Public Lecture

Earth's Climate Trajectory, Past and Future

University of Arizona
May 8, 2019

As atmospheric carbon dioxide levels climb higher than they have been in the last two million years, we face the challenge of adapting to and mitigating the effects of climate change. How do we know that humans are responsible for climate change? What effects of climate change can we see already? How can geology help understand what a future warm world might look like? In this talk, Dr. Tierney will take us through the past, present, and future trajectory of Earth’s climate and discuss how paleoclimatologists query the ancient record of climate change to improve our understanding of the future.

Chapters (navigate to in progress bar or lower-right corner of the video):
1. Beginning (00:18)
2. Carbon dioxide measurements and its sources (01:42)
3. Fourier, carbon dioxide, and electromagnetic spectrum (05:58)
4. Greenhouse effect (09:36)
5. Global temperature record (11:42)
6. Receding glaciers, Miami sea level rise, California 1000-year drought, climate extremes (12:32)
7. Paleoclimate as a window to future (14:50)
8. Ice cores and 800,000 years of carbon dioxide and methane (16:30)
9. Sediment cores and proxies for climate (17:30)
10. Foraminifera, a paleo geologist’s friend (19:32)
11. 2.5Ma (million years ago), last time the for an atmosphere with over 400ppm CO2—until today (20:38)
12. Humans are an ice-age species (21:44)
13. Model of Pliocene temperature (23:20)
14. Temperature of past 65Ma, CO2 and greenhouse climate of 56-34 Ma Eocene. Giant snakes and crocodiles in Arctic! (23:41)
15. Palms in Antarctica! (27:30)
16. Eocene ocean temperature/warm poles (28:06)
17. Eocene not a stable climate, PETM (Paleo Eocene Thermal Maximum) 55Ma (29:17)
18. PETM and loss of shell carbonates 100,000-year recovery (30:34)
19. Present warming rate is faster than PETM (33:50)
20. Summary: climate change is real and bad, but there is hope for us (34:52)
21. IPCC projections/Pliocene vs Eocene as our possible future (35:42)
22. Nobel scientist Sherwood Rowland quote (37:58)
23. End (38:40)