Cycle 24, the current sunspot cycle is believed to last approximately from the year 2008 to the year 2019. Thus, we haven’t reached the lowest ebb of the cycle yet, and no one knows precisely when that will happen. However, solar physicists believe it’s probably close. Cycle 24 has been strange, with fewer dark sunspots visible on the sun’s surface than previously thought.
Now that the next cycle is set to start, experts are beginning to project what will happen when the sun revs up again and begins generating more sunspots. Will the next sunspot cycle be less strange than this one, or will we see a decreased number of spots again?
Last Thursday, the Center of Excellence in Space Sciences India (CESSI) reported that two of its scientists had predicted the upcoming sunspot cycle. Solar physicist Dibyendu Nandi and his Ph.D .student Prantika Bhowmik have come up with a new prediction technique, one that simulates conditions both in the sun’s interior, where sunspots are produced and on the solar surface, where sunspots are destroyed.
Earlier predictions (such as this one) have proposed that the coming sunspot cycle 25 will be weaker than the present cycle 24. However, based on their model, Nandi and Bhowmik think cycle 25 could be similar to or even stronger than 24. They expect the next cycle to start rising about a year from now and to peak in 2024. Their work was recently published in the peer-reviewed journal Nature Communications.
Since high activity on the sun can negatively affect some earthly technologies, including, electric grids and orbiting satellites many people like to follow the sunspot cycles, thus, just like Nandi and Bhowmik highlight, an accurate prediction of a coming solar cycle could assist space scientists in planning satellite launches and estimating the lifetimes of satellite missions.
Moreover, a different sun-Earth issue has especially piqued the public’s curiosity: a little-understood, possible connection between activity on the sun and Earth’s climate.
A statement from CESSI explained the climate question:
The current sunspot cycle, known as solar cycle 24, is coming to an end, and it has been one of the weakest cycles in the last one hundred years. In fact, over the last several decades, successive sunspot cycles have significantly weakened in strength, and some earlier studies based on simplistic statistical approaches have claimed that a notable weakening of the sun’s activity is forthcoming, which would result in a loss of sunspot cycles.
The last episode of this type, dubbed the Maunder minimum, took place between 1645 and 1715 and coincided with the Little Ice Age, a time of long winters and global cooling.
So did the weakened activity on the sun cause the Little Ice Age? If so, could a series of weak solar cycles result in another global cooling in the future? If that occurred, the cooling would come on top of the ongoing trend of global warming, which nearly all climate scientists agree is the result of human activities.
For scientists, there are two main issues with the idea of a sun-caused cooling (or sun-caused warming, even). For one, no known physical mechanism has been discovered, explaining exactly how a change in solar activity affects Earth’s climate.
For two, scientists are aware of only one episode of decreased sunspots during a time of global cooling. The coincidence of the Maunder Minimum and Little Ice Age is suggestive but has not proven anything for scientists.
Nevertheless, the coincidence is there, and the concept is interesting. So scientists have been asking the question: will a significantly weak sunspot cycle 25 – in the next ten years – temporarily mitigate ongoing global warming?
As per Bhowmik and Nandi, that question may be moot. The sun could see it’s more “normal” activity resume in the coming decade and might begin generating many more sunspots.
Bhowmik and Nandi stated that they have found no evidence of an impending disappearance of sunspot cycles and therefore conclude that speculations of an imminent sun-induced cooling of global climate are very improbable.
Of course, only time will tell.