Exame Informática | Abrupt breakdown of sunlight will have turned the Earth into a 'snowball' on two occasions

The phenomenon happened twice on dates geologically
very close for about 700 million years: the whole planet became involved
in a layer of ice and snow, in an event that is known as ‘Snowball Earth’
(Snowball Earth). Although the reasons for this effect are not known,
it was assumed that phenomena such as the sharp reduction in solar radiation or levels
of carbon dioxide in the atmosphere may have led to this result.

An MIT team now suggests that a global ice age may be triggered for other reasons: it is not necessary for the volume of solar radiation to be below a certain value, but the ice age may happen if there is a decrease in sunlight more faster than a certain pace. Scientists published a paper in the Proceedings of the Royal Society in which they describe that dispersed and occurring volcanic eruptions at the same time or the formation of clouds may have blocked the sun's rays, leading to the 'Earth snowball' effect. These conclusions can also be extrapolated to other planets, with those that resemble Earth being more propitious to this type of events.

The team of researchers estimates that as the light
the sun started to decrease, the ice started to expand from the poles to the equator,
resulting in greater reflection and cooling the surface, then reaching the
glaciation. The phenomenon turns out to be temporary due to the nature of the
planet, since the released carbon dioxide ends up being retained in the
atmosphere, leading to a greenhouse effect that eventually leads to thaw.

Constantin Arnscheidt, who led the MIT study, points out
that “there are many ideas about what may have caused these glaciations, but all
gravitate towards an implicit modification of exposure to solar radiation (…)
In the course of the exercise, we concluded that there was an immediate way to make an appointment
position when applying ideas like the gradual reduction, the snowball Earth and the
habitability conditions ”.

The mathematical model developed includes equations that
represent the relationship between the entry and exit of solar radiation, the
temperature at the Earth's surface, the concentration of carbon dioxide in the air and
other effects. “It is reasonable to assume that past glaciations were induced
by geologically rapid changes in solar radiation, ”says Arnscheidt.
Thus, it will not be necessary to go beyond a certain threshold for the same phenomenon
can happen again, with just a quick reduction.

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