蜜桃恋人

Solar Minimum Approaching | A Mini Ice Age?

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The Sun three years ago when storms were still visible on its surface. This image was taken by my friend Matt Francis, the director of the Prescott Observatory.   

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Could a Deep Solar Minimum Bring About a New Ice Age?

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Sunspots are disappearing more rapidly than usual as the Sun prepares to enter the solar minimum. The last time the absence of sunspots was so prolonged was the 鈥淟ittle Ice Age,鈥 which happened back in the 1600s. Will Earth experience another cold snap?

First, understand that the Sun normally follows sunspot cycles of roughly 11 years. Think of sunspots as storms on the Sun. Learn more about sunspots here.

The cycle starts out hot with a 鈥渟olar maximum鈥 littered with solar storms and sunspots; then the temperature cools and we enter a 鈥渟olar minimum鈥 with a decrease in sunspots. Then the cycle begins again. However:

  • The current cycle 24 (which began in 2008鈥攖wo years late) has been very strange. Its 鈥渕aximum鈥 in 2014 was the lowest sunspot peak since the early 1800s. That was followed by years of decreased sunspots until now, this past year, when we鈥檝e gone weeks at a time without a single spot on the Sun鈥檚 face. 
  • The prior cycle 23 also had an extended period of very few sunspots compared to any cycle this past century.

We Have a Stake in the Outcome

In an op-ed that accompanied the publication of my book 鈥淭he Sun鈥檚 Heartbeat,鈥 I wrote in 2011 that, 鈥済lobal temperatures are now so steadily high that even with the recent reduced rate of warming, 2010 still managed to join 1998 as one of the warmest years ever recorded.鈥 

鈥淚f the upcoming solar max of cycle 24 is normal or robust,鈥 I continued, 鈥渁nd especially if an El Nino follows it two years later (as often happens), then the middle of this decade will be the hottest period since humans arrived on Earth. However, if the upcoming maximum is wimpy, as most solar researchers expect, or if the Sun is now entering an extended period of low activity with another deep minimum to follow, that is the best thing it could possibly do for us. Such a scenario would mitigate climate change. Essentially, the Sun has been buying us time.鈥

Want to know what happened? Well, cycle 24 has now run its course. Sunspots are vanishing even faster than we expected. Forecasters have been saying for years that this would happen as cycle 24 comes to an end. The surprise is how fast. The National Oceanic and Atmospheric Administration (NOAA) agrees, saying: 鈥淪olar cycle 24 is declining more quickly than forecast.鈥

As the NOAA graph makes clear, we are bottoming out now, with almost no solar storm activity.

Solar Cycle Sunspot Number

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How Does the Sun Affect Earth鈥檚 Climate?

This affects us because Earth鈥檚 climate gets cooler when there are fewer solar storms. The extreme example happened between 1645 and 1715 when the normal 11-year sunspot cycle vanished. This period, called the Maunder Minimum, was accompanied by bitterly cold winters in the American colonies. Fishing settlements in Iceland and Greenland were abandoned. Icebergs were seen near the English channel. The canals of Venice froze. It was a time of great hardship.

No one understands why the 11-year sunspot cycle could simply stop for a full human lifetime. (Back then, it strangely coincided with the rule of the French 鈥淪un King,鈥 Louis XIV). There鈥檚 no way to know if we鈥檙e really currently on the cusp of a repeat performance.

But if this strange recent solar activity means that another Maunder Minimum is nearly upon us, as a few solar researchers believe, the global cooling would be mitigating Earth鈥檚 warming at the best possible time. 

However, if we do have a 鈥淢aunder Minimum,鈥 it would not be a return to the 鈥淟ittle Ice Age.鈥 Solar radiation expert Judith Lean, PhD, of the Naval Research Laboratory points to a current global surface temperature that鈥檚 about 1.8 degrees Fahrenheit, warmer than at the time of the Maunder Minimum and says that a return to a Maunder Minimum phenomenon would lead to a cooling by only one-tenth of a degree C or 0.18 degree F.

We鈥檒l have to wait and see.

For the moment, if you have a leftover solar filter from last August鈥檚 eclipse, take a glance at the Sun these days. You鈥檒l see a strange blank disk.

See our full update on solar activity, the Little Ice Age, and cycle 24.

About The Author

Bob Berman

Bob Berman, astronomer editor for The Old Farmer鈥檚 蜜桃恋人, covers everything under the Sun (and Moon)! Bob is the world鈥檚 most widely read astronomer and has written ten popular books. Read More from Bob Berman