{"id":7050775,"date":"2026-08-29T09:23:23","date_gmt":"2026-08-29T09:23:23","guid":{"rendered":"https:\/\/peraltafinancing.com\/aerospace\/forests-didnt-fare-well-during-an-ancient-global-warming-event-offering-a-cautionary-tale-about-todays-climate-change\/"},"modified":"2026-08-29T09:23:23","modified_gmt":"2026-08-29T09:23:23","slug":"forests-didnt-fare-well-during-an-ancient-global-warming-event-offering-a-cautionary-tale-about-todays-climate-change","status":"publish","type":"post","link":"https:\/\/fivemor.com\/?p=7050775","title":{"rendered":"Forests Didn’t Fare Well During an Ancient Global Warming Event, Offering a ‘Cautionary’ Tale About Today’s Climate Change"},"content":{"rendered":"


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An intense global warming event 56 million years ago caused a forest in modern-day Wyoming to lose around 60 percent of its canopy cover, and it took more than 100,000 years to bounce back, a study suggests<\/h2>\n
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Sara Hashemi<\/a><\/p>\n

| Daily Correspondent<\/span><\/p>\n

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Scientists reconstructed the ancient forest canopy using fragments of fossilized leaves.
\n Regan Dunn<\/span>
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About 56 million years ago, Earth experienced one of its most intense periods of global warming, known as the Paleocene-Eocene Thermal Maximum, or PETM. As atmospheric carbon dioxide levels surged, forests suffered a massive decline in canopy cover, and they took more than 100,000 years to recover, researchers report in a study published on August 13 in the journal\u00a0Science<\/em><\/a>.<\/p>\n

The findings offer a sobering look into what our planet\u2019s future might look like because of ongoing human-caused climate change.<\/p>\n

\u201cThe Earth has never experienced a carbon release at the pace we\u2019re creating today,\u201d says\u00a0Regan Dunn<\/a>, a study co-author and paleobotanist at the Natural History Museum of Los Angeles County, in a\u00a0statement<\/a>. \u201cThe PETM gives us our best window into how Earth\u2019s climate and ecosystems respond to a massive carbon injection before humans began reshaping the planet.\u201d<\/p>\n

Humans are currently putting carbon dioxide in the atmosphere at an unprecedented rate<\/a>. Predicting the effects of the planet-warming greenhouse gas on vegetation is complicated. Since plants need the gas for photosynthesis, elevated carbon dioxide levels should theoretically lead to enhanced plant growth. But too much heat and its consequences, like extreme weather events and an increase in pathogens, can also stress and kill plants.<\/p>\n

That\u2019s why Dunn and her colleagues turned to the past to see what might happen to today\u2019s forests. They collected fossilized leaf fragments hidden in the rocks of Hanna Basin in south-central Wyoming. The specimens preserve the shapes of the leaves\u2019 outermost cells, which can reveal how much sunlight the leaf received as it grew.<\/p>\n

\u201cThere\u2019s this difference between sun leaves and shade leaves, even on the same plant,\u201d Dunn tells James Dinneen at\u00a0Nature<\/em><\/a>. Leaves that grow in the shade have longer cells that stretch out looking for light, while those exposed to the sun are shorter and rounder.<\/p>\n

The information helped the team calculate the density of the forest canopy, which they tracked across the entire PETM. At first, the forest flourished thanks to the elevated carbon dioxide. But that growth spurt didn\u2019t last. The canopy then quickly lost around 60 percent of its leaf coverage, and it stayed around 35 percent thinner than it started through the rest of the PETM.<\/p>\n

\u201cThis should be a concern because the rate of carbon release has never been higher than now,\u201d Dunn tells the\u00a0Guardian<\/em><\/a>\u2019s Oliver Milman.<\/p>\n

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Did you know? Resilient rainforest<\/p>\n

The Amazon rainforest might be more resilient to climate change than scientists previously thought. Average tree size increased by 3.3 percent<\/a> each decade between 1971 and 2015, according to a study published last year.<\/p>\n<\/p><\/div>\n<\/div>\n

This change affected the surrounding environment too. Ferns replaced the broad-leafed relatives of elms, walnuts and avocado trees. Plants and soils stored less carbon, and rivers carried more sediments.<\/p>\n

\u201cThe changing climate changed the forest, and the forest changed the landscape,\u201d Dunn writes for the\u00a0Conversation<\/em><\/a>. Leaf coverage didn\u2019t return to its extremely dense state until at least 55.7 million years ago, the team estimated.<\/p>\n

These changes mirror what we\u2019re seeing in our forests today. Starting in the 1980s, satellite images showed a greening trend because of anthropogenic carbon dioxide emissions. But around the year 2000, researchers found that the pattern had\u00a0reversed<\/a> in more than 90 percent of the world\u2019s vegetated area.<\/p>\n

What happened during the PETM is certainly \u201ccautionary,\u201d says\u00a0Gabriel Bowen<\/a>, a palaeoclimatologist at the University of Utah who wasn\u2019t involved in the study, to\u00a0Nature<\/em>. \u201cWhat we\u2019re looking for is guides from the past about what can happen.\u201d<\/p>\n

And worryingly, the stress we\u2019re putting on our forests today is nothing like the slow release of carbon dioxide, likely from volcanic eruptions, that happened over thousands of years during the PETM. Modern-day plants face rising temperatures along with pollution, deforestation, fragmentation, wildfires and other stressors.<\/p>\n

\u201cIf forests thinned under the slower and cleaner version of this experiment, that is not a reassuring precedent,\u201d Trevor Keenan<\/a>, an environmental scientist at the University of California, Berkeley who wasn\u2019t involved in the work, tells the\u00a0Guardian<\/em>.<\/p>\n

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