Figure 3. Reconstruction of the temperature in Central Greenland (Alley, 2000).Figure 4. Reconstruction of GISP2 temperature since the glacier radial of the Younger Dryas (Kobashi et al., 2017).

The Arctic has been "so warm" or warmer at times over the past 5,000 years:

Figure 5. Reconstruction of GISP2 temperature since 4000 BC Climate and historical periods from Grosjean et al., 2007.Figure 6. Reconstruction of the Arctic climate since 1 AD (McKay & Kaufman, 2014).

The Arctic may have been "so warm" or warmer in the early part of the 20th century:

Figure 7. Reconstruction of GISP2 temperature since 1900 AD. RMS Titanic, glacier girl, the ice age is coming? and Summit Station temperatures for "scale" included … 😉Figure 8. Reconstruction of the Arctic climate since 1900 AD (McKay & Kaufman, 2014).

The extent of the Arctic sea ice has been largely less in the past 10,000 years than it is today.

Figure 9. Cross section of the sediment core. The current sea ice conditions at these locations are seasonal and higher than in most of the last 10,000 years (PIP25 0.5 to 0.7). (Stein et al., 2017)

Conclusions

If you don't want your article to be ridiculed, make sure the title / headline isn't dumber than slate. Geologists should know that atmospheric CO2 and temperature are not interchangeable or synonymous. If atmospheric CO2 was indeed a major driver of climate change, the Arctic should Be much warmer now than it was in the last 3 million years. It is not so.

The University of Massachusetts Amherst receives a Ron White Lifetime Achievement Award …

References

Alley, R.B. 2000. "The Cold Interval of the Younger Dryas as seen from Central Greenland". Quaternary Science Reviews 19: 213-226.

Alley, R.B. 2004. "GISP2 Ice Core Temperature and Accumulation Data".
IGBP-SEITEN / World Data Center for Paleoclimatology Data Contribution Series # 2004-013. NOAA / NGDC Paleoclimatology Program, Boulder CO, USA.

Grosjean, Martin, Suter, Peter, Trachsel, Mathias & Wanner, Heinz. (2007). "Ice prehistoric finds in the Swiss Alps reflect Holocene glacier fluctuations". Journal of Quaternary Science. 22. 203 – 207. 10.1002 / jqs.1111.

Kinnard, C., Zdanowicz, C. M., Koerner, R., Fisher, D. A., 2008. "A Changing Arctic Seasonal Ice Zone – Observations from 1870-2003 and Possible Oceanographic Consequences". 35, L02507. Kinnard_2008

Kobashi, T., J.P. Severinghaus and K. Kawamura (2008a). "Argon and nitrogen isotopes of the air trapped in the GISP2 ice core during the Holocene (0–11,600 BC): Methodology and effects on gas loss processes". Geochim. Cosmochim. Acta. 72, 4675-4686, doi: 10.1016 / j.gca.2008.07.006.

Kobashi, T., Kawamura, K., Severinghaus, J. P., Barnola, J. M., Nakaegawa, T., Vinther, B. M., Johnsen, S. J. and Box, J. E. (2011). "High variability in the surface temperature of Greenland over the last 4000 years, estimated from the presence of air trapped in an ice core". Geophysical research letters. 38, L21501, doi: 10.1029 / 2011GL049444.

T. Kobashi, L. Menviel, A. Jeltsch-Thömmes et al. "Volcanic influence on the hundred-year to thousand-year temperature change in Holocene Greenland". Scientific reports 7, 1441 (2017). https://doi.org/10.1038/s41598-017-01451-7

McKay, N., Kaufman, D. "An Extended Arctic Proxy Temperature Database for the Past 2,000 Years". Scientific data 1. 140026 (2014). https://doi.org/10.1038/sdata.2014.26

Members of the North Greenland Ice Core Project. 2004. “High-resolution recording of the climate of the northern hemisphere up to the last interglacial period”. Nature 431 (7005): 147-137; 151

Stein, R., Fahl, K., Gierz, P. et al. Sea ice cover of the Arctic Ocean during the penultimate glacier and the last interglacial. Nat Commun 8th, 373 (2017). https://doi.org/10.1038/s41467-017-00552-1

Stein, R., Fahl, K., Schade, I., Manerung, A., Wassmuth, S., Niessen, F. and Nam, S. (2017), Holocene variability in sea ice cover, primary production and the Pacific water influx and climate change in the Chukchi and East Siberian Seas (Arctic Ocean). J. Quaternary Sci., 32: 362-362; 379. doi: 10.1002 / jqs.2929 stein2017

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