RESEARCHERS from the University of St Andrews have studied how carbon dioxide (CO2) affected Earth's climate millions of years ago.
The new study published in Nature Geoscience sheds light on how CO2 acted to warm and cool the planet over eons.
A team from The University of St Andrews examined fossils and looked at CO2 levels during the Carboniferous and Permian periods, about 335 to 265 million years ago, a time known as the Late Palaeozoic Ice Age.
They discovered that CO2 levels were low during this time, but they suddenly rose 294 million years ago due to large volcanic eruptions.
This caused the planet to warm and the ice to melt.
Dr Hana Jurikova, the lead researcher from St Andrews, said: “The end of the Late Palaeozoic Ice Age was a turning point in the evolution of life and the environment, leading to the rise of reptiles. Now we know it was paced by carbon dioxide.”
The researchers used fossil shells from brachiopods, ancient clam-like creatures, to measure CO2 levels from the past. These shells are found throughout the fossil record and help scientists understand how Earth's climate and environment have changed.
By analysing various chemical fingerprints, they were able to determine the CO2 levels in Earth's atmosphere in the past and track how it changed.
Dr James Rae, co-author of the study, warned that CO2 emissions in the past caused global warming and rising sea levels, and could do so again if not controlled.
“CO2 emissions in the past caused major global warming and sea level rise, and if left unchecked, will do so again in future.”
