At a Glance

The sun periodically goes through a time of diminished magnetism known to scientists as a grand solar minimum. Scientists believe the last grand minimum occurred in the 17th century.

The sun is likely to emit less UV radiation for a period of time by mid-century, a new study says, which may "slow down but not stop global warming."

The that'sknown to scientists as a grand solar minimum, according to the Scripps Institutionof Oceanography.The next grand minimum could come by mid-century based on historical sunspot patterns and data, researchers say.

Scientists believe this periodic dimming of the sun is triggered by fluctuationsinits magnetic field, which leads to fewersunspots and less ultraviolet radiation reaching the earth's surface.

Magnetic loops gyrate above the sun, March 23-24, 2017.

(NASA/GSFC/Solar Dynamics Observatory)

The last time a grand minimum occurred was in the 17th century, scientists determined,using reconstructions based on geological and historical data. Known as the Maunder Minimum,the period was so cold that the Thames River in England froze frequently, SIC notes. It was also cold enough to freeze the Baltic Sea, which allowedthe Swedish army to invade Denmark in 1658 on foot.

During a grand minimum, weather patterns do change but the cooling is not uniform. During the Maunder Minimum, for example, temperatures across Europe did drop but other areas like Alaska and southern Greenland warmed significantly.

The researchers of the said that while a short-term cooling here on earth can be expected, it will have little impact on global warming in the long run. A separate study determined that , perhaps for as many as 50 years, temperatures will quickly catch up to current predictions forfuture warming.

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The Scripps team was the first to estimate just how much less UV radiationis expected to be emitted by the sun during the next grand minimum,based onan 11-year cycle known as a "solar minimum" during which the sun's ultraviolet radiation peaks and declines. Lubin and his team believe that UV radiation drops an additional 7 percent below the lowest solar minimum decline during a grand minimum.

“Now we have a benchmark from which we can perform better climate model simulations,” Lubin said. “We can,therefore, have a better idea of how changes in solar UV radiation affect climate change.”