4,280 BC to 4,040 BC: Timeline of World prehistory including: archaeological data, solar activity, climate data, (h1)
4,236 BC: First date in the Egyptian calendar.
4,230 BC: Historical grand minima solar.
4,200 BC: Susa began as a Copper Age state and ended in 2,330 BC:
~ U.S.: Increase in mean annual temperature and decrease in rainfall in the Mississippi Valley.
~ Evidence for land clearance for agriculture has been found in southwest Ireland.
~ Ireland: Cairns of various form built from this time included: passage and court cairns. Evidence of land clearance for agriculture in the southwest by this time.