Scorching heat may become the norm by the end of the century

According to a team of scientists at the University of Bristol, climate change could cause Western Europe and New Zealand to relapse to the hot tropical climate of the early Paleogene, the first period of the Cenozoic Era which took place 56-48 million years ago.

Currently, a heat wave across Europe is affecting health, drying out land, and triggering wildfires.

The early Paleogene is particularly significant to climate scientists because carbon dioxide levels at that time were similar to those predicted for the end of this century.

Dr. David Naafs from the University of Bristol’s School of Earth Sciences is the lead author of the study.

“We know that the early Paleogene was characterized by a greenhouse climate with elevated carbon dioxide levels,” said Dr. Naafs.

“Most of the existing estimates of temperatures from this period are from the ocean, not the land – what this study attempts to answer is exactly how warm it got on land during this period.”

By analyzing the molecular fossils of microorganisms preserved in ancient peat, the team was able to estimate the land temperature 50 million years ago.

The scientists found that average temperatures in Western Europe and New Zealand were between 23 and 29 degrees Celsius, which is at least 10 degrees higher than current temperatures across these regions.

The findings suggest that the scorching temperatures of the current heat wave will become the new norm by the end of this century if atmospheric carbon dioxide levels continue to rise.

“Our work adds to the evidence for a very hot climate under potential end-of-century carbon dioxide levels,” said study co-author Professor Rich Pancost. “Importantly, we also study how the Earth system responded to that warmth. For example, this and other hot time periods were associated with evidence for arid conditions and extreme rainfall events.”

The researchers will now investigate how hot land temperatures became in lower latitudes during the early Paleogene.

“Did the tropics, for example, become ecological dead zones because temperatures in excess of 40 °C were too high for most form of life to survive? Some climate models suggest this, but we currently lack critical data,” said Dr. Naafs.

“Our results hint at the possibility that the tropics, like the mid-latitudes, were hotter than present, but more work is needed to quantify temperatures from these regions.”

The study is published in the journal Nature Geoscience.

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By Chrissy Sexton, Earth.com Staff Writer