251 / 2022-03-30 12:22:34

Collapse of coal forests triggered the demise of the late Paleozoic icehouse

Cyclostratigraphy,Late Paleozoic ice age,Carbon burial,Icehouse-to-greenhouse transition

The demise of late Paleozoic icehouse is Earth’s first icehouse-to-greenhouse transition in an extensively vegetated world. In this paper, an astronomically forced teleconnection on a global scale is made to delineate a dynamic carbon sequestration history and its impact on icehouse termination. After a loss of coal forests in tropical Euramerica, floral survival became linked with 1.28 Myr hydroclimate cycles between low-latitude North China and high-latitude Gondwana from ~299.2–295.5 Ma. The expansion of coal forests enhanced carbon burial that increased O₂ and lowered CO₂ levels in the atmosphere, elevating atmospheric O₂/CO₂ to the point of crossing a threshold and triggering the collapse of coal forests at ~295 Ma. Subsequently, tropical vegetation was lost as a sink for atmospheric CO₂, promoting icehouse termination. These results demonstrate that the disappearance of coal forests reversed feedback pathways involving carbon burial and atmospheric composition, and led to termination of the late Paleozoic icehouse.