Nearing the End of Solar Cycle 24

And What That Means for Earth's Weather

June 12, 2018
Sunspots - NASA

Sunspots recorded on October 18, 2014.


Solar Cycle 24 is approaching its end, which will mean the beginning of Solar Cycle 25. What does that mean for Earth’s weather—and for us?

Fig. 1 (below) is a graph from the NOAA Space Weather Prediction Center showing Cycle 24’s very low level of solar activity—the lowest in more than two centuries, even lower than the level in the early 1900s and comparable to the very low levels of solar activity that occurred in the early 1800s (the period referred to as the “Dalton Minimum,” which coincided with the “Little Ice Age”).

Solar Cycle Sunspot Numbers. Graphic by NOAA SWPC.
Fig. 1

As shown in Fig. 2 (below), these three periods have brought the lowest solar activity levels since the Maunder Minimum, the period from about 1645 to 1715, when solar cycles apparently stopped and sunspots were exceedingly rare.

400 Years of Sunspot Observations.
Fig. 2

As you may know, we at The Old Farmer’s Almanac use solar activity as the primary driver of our long-range weather forecasts. We believe that changes in the Sun’s output, although relatively small, are sufficiently amplified in Earth’s upper atmosphere to strongly influence Earth’s weather patterns.

One of the most significant relationships that we have found is that periods of low solar activity are associated with colder temperatures, averaged across Earth. Our viewpoint is a controversial one, as most scientists believe that the magnitude of changes in solar activity are insufficient to have a significant effect on Earth’s weather, and they view as coincidence that past periods of exceptionally low solar activity have historically corresponded with cold periods.

However, an increasing amount of research seems to be giving credence to our theory: Although the changes in magnitude of solar activity are small, there is a mechanism in the upper atmosphere that can amplify these changes, causing larger ripples in the lower portion of Earth’s atmosphere, where weather occurs.

Historically, all of the periods in the known sunspot record that have had low activity have also had relatively cool temperatures, averaged across the globe. The Maunder Minimum coincided with an exceptionally cold period in many parts of the globe. We believe that with low solar activity continuing for at least the next 10 to 30 years, global temperatures will be cooler than they would otherwise be.

Despite the recent low solar activity, April 2018 was the third warmest April ever recorded, averaged across the globe, behind only April 2017 and April 2016. Incredibly, April was the 400th consecutive month in which temperatures averaged across the entire Earth were warmer than the month’s 20th-century average temperature.

Other Factors That Affect the Weather

So why, you might ask, have Earth’s temperatures been so consistently warm when our forecast methodology, which is based primarily on solar activity, says that they should be cool?

The answer is that solar activity is not the only factor in Earth’s weather.

For example, one factor that all atmospheric scientists believe can make Earth colder for as much as a few years is a volcanic eruption that spews ash into the middle and upper portions of the atmosphere. While this has not been a major factor in recent years, it has been at times in the past and could be again in the future.

Another factor is increased urbanization. The heat from buildings and human activities in cities makes them warmer than the surrounding countryside—something known as “the urban heat island effect.” However, most atmospheric scientists believe that this is a local effect that does not significantly raise Earth’s average temperatures.

It is important to note that although Earth, on average, has been warming for decades, not every place is or will be warmer than normal each season. Remember: Other factors are at play, including the normal variation in weather that occurs from day to day and year to year.

The most significant factor (in addition to solar activity) that has been affecting our weather in recent years has been the increase in greenhouse gases—most notably, carbon dioxide and methane—which most (but not all) atmospheric scientists believe has been making Earth progressively warmer. We have been incorporating the influence of these increases into our forecasts as a factor that will offset much of the cooling from our current period of low solar activity.

If we are correct in these factors, what this means is that the current period of low solar activity has been partially offsetting the greenhouse warming that has been occurring. This suggests that when the current period of exceptionally low solar activity ends and solar activity returns to a more normal level—perhaps in 30 years or so—we will see a rapid jump in the Earth’s average temperatures. Until that time, we would expect the general warming trend to continue, but as a slow warming in which some months set new records for global warmth but many do not.

Read more Weather Updates from Michael Steinberg.

Reader Comments

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Magnetic Effects on Earth Core and Volcanism.

There is also a direct correlation between less solar activity and increased seismic and volcanic activity.

Theory goes: magma convection cells in earth's core are maintained by higher solar activity in the form of magnetic energy, or solar winds. When solar activity eases, so eases the magnetic tension keeping these convection cells stable. Instability in the earth's magnetic field releases the convection cell's balancing tension, thus increasing non-structured fluidity in earth's magma core. This sagging effect in the earth's internal structure releases latent energy in the form of increased seismic and volcanic activity.

You'll also see pockets of polarity switching, (earth's magnetic poles changing charge, when the sun rises in the east..) telltales of this slow polarity shift are navigation problems in birds, or whole flocks of birds flying into the ground en mass death. This has been happening recently.

The clouds also begin to show as Ice Age clouds. When you view landscape paintings at the Met and other museums you'll notice that art done during the Little Ice Age express clouds which are more distant, more dramatic. There is also a visceral reaction in the psyche of northern tribes, a form of genetic memory. A genetic reaction to these clouds, and the crisp smells invoked by the changing times -- winter is coming (also manifest in literary expression).

At these minimums described in this article; typically a glaciation is triggered when a enough volcanism 'snowballs' an irreversible cooling; whether that be multiple small eruptions or a super-volcanic event. Super volcano is instant glaciation of the northern hemisphere, when in a solar minimum.

Shifting magnetic core of the Earth

In conjunction with the solar activity, the Earth's magnetic field bends and focuses the radiation of the Sun on the polar regions. The Earth's core has moved significantly in the last century. In my opinion; the resulting additional water vapor, and increased temperatures in the polar regions, have been the source of recent weather pattern variations. I am not a meteorologist, I am a retired surveyor who made a living with a compass and watched declination changes, I also watched the weather for appropriate dress, and as a result have seen a connection.

Urban Temps

Most of the temperatures come from stations that are near big cities so as these cities get hotter, average temperatures will rise. We have already seen this.

The energy that CO2 absorbs mostly comes from IR emissions from Earth so if we can cool the ground, the atmosphere will cool. However water vapor is far and away more important when it comes to warming as it can absorb wavelengths from IR and the Sun.

The changes in solar output is significant on Earth's temperatures just as temps have changed on Mars. I believe we are going to see a cooling trend because of the solar minimum IF it pans out as expected. NASA's solar observatories are giving us invaluable data. Scientists have been telling us that the weather has been unusually calm and constant over the past 100 years. I expect that to change. I only wish I could see the tidal pools return to the Sahara, and yes they will return in about 300 years.

Earths urban temperatures

I think all the black asphalt parking lots should be painted white. Sometimes they are so hot a bird or a butterfly couldn’t land there. I’m surprised they don’t melt tires. You can cook an egg on them


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