New imaging finds trigger for massive global warming 56 million years ago

Enlarge / Scientists about to sink an Ocean Bottom Seismometer to the Atlantic seabed in 2021.

Scientists have scanned a section of the North Atlantic and revealed the remnants of what had been a huge pulse of hot rock that initiated a rapid climate warming event 56 million years ago.

The climate event, known as the Paleocene-Eocene Thermal Maximum (PETM), warmed the already-hot climate of the time by about 5.6 C due to a jump in atmospheric CO₂. Levels of that greenhouse gas rose from about 1,120 parts per million to about 2,020 ppm-much higher than today's 417 ppm. Although it didn't trigger a major extinction, it still exterminated some deep-sea creatures and tropical plants. Scientists want to understand the PETM better, because it's an example of how the Earth reacted to a rapid rise in atmospheric CO₂ a bit like we're currently experiencing, albeit starting from a hot, ice-free climate.

Finding a cause

Although the cause of PETM has been debated since it was discovered in the 1990s, more and more evidence has accumulated that points to massive quantities of CO₂ and methane emitted due to volcanic activity in the North Atlantic as the primary cause. This activity created what's now known as the North Atlantic Igneous Province- the same kind of enormous volcanic phenomenon linked to climate disruption and extinctions at other times in Earth's past, like the end-Triassic, the end-Permian, the early Jurassic, and others.

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