A group of scientists from the USA and Great Britain came to the conclusion that anthropogenic emissions of greenhouse gases by 2030 will "roll back" the Earth's climate three million years ago, and by 2150 - 50 million years ago. The atmosphere of those times was warmer and contained more energy, which is released in the form of natural disasters. An article by climatologists was published in the journal Proceedings of the National Academy of Sciences.
Researchers have quantified the similarities between climate in the near future and climate in different geologic epochs on Earth using different models that took into account carbon emissions over the next decades. In one scenario - RCP8.5 - humanity does not make any efforts to reduce the amount of carbon dioxide emitted into the atmosphere, and in the RCP4.5 scenario, a moderate reduction in emissions is assumed. The climate models used in the work were developed by the Hadley Center for Climate Research and Prediction, the Goddard Space Research Institute and the University's Atmospheric Research Corporation.
Scientists have demonstrated that in the RCP8.5 scenario, by 2030, the climate will return to that of the Middle Pliocene (three million years ago), when the average atmospheric temperature was 2-3 degrees higher than now, the Arctic ice was one-year, and the sea level was 25 meters higher. By 2150, the climate will become Eocene, that is, it will "roll back" 50 million years ago. In those days, a thermal maximum occurred on Earth - a sharp warming of the climate by eight degrees Celsius, which led to the mass extinction of species. The content of carbon dioxide in the Eocene in the atmosphere - hydrosphere system was 5-8 times higher than it is now.
According to the RCP4.5 scenario, the climate will stabilize at the Pliocene level in 2040, and the visible changes in weather events will be negligible and will affect less than one percent of the world. However, in the case of RCP8.5, the new climate will be characteristic for 8.7 percent of the territories and will affect mainly land. According to scientists, such changes go beyond the adaptive capabilities of many species, which will inevitably lead to mass extinction. At the moment, the researchers believe, humanity is between RCP4.5 and RCP8.5 and is moving towards the latter every year, but taking urgent measures will help realize a more optimistic scenario.