Solar Minimum Approaching | A Mini Ice Age?

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

February 27, 2019
Sunspots

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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 “Little Ice Age,” 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 “solar maximum” littered with solar storms and sunspots; then the temperature cools and we enter a “solar minimum” with a decrease in sunspots. Then the cycle begins again. However:

  • The current cycle 24 (which began in 2008—two years late) has been very strange. Its “maximum” 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’ve gone weeks at a time without a single spot on the Sun’s 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 “The Sun’s Heartbeat,” I wrote in 2011 that, “global 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.” 

“If the upcoming solar max of cycle 24 is normal or robust,” I continued, “and 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.”

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: “Solar cycle 24 is declining more quickly than forecast.”

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

Solar Cycle Sunspot Number

sunspot-chart_full_width.png

How Does the Sun Affect Earth’s Climate?

This affects us because Earth’s 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 “Sun King,” Louis XIV). There’s no way to know if we’re 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’s warming at the best possible time. 

However, if we do have a “Maunder Minimum,” it would not be a return to the “Little Ice Age.” Solar radiation expert Judith Lean, PhD, of the Naval Research Laboratory points to a current global surface temperature that’s 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’ll have to wait and see.

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

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

About This Blog

Welcome to “This Week’s Amazing Sky,” the Almanac’s hub for everything stargazing and astronomy. Bob Berman, longtime and famous astronomer for The Old Farmer’s Almanac, will help bring alive the wonders of our universe. From the beautiful stars and planets to magical auroras and eclipses, he covers everything under the Sun (and Moon)! Bob, the world’s mostly widely read astronomer, also has a new weekly podcast, Astounding Universe