If the sun goes into ‘hibernation,’ it won’t stop global warming

by Joseph Romm.

The anti-science disinformers are ecstatic over that says by 2020, we might be entering a long period of anomalously low solar activity. The at Fox Nation is:

No. Not even close, actually.

Yes, there is a based on independent studies that we could possibly be entering a so-called “grand minimum” in solar activity. And yes, the last one on record, the “Maunder Minimum,” which occurred between 1645 and 1715, coincided with the so-called Little Ice Age.

But the Little Ice Age wasn’t just driven by a drop in solar forcing—it was also driven by . And now we have human-caused greenhouse gases that have overwhelmed the much, much smaller solar forcing.

You’d never know it from the anti-science crowd, but last year, Geophysical Research Letters (GRL) published [PDF] of this precise situation, “On the
effect of a new grand minimum of solar activity on the future climate on Earth.” That peer-reviewed study concluded that if we did see a Maunder Minimum this century:

[G]lobal mean temperatures in the year 2100 would most likely be diminished by about 0.1 degrees C [0.18 degrees F].

That means, on our current emissions path, we would be only about 9 to 11 degrees F warmer than pre-industrial levels in 2100, rather than, say, about 9 to 11 degrees F warmer. I would note that the 2010 analysis did not include major carbon cycle feedbacks like , whose impact will likely exceed that of any drop in solar irradiance this century.

Here are three key points:

The sun is “the dominant source of energy for Earth’s climate system” as the GRL paper notes, but “changes associated with solar variability are small” and “their contribution to recent warming is negligible.”

2010 was tied with 2005 as in spite of coming at the end of “.”

As NASA , “let’s assume that the solar irradiance does not recover. In that case, the negative forcing, relative to the mean solar irradiance is equivalent to seven years of CO2 increase at current growth rates. So do not look for a new ‘Little Ice Age’ in any case.”

A Maunder Minimum can’t stop catastrophic global warming—only we can, by slashing CO2 emissions!

The GRL analysis was in fact done because of this deep solar minimum, which is plotted below:

Now, as we are have finally come out of that deep minimum, we have this new :

As the current sunspot cycle, Cycle 24, begins to ramp up toward maximum, independent studies of the solar interior, visible surface, and the corona indicate that the next 11-year solar sunspot cycle, Cycle 25, will be greatly reduced or may not happen at all.

The results were announced at the annual meeting of the Solar Physics Division of the American Astronomical Society, which is being held this week at New Mexico State University in Las Cruces.

“This is highly unusual and unexpected,” Dr. Frank Hill, associate director of the National Solar Observatory’s Solar Synoptic Network, said of the results. “But the fact that three completely different views of the Sun point in the same direction is a powerful indicator that the sunspot cycle may be going into hibernation.” …

All three of these lines of research to point to the familiar sunspot cycle shutting down for a while.

“If we are right,” Hill concluded, “this could be the last solar maximum we’ll see for a few decades. That would affect everything from space exploration to Earth’s climate.”

Yes, it would affect the climate, just not much.

The Naval Research Laboratory and NASA reported in 2009 that, “if anything,” the sun contributed “a very slight overall cooling in the past 25 years.” The study, “,” found:

According to this analysis, solar forcing contributed negligible long-term warming in the past 25 years and 10 percent of the warming in the past 100 years…

Source: If the sun goes into ‘hibernation,’ it won’t stop global warming.