Mail
NEW

Palaeoclimate around 3000 BCE

The land surface conditions at present and 6000 Uncal BP (around 5000 BCE) has been evaluated by the BIOME6000 project. The climate of 5000 BCE has these values. More information on palaeoclimate is here.

Abstract of the main paper (Cheddadi, R. Yu, G. Guiot, J., Harrison, S.P. and Prentice, I.C., The climate of Europe 6000 years ago. Climate Dynamics, 13, 1997: pp 1-9):

Palaeoclimates across Europe for 6000 Uncal BP were estimated from pollen data using the modern pollen analogue technique constrained with lake level data. The constraint consists of restricting the set of modern pollen samples considered as analogues of the fossil samples to those locations where the implied change in annual precipitation minus evapotranspiration (PE) is consistent with the regional change in moisture balance as indicated by lakes. An artificial neural network was used for the spatial interpolation of lake level changes to the pollen sites, and for mapping palaeoclimate anomalies. The climate variables reconstructed were mean temperature of the coldest month (T_c), growing degree days above 5 [°C] (GDD), moisture availability expressed as the ratio of actual to equilibrium evapotranspiration, and PE. The constraint improved the spatial coherency of the reconstructed palaeoclimate anomalies, especially for PE.
The reconstructions indicate clear spatial and seasonal patterns of Holocene climate change, which can provide a quantitative benchmark for the evaluation of palaeoclimate model simulations. Winter temperatures (T_c) were 1-3 [°K] greater than present in the far N and NE of Europe, but 2-4 [°K] less than present in the Mediterranean region. Summer warmth (GDD) was greater than present in NW Europe (by 400-800 [°K day] at the highest elevations) and in the Alps, but > 400 [°K day] less than present at lower elevations in S Europe. PE was 50-250 [mm] less than present in NW Europe and the Alps, but was 10-15% greater than present in S Europe and PE was 50-200 [mm] greater than present in S and E Europe.

I have constructed two pictures out of this data for Ireland:

Mean temperature of the coldest month (T_c) in 6000 Uncal BP
relative to present day values

Growing Degree Days above 5 [°C] (GGD) at 6000 Uncal BP
relative to present day values

So in general for Ireland (and UK) around 6000 Uncal BP (around 5000 BCE):

In winter the days were colder than present, on average some 1.5 (1.3) [°C]
In summer the days were warmer than now a days, on average some 150 (120) [°K day]
There was less 'rain' (PE) than present, on average some 150 (140) [mm]

To get the climate around 3000 BCE, the above 5000 BCE values have been linearly interpolated and this give the following values for Ireland (and UK):

In winter the days were colder than present, on average some 1.1 (0.9) [°C]

In summer the days were warmer than now a days, on average some 110 (90) [°K day]

There was less 'rain' (PE) than present, on average some 110 (100) [mm]

Disclaimer and Copyright

Home

Mail

Last major content related changes: May 12, 2001