Will Thames Freeze Again? UK Vulnerable to Cooling Catastrophe

By Vijay Jayaraj writing at CNSNews.com

[. . . ]

Studies suggest that the previous lows in solar activity—solar cycles 5 and 6 during the Dalton Minimum (1790–1830)—coincided with the Little Ice Age that disrupted the entire Northern Hemisphere. It was during this time that London’s River Thames (not far from the Parliament) froze, and agriculture in Britain and elsewhere came to a standstill.

According to recent research papers by scientists, the two coming solar cycles—25 and 26—will display much lower solar activity than the solar cycles of the Little Ice Age, with a potential period of cooling, as NASA suggests.

“The solar cycle 25 will start in the year 2021 (January) and will last till 2031 (February), while the solar cycle 26 will start in the year 2031 (March) and will last till the year 2041 (February),” said the report.
The scientists concluded, “We have also compared the activities of solar cycles 5 and 6 (Dalton minima periods) to solar cycles 25 and 26 and have observed that the other solar minimum is underway.”

Such a period could demolish the UK’s agricultural sector. It would also negatively affect agriculture in the rest of the world. There could be a complete lockdown of agriculture and a severe proven stress on the energy sector, including electricity generation, not just in Britain but throughout the Northern Hemisphere.

Warnings about the on-going solar minima should not be ignored. Yet the climate crisis movement, focusing exclusively on warming as a threat, promotes a lack of awareness of this threat.

The full article is HERE.

1921 Solar Event May Have Been Bigger than Carrington Event

Details at ARRL Newsletter.

Scientific American reports that, according to new data, the “New York Railroad Storm” of 1921 may have surpassed the intensity of the famous Carrington Event of 1859. In his paper published in the journal Space Weather, Jeffrey Love of the US Geological Survey and his colleagues reexamined the intensity of the 1921 event in greater detail than previously.

Although different measures of intensity exist, geomagnetic storms are often rated on an index called disturbance storm time (Dst) — a way of gauging global magnetic activity by averaging out values for the strength of Earth’s magnetic field measured at multiple locations. Earth’s baseline Dst level is about -20 nanoteslas (nT), with a “superstorm” condition occurring when levels fall below -250 nT. Studies of the very limited magnetic data from the Carrington Event peg its intensity at anywhere from -850 to -1,050 nT. According to Love’s study, the 1921 storm came in at about -907 nT.

Peter Ward in his 2017 New York History Blog article “Strange Phenomena: The New York Railroad Storm” recounted that theatre-goers in New York City “marveled at the spectacle” of an iridescent cloud that was brighter than the moon. “On the roof of the Times Building, reporters, having discovered the telegraph lines to be curiously blocked, gathered to watch the aerial kaleidoscope,” he wrote.

As with the earlier Carrington Event, telegraph operators experienced wild fluctuations in the current on their circuits, while wireless propagation was enhanced. “The next day, papers reported that the Central New England railroad station (also home to the telegraph switchboard) had burned to the ground.” Railroad officials later blamed the fire on the aurora.

According to Ward’s article, the lights were visible in New York, California, and Nevada. Especially in rural areas, “the lights were said to be brighter, appear closer to the ground, and even move with a swishing sound.”

Railroad and telegraph service were restored the following week, although one Western Union transatlantic cable showed signs of damage. “Delays and damage lead to some referring to it as the New York Railroad Storm,” Ward wrote.

A dramatic description of the event on the SolarStorms.org website said, “At 7:04 AM on May 15, the entire signal and switching system of the New York Central Railroad below 125th Street was put out of operation, followed by a fire in the control tower at 57th Street and Park Avenue.”

The short article said a telegraph operator reported being driven away from his station by flames that enveloped his switchboard and set the building on fire. “In Sweden a telephone station was reported to have been ‘burned out,’ and the storm interfered with telephone, telegraph, and cable traffic over most of Europe,” the article said.

