Antonio Manaytay – Fourth Estate Contributor
San Diego, CA, United States (4E) – Less radiation from the Sun by mid-century could help slow down Earth’s warming but won’t stop climate change due to heightened human activities.
Modelling on geological and historical data when in the middle of the 17th century Europe was colder than expected due to an event called as “Maunder Minimum,” the scientists said the Sun’s magnetism will be greatly diminished, infrequent sunspots formation, and ultraviolet radiation will be lesser due to the fluctuations of the Sun’s magnetic field.
The scientists termed the event as a grand minimum.
During the cooling down of the Sun during the mid-17th century, the temperatures were too low enough to have the Thames River frozen. It had also frozen the Baltic Sea which gave the Swedish army to attack Denmark in 1658 by crossing the sea ice on foot.
Dan Lubin, a research physicist at Scripps Institution of Oceanography at the University of California San Diego, and his colleagues had developed a method to estimate the cooling down of the Sun when the next grand minimum will occur.
Lubin had estimated that UV radiation will drop by an additional seven percent below the lowest point of the Sun’s 11-year cycle during which the solar UV radiation peaks and declines due to sunspot activity.
“Now we have a benchmark from which we can perform better climate model situations,” Lubin said, adding that “we can, therefore, have a better idea of how changes in solar UV radiation affect climate change.”
Lubin, together with David Tytler and Carl Melis of UC San Diego’s Center for Astrophysics and Space Sciences, calculated the level of the next grand minimum by studying the 20-year data from the International Ultraviolet Explorer satellite mission. Then, they looked into the radiation of stars that are almost similar with the Sun and determined the ones that experienced minima.
When the energy from the Sun will be greatly diminished it will set series of events on Earth that starts with the thinning of the ozone layer at the stratosphere. As the ozone layer will become thinner than normal the temperature structure of the stratosphere changes, which in turn changes the weather and wind patterns.
Lubin said the cooling down will not be uniform. Europe will be colder than usual during the minimum but other areas like Alaska and southern Greenland will be warmer.
Lubin and his team believed that the present downward sunspot patterns recently are similar to the solar events before the last minimum.
The researchers, however, warned that the predicted cooling down cannot stop the present warming since the cooling effect of the grand minimum is only a small fraction of the warming effect due to the presence of greenhouse gases in the atmosphere.
The study, “Ultraviolet Flux Decrease Under a Grand Minimum from IUE Short-Wavelength Observation of Solar Analogs,” published in the Astrophysical Journal Letters was supported by the state California.
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