"Pink elephant in the room" time: 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.
The amount of solar energy that Earth receives has followed the Sun’s natural 11-year cycle of small ups and downs with no net increase since the 1950s. Over the same period, global temperature has risen markedly. It is therefore extremely unlikely that the Sun has caused the observed global temperature warming trend over the past half-century. Credit: NASA/JPL-Caltech
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.
But how big of an effect might a Grand Solar Minimum 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. Because more factors than just the Sun’s output determine global temperatures on Earth, the most dominant of those today being the warming coming from human-induced greenhouse gas emissions.
