Sunspot cycle: No ice age in next solar cycle

The sun would not usher in a fresh “little ice age” on earth in the next decade, assure Indian physicists.

Research by two Indian physicists has shown that the next solar cycle would not be too weak to trigger a global cooling effect, as predicted by other researchers three years ago.

Just like weather on earth, there is weather in space, which is affected by the 11-year sunspot cycle. Predicting how the cycle would behave is crucial not only for the functioning of the satellites, power-grids and telecommunication networks that can be hit by solar storms, but also for the global climate, which is getting warmer.

Dibyendu Nandi, a professor at the Indian Institute of Science, Education and Research, Kolkata and his colleague Prantika Bhowmik found out a new forecast model to predict the behaviour of the next sunspot cycle, which would begin around 2020.

Their technique has been very successful in matching sunspot activity observations over the last 100 years. Their method also makes it possible to make predictions almost a decade before the next sunspot cycle activity peaks in strength, which was not possible so far.

“The next solar cycle would not be too weak as suggested by others. The radiation output would be similar as the ongoing cycle. There would not be any widespread cooling or long winters to offset the warming trend,” Nandi told DH. 

The current sunspot cycle, dubbed as 'solar cycle 24' began in 2009 and is about to end. It has been one of the weakest cycles in the last four decades. In fact, 1980 onwards, successive sunspot cycles have significantly weakened in strength.

Because of the weakening nature of the sunspot cycles, another group of scientists at Northumbria University had earlier suggested the 25th solar cycle would trigger a global cooling effect like what was seen more than 300 years ago.

The episode, known as the Maunder minimum, occurred between 1645 and 1715 and coincided with the little ice age, a period of long winters and global cooling. Because of the startling nature of their claims, they hit the media headlines all over the world.

“There would not be any such little ice age. In fact, the chances of the next sunspot cycle adversely impacting the satellites, telecommunication and power grids would be slightly higher than the ongoing the cycle,” asserted Nandi. The research paper has been published in the journal Nature Communications.

Solar cycles are associated with the appearance of the sunspots. In a solar cycle there may be several thousands sunspots and some of them can release a very strong jet of charged particles — known as space storms — crippling satellites, tripping electric power grids and leading to large-scale telecommunication breakdowns. One such severe solar storm knocked off the power grids in North America was in 1989.

In the case of Maunder minimum, the number of sunspots came down to 50. It led to large scale reduction in solar irradiation, causing widespread cooling effect. As a consequence, the Thames and Danube rivers froze, the Moscow river was covered by ice in every six months and Greenland was covered by glacier.

Such a situation is unlikely to be repeated in the next decade, suggests the new study.

The research by Nandi would come in handy for Indian Space Research Organisation's first mission to the Sun — known as Aditya-L1.

“Their research show considerable predictive power, and it looks like we will now be able to predict the fluctuations of solar activity much more reliably. It would provide key inputs for the Aditya mission on which we are collaborating,” Somak Raychaudhury, director of the Inter-University Centre for Astronomy and Astrophysics, Pune, who is not associated with Nandi's reserch told DH.

“It's a significant research work from our institute. We plan to recruit more scientists and expand our Center of Excellence in Space Sciences,” commented IISER director Sourav Pal.