I’ve no objection at all and much praise when scientists actually make falsifiable predictions based on their understanding of the science. Thus when David Hathaway predicts that Solar Cycle 24 will be as large or larger than Solar Cycle 23, I applaud that boldness.
In this article on space.com, several aspects to the current solar minimum are discussed:
The sun’s surface has been fairly blank for the last couple of years, and that has some worried that it may be entering another Maunder minimum, the sun’s 50-year abstinence from sunspots, which some scientists have linked to the Little Ice Age of the 17th century.
Could a new sunspot drought plunge us into another decades-long cold spell?
It’s not very likely, says David Hathaway a solar physicist at NASA’s Marshall Space Flight Center in Huntsville, Ala.
Fair enough. Perhaps if I used IPCC-speak, we’d give that a 10-20% probability?
Hathaway continues to make bold observations and predictions:
The sun’s energy drives all climate and weather on Earth. And Hathaway does agree there are good indications that fluctuations in solar output related to sunspot cycles influence the Earth’s climate. And the Maunder minimum isn’t the only evidence — scientists have linked two smaller sunspot minimums (periods of time with very few sunspots) in the early 19th century to cold spells, as well as periods before the Maunder minimum deduced from tree ring records, he said.
But the sun isn’t the only thing that influences our climate: volcanic eruptions, large-scale phenomena such as El Nino, and, more recently, the accumulation of greenhouse gases in the atmosphere also affect the global climate.
Prior to the industrial revolution, the sun probably accounted for about 10 to 30 percent of climate variability, Hathaway told SPACE.com, but now that greenhouse gases have started to build up, “the sun’s contribution is getting smaller and smaller,” he added.
So the pre-industrial climate change on Earth was only 10-30% driven by solar variability. I wonder what the other 70-90% were.
Hathaway hints that volcanic eruptions have an effect, but as far as I am aware such eruptions only cool for perhaps 2 or 3 years, hardly causing a blip in a climate trend [unless we’re talking about supervolcanic events which can cause climate cooling for decades, but we haven’t had one of those for 70,000 years with the Toba explosion]. Is the rest caused by the ENSO cycle?
What of the current solar minimum and the sputtering start to Solar Cycle 24?
Signs of the current, new solar cycle (which actually overlaps with the last cycle) showed up in November 2006, and its first sunspots were seen in January of this year, and again in April, Hathaway said. So already that rules out another Maunder minimum, Hathaway says, since this solar cycle has already begun producing spots, even if there haven’t been many of them yet.
This cycle is just simply “off to a slow start,” Hathaway said.
The last three solar cycles were also what Hathaway calls “big cycles,” meaning they had more than the average number of sunspots (the average is around 110 to 120 sunspots on any given day during the cycle’s maximum). It’s not unusual for such a spate of prolific cycles to be followed my more muted solar cycles (such as the cycle that preceded the last three biggies).
Hathaway says that solar physicists are divided on their predictions of this new solar cycle — some say it will be small, others say it will be another doozy. Predictions have ranged anywhere from 75 to 150 maximum spots during its peak. “There really are two camps,” Hathaway said. Whatever the number ends up being, though, “it’s not zero,” he added.
That depends on whether the Maunder Minimum was really devoid of sunspots or had sporadic “Tiny Tim” spot groups which were not seen because of the technology used at the time.
It’s doubtful that it was really zero during that time.
Here’s the clincher:
Why the sun is so fickle in its sunspot production is still something of a quandary. “We still don’t fully understand how the sun does this,” Hathaway noted.
Now that statement I regard as the most important of the article. It might not be a popular statement with people on either side of the argument, but as far as solar cycle prediction is concerned, nobody knows for sure what will happen with the Solar Cycle next week, never mind next year or five or ten years hence.
The science of the variation of the Sun’s solar cycle is in its vary early stages. No-one, not even David Hathaway, knows what will happen next. That’s why he’s checking the Sun every day.
