Sunspot Drop Won’t Cause Global Cooling | Wired Science | Wired.com
The cooling impact of the last prolonged solar lull “was probably only a couple tenths of a degree Celsius,” said climatologist Michael Mann of Penn State University. “It’s a tiny blip on the radar screen if you’re looking at the driving factors behind climate change.”
“The example I like to use is that greenhouse warming right now is the equivalent of 2 watts of power illuminating every square meter of the Earth’s surface. It’s like a Christmas tree light over every square meter. By mid-century, it will be closer to 4 watts,” said Mann, who was a co-author on that 2001 Science paper. “The maximum impact factor of the sun is 0.2 watts per meter squared.”
At most, a prolonged solar minimum would temporarily offset rising global temperatures for a few years, perhaps a couple decades, said NASA climatologist David Rind, who has also studied Maunder Minimum dynamics. But “when the sunspots return, the additional energy will cause additional warming,” he said.
“To point to this as something that could in any way ameliorate greenhouse gas warming is folly,” said Mann.