3 to 4 degrees centigrade warmer, in fact. Far greater than recent warming.
The new paper, Kulman et al. 2018 relies on paleoclimatology, which as we’ve learned from Mann, can be taken with a grain of salt.
Because trees may only grow within narrowly-defined temperature ranges and elevations above sea level, perhaps the most reliable means of assessing the air temperatures of past climates is to collect ancient treeline evidence.
In a new paper, Kullman (2018) found tree remnants at mountain sites 600 to 700 meters north of where the modern treeline ends, strongly implying Early Holocene air temperatures in northern Sweden were 3-4°C warmer than recent decades.
“The present paper reports results from an extensive project aiming at the improved understanding of postglacial subalpine/alpine vegetation, treeline, glacier and climate history in the Scandes of northern Sweden. The main methodology is analyses of megafossil tree remnants, i.e. trunks, roots, and cones, recently exposed at the fringe of receding glaciers and snow/ice patches. This approach has a spatial resolution and accuracy, which exceeds any other option for tree cover reconstruction in high-altitude mountain landscapes.”
“All recovered tree specimens originate from exceptionally high elevations, about 600-700 m atop of modern treeline positions.”
“Conservatively drawing on the latter figure and a summer temperature lapse rate of 0.6 °C per 100 m elevation (Laaksonen 1976), could a priori mean that summer temperatures were at least 4.2 °C warmer than present around 9,500 years before present. However, glacio-isostatic land uplift by at least 100 m since that time (Möller 1987; Påsse & Anderson 2005) implies that this figure has to be reduced to 3.6 °C higher than present-day levels, i.e. first decades of the 21st century. Evidently, this was the warmth peak of the Holocene, hitherto.”
“This inference concurs with paleoclimatic reconstructions from Europe and Greenland (Korhola et al. 2002; Bigler et al. 2003; Paus 2013; Luoto et al. 2014; Väliranta et al. 2015).”
…
This study adds seven new dates of mega fossil tree remnants (4 Betula, 2 Pinus, 1 Picea) to a
previous sample of 21 specimens from the same glacier (12 Betula, 9 Pinus) (Kullman &Öberg
2015). Individual dates are given in Table 1 and the samples are depicted in Figures 5-7. They range
in elevation between 1410 and 1275 m a.s.l., which is about 600 and 700 m higher than the nearest
present-day treelines of these species. The ages all represent the early Holocene, c. 11 200 to 6700
before present.
There’s also this new paper:
Greenland Ice Sheet 2-5°C Warmer With Much Lower Volume During The Early Holocene
“The Holocene climatic optimum was a period 8–5 kyr ago when annual mean surface temperatures in Greenland were 2–3°C warmer than present-day values. … The initial mass loss in response to the temperature increase in the early Holocene is largest when forcing the ice sheet with the temperature and accumulation reconstructions from Gkinis and others (2014) (Experiment 5). In this simulation, temperature anomalies peak at more than 5°C above the present-day reference climate in the early Holocene and the ice sheet loses 20% of its volume in the 3000 years following the onset of the Holocene through increased surface melting.”
“The largest and most rapid retreat of the ice sheet was found for Experiment 5, which was forced by the temperature and accumulation reconstructions of Gkinis and others (2014). In this temperature reconstruction, temperature increases rapidly at the onset of the interglacial and has several shorter periods with temperatures more than 5°C above present in the early Holocene. .. Geological evidence suggests further that the ice-sheet margins in the southwest retreated up to ∼ 100 km behind their present-day position during the mid-Holocene (Funder and others, 2011). This evidence is further supported by interpretations of relative sea-level records and bedrock uplift rates that also point towards ice sheet retreat beyond the present ice volume in the mid-Holocene (Khan and others, 2008; Funder and others, 2011; Lecavalier and others, 2014).”
“We find that the ice sheet retreats to a minimum volume of ∼0.15–1.2 m sea-level equivalent smaller than present in the early or mid-Holocene when forcing an ice-sheet model with temperature reconstructions that contain a climatic optimum, and that the ice sheet has continued to recover from this minimum up to present day.”
Graph Source: Nielsen et al., 2018 and Briner et al., 2016
Full paper available here:
https://www.researchgate.net/publication/324991910_Further_Details_on_Holocene_Treeline_GlacierIce_Patch_and_Climate_History_in_Swedish_Lapland
In Finland Lauri Timonen has lead collector of treeline evidence about past climate. http://lustiag.pp.fi/ Lot of science http://lustiag.pp.fi/suofintr.htm.
Mauri Timonen. Those dendro people tend to be quite skeptical, I wonder why?
