Could be heading towards a Grand Solar Minimum but not an ice age

The last relatively low energy 11 year solar cycle, according to some scientists, suggests the planet could be heading for a Grand Solar Minimum. The last time this happened over three hundred years ago Earth experienced the Little Ice Age, but even if we do experience a Grand Solar Minimum it ios thought that global warming will more than compensate, so no ice age is expected.

NASA Climate Blog: There Is No Impending ‘Mini Ice Age’

There is no impending “ice age” or “mini ice age” to be caused by an expected reduction in the Sun’s energy output in the next several decades.

Through its lifetime, the Sun naturally goes through changes in energy output. Some of these occur over a regular 11-year period of peak (many sunspots) and low activity (fewer sunspots), which are quite predictable.

temperature vs solar activity

The above graph compares global surface temperature changes (red line) and the Sun’s energy that Earth receives (yellow line) in watts (units of energy) per square meter since 1880. The lighter/thinner lines show the yearly levels while the heavier/thicker lines show the 11-year average trends.

But every so often, the Sun becomes quieter, experiencing much fewer sunspots and giving off less energy. This is called a “Grand Solar Minimum,” and the last time this happened, it coincided with a period called the “Little Ice Age” (a period of extremely low solar activity from approximately AD 1650 to 1715 in the Northern Hemisphere, when a combination of cooling from volcanic aerosols and low solar activity produced lower surface temperatures).

Some scientists have suggested that the relatively small magnitude of the last solar cycle (SC 24) presages a new Grand Solar Minimum in the next few decades.

grand solar minimum on timeline

In terms of climate forcing – a factor that could push the climate in a particular direction – solar scientists estimate it would be about -0.1 W/m2, the same impact of about three years of current carbon dioxide (CO2) concentration growth.

Thus, a new Grand Solar Minimum would only serve to offset a few years of warming caused by human activities.

What does this mean? The warming caused by the greenhouse gas emissions from the human burning of fossil fuels is six times greater than the possible decades-long cooling from a prolonged Grand Solar Minimum.

Even if a Grand Solar Minimum were to last a century, global temperatures would continue to warm. Because more factors than just variations in the Sun’s output change global temperatures on Earth, the most dominant of those today being the warming coming from human-induced greenhouse gas emissions.

So it would only impact slightly on the current rate of warming.

We’ve just had five consecutive mornings of light frosts here in Dunedin, which is a bit unusual compared to the last few years where winters have been milder and frosts have been uncommon even in June/July, but this has nothing to do with the grand scheme of things, it’s just a minor variation in the current living level.