Can abrupt climate changes cause fluctuations in parts of the earth system? What effects would those events have on human society?
An international team of natural and social scientists observedrapid changes over the last 30,000 years and published their review in Nature Geoscience. They have shown that tipping points were preceded by “early warning signals” – and similar signs can help inform our response to the current climate crisis.
Prof. Victor Brovkin from the Max Planck Institute for Meteorology (MPI-M) and lead author of the study, attempted to find the surprises that might be ahead of us, by looking into the past and spotting abrupt changes and tipping points, that could lead to big effects. They explored the geological archives to analyze the abrupt changes in the past and their cascading consequences.
The tipping points are known to cause changes that challenge the very capacity of human society, leading them to adapt to environmental pressures. Like the catastrophes of melting of the ice sheets atop Greenland and West Antarctica, which contain enough frozen water to lift oceans more than a dozen meters (40 feet). But these are very difficult to anticipate, due to very small changes.
Dr. Sebastian Bathiany, co-author of the Helmholtz Center Hereon found a method to decipher those changes in spatial patterns by using ‘early warning signals. He explains:
There are useful statistical indicators that can be interpreted as harbingers of abrupt changes. These include the so-called slowing down of temporal fluctuations before sudden changes, e.g. in the oceanic circulation, or the increased spatial variance, for example, of vegetation cover before the end of the African humid period. At the same time, one must be careful because some abrupt changes, such as the flooding of the Black Sea around 9,500 years ago, cannot be detected with such methods.
Dr. Martin Claussen, co-author of the study emphasizes defining abruptness of the changes, as, “The changes in most of the records that are included in Our study evaluated are about ten times faster than the changes in the relevant drives “.
From the Bølling–Allerød warming event nearly 15,000 years ago when air temperature soar to 14°C, over Greenland to African humid period around 6,000-5,000 years ago, the scientists analyzed ocean dynamics, rainfall patterns, and similar events to get to the tipping point, that cause irreversible effects.
Tim Lenton, review co-author and director of the University of Exeter’s Global Systems Institute said,
Earth’s recent past shows us how abrupt changes in the Earth system triggered cascading impacts on ecosystems and human societies, as they struggled to adapt.
He believed that the mankind again is at the risk of cascading tipping points, but this time, human is the one causing these problems and the impacts will be global.
Scientists believe that the current effects like ice-sheet melt are a result of carbon pollution, as the current atmospheric CO2 levels are soaring high around 412 parts per million. This in addition to other abrupt changes could lead to a plant-wide disruption. In short, this new research warns that the earth may be approaching key tipping points, including the runaway loss of ice sheets, that could fundamentally disrupt the global climate system. A growing concern is a change in ocean circulation, which could profoundly alter climate patterns.