Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 Climate Change in the Geologic Record Miriam S. Andres, Angela Hessler, Tim McHargue Carbonate Research & Development Team ETC-Chevron, San Ramon December 2009

Climate Change Workshop – BAESI – 5 th Nov © Chevron Taken from Ruddiman: Earth’s Climate: Past and Future

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 Temperature in the Geologic Record 3

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 Temperature in the Geologic Record – A Matter of Time Scales 4 PETM Anthropocene Younger Dryas Cretaceous Supergreenhouse

Climate Change Workshop – BAESI – 5 th Nov © Chevron The Cretaceous – Super Greenhouse Climate 2011 (389 pp) ppm; 8x pre-industrial levels High sea level; abundant inundated shallow shelf areas. one-third of Earth's present land area was submerged Taken from Ruddiman: Earth’s Climate: Past and Future

Climate Change Workshop – BAESI – 5 th Nov © Chevron The Cretaceous – Super Greenhouse Climate Why did it not get warmer and warmer? Taken from Ruddiman: Earth’s Climate: Past and Future

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 Temperature in the Geologic Record – A Matter of Time Scales 7 PETM Anthropocene Younger Dryas Cretaceous Supergreenhouse

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 Paleocene-Eocene Thermal Maximum ~56Ma 8 Taken from National Geographic, October 2011

Climate Change Workshop – BAESI – 5 th Nov © Chevron Taken from National Geographic, October 2011

Climate Change Workshop – BAESI – 5 th Nov © Chevron Taken from National Geographic, October 2011

Climate Change Workshop – BAESI – 5 th Nov © Chevron Taken from National Geographic, October 2011

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 PETM vs. current warming 12 Source:

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 Comparison 13 Source:

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 Temperature in the Geologic Record – A Matter of Time Scales 14 PETM Anthropocene Younger Dryas Cretaceous Supergreenhouse

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 The End of the Last Glacial 15 Ice retreating but then… Taken from Ruddiman: Earth’s Climate: Past and Future

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 The Younger Dryas – return to glacial conditions 16 The 90 Minute Hollywood Version

Climate Change Workshop – BAESI – 5 th Nov © Chevron The prevailing theory holds that the Younger Dryas was caused by a significant reduction or shutdown of the North Atlantic thermohaline circulation in response to a sudden influx of fresh water from Lake Agassiz (size of UK) and deglaciation in North America. But still a lot of uncertainty and contradicting data sets. -> Bolide impact? -> Other outflows? A Lake? Are you serious? Mark Bateman, Sheffield University

Climate Change Workshop – BAESI – 5 th Nov © Chevron Rate of change: Temperature drop within a human life span (~30yrs) Global effects: not always cooling, but sometimes drought Summit of Greenland was ~15°C colder during the Younger Dryas than today. In the UK, (fossil beetle) evidence suggests mean annual temperature dropped to approximately 5°C, and periglacial conditions prevailed in lowland areas, while icefields and glaciers formed in upland areas. Whatever the cause – the result impressive: & Carlson, 2010

Climate Change Workshop – BAESI – 5 th Nov © Chevron 2011 Temperature in the Geologic Record – A Matter of Time Scales 19 PETM Anthropocene Younger Dryas Cretaceous Supergreenhouse