A new study by the Massachusetts Institute of Technology on climate extremes in the early Earth confirms that the current warming process could become even more volatile.
In a new study, the authors examined data on the paleoclimate over the past 66 million years, in particular the Cenozoic era, which began shortly after the extinction of the dinosaurs.
Scientists found that during this period, the fluctuations in the Earth’s climate were surprisingly drawn to a constant increase in temperature. In other words, there have been many more periods of prolonged global warming that lasted from thousands to tens of thousands of years. Moreover, these periods tended to be more extreme in terms of temperature changes.
The warming is likely due to what is known as a multiplier effect, the researchers say: in this case, a moderate degree of warming, for example, due to volcanoes emitting carbon dioxide into the atmosphere, accelerates certain biological and chemical processes, and as a result, warming still increases more strongly.
The authors note that this warming trend faded about 5 million years ago, around the time ice sheets began to form in the Northern Hemisphere. It is not yet known what effect the ice had on the cooling of the Earth. The authors believe that the current massive melting of ice can also lead to a multiplier effect.
During the work, the authors turned to large databases of deep-sea organisms, the shells of which are preserved in sediments. The composition of these shells depends on the temperature of the ocean, therefore, they are considered a reliable indicator of changes in the Earth’s temperatures over a long period of time.
The team analyzed the data statistically and noticed that the distribution of global fluctuations has shifted towards warming over the past 66 million years. In particular, the temperature was extreme and varied frequently, in contrast to periods of cold snap.