Every few years, there comes along a heartening piece of research that will have us believe global warming is not our cross to bear. One such happy theory that did the rounds a few years ago attributed rising temperatures on Earth to sunspots—cool, dark regions of high magnetic energy that occur periodically on the Sun and are accompanied by intense solar activity—and came with the more suspect corollary that soon, a dip in solar activity will cause a mini ice age. As it turns out, even as parts of India prepare for higher temperatures, solar activity is at a 100-year low and, according to experts, it is very unlikely to induce a cold wave.
Since the mid-19th century, astronomers have known that sunspots, which often have a magnetic field 10,000 times that of the Earth, follow an 11-year cycle. As it waxes to its peak, a cycle may be marked by as many as a hundred sunspots, violent explosions known as solar flares, and mass ejections of plasma from the Sun’s atmosphere. As recently as in February, two years into the new solar cycle known as cycle 24 kicked off, a giant solar flare—the largest in four years—and a mass ejection triggered fears of a ‘solar storm’ that could cause damage to the tune of $2 trillion. “A large solar flare can release energy a thousand billion times that of an atom bomb and such a major discharge, which also hurls accelerated particles into space, can disrupt the Earth’s ionosphere and its magnetic field, interfering with radio and satellite communications and causing power grids to trip. Each sunspot cycle varies in intensity—a stronger cycle will have more such events,” says Arnab Rai Choudhuri, a professor at the Department of Physics, Indian Institute of Science, and an authority on sunspots, who has developed a theoretical model that predicts the intensity of a sunspot cycle. And the present cycle, he says, will be the weakest in a long time.
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