Scientists say rare drop in sunspot activity could cause global cooling

Scientists say that the sun’s usual cycle of sunspots seems to be entering a hibernation period that could last for several decades, a drastic change that would mean slightly cooler global temperatures.

Sunspots are fading and may vanish from the sun’s surface, according to three studies presented Tuesday at the American Astronomical Society's Solar Physics Division in New Mexico, reports Agence France-Presse. The studies predict a weakening of the sun's magnetic field, resulting in a temporary disappearance of sunspots and solar flares.

The decline in solar activity is unusual and unexpected, and scientists are wondering if this could be the start of a second “Maunder Minimum,” a 70-year period that began around 1645 when hardly any sunspots were observed. This decline in sunspots coincided with below-normal temperatures, in a climate period known as the “Little Ice Age.”

But scientists warn that the temperature change due to a decline in sunspot activity would likely be minimal and not enough to compensate for global warming.

"A new Maunder-type solar activity minimum cannot offset the global warming caused by human greenhouse gas emissions," wrote authors Georg Feulner and Stefan Rahmstorf, AFP reports.

"Moreover, any offset of global warming due to a grand minimum of solar activity would be merely a temporary effect, since the distinct solar minima during the last millennium typically lasted for only several decades or a century at most."

Fading sunspots would, however, be good news for satellites and astronauts, the Christian Science Monitor reports. Solar flares and storms can interfere with space exploration, satellite communications and GPS systems.

For example, warnings were issued last week when a moderate solar flare sent a coronal mass ejection in the direction of the Earth.

Sunspots, which are relatively cool regions of hot gas on the sun’s surface caused by intense magnetic activity, tend to wax and wane every 11 years or so.