File: <climate.htm>








80,000 B.C. --------- Modern humans appear in southern Africa (judged from jewelry production)

80-40,000 B.C. ---- Several catastrophic climatic changes decimate human population

40,000 B.C. --------- Small group of modern humans cross Red Sea to Yemen

39,000 B.C. -------- Artistic cave paintings appear at diverse locations

28,000 B.C. --------- Small carvings of human females appear from Europe through Asia

16,000 B.C. ---------The climate begins to warm
13,000 B.C. --------- Advance of glaciers stops, and sea levels begin to rise

12,000 B.C. --------- Flooding over vast areas of the earth intensifies

10,000 B.C. --------- Development of reliable ocean navigation opened up the world around

9,000 B.C. --------- Mini Ice Age lasts a few hundred years. Seafarers from Morocco and northern

Spain explore entire west coast of Europe. Caucasian race appears in Libya
8,000 B.C. --------- Ice Age megafauna goes extinct. Societies become more centrally directed.

Specialized trades expand, longevity increases. Ireland to Scandinavia colonized.
6,000 B.C. -----------Bering Strait land bridge drowned, halting migration of humans and animals

5,500 - 6,000 B.C.-- Language becomes more organized and developed (see Linguistics)

6,000-3,500 B.C.---- Migrations out of North Africa to points east and north (as desert expands)

4,000 B.C. ----------- The Holocene Maximum warm period

1,700 B.C. ----------- Peteroborough, Canada petroglyphs carved (see Bronze Age)

1,420 B.C. ----------- Isle of Thera volcano erupts, devastating Crete & other areas

1,290 1,180 B.C. -- Major attacks by Sea Peoples on Egypt (attempt to reestablish Goddess religion)

1,100 B.C. -------- Hebrews leave Egypt

597 A.D. ---------- Benedictine clerics expand Christian conversion activity in Europe

600-700 A.D. ----------Horsecreek Petroglyph carved in West Virginia ? (see Horsecreek)

635 A.D. ---------- Roman Catholic sponsored Invention of modern European languages expanded

1000-1350 A.D. ---- Medieval Warm Period

1400-1860 A.D. ---- Little Ice Age

1870 present ---Industrial Age Global Warming




The Earth has been ice-free (even at the poles) for most of its history. However, these iceless periods have been interrupted by several major glaciations (called glacial epochs) and we are in one now in the 21st Century.   Each glacial epoch consists of many advances and retreats of ice fields.  These ice fields tend to wax and wane in about 100,000, 41,000 and 21,000 year cycles.  Each advance of ice has been referred to as an "ice age" but it is important to realize that these multiple events are just variations of the same glacial epoch.  The retreat of ice during a glacial epoch is called an inter-glacial period and this is our present climate system.


The existing Plio-Pleistocene Glacial Epoch began about 3.2 million years ago and is probably linked to the tectonic construction of the Isthmus of Panama which prevented the circulation of Atlantic and Pacific waters and eventually triggered a slow sequence of events that finally led to cooling of the atmosphere and the formation of new ice fields by about 2.5 million years ago.


Thus far, the Earth has had around 15 to 20 individual major advances and subsequent retreats of the ice field in our current glacial epoch.  The last major advance of glacial ice peaked about 18,000 years ago and since that time the ice has generally been retreating although with some short term interruptions (see diagram).



See Paleontological Science Center,