The anti-science disinformers are ecstatic over an analysis that says by 2020 we might be entering a long period of anomalously low solar activity. The headline at Fox Nation is:
Not. Not even close, actually.
Yes, there is a credible prediction 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 LIA wasn’t just driven by a drop in solar forcing – it was also driven by a burst of volcanic activity (see “A detailed look at the Little Ice Age“). 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 a major analysis of this precise situation, “On the effect of a new grand minimum of solar activity on the future climate on Earth,” (PDF here). That peer-reviewed study concluded that if we did see a Maunder minimum this century:
In summary, global mean temperatures in the year 2100 would most likely be diminished by about 0.1°C
That means, on our current emissions path, we would be only about 9°F to 11°F warmer than preindustrial levels in 2100, rather than, say about 9°F – 11°F warmer. I would note that the 2010 analysis did not include major carbon cycle feedbacks like the tundra, whose impact will likely exceed that of any drop in solar irradiance this century (see NSIDC bombshell: Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100).
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” (see links below).
- 2010 was tied with 2005 as the hottest year on record in spite of coming at the end of “the deepest solar minimum in nearly a century.”
- As NASA wrote during the deep 2009 minimum, “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:
The Chamber of Commerce, as ThinkProgress has extensively documented, went to great lengths 
Since it was passed in 2009, Republicans have derided the American Recovery and Reinvestment Act of 2009, 
Turns out that one of the most inconspicuous home fixtures is one of the biggest energy hogs — even when they aren’t recording or replaying programs!