At Strathcona Fiord on the west central coast of Ellesmere Island (170 km -110 mi) to the south of Eureka Nunavut, Canada, they have found a fossil record of tremendous international scientific significance. These fossils, including plant and animal remains, have provided a unique opportunity for understanding the effect of climatic change through the past 4 or 5 million years on the Arctic environment, and on its flora and fauna.
Pliocene fossils (3-5 million years old): Paleoclimatic reconstruction suggests a mean annual temperature that was 14–19 °C (25–34 °F) warmer than present day.
Eocene fossils (about 50 million years old): These earliest finds include the fossil remains of an alligator. Very notable are the petrified tree stumps, some of which are preserved in their original growth position. The trees show wide growth rings indicating favorable growth conditions.The fossil flora indicates the presence of rich floodplain forests dominated by dawn redwood (Metasequoia glyptostroboides), together with ginkgo (Ginkgo adiantoides), walnut family (Juglans and other Juglandaceae), elms (Ulmus spp.), birch and alder (Betulaceae), and katsura (Cercidiphyllum). Analysis of nearby fossil leaf sites from central Ellesmere Island of the same age indicate that these forests grew under very high rainfall, and can be considered to have represented a polar rainforest.
This lush Eocene ecosystem thrived under a polar light regime. Like today, the region would have seen 24-hour sun in the summer and 24-hour darkness in the winter as it was positioned at almost the same latitude in the Eocene as it is today. Despite an early Eoceneclimate with generally mild frost-free temperatures, the polar light regime likely forced these plants to be deciduous.
https://en.wikipedia.org/wiki/Strathcona_Fiord
http://www.kgs.ku.edu/Publications/PIC/28figures/fig3.gif
That’s not possible. SUVs hadn’t been invented yet.
3-4C warmer post-glacial in the subarctic in one location. Why is this “inconvenient”, it’s not even controversial.
And it was said by the prophets and wise men, ‘The warmists shall claim it’s just one isolated example as they have with every other warm period that damaged their narrative. And in each of those more evidence crept in showing that no, they were not localized or isolated.’ And lo, Harry Twinotter promptly obliged.
Yet Harry is right. Among specialists this is not controversial. What is controversial is saying that the present is warmer than the Holocene Climatic Optimum.
Javier.
Who said the current global warming is warmer than the optimum? Do you have a reference? I check extraordinary claims.
Marcott et al., 2013 did. And it had a huge repercussion in the press. There were several cartoons made about riding the global temperature anomaly. One of them illustrates the NOAA article “What’s the hottest Earth has been “lately”?”
https://www.climate.gov/news-features/climate-qa/what%E2%80%99s-hottest-earth-has-been-%E2%80%9Clately%E2%80%9D
Where it is said:
“For most of the past 10,000 years, global average temperature has remained relatively stable and low compared to earlier hothouse conditions in our planet’s history. Now, temperature is among the highest experienced not only in the “recent” past—the past 11,000 years or so, during which modern human civilization developed—but also probably for a much longer period.
Carrie Morrill of the National Climatic Data Center explains, “You’d have to go back to the last interglacial [warm period between ice ages] about 125,000 years ago to find temperatures significantly higher than temperatures of today.””
The article was reviewed by Marcott.
This opinion, dressed as scientific fact, is based on careful proxy selection and incorrect statistics. It is hugely controversial among scientists like Leif Kullman (of Swedish treeline studies), that see the present period as well within Holocene variability.
Good reference, thanks for that. One study. But the study does not say they are sure that current temps are warmer than the optimum. From the abstract: “Temperatures have risen steadily since then, leaving us now with a global temperature higher than those during 90% of the entire Holocene.”
They are hedging because of the uncertainties involved. That is the wise thing to do.
The article does not say highest either, as your quote clearly shows.
All evidence from every possible source shows that the Holocene Optimum (5 Ka) was warmer than or as warm as the Egyptian Warm Period (4 Ka) and the Minoan WP (3 Ka), while definitely hotter than the Roman WP (2 Ka) and the Medieval WP (1 Ka).
The Modern Warm Period has yet to enjoy the same peak warmth as the Medieval. One can only hope that we do, but that’s not the way to bet.
The Holocene is on the slow path toward the next glaciation, sadly.
“All evidence from every possible source”? If I told you once, I have told you a thousand times, never ever ever exaggerate 🙂
Yep, the good ol’ MWP. It was like a sauna, every possible sources confirms this (not).
davefreer.
Other than your poor attempt to sound funny. The Holocene Climatic Optimum is not an isolated example, there is plenty of evidence for it. So I don’t get your point, if you even have one.