The last ice age undoubtedly changed the evolution of our species. And next one can have a similar effect. Above all, if you arrive earlier than thought. And that is the position of a team of scientists from the University of California, Santa Barbara.
According to the study, published in Science, the changes in the inclination of the Earth with respect to the Sun have governed the movements of the giant ice layers During the last 800,000 years, which has caused the beginning and end of eight glacial ages.
The study indicates a “surprising correlation” between the inclination of the earth and the formation of the ice layers, according to the main author, Stephen Barker. Based on these findings, The results estimate that the next glacial era would be underway in 11,000 years … if it were not for global warming caused by humans.
“The prediction is that the next glacial era will begin within the next 10,000 years -explains Barker in a statement -. However, This result does not take into account our growing greenhouse gas emissionsthat are heating the planet to the point of preventing the glacial eras. ”
Ice eras, or glacier periods, are extremely cold periods of time that occur approximately every 100,000 years and cover much of the planet with huge layers of ice for thousands of years. The glaciers periods are separated by warmer interglacial periods, when the ice layers go back to the poles. The Earth is currently in an interglacial period, and the last glacier period reached its maximum point about 20,000 years ago.
Scientists have previously suggested that the position and angle of the earth in relation to the sun affect the formation of ice layers. The axis of the Earth is currently inclined at an angle of 23.5 degrees with respect to the vertical while revolving around our star, which It affects the amount of solar energy that reaches each of the poles, in particular.
But the inclination of Earth axis naturally becomes larger or smaller in a cycle that lasts about 41,000 years. The axis also staggers on itself as a decentrally peonza, which affects the amount of solar energy that reaches equatorial regions during the summer in periods of time of about 21,000 years.
For the study, the authors drawn the changes known in obliqueness and precession during the last 800,000 years. They also determined the expansion and recoil of ice layers during this period using existing data of microscopic shells, called foraminifera, in oceanic sediment nuclei. The relative abundance of certain types of oxygen in foraminifers reveals how far the ice layers extended when organisms were alive.
“The results of the combination of these graphics were surprising -adds Baker -. We discover an amazing correlation that says that there is a direct relationship between the phase of obliqueness and precession, and the duration resulting from how long the ice layers take to disintegrate”
In a nutshell, The expansion of the ice layer from the poles to Ecuador seems to be governed directly by obliqueness. The recoil of ice layers from Ecuador to the poles, on the other hand, depends more on precession.
The graphics were so precise that the scientists extrapolated the data and calculated when the next glacial period would occur if the weather was changing only according to the natural cycles, said Barker. More research is needed to specify the times, but the ice layers probably They would begin to expand around 10,000 to 11,000 years and reach their maximum extension within the next 80,000 to 90,000 years. Then it would take another 10,000 years to go back to the poles.
There is a lot of debate about the moment when the next glaciation will occur, but most experts agree that human beings are altering these cycles through global warming. “If the CO₂ remains at high levels, there will be no new glaciation”, Says Baker.
The objective of this study and future investigations is Build an image of what the weather would do for the next 10,000 to 20,000 years Without the impact of human activity, the authors conclude. The objective is then to provide a long -term estimate of the impact of humanity on the planet.