British scientists have proposed a new explanation for the "problem of 100 thousand years", that is, the emergence of ice ages on Earth every hundred thousand years. They believe that the main reason is ice on the surface of the World Ocean. But Russian experts think otherwise and predict the coming of cold weather in 15 years - due to solar activity. "Lenta.ru" found out whose theory is more plausible and when the global frosts will hit.
Mathematicians joined the study of global climate change and predictions of the next ice age, creating a new theory. According to a study by Valentina Zharkova from the University of Northumbria in the UK, the next glaciation will occur in 2030, that is, literally in 15 years. Zharkova's work published a year ago caused a great resonance in the scientific community, but recently attention was paid to it in connection with the scientist's speech at the National Astronomy Meeting.
According to Zharkova, the drop in temperature on Earth is directly related to solar activity and soon we will have a small ice age, the same as in the 17th and 18th centuries. Then the Maunder minimum was recorded - the number of sunspots decreased from 40-50 thousand to only 50 units. Winters were much colder than usual and lasted longer. The average air temperature on the planet dropped by 1.3 degrees, which led to the loss of crops and other serious consequences.
A team of physicists, mathematicians and astronomers, led by Zharkova, claims solar activity will drop by 60 percent between 2030 and 2040. However, it will last not 60 years, as with the Maunder minimum, but 30 years. According to the hypothesis, magnetic waves on the Sun appear in pairs, the main one of which is responsible for the graduation changes observed by researchers when solar activity changes. The frequency of fluctuations is about 11 years, which corresponds to the claim cycle. Thus, the researchers linked the evolution of the Sun's magnetic field with the minima and maxima of the star's activity, as well as its influence on the climate.
This theory has many opponents, since the Maunder minimum cannot be directly associated with the Little Ice Age. Volcanoes, whose ash obscured sunlight, slowing down or even completely stopping the thermal circulation of ocean waters, or stopping the massive burning of forests by the American Indians, which became extinct as a result of infections, could also affect the temperature in that era.
In addition, the theory was developed not by climatologists, but by physicists who studied only solar activity. The model created by Russian, Ukrainian and British scientists can explain the Maunder minimum, but it is incorrect to apply it to predict ice ages. Effective climate models include not only solar activity but many other factors as well.
But ice ages do repeat themselves. At first, the Earth plunged into coldness every 40 thousand years, and a million years ago, during the Middle Pleistocene transition, the intervals increased. Now global cooling occurs every 100 thousand years, and so far there is no reliable explanation.
Geophysicists from Cardiff University in Great Britain put forward a new theory to explain the "100 thousand years problem". According to a report published in the journal Geology, the whole thing is in the oceans, more precisely, in its absorption of carbon dioxide.
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Using data obtained in the framework of the Deep Sea Drilling Project, specialists studied the bottom layers of the ocean and discovered an interesting pattern: in the fossil organisms and rocks belonging to the ice ages, an increased content of carbon dioxide. This, according to scientists, could have caused the glaciation of the Earth.
“We associate global cooling with“breaths”and“exhales”of carbon dioxide from the World Ocean. When the ice reaches great thickness, the ocean begins to absorb gas from the atmosphere, thereby lowering the temperature of the planet, - comments the lead author of the study, Professor Carrie Lear. "Looking at the fossils on the ocean floor, we determined that every 100,000 years, the ocean absorbs more carbon dioxide."
The scientist compares the ice on the surface of the ocean with a cover that prevents the free release of carbon dioxide into the atmosphere. Algae, which play a critical role in removing carbon dioxide from the atmosphere, can absorb it freely, but this ice cover prevents the reverse process.
As the ice gets thinner, the ocean starts releasing carbon dioxide and raises the Earth's temperature. This process is observed now, since the last glaciation ended more than 11 thousand years. Since then, the temperature and level of the oceans have risen, and the ice caps have again moved to the poles. In addition, human carbon dioxide emissions contribute to the greenhouse effect.
“We are close to unraveling why ice ages occur, but we still do not know why the cycle increased from 40 thousand years to 100. We cannot make predictions about the climate if we do not know how these processes occur. Our work sheds light on some aspects,”Lear told the International Business Times.
Vlad Massino
