From my bro recently....
In addition to the cold and warm phases, the new climate curve also exhibits
a phenomenon that was not expected in this form. For the first time,
researchers have now been able to use the data derived from tree-rings to
precisely calculate a much longer-term cooling trend that has been playing
out over the past 2,000 years. Their findings demonstrate that this trend
involves a cooling of -0.3°C per millennium due to gradual changes to the
position of the sun and an increase in the distance between the Earth and
the sun.
"This figure we calculated may not seem particularly significant," says
Esper, "however, it is also not negligible when compared to global warming,
which up to now has been less than 1°C. Our results suggest that the
large-scale climate reconstruction shown by the Intergovernmental Panel on
Climate Change (IPCC) likely underestimate this long-term cooling trend over
the past few millennia."
But read the whole thing... a honest report for once...
Climate in northern Europe reconstructed for the past 2,000 years: Cooling trend calculated precisely for the first time