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Monday, April 15, 2019

Postglacial tree line in Northern Sweden -- it was was warmer there thousands of years ago


Source:
https://www.researchgate.net/publication/324991910_Further_Details_on_Holocene_Treeline_GlacierIce_Patch_and_Climate_History_in_Swedish_Lapland

or


http://dx.doi.org/10.20431/2454-8685.0304008 



International Journal of 
Research in Geography
Volume 3, Issue 4,  2017, 
Pages 61 through 69 


"Further Details on 
Holocene Tree Line, 
Glacier / Ice Patch 
and Climate History
in Swedish Lapland" 
  by Leif Kullman 
Department of Ecology and 
Environmental Science, 
SE 90187 
Umeå, Sweden 

Note:
There will be no wild guess
predictions of a coming climate
change catastrophe, that will 
never happen, as you read
in most mainstream media 
climate change articles.

Real science is concerned with
climate history -- reality -- not
imagined coming catastrophes !


SUMMARY:
This is a real science study 
of the climate history in
northern Sweden, looking at
plant growth during warmer
periods of the current Holocene
interglacial. 

We are NOT living in the warmest
portion of the current interglacial.

It was several degrees C. warmer
during the Holocene Optimum
period, roughly 5,000 to 10,000
years ago.

The fossil evidence in this study
suggests it was +3.6 degrees C. 
warmer in Northern Sweden 
many thousands of years ago.


DETAILS:
The study was carried out 
in the central Swedish Scandes, 
in the southern part of the province 
Lapland. 

Glacier / ice patch melting
during the global warming
in the past 300+ years
exposed previously ice-covered 
fossil tree remains in many parts 
of the world. 

This study analyses fossil tree 
remnants ( trunks, roots and cones ), 
in Sweden, recently exposed 
at the fringe of receding glaciers 
and snow / ice patches.  

These ancient remnants offer a 
unique opportunity to improve 
our understanding about past tree line 
positions, and associated plant cover 
characteristics.

These plant fossils indirectly 
provide clues to ancient climates.




This approach has an accuracy 
exceeding any other option 
for tree cover reconstruction
in high-altitude mountain 
landscapes. 

This approach has proven accuracy 
in time, space and species composition, 
going far beyond the resolution of 
pollen analysis, and other microfossil 
approaches.




The main focus was on the
fore fields of the glacier Tärnaglaciären 
in the southern Swedish Lapland.

Seven fossils were found, 
and radio-carbon dated 
(4 Betula, 2 Pinus, and 1 Picea). 

Betula and Pinus ranged in age 
from 9,435 to 6,665 years old.

A cone of Picea abies, 
contained in an outwash 
peat cake, was 11,200 
years old.

All recovered tree fossils were
found at very high elevations, 
about 600 to 700 meters above
the modern tree lines.

This implies, corrected for land uplift, 
summer temperatures were at  least 
+3.6 °C. higher back then, compared
with present-day temperatures.




These results, plus results from
other Swedish glaciers, create a  
new view of the early postglacial 
landscape and climate in the 
high-altitude Swedish Scandes.

In the Swedish Scandes, 
findings of fossil trees,
high above current tree lines,  
have been discussed in  
these studies: 
Kullman  2004;  
Öberg & Kullman 2011;  
Kullman & Öberg  2013,  2015; 
Kullman  2017.