As Kenneth Tapping has already reported (and I blogged his observation) long solar cycles are not that unusual historically and are not in themselves indicative of how powerful are the succeeding cycles. Tapping noted that the long and weak Solar Cycle 20, (which occurred during a global cool period on Earth), was succeeded by Solar Cycles 21, 22 and 23 all of which were relatively powerful (and coincided by chance with a global warming on Earth).
But on the point of whether even a Maunder Minimum style collapse would cool the Earth, Hathaway admirably sticks with the IPCC-derived consensus:
One idea springs from the fact that the sun emits much more ultraviolet radiation when it is covered in sunspots, which can affect the chemistry of Earth’s atmosphere. The other is that when the sun is active, it produces tangled magnetic fields that keep out galactic cosmic rays. Some scientists have proposed that a lack of sunspots means these cosmic rays are bombarding Earth and creating clouds, which can help cool the planet’s surface.
But these ideas aren’t yet proven, and anyway, the sun’s contribution is small compared to volcanoes, El Nino and greenhouse gases, Hathaway notes.
Even if there were another Maunder minimum, he says, we would still suffer the effects of greenhouse gases and the Earth’s climate would remain warm. “It doesn’t overpower them at all,” Hathaway said.
So according to Hathaway, greenhouse gases are warming the Earth to such an extent that solar variation becomes unimportant. Never mind whether I agree with him (and who am I to disagree with an expert?), I applaud David Hathaway for making such scientifically falsifiable statements.
I hope he’s right about the warming. So far, during the current warming, we’ve had the major deserts contract, the tropics expand and possibly a general reduction in hurricane frequency globally during the 20th Century.
This one could be filed under “Solar Cycle 24 pessimism”
Lawrence Solomon in the Financial Post (Canada) writes:
You probably haven’t heard much of Solar Cycle 24, the current cycle that our sun has entered, and I hope you don’t. If Solar Cycle 24 becomes a household term, your lifestyle could be taking a dramatic turn for the worse. That of your children and their children could fare worse still, say some scientists, because Solar Cycle 24 could mark a time of profound long-term change in the climate. As put by geophysicist Philip Chapman, a former NASA astronaut-scientist [pictured above] and former president of the National Space Society, “It is time to put aside the global warming dogma, at least to begin contingency planning about what to do if we are moving into another little ice age.”
The sun, of late, is remarkably free of eruptions: It has lost its spots. By this point in the solar cycle, sunspots would ordinarily have been present in goodly numbers. Today’s spotlessness — what alarms Dr. Chapman and others — may be an anomaly of some kind, and the sun may soon revert to form. But if it doesn’t – and with each passing day, the speculation in the scientific community grows that it will not – we could be entering a new epoch that few would welcome.
It’s interesting that not everybody has swallowed the idea that cooling down the Earth is Good Idea.
The Little Ice Age was no fun at all
The consequences of the Little Ice Age, because they occurred in relatively recent times, have come down to us through literature and the arts as well as from historians and scientists, government and business records. When Shakespeare wrote of “lawn as white as driven snow,” he had first-hand experience – Europe was bitterly cold in his day, a sharp contrast to the very warm weather that preceded his birth. During the Little Ice Age, the River Thames froze over, the Dutch developed the ice skate and the great artists of the day learned to love a new genre: the winter landscape.
In what had been a warm Europe , adaptations were not all happy: Growing seasons in England and Continental Europe generally became short and unreliable, which led to shortages and famine. These hardships were nothing compared to the more northerly countries: Glaciers advanced rapidly in Greenland, Iceland, Scandinavia and North America, making vast tracts of land uninhabitable. The Arctic pack ice extended so far south that several reports describe Eskimos landing their kayaks in Scotland. Finland’s population fell by one-third, Iceland’s by half, the Viking colonies in Greenland were abandoned altogether, as were many Inuit communities. The cold in North America spread so far south that, in the winter of 1780, New York Harbor froze, enabling people to walk from Manhattan to Staten Island.
Actually the Viking colonies were not abandoned. The colonists were marooned on Greenland because a) the Viking boats could no longer get to them because of advancing glaciers and sea ice and b) they had no wood to spare to make boats.
So they dwindled and eventually starved to death.
By complete coincidence this coincided with a solar minimum lasting around 70 years.
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?
