The Effects of Sunspots on Earth's Climate

Sunspots

• Sunspots are dark areas on the sun caused by anomalies in the star's magnetic activity. They are thousands of degrees cooler than the rest of the sun's surface, making them comparatively darker. Sunspot activity does not remain constant. It increases and decreases over the course of a solar cycle, which takes 11 years. The lowest point of the cycle is the solar minimum, when sunspot activity is low or non-existent. The solar maximum, on the other hand, involves a great deal of sunspot activity.

Effect on Climate

• Because the sun has a direct impact on the Earth's climate, sunspots do as well. However, "Solve Climate News" explains that these effects are minor compared to those caused by global emissions. Georg Feulner and Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research conducted a study to model the effects of low sunspot activity. According to their conclusions, a sudden reduction in sunspot activity would reduce the average global temperature by 0.26 degrees Celsius in the year 2100. When human activity is taken into consideration, an average rise in global temperature from 3.7 to 4.5 degrees Celsius is expected by 2100.

Sunspots as Scapegoats

• In the United States, opinions are sharply divided as to whether man-made global warming exists. Although sunspots do cause some climate change, "Scientific American" explains that they are a focal point for global-warming deniers. Specifically, "Some skeptics of human-induced climate change blame global warming on natural variations in the sun's output due to sunspots and/or solar wind." On the opposite side, Joerg Knipprath, a law professor at Southwestern University and a conservative blogger, claims that "[V]ariations in solar energy output have far more effect on Earth's climate than soccer moms driving SUVs."

The Maunder Minimum

• The Maunder Minimum was a period of extremely low sunspot activity that lasted from 1650 to 1710. It was "associated with markedly cooler temperatures," according to "Solve Climate News." On the surface, this would seem to indicate that sunspots can have a significant effect on climate. However, the global cooling was caused by a reduction in atmospheric ozone, according to researchers at the NASA Goddard Institute for Space Studies. Ozone formation is fueled by solar radiation; with less radiation, less ozone was produced. This resulted in a chain reaction that pushed many more winter storms over the Atlantic to Europe.