Around 56 million years ago, the Earth experienced one of its most intense warming events—the Paleocene-Eocene Thermal Maximum (PETM). Global temperatures rose by about 6°C over approximately 5,000 years due to a drastic increase in atmospheric carbon.
This heatwave lasted over 100,000 years, profoundly affecting ecosystems and climate regulation through terrestrial vegetation changes., says a new research published in Nature Communications,
How Plants Regulate Climate Through Carbon Sequestration
Plants play an essential role in regulating Earth’s climate by capturing atmospheric CO2 through photosynthesis, storing carbon in their biomass and soils. During abrupt warming like the PETM, vegetation’s ability to sequester carbon can diminish temporarily, potentially extending the warming period by weakening natural climate feedback loops.
Fossil Pollen and Computer Models Reveal Vegetation Shifts
Researchers combined fossil pollen data from sites in the Bighorn Basin (USA), North Sea, and Arctic with computer simulations of plant evolution, dispersal, and carbon cycling. Mid-latitude sites showed a shift toward smaller, drought-resistant plants like palms and ferns with increased leaf mass and decreased deciduous trees. These changes indicated reduced carbon storage in plants and soils.
Contrasting Vegetation Responses in High Latitudes
In the Arctic, vegetation height and biomass increased, with conifer forests replaced by broad-leaved swamps and presence of subtropical plants such as palms. High-latitude regions appeared better able to adapt and even increase productivity under warmer climate conditions, highlighting important regional differences.PETM vegetation shifts, plant carbon capture past warming, mid-latitude vs Arctic vegetation, ancient plant adaptation climate change
Implications for Modern Climate Change Adaptation
The PETM vegetation disruption likely reduced terrestrial carbon sequestration for 70,000–100,000 years, prolonging warming. Today’s global warming occurs about ten times faster, placing greater strain on modern plants’ ability to adapt and regulate climate. Understanding past biological responses is critical to anticipate ecosystem resilience under future rapid warming scenarios.
The PETM serves as a natural experiment illustrating how abrupt warming affects global vegetation and carbon cycles. This knowledge enhances predictions of ecosystem responses amidst ongoing climate change.
Q&A: Key Insights on Plant Responses to PETM Warming
Q: How fast did temperatures rise during the PETM?
A: Approximately 6°C over 5,000 years, triggering profound ecological changes.
Q: What caused the prolonged warming duration?
A: Reduced carbon sequestration due to plant and soil disruption slowed climate recovery.
Q: How did vegetation differs between mid and high latitudes?
A: Mid-latitudes shifted to smaller, drought-resistant plants; high latitudes gained biomass and subtropical species.
Q: Why study fossil pollen?
A: Pollen is abundant, widely dispersed, decay-resistant, providing detailed ancient vegetation records.
Q: What lessons does PETM offer for today?
A: Rapid warming challenges plant adaptation and carbon capture, highlighting urgency for climate action.
