Do you know how often the earth plunges into ice ages?
It may seem silly to think of Ice Ages - especially now, when you only talk about global warming. But the fact is that, over its 4.5 billion years, the Earth has plunged into various periods of glaciation, the last of which is what we are currently living and which began about 2.7 million years ago. years (depending on the time subdivision we consider as a reference).
Because if the Ice Ages - marked by falling global temperatures and the formation of large ice sheets - are periodic events, that means they occur frequently and can happen again in a while, do you agree? However, do you know how and how often they occur?
According to Laura Geggel of the Live Science website, to our knowledge, our planet has been the scene of five great ice ages, and the truth is that not even scientists know for sure what drives our planet into one of them. However, one of the most widely held theories is that these long intervals of global cold can be caused by the sudden drop in carbon dioxide levels in the atmosphere. Interesting, no?
Disappearing with CO2
According to one of the most well-known theories (the so-called tectonic weathering hypothesis) to explain the occurrence of ice ages, as the tectonic plates were elevating the mountain ranges, new portions of rock were eventually exposed and undergoing the weathering process. - or natural degradation.
The material resulting from the decomposition of the rocks ended up in the oceans, providing in turn the necessary ingredients for many marine organisms to build rigid shells and shells. Then, over time, both rocks and ocean animals absorbed more and more carbon dioxide from the atmosphere and, together with other factors, contributed to a dramatic fall in this compound.
Whether this is the process responsible for a glaciation or not, as we said, the earth has gone through five great ice ages. The first was the Huronian Glaciation, which took place between 2.4 and 2.1 billion years ago, followed by the Cryogenian (720-635 million years ago), Andes-Saharan (450-420 million years), the from the end of the Paleozoic (335-260 million years) and the Quaternary - which we are living now.
Icy cycle
Within these five great ice ages mentioned above, there have also been several smaller glaciers, as well as warmer periods, known as interglaciers. In the case of the ice age that began 2.7 million years ago (in the Quaternary), mini-glaciations occurred every 41, 000 years or so until a million years ago - when they became less frequent.
According to Laura, over the past 800, 000 years, the large ice sheets have started to appear every 100, 000 years or so, in a process in which the ice sheets have grown in size over 90, 000 years and take 10, 000 to enter. collapsing over interglacial periods - after which the whole cycle begins again.
Considering that the last mini glaciation ended about 11, 700 years ago, the Earth should be entering a new ice age - or should have been! However, according to experts, factors related to Earth's orbit, as well as the enormous amount of carbon dioxide we release into the atmosphere, are interfering with the cycle, and estimates indicate that we will not see the planet cooling over the next 100, 000 years.
Orbital and human interference
According to a theory proposed by Serbian astronomer Milutin Milankovitch, as the earth travels in its orbit around the sun, its inclination, eccentricity (or variation in the distance between our planet and the star along the way) and its orbital oscillation interfere in the amount of solar radiation that comes to us.
For these three parameters seem to be related to glaciation cycles, and the problem is that if global temperatures are too high, they become indifferent - as regards the formation and expansion of the ice sheets. This is where the issue of carbon dioxide emissions comes in, which, as you know, is a greenhouse gas.
According to Laura, over the past 800, 000 years, CO2 levels on Earth have ranged from 170 ppm (parts per million) to 280 ppm, resulting in the known mini-glacial cycle and interglacial periods. But in recent decades, the levels of this compound recorded in the atmosphere have been much higher - with Antarctica hitting 400 ppm in 2016.
Remember that our planet has gone through periods of high temperatures in the past, as was the case when dinosaurs reigned here. However, the problem is that humanity has released a huge amount of CO2 into the atmosphere in a very short period of time - and the consequences of our actions (and the resulting global warming) can be devastating.
If you are imagining that the earth would turn into a huge ice ball if it plunged into a new ice age, know that in the last glaciation global temperatures were, on average, only 5 ° C lower than now. On the other hand, if they do not stop rising and warming leads to the melting of the Antarctic and Greenland ice sheets, the sea levels should rise by 60 meters. And what do you think is best: seeing coastal cities and islands disappearing under water or feeling a little colder?
Recommended
