All Objective Climate Research Show Earth in 4000 yr cooling All Objective Climate Analyses show that the earth is in a 4000 year cooling trend, consistent with the approach of the next glacial period..
The record shows a clear long-term cool- ing trend of 0.4°C/1000years; a warm HTM with temperatures of ~7°C ended at 5.2 ka BP with subsequent cooling to tempera- tures of ~4°C during the last 1200years when sea ice presence increased.
Superimposed on this trend are multi-centennial vari- ations in aSST of 1–2°C, with warmer temperatures at c. 6.8, 6.1–5.9, 5.4–5.2 and 4.1–3.6 ka BP and colder temperatures at c. 5.5, 5.2–4.1, 3.6–3.1, 1.3 and 1–0 ka BP.
The long-term cooling trend can likely be attributed to declining Northern Hemisphere summer insolation and decreasing stratifica- tion of the water column with changing salinity.