We might have been wrong about how dire climate change really is. New research points out methodology to work out sea temperatures may have been based on an error – so millions of years ago, the oceans may have been colder than scientists thought. Study co-author Anders Meibom of the University of Lausanne in Switzerland said, “If we are right, our study challenges decades of paleoclimate research.”
Global warming actually might be “an unprecedented event in the last hundred million years,” according to the University of Lausanne, if the study from a team of French and Swiss researchers is correct. 100 million years ago, sea temperatures in the deep ocean and polar ocean’s surface were 15 degrees higher than current temperatures, scientists thought. But that figure may be incorrect – instead, ocean temperatures could have been more stable. That means the warming we’re seeing today is more distressing.
The Independent explains scientists used to determine temperatures with the help of foraminifera, or tiny marine organism fossils. The shells of these creatures have more or less of an oxygen isotope based on water temperature, so scientists could estimate water temperature of the past based on the oxygen content of the shells.
Sounds fairly straightforward, right? The problem is oxygen amounts in the shells don’t stay constant over time, says this new research, which suggests oxygen content can change without a trace that would clue scientists in on that change. Meibom said in a statement (translated by The Independent), “To revisit the ocean’s paleotemperatures now, we need to carefully quantify this re-equilibration, which has been overlooked for too long. For that, we have to work on other types of marine organisms so that we clearly understand what took place in the sediment over geological time.” The University of Lausanne reports the scientists are already at work on this task.
Ocean temperatures are important in our understanding of climate change. Meibom said, “The oceans cover 70 percent of the Earth. They are a key player in the Earth’s climate. We must therefore know the evolution of their temperature over geological time to understand precisely how they behave and thus, to better predict the consequences of the current climate disruption.”
Nature Communications published the research online this week. Sylvain Bernard of the Institute of Mineralogy, Materials Physics, and Cosmochemistry in Paris, France is the lead author.