A multidisciplinary team of researchers of the greenhouse effect and global warming, warn about the consequences that today the planet is heating up much faster than in any other period.
Future global warming may be twice as warm as projected by scientific models, and sea levels can rise six meters or more, warned a group of researchers from 17 countries.
The results of an investigation are based on observational evidence of three warm periods in the last 3.5 million years, when the world was 0.5 to 2 degrees Celsius warmer than the pre-industrial temperatures of the 19th century.
The data were recently published in the journal “Nature Geoscience” and disseminated by the University of New South Wales (UNSW) in Australia.
The professor at the University of Bern (Switzerland) and lead author of the climate model, Hubertus Fischer, explained that observations of periods of warming in the past suggest that it increases in the long term beyond projections.
To obtain their results, the researchers analyzed three of the best documented warm periods, the Holocene thermal maximum (5000-9000 years ago), the last warm interglacial period (129,000-116,000 years ago) and the Pliocene middle warm period (3.3 – 3 million years ago).
The heating of the first two periods was caused by predictable changes in Earth’s orbit, while the middle Pliocene event was the result of carbon dioxide concentrations in the atmosphere of 350-450 ppm (parts per million), almost the same as today.
Therefore, by combining a wide range of measurements of ice cores, sediment layers, fossil recordings, dating using atomic isotopes and a series of other established paleoclimate methods, the researchers reconstructed the impact of these climate changes.
From these data, they consider that today the planet is warming up much faster than any of these periods, since carbon dioxide emissions caused by humans continue to grow, even if the emissions stop, it would take centuries or millennia to achieve balance
The changes in the Earth in those past conditions were profound: there were important retreats of the ice sheets of Antarctica and Greenland, and as a consequence the sea levels increased at least six meters; the marine plankton ranges changed reorganizing whole marine ecosystems.
Oregon State University co-author Alan Mix said that even with 2 ° C of warming, and possibly only 1.5 ° C, significant impacts on the Earth system are profound.
“We can expect sea level rise to become unstoppable for millennia, affecting a large part of the world’s population, infrastructure and economic activity,” he said.
However, these significant changes observed are generally underestimated in the projections of the climate model that are focused in the short term.
UNSW study co-author and director, Katrin Meissner, emphasized that climate models seem to be reliable for small changes, such as scenarios of low emissions in short periods, for example in the coming decades until 2100.
He said that this research is a call to action: “it tells us that if today’s leaders do not urgently address our emissions, global warming will bring profound changes to our planet and our way of life, not only for this century but beyond.”
Source: Nature Geoscience