Record snow and cold spans the country this Fall at the same time scientists say our Sun is nearing what’s called ‘solar minimum’ - a low point in solar activity.
There has been speculation that there is a correlation between a weak sun and a cold earth, but it’s not that easy to prove.
Solar minimum is often accompanied by little or no sunspots. Those are disruptions in the sun's atmosphere caused by intense magnetic energy. They appear visibly as dark patches on the surface of the sun.
“The number of spots waxes and wanes over the course of about 11 years. That’s called the sun spot cycle,” said Scott McIntosh, director of the High-Altitude Observatory in Boulder, Colorado. He’s also currently the interim director of the NCAR (National Center for Atmospheric Research).
McIntosh said the sun has been relatively spot free for more than a year. An indication that it is nearing solar minimum.
He says we are about 10 years into the current sun spot cycle, which even at its peak in 2014, was the weakest in nearly 100 years.
“So, solar activity is very low, and it’s been going down for the last 25 to 30 years, so it’s been trending down by about 25 percent per decade,” said McIntosh.
Now the Colorado high country is benefiting from a cold and snowy Fall, the most early-season snow cover across North America in 50 years, and global temperatures dropping slightly over the last two years.
2017 was slightly cooler than the record breaking heat of 2016, and 2018 is on pace to be just slightly cooler than 2017, although the last 4 years will still rank as the top 4 warmest in recorded history.
Those are the kind of numbers that have been fueling speculation that the lack of solar activity is responsible for cooling on Earth.
“We talk about a lot of that stuff as being third-rail science,” said McIntosh. “Stuff that you’ve got to tread really carefully on when you’re talking about it because it’s not widely excepted in the scientific community.”
McIntosh says the sun's energy only varies by about 0.1 percent at max. That's not enough to change weather, but he says its magnetic energy could impact the weather more than we think. We just don’t know enough about it to draw conclusions.
There have even been headlines - by social media scientists and non-accredited news organizations - claiming that a mini Ice Age is looming. The claim is based on an extended solar minimum, called the Maunder Minimum, which occurred in the late 17th and early 18th centuries.
Cold global temperatures during that period earned it the nickname 'Little Ice Age,' not a true Ice Age.
McIntosh said another extended solar minimum like that is unlikely to occur today, but he won’t completely disregard some of the data correlation between cold winters and solar minimums.
“If the commercial guys that are making money off of this are noticing these empirical relationships between weather and solar activity, at that kind of gross scale, then maybe there’s something to it,” said McIntosh. “Maybe it’s our job to get in there under the hood and try and figure out why that may work.”
McIntosh said solar minima usually last 9 to 14 years, and the true solar minimum of this cycle will likely occur sometime during 2019, but could take longer.
Once it bottoms out, the sun will start Cycle 25. What’s that going to be like?
“That’s the 64-million-dollar question if you’re speculating on that stuff,” said McIntosh. “Based on the trends and the modeling, I would say it’s probably going to go down and be even less active, but there are slight indicators that are very subtle but have borne the test of time for over a century or more, showing that the next cycle will be a little bit higher.”