Paleontologists Reconstruct Forests of 56 Million Years Ago With Chilling Parallels for Our Time
hubie writes:
If you want to know how rapidly pumping carbon dioxide into the atmosphere will impact future forest ecosystems, you have to look into the distant past. The researchers behind a new study published in Science have done just that, reconstructing the forest canopy of 56 million years ago, during a massive and abrupt emission of carbon into the atmosphere during the Paleocene-Eocene Thermal Maximum (PETM). For the first time, the authors of the study used fossilized leaf cells to reconstruct the tree canopy of the PETM, Earth's most recent period of comparable global warming, with chilling implications for our near future.
"We are putting CO into the atmosphere faster than any known natural process," says lead author and paleobotanist Dr. Regan Dunn, Assistant Deputy Director and Associate Curator of the Samuel Oschin Global Center for Ice Age Research at La Brea Tar Pits and the Natural History Museum of Los Angeles County. "The Earth has never experienced a carbon release at the pace we're creating today. The PETM gives us our best window into how Earth's climate and ecosystems respond to a massive carbon injection before humans began reshaping the planet."
The authors found that the PETM was marked by a widespread browning of Earth's landscapes. Against a backdrop of elevated atmospheric CO, global warming, and reduced rainfall triggered by volcanically driven carbon release, plant species migrated northwards, and canopy cover declined, accelerating erosion and disrupting the terrestrial water cycle. The human-caused climate change happening now is pumping CO2 at an order of magnitude faster than the ancient parallel. Trees are at the root of these drastic changes.
"There are significant tree mortality events everywhere on Earth right now," says Dunn. "Forests are in decline because of warming temperatures, drought stress, pathogen and insect infestations, and wildfires-when you start losing the trees, our canaries in the coal mine, you're in trouble. It's almost universally true in all of Earth's five major extinction events."
Journal Reference: https://doi.org/10.1126/science.aec4776
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