This week, warnings of an impending “mini ice age,” set to hit in the 2030s, have been circulating in the media. It’s a story that has caused shivers among the public, but there’s one problem: Climate scientists aren’t buying it.
The ice age idea got rolling last week when researcher Valentina Zharkova, a professor of mathematics at Northumbria University in England, presented some of her recent research into solar variations at the Royal Astronomical Society’s National Astronomy Meeting in Wales. The presentation was based on a study she had published last year in the Astrophysical Journal, which presented a technique for understanding variations in solar radiation and made some predictions about how this radiation will change in the near future. Most notably, the research predicts that between 2030 and 2040, solar activity should drop significantly, leading to a condition known as a “solar minimum.”
According to the research, solar activity at this time should resemble conditions last seen in the mid-1700s during a period known of low solar radiation known as the “Maunder Minimum.” The interesting thing about this period was that it coincided with a “little ice age” in Europe and North America — a time marked by unusually cold temperatures and bitter winters. Now that Zharkova and her colleagues are predicting another solar minimum coming up, media coverage has jumped on the idea that a modern “mini ice age” is in store.
It’s a dramatic idea, but it isn’t being embraced by many climate scientists, who argue that anthropogenic global warming — brought on by a human outpouring of greenhouse gas emissions into the atmosphere — will far outweigh any climate effects that might be caused by the sun. As far as the solar variations go, “The effect is a drop in the bucket, a barely detectable blip, on the overall warming trajectory we can expect over the next several decades from greenhouse warming,” said Michael Mann, distinguished professor of meteorology at Pennsylvania State University, in an e-mail to The Washington Post.
However, the issue isn’t so simple for Zharkova, who is openly skeptical about the strength of anthropogenic greenhouse gases when compared to the influence of the sun.
On the one hand, Zharkova maintains that her research was not intended to make assumptions about the effects of solar variation on climate — only to lay out predictions about the solar activity itself. “What will happen in the modern Maunder Minimum we do not know yet and can only speculate,” she says. On the other hand, she adds, her gut assumption is that temperatures will drop as they did 370 years ago.
The reason, she says, is her belief that the sun is a bigger influence on earthly climate than the effects of greenhouse gases in the atmosphere. “I am not convinced with the arguments of the group promoting global warming of an anthropogenic nature,” Zharkova says, adding that she would need to examine more research before she could take a clear stance on anthropogenic climate change. Given the right evidence, she says she might accept that human-caused climate change is a bigger factor — but her belief for the time being is that changes in solar radiation are likely to have a bigger influence on temperature changes on Earth, not just during times of solar minimum, but throughout history.
However, this belief is in direct contrast with much literature on the topic. Georg Feulner, deputy chair of the Earth system analysis research domain at the Potsdam Institute on Climate Change Research, co-authored a paper in 2011 specifically examining the effect a solar minimum might have on Earth’s climate. His paper, and subsequent related research has concluded that any solar-related temperature drops would be far outweighed by human-caused global warming. In the case of a solar minimum, such as the one predicted by Zharkova and colleagues, “The expected decrease in global temperature would be 0.1°C at most, compared to about 1.3°C warming since pre-industrial times by the year 2030,” Feulner wrote in an e-mail to the Post.
Complicating the matter further is the idea that the 17th century’s “little ice age” wasn’t even really the result of the solar minimum going on at the time. Feulner also authored another 2011 paper that concluded that volcanic activity was the major cause of a cooler climate during this time, rather than solar variations. The takeaway is that changes in solar radiation are unlikely to hold a candle to the climatic effects being brought about by human-related greenhouse gas emissions.
While Zharkova is one of a small minority of scientists who do not fully accept human activities as the greatest drivers of current climate change, she says she’s surprised at the media response her study has garnered. “I didn’t realize there would be such a strong response from the climate people,” she says, adding that she would need to repeat the calculations of mainstream climate scientists and examine the evidence herself to decide if she can accept their point that anthropogenic influences outweigh those of the sun.
So there may well be a solar minimum in store for the near future — but it’s still probably safe to put your scarves and mittens back in storage for now. Research in the area suggests that greenhouse gas-related warming, not solar variations, will be the dominant climate factor for many years to come.
Still, Zharkova cautions, there’s not much time left until her predicted solar minimum hits. “We have only 15 years to wait, so we’ll learn soon enough,” she says.
Also in Energy & Environment: