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View Full Version : Timeline of North-Europe temperature shifts since 138 BC.



LeBrok
17-12-12, 02:57
Thanks to recent works of many researchers we are getting a clearer picture of climatic events in Northern hemisphere with emphases on Europe. I would like to present the most detailed temperature charts of Northern Europe for last 2,000 years.

July 9, 2012 — An international team that includes scientists from Johannes Gutenberg University Mainz (JGU) has published a reconstruction of the climate in northern Europe over the last 2,000 years based on the information provided by tree-rings. Professor Dr. Jan Esper's group at the Institute of Geography at JGU used tree-ring density measurements from sub-fossil pine trees originating from Finnish Lapland to produce a reconstruction reaching back to 138 BC. In so doing, the researchers have been able for the first time to precisely demonstrate that the long-term trend over the past two millennia has been towards climatic cooling.
http://www.sciencedaily.com/releases/2012/07/120709092606.htm

Here is the map, with overlaid finer scale.

Black lines:
- 0 C - current median summer temperature
- around +1 C - warmest temp during Roman Empire.
Red line shows gradual cooling of 0.3 C per millennium

5787

This research is validated by other dendrochronologists who recreated temperature record for last 400 years:
http://www.ufz.de/export/data/1/27554_PM_2010___Kola_Temperaturen_1600_2000___Diag ramm.jpg
Researchers from the Institute of Geography in Moscow, Hohenheim University and the Helmholtz Centre for Environmental Research
http://www.ufz.de/index.php?en=19808


Here is a map of Greenland temperatures derived from ice cores. Showing the whole helocen cycle on Greenland, based on data NOAA Paleoclimatology.
http://www.ncdc.noaa.gov/paleo/metadata/noaa-icecore-2475.html
And ploted by http://alethonews.wordpress.com/2010/01/16/climate-science-models-vs-observations/

http://4.bp.blogspot.com/_WWYveRtoZBA/S1y8aaKUaHI/AAAAAAAAAZo/0GBTzC9FDWM/s320/Greenland-9KBC-1900.png


Last 2.5k years:
http://4.bp.blogspot.com/_WWYveRtoZBA/S2IS5y20xRI/AAAAAAAAAaw/6fmMNGqxQcY/s320/Composite-500BC-1900.png

Note that lighter line is from station in Antarctic and shows mostly negative mirroring.

Maciamo
17-12-12, 12:39
That's very interesting. The Earth was much warmer from the Neolithic period to the end of the 5th century CE. I already knew that the collapse of the Roman Empire coincided with a cooling of the climate (and the subsequent failing of crops) and that the Renaissance underwent a "mini Ice Age". But what interests me here are the prehistoric events:

- 6500 to 6000 BCE : major cooling of the climate, which corresponds to the expansion of agriculture from Anatolia to the southern Europe and North Africa.

- 6000 to 5500 BCE : gain of 4°C, allowing the spread of agriculture northward to the Pontic Steppes, the Danube Basin, Germany and northern France.

- 2900 to 2500 BCE : sudden drop in temperatures, coinciding with the first migration of the Steppe people to the Balkans and Central Europe.

- Around 1200 BCE : peak in temperatures, coinciding with the collapse of Near Eastern civilisations (Sea Peoples) and the flourishing of the Hallstatt, Atlantic and Nordic Bronze Age cultures in Central, Western and Northern Europe.

LeBrok
17-12-12, 22:44
There are other weather trends like dry-wet cycles which work fairly independently from warm-cold cycles. I'm still unable to locate a chart showing wet-dry phases of Holocene or CE. Globally there is a correlation between warm being wetter times, due to increased water evaporation, but local climates generally don't adhere to this, showing stronger decadal variations.
It would be nice to overlay temps chart with precipitation one, for North and South Europe to see the great picture of weather effects on European history.

There are decades (regardless if it's warm or cold period) when summers are to dry for good agriculture in South Euorpe, like on this map:
http://static.guim.co.uk/sys-images/Observer/Pix/pictures/2012/10/5/1349450148331/Map---Europe-rainfall-001.png
http://www.guardian.co.uk/science/2012/oct/07/north-atlantic-ocean-wet-summer


This scenario would allow peoples of North like Germanic and Slavic to build up manpower to overwhelm Roman Empire (in its worst times).

On top of it there are decades, like 80-90s, when North have mild winters but South freezes more than ever.
http://www.climate4you.com/images/C4Y%20Europe%20DJF%20change%2011y%201975-2000.gif




http://www.climate4you.com/EuropeTempChange%20DJF%201975-2000.htm


This scenario might even give advantage to steppe tribes before pushing West.

Yetos
18-12-12, 03:51
Weather and climate conditions follow the Sun circles activities, which are periodical phenomena, so by following the line we see periods of years that we have a repeat,
as student I study a work of Th. Landscheidt which was giving the periods, based in many others works,
it seems that 300-600 AD we have a very low peak which is about to start today (new little ice age theory)
and passed before in 900-1100 BC, 2100-2400 BC etc 3300-3700 BC etc yet smaller phenomena seems to play important role in huge areas, the Thera (santorini) Volcano seems to create a cold effect in Central mediterenean even to Egypt that lasted decades,
in fact if these theories are correct seems that we are entering a little ice age which will last 60-120 years instead of IPCC global warming theories and predictions that most fail, little ice age does not mean the Ice ages we know.

by following the periodical phenomena of sun you can estimate good enough warm and froast dates after last big Ice age, except if some big local phenoma (mainly tectonic, or electrofreezing clouds etc) change territorial climate, Iceland Hawai Indochina Chile can be exceptions of that rule until today, although seems that volcanic activity or some humidity-cloud has a small connections with Solar activities.