If throughout history, the human species has always been able to adapt, the current climatic challenges are perhaps too great. According to a recent study exploring the evolution of Earth’s surface temperature over the past few hundred million years, temperature fluctuations are greater than we thought.
Worrying temperature fluctuations
As temperatures gradually but rapidly increase almost everywhere on Earth, the question of adaptation of the human species arises more and more. A study carried out by the department of geosciences at the University of Arizona in Tucson (United States) and published in the journal Science on September 20, 2024 helps to better understand this fear. The study in question provided new insight into the evolution of temperature on the Earth’s surface over the last 485 million years. However, the results revealed larger temperature fluctuations compared to those acquired by the scientific community so far. In addition, this research highlights a very close link between the average temperature on the surface of the globe and the quantity of CO2 contained in the atmosphere.
This work made it possible to reconstruct a global average temperature curve which covers a large part of the Phanerozoic eon. Lasting 541 million years (until today), this eon, which is also the last of the four eons in Earth’s history, is characterized by the appearance of complex life forms, but also the first fish, dinosaurs, land plants and mammals. The late appearance of humans was then synonymous with the colonization of land and the appearance of several mass extinctions.
Unprecedented thermal conditions on the scale of our evolution
According to researchers, the preservation of temperature indicators in such ancient rocks is extremely rare. However, even going back this far, the clues are very rare. Despite this, the authors of the study managed to combine geological data and climate models using a rather specific data aggregation technique. However, if the latter was initially designed to predict the weather, researchers have drawn up relevant conclusions. According to the results, the Earth has experienced temperature variations of between 11°C and 36°C over the last 485 million years. This is a greater amplitude than that acquired until today, which demonstrates the extreme sensitivity of the climate system terrestrial to environmental changes.
The study confirms once again that the main responsible for regulating the earth’s temperature is none other than carbon dioxide (CO2). So, models show that high CO2 levels equal heat and vice versa. Furthermore, the authors of the study are more concerned about the speed of current warming than the average surface temperature. Indeed, we observe here a rhythm which far exceeds that observed for the Earth’s geological past.
Rising temperatures are already endangering many living species and ecosystems, testifying to their inability to adapt. For humanity, this question of adaptability therefore arises more than ever. Let us remember, however, that humans developed within a temperature range of around 5°C, in other words a fairly stable global average temperature. However, to the extent that we are heading towards unprecedented thermal conditions on the scale of our evolution, it is difficult to predict the future, despite our remarkable capacity for adaptation. Furthermore, the absence of strong actions to reduce the intensification of global warming is not a source of optimism.
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