Here at the Almanac, we have long believed that solar activity can influence weather here on Earth. Here’s information and solar cycles and sunspots—as well as solar activity forecasts for 2016.
What is Solar Activity?
First, what IS solar activity? Well, just like planet Earth, the Sun has weather. It has storms. And its storms can affect Earth’s weather.
- Sunspots are magnetic storms on the surface of the Sun.
- Solar flares are strong flashes of x-rays and light energy that shoot off of the Sun’s surface into space at the speed of light.
- Coronal mass ejections (CMEs) are massive clouds of gas and magnetic matter that are eruptions spreading into space.
- Other solar events include solar wind streams that come from the coronal holes on the Sun and solar energetic particles that are primarily released by CMEs.
Solar Flare. Credit: NASA
What is a Solar Cycle?
The number of sunspots increase and decrease over time in a regular, approximately 11-year cycle, called the solar or sunspot cycle. More sunspots mean solar activity. The highest number of sun spots in any given cycle is designated “solar maximum,” while the lowest number is designated “solar minimum.”
Eleven years in the life of the Sun from 1980 (start of solar maximum) to 1986 (near minimum) to 1989 (near maxium again). Credit: NASA
How Does Solar Activity Affect Weather and Earth?
Solar activity affects the Earth in many ways, some which we are still coming to understand.
- Damage to 21st-century satellites and other high-tech systems in space can be caused by an active Sun. Large solar flares—have the potential to cause billions of dollars in damage to the world’s high-tech infrastructure—from GPS navigation to power grids to air travel to financial services.
- Radiation hazards for astronauts and satellites can be caused by a quiet Sun. Weak solar winds allow more galactic cosmic rays into the inner solar system.
- Weather on Earth can also be affected. According to Bob Berman, astronomer for The Old Farmer’s Almanac: NOAA scientists have now concluded that four factors determined global temperatures: carbon dioxide levels, volcanic eruptions, Pacific El Niño pattern, and the Sun’s activity.
- Global climate change including long-term periods of global cold, rainfall, drought, and other weather shifts may also be influenced by solar cycle activity.
The Maunder Minimum or “Little Ice Age”
Times of depressed solar activity seem to correspond with times of global cold.
For example, between 1645 and 1715—during what we now call the “Maunder Minimum”—there were only about 50 sunspots (instead of the usual 40 to 50 thousand!) and harsh winters.
For 70 years, temperatures dropped by 1.8 to 2.7 degrees Fahrenheit.
Painting by Abraham Hondius, “The Frozen Thames, looking Eastwards towards Old London Bridge,” 1677. Image credit: Museum of London.
Conversely, times of increased solar activity have corresponded with global warning. During the 12th and 13th centuries, the Sun was active, and the European climate was quite mild.
Solar Cycle 24: A Quick Summary
The sun is currently in solar cycle 24, which means the 24th cycle since record-keeping began in 1755.
The solar minimum occurred in December of 2008. (At the time, it was thought that solar cycle 24 would be below average in intensity, with a maximum sunspot number of 90, and the consensus option was that the solar maximum would occur in May, 2014.)
- Cycle 24 began in early 2008. During 2008 and 2009, there were almost NO sunspots, a very unusual situation that had not happened for almost a century. Due to the weak solar activity, galactic cosmic rays were at record levels.
- The Sun’s record-breaking sleep ended in 2010. In 2011, sunspot counts jumped up. In February of 2012, the sunpot numbers reached a peak of 66.9. In late 2013, NASA reported, “The Sun’s global magnetic field is about to reverse polarity.” The sunspot number climbed into the 70s. This is still very low. By February of 2014, sunspots averaged 102.8 spots a day, which is the first time the cycle broke 100.
- The solar maximum for Cycle 24 was reached In April, 2014, when the sunspot number peaked a second time, reaching 81.9. Many cycles are double peaked, however, this is the first time the second peak was larger than the first peak (in February, 2012).
In 2015, the sun grew quieter. Cycle 24 declined in terms of sunspot number. There were two significant events with geomagnetic storms on June 22 and March 17. That said, Cycle 24 is the weakest cycle since Cycle 14 (which had a maximum of 64.2 in February of 1906). “The 3-month moving averages of sunspot numbers centered on January through December 2015 were 98.2, 78.1, 68.2, 72.4, 77.7, 76.3, 69.1, 67.5, 64.5, 64.6, 58.5 and 55.4. With this moving average you can see a smooth, steady decline in cycle 24.” –K7RA Solar Update
Solar Activity Forecast 2016
We remain in solar cycle 24. Thus far in 2016, sunspot activity is quiet. Most scientists predict that geomagnetic activity will be remain weak.
- According to NOAA’s Space Weather Prediction Center (SWPC), the monthly sunspot numbers will drop to the low 40’s during 2016, declining to the 30’s by fall of 2016.
- K7RA Solar Updates also report low levels of activity this year.
When will solar cycle 24 end? What will happen next? Stay tuned!
What Does All This Mean?
Quiet-to-average cycles may mean a cooling pattern over the next few decades. Temperatures have been colder than it would have been otherwise.
Sunspots are similar to a bathtub of lukewarm water; if you trickle in cold or hot water, it may take a while to notice the difference.
If this cooling phase on Earth, however, is offset by any warming caused by increasing greenhouse gases, they also raise the question of whether an eventual warming cycle could lead to more rapid warming on Earth than expected.