New fossils from the most famous great extinctions of the earth show that a climate thinking has been overcome

Circa 250 million years agoThe most catastrophic mass -has taken place on earth, the so ground “Great extinction” (O Die out), which led to the disappearance of 80-90% of the types of marine invertebrates, as well as many terrestrial species both animal and vegetables. The most common hypothesis is that the event is caused by a period of intense volcanic activity In Siberia, followed by an extreme warming period of the earth for the large quantity of SERRA GAS placed in the atmosphere. Until now, however, it was not clear why the high temperatures lasted so long over time, for approximately 5 million years. According to the results of one studio Posted Nature communicationThe reasons would be linked to the decrease of foreststhat would have delayed the reabsorption of greenhouse gases and in particular from the CO₂.

The study

During large field studies, carried out at locations that are spread all over the world (from Siberia to different areas of China, to the United States, to some areas of Europe and Asia, to South Africa, Australia, Antarctic and Argentina), the authors and authors of the study have a new type of analysis of the fossil finds and of the “instructions” about the climatic conditions of the past in some rock formationsWith the aim of reconstructing the changes by reconstructing vegetation during the great extinction of the Perm-Ciasic.

The analyzes showed that the decline of the forests, especially those tropicalThe carbon cycle is said to be changed, so that the seizure of the CO was delayed₂ of the atmosphere and extending the consequences ofcash. In fact, plants offer fundamental service to the planet: they grab carbon dioxide from the atmosphere and convert it into more complex and carbon molecules through photosynthesis.

The points of no climate no return

‘The causes of such extreme heating during this event [di estinzione di massa, nda] have long been discussed“Explains Zhen Xu, the first author of the study and researcher at the School of Earth and Environment from the University of Leeds (United Kingdom).”In particular, this is the only event characterized by high temperatures in the history of the earth in which the biosphere of the tropical forest collapsed, which gave rise to our initial hypothesis. Now, after years of fieldwork, analysis and simulations, we finally have the data that supports it“.

According to the authors, these observations would strengthen the concept of the cases “Points of no climate back” (Climate point), that is, the existence of specific barriers, which would then be difficult to return to the initial balance. Climate change experts talk about “CO2 -Budget” ResiduTo indicate the amount of carbon dioxide that we can still enter into the atmosphere before we can reach the critical threshold from which it would be very difficult to go back.

What the big extinction of the Perm-Criasic teaches us

According to Benjamin Mills, one of the coordinators of the study and professor at the School of Earth and Environment from the University of Leeds, the results of the study represent a warning of theimportance of current tropical forests from the earth: “If the fast heating collapses in a similar way [a quanto avvenuto durante la Grande Estinzione del Permiano-Triassico, nda]We should not expect our climate to cool to pre -industrial levels, even if we stop emitting Co₂“He explains. In a similar scenario he concludes the teacher, the heating can in fact continue to speed up, even if we reset the emissions, because the carbon cycle would be changed in a way that may be required Geological times To return to the departure state, “As happened in the past of the earth“.