– It’s getting warmer and our climate is changing very fast.
A new study shows by the 23rd century, the climate could reach a warmth not seen in 420 million years. Furthermore, researchers have calculated that over the next 100 to 200 years, carbon dioxide concentrations in Earth’s atmosphere will head towards values not seen since the Triassic period, 200 million years ago.
Researchers from the University of Southampton have examined data on fossilized plants, the isotopic composition of carbon in soils and the oceans, and the boron isotopic composition of fossil shells.
Their results show that if humanity burns all available fossil fuels in the future, the levels of CO2 contained in the atmosphere may have no geologically-preserved equivalent during this 420-million-year period.
“We cannot directly measure CO2concentrations from millions of years ago. Instead we rely on indirect ‘proxies’ in the rock record. In this study, we compiled all the available published data from several different types of proxy to produce a continuous record of ancient CO2 levels,” Gavin Foster, lead author and Professor of Isotope Geochemistry at the University of Southampton said.
The connection between carbon dioxide and the sun’s brightness has significant implications for the history of life on Earth.
“Up until now it’s been a bit of a puzzle as to why, despite the sun’s output having increased slowly over time, scant evidence exists for any similar long-term warming of the climate. Our finding of little change in the net climate forcing offers an explanation for why Earth’s climate has remained relatively stable, and within the bounds suitable for life for all this time,” Professor Dana Royer, from Wesleyan University in the US said.
It is well recognized that the climate today is changing at rates well above the geological norm. If humanity fails to tackle rising CO2 and burns all the readily available fossil fuel, by AD 2250 CO2 will be at around 2000 ppm — levels not seen since 200 million years ago.
Professor Foster adds: “However, because the Sun was dimmer back then, the net climate forcing 200 million years ago was lower than we would experience in such a high CO2 future. So not only will the resultant climate change be faster than anything Earth has seen for millions of years, the climate that will exist is likely to have no natural counterpart, as far as we can tell, in at least the last 420 million years.”