No ice age

"Pink elephant in the room" time: There is no impending “ice age” or "mini ice age" if there's a 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.

But every so often, the Sun becomes quieter for longer periods of time, 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). Anomalous periods like a Grand Solar Minimum show that magnetic activity and energy output from the Sun can vary over decades, although the space-based observations of the last 35 years have seen little change from one cycle to the next in terms of total irradiance. Solar Cycle 24, which began in December 2008 and is likely to end in 2020, was smaller in magnitude than the previous two cycles.

On occasion, researchers have predicted that coming solar cycles may also exhibit extended periods of minimal activity. The models for such predictions, however, are still not as robust as models for our weather and are not considered conclusive.

But if such a Grand Solar Minimum occurred, how big of an effect might it have? 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. The reason for this is because more factors than just variations in the Sun’s output change global temperatures on Earth, the most dominant of those today is the warming coming from human-induced greenhouse gas emissions.