TLDR: PETM event 56 million years ago caused global warming, expanded rainforests, and impacted marine life; offers insights for today’s climate change.
This article is a summary of a You Tube video “The Last Time the Globe Warmed” by PBS Eons
Key Takeaways:
- Ancient Warming Event – Paleocene-Eocene Thermal Maximum (PETM): An event 56 million years ago, where global temperatures rose 5 to 8 degrees Celsius over 20 thousand years, more at higher latitudes.
- Rainforests in the Arctic: During PETM, tropical rainforest vegetation expanded far beyond current equatorial regions, with evidence found in North America, Europe, and Asia.
- Carbon Dioxide Spike: A significant increase in carbon dioxide and other greenhouse gases in the ocean was recorded, likely from organic sources.
- Sources of Greenhouse Gases: Possible causes include massive wildfires, volcanic activity heating coal, or melting of methane hydrates.
- Positive Feedback Loop: Warming led to more methane release from hydrates, exacerbating the greenhouse effect.
- Comparatively Slower Ancient Carbon Emission: During PETM, up to 1.7 billion metric tons of carbon were released annually, less than current rates.
- Impact on Life: The warming led to flourishing rainforests and diversification of early mammals, especially primates. However, marine life suffered due to heat and ocean acidification.
- Marine Life Hardship: High ocean temperatures and acidification devastated plankton populations and coral reefs.
- Cooling and Ice Caps Formation: The climate eventually cooled, leading to the formation of polar ice caps towards the end of the Eocene Epoch.
- Implications for Current Climate Change: Today’s warming rate exceeds that of the PETM, providing insights into potential climate change impacts.
