A new study by scientists at the University of California has revealed that the Earth’s climate has been warm and mild for the majority of the past billion years. The research, published in the journal Science, shows that glaciers have only existed for around a quarter of the time period studied. However, the study also highlights several significant cold periods, including the Andean-Saharan Ice Age, which occurred around 450 million years ago and led to the second largest mass extinction in history. The researchers suggest that the formation of the Appalachian Mountains during this time was a key factor in the onset of the ice age.
According to the study, the collision of a volcanic island chain with a large landmass led to the formation of the Appalachian Mountains and the release of large amounts of ophiolite, a type of rock containing calcium and magnesium. These elements combined with CO2 in the atmosphere to form calcium carbonate, which was then deposited in the oceans and removed from the atmosphere. This process effectively reversed the current trend of human-induced climate change, as the decreasing levels of CO2 in the atmosphere led to a cooling of the Earth’s climate and the onset of the ice age.
The study also highlights the importance of the location of the collision, as the tropical climate of the Appalachian region at the time accelerated the weathering process that led to the removal of CO2 from the atmosphere. The researchers suggest that similar processes are currently occurring between Australia and the Indonesian archipelago, but at a much slower rate that cannot offset the effects of human-induced climate change.
