A new study, published in the journal Science , shows the results of recent observations of tiny undersea amoebas called forams that have been consuming plant and animal life for billions of years. The studies have helped scientists piece together a history of the planet's climate.
The findings aren't looking too good.
The new report details Earth's climate swings across the entire Cenozoic era — the 66 million-year period that began with the death of the dinosaurs and extends to the present epoch of human-induced climate change. The results show how Earth transitioned through four distinct climate states — dubbed the Warmhouse, Hothouse, Coolhouse and Icehouse states — in response to changes in the planet's orbit, greenhouse gas levels and the extent of polar ice sheets.
"Now that we have succeeded in capturing the natural climate variability, we can see that the projected anthropogenic warming will be much greater than that," study co-author James Zachos, professor of Earth and planetary sciences at the University of California, Santa Cruz, said in a statement. "The Intergovernmental Panel on Climate Change (IPCC) projections for 2300 in the 'business-as-usual' scenario will potentially bring global temperature to a level the planet has not seen in 50 million years." (The IPCC is a United Nations group that assesses the science, risks and impacts of climate change on the planet.)
"We now know more accurately when it was warmer or colder on the planet and have a better understanding of the underlying dynamics and the processes that drive them," lead study author Thomas Westerhold, Director of the University of Bremen Center for Marine Environmental Sciences in Germany, said in the statement. "The time from 66 [million] to 34 million years ago, when the planet was significantly warmer than it is today, is of particular interest, as it represents a parallel in the past to what future anthropogenic change could lead to."