Solar Science

A blog of solar physics

Popular Mechanics on the Solar Minimum

with 7 comments

Joe Pappalardo at Popular Mechanics has a fascinating article on the possible (probable?) result of an extended solar minimum such as that which we are experiencing: global cooling:

Every day, scientists hoping to see an increase in solar activity train their instruments at the sun as it crosses the sky. This is no idle academic pursuit: A lull in solar action could potentially drive the planet’s temperature down, or even prompt a mini Ice Age.

Woah! I wonder if Joe has heard about the overwhelming scientific consensus that denies such a result? Maybe I should sic James Hansen on him…

For millennia, thermonuclear forces inside the star have followed a regular rhythm, causing its magnetic field to peak and ebb, on average, every 11 years. Space weathermen are watching for telltale increases in sunspots, which would signal the start of a new cycle, predicted to have started last March and expected to peak in 2012. “When the sun’s active, it’s a little bit brighter,” explains Ken Tapping, a solar researcher and project director for Canada’s National Research Council.

So far, Tapping reports no change in the magnetic field strength, as measured by radio telescopes. On the more positive side, last month NASA reported a small, earth-sized sunspot with a magnetic field pointing in the opposite direction from those in the previous cycle; qualities that designate the spot as a signal of a new upturn in activity. At the solar maximum, scientists expect to see between 75 and 150 such sunspots per day.

Tapping oversees the operation of a 60-year-old radio telescope that he calls a “stethoscope for the sun.” Recent magnetic field readings are as low as he’s ever seen, he says, and he’s worked with the instrument for more than 25 years. If the sun remains this quiet for another a year or two, it may indicate the star has entered a downturn that, if history is any precedent, could trigger a planetary cold spell that could bring massive snowfall and severe weather to the Northern Hemisphere.

The last such solar funk corresponded with a period of bitter cold that began around 1650 and lasted, with intermittent spikes of warming, until 1715. While there were competing causes for the climatic shift—including the Black Death’s depopulation of tree-cutting Europeans and, more substantially, increased volcanic activity spewing ash into the atmosphere—the sun’s lethargy likely had something to do with it.

Of course, no mention of greenhouse gases.

Just how much influence the sun has on global temperatures has been the subject of sometimes acrimonious debate. While an upswing in solar activity may cause a warming trend, it was discounted in the mid-1990s as the sole driver of current climate change. And for anyone hoping that a solar downswing might bail us out of our current dilemma: Solar influence on climate is slight compared to the impact of man-made greenhouse gases, a National Academy of Sciences report concluded in 1995.

Ah, there it is! So what we have is a contest between global warming due to greenhouse gases, and global cooling due to solar dimming.

Its a dilemma as to what to wish for. Global cooling such as the Little Ice Age would have been a technological challenge to modern 21st Century agriculture, technology and energy resources. What’s there to worry about with global warming? Deserts like the Sahara shrinking is a bad thing to be avoided…like the Plague?


Written by John A

February 7, 2008 at 12:32 pm

7 Responses

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  1. The article implicitly accounts ‘increased volcanism’ as an independent cause, with respect to diminished insolation, of global cooling. I don’t have a paper to cite, but have heard noises that minima in the solar and terrestrial magnetic fields are somewhat positively correlated with increased volcanism.

    Gary Gulrud

    February 12, 2008 at 5:51 pm

  2. yes, i’ve heard too


    February 12, 2008 at 6:14 pm

  3. We are discovering new relationships all the time, who knows what we don’t know?

    Not as many as you’d think. Humans, for the most part, don’t have a clue. Don’t want one, either. They’re happy. They think they’ve got a pretty good bead on things.

    Why the big secret? People are smart, they can handle it.

    A person is smart. People are dumb. Everything they’ve ever “known” has been proven to be wrong. A thousand years ago everybody knew as a fact, that the earth was the center of the universe. Five hundred years ago, they knew it was flat.
    Fifteen minutes ago, you knew we humans were alone on it. Imagine what you’ll know tomorrow.


    February 13, 2008 at 2:44 am

  4. We’re waiting for sunspots…where are they?

    What are
    the chances of an Ice Age?

    The Apocalypse Times

    February 22, 2008 at 4:57 pm

  5. ‘Five hundred years ago, they knew it was flat.’

    500 years ago, Columbus KNEW it was Round- it was the diameter of the globe they got wrong. Even though the diameter had been figured fairly close almost 2000 years earlier, by the Greeks.

    I am NOT looking forward to -40 weather in Southern Ontario- in October.


    March 7, 2008 at 12:34 am

  6. The Popular Mech. article said, “..for anyone hoping that a solar downswing might bail us out of our current dilemma: Solar influence on climate is slight compared to the impact of man-made greenhouse gases, a National Academy of Sciences report concluded in 1995.”

    Well under normal circumstances, yes, that’d be true for a single solar cycle.

    But that’s not the problem, we’re looking at an extended run of FIVE long-frequency, low-amplitude solar cycles, and NASA found in a 2001 study that such a “grand minimum” will commence a real miniature ice age.

    The reason is the severity of continental winters aren’t softened by oceanic moist warm air currents borne by strong solar-driven winds. Successive low-amplitude solar cycles yield more globe-cooling La Ninas & more cloud cover.


    Better yet, data from mud & ice core samples show that these bi- & tri-centennial slumps in solar activity cause significant declines in ocean and plant productivity (see also: Tim Patterson’s mud core & Don Easterbrook’s ice core studies that show high correlations with solar cycles, both 11-year and grand minima)

    Current supporting data for an early onset of a solar grand minimum:

    Sunspot motion speed lowest in centuries, portent of very weak SC 25.

    Cumulative spotless days accumulating faster than 19th century intercycle transits:

    There is of course other data, but these are two of the more forward-looking trend analyses.

    lee rodgers

    April 21, 2008 at 4:01 pm

  7. I do not agree with pitting two unrelated theories against one another. Global warming is a side effect of an over populated, over industrialized planet. A Maundin Minimum is the result of a large scale solar cycle whose effects we do not completely understand. What is being compared in this post is a side effect of a planet containing “intelligent” life and cycles the sun goes through over the course of billions of years. I believe the 11 year cycles are apart of a greater, longer cycle the sun goes through. Earth is just another planet in the rather inhospitable space. Whether or not we will feel similar effects of the last Maundin Minimum the same way is yet to be seen. Whether global warming will counter act the effects of a dimmer sun and a lull in solar activity simply cannot be proven. There is absolutely no way to test the theory. Debating over it is a waste of time. Instead, inhabitants of Earth should strive to be good stewards regardless.

    The sun absolutely has an effect on the over-all climate of the planet. To test this, go outside and stand in the shade…then stand in the sunlight. Which one is cooler and which is warmer? This is just common sense. If the sun is putting out less radiation (which heats the Earth) it seems sensible to expect cooler temperatures, especially in the Northern Hemisphere. Space and Solar weather is a developing field of science. By observing and forecasting solar activity we can at least begin to place markers and thresholds on the influence of the sun on the planet. A complete understanding is improbable, however even a mediocre understanding will probably take a hundred years or more of data. In other words, the amount of data and length of observation has not been accomplished.


    October 31, 2009 at 4:34 am

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