Plasma flow near the sun’s surface explains sunspots, other solar phenomena

Understanding the previously mysterious properties of the sun.
Every 11 years or so, the Sun’s magnetic field completely flips. This means that the Sun’s north and south poles switch places. Then it takes about another 11 years for the Sun’s north and south poles to flip back again.

The solar cycle affects activity on the surface of the Sun, such as sunspots which are caused by the Sun’s magnetic fields. Until now, various theories have tracked sunspots, but unable to explain why the number of spots peaks every 11 years.

In an effort to understand it, scientists at the University of Washington have proposed a model of plasma motion to explain the 11-year sunspot cycle and several other previously mysterious properties of the Sun.

Scientists created this model by relying on their previous work with fusion energy research. The model demonstrates that a slight layer underneath the Sun’s surface is key to many highlights we see from Earth, such as sunspots, magnetic reversals, and solar flow.

The fusion reactor uses very high temperatures similar to those inside the Sun to separate hydrogen nuclei from their electrons. In both the Sun and in fusion reactors, the nuclei of two hydrogen atoms fuse, releasing vast amounts of energy.

The type of reactor scientists have focused on; a spheromak contains the electron plasma within a sphere that causes it to self-organize into specific patterns. When they began to consider the Sun, they observed similarities and created a model for what might be happening in the celestial body.

First author Thomas Jarboe, a UW professor of aeronautics and astronautics, said, “Our model is completely different from a normal picture of the Sun. I think we’re the first people that are telling you the nature and source of solar magnetic phenomena—how the Sun works.”

In the new model, a thin layer of magnetic flux and plasma, or floating electrons, moves at different speeds on a different part of the Sun. The distinction in speed between the flows makes bits of magnetism, known as magnetic helicity, that are similar to what happens in some fusion reactor concepts.

Jarboe said, “Every 11 years, the Sun grows this layer until it’s too big to be stable, and then it sloughs off. Its departure exposes the lower layer of plasma moving in the opposite direction with a flipped magnetic field.”

“When the circuits in both hemispheres are moving at the same speed, more sunspots appear. When the circuits are different speeds, there is less sunspot activity. That mismatch may have happened during the decades of little sunspot activity known as the “Maunder Minimum.”

“If the two hemispheres rotate at different speeds, then the sunspots near the equator won’t match up, and the whole thing will die.”

“Scientists had thought that a sunspot was generated down at 30 percent of the depth of the Sun, and then came up in a twisted rope of plasma that pops out. Instead, his model shows that the sunspots are in the “supergranules” that form within the thin, subsurface layer of plasma that the study calculates to be roughly 100 to 300 miles (150 to 450 kilometers) thick, or a fraction of the Sun’s 430,000-mile radius.”

“The sunspot is an amazing thing. There’s nothing there, and then all of a sudden, you see it in a flash.”

“Other properties explained by the theory include flow inside the Sun, the twisting action that leads to sunspots and the entire magnetic structure of the Sun. The paper is likely to provoke intense discussion.”  [Emphasis added]

“I hope that scientists will look at their data in a new light, and the researchers who worked their whole lives to gather that data will have a new tool to understand what it all means.”

The study describing the model is published in the journal Physics of Plasmas

Another link to the paper:  https://aip.scitation.org/doi/10.1063/1.5087613

Question:  How does this model fit with Professor Valentina Zharkova model of the sun with four plasma layers?  I may have to find the time to re-read the Professors paper and compare. If a reader gets the paper read before I do please post your analysis in the comments. Thanks.

NASA – Next Solar Cycle will be Weakest in 200 Years

September 5, 2019 by Robert at Ice Age Now

NASA dropped this bombshell announcement in a little-heralded news release coyly entitled “Solar Activity Forecast for Next Decade Favorable for Exploration.” In other words, NASA tried to make it sound like good news.

In the release, dated 12 June 2019, NASA described the upcoming decline in solar activity as a window of opportunity for space exploration instead of acknowledging the disastrous consequences such a decline could wreak on civilization.

Here are some direct quotes from the news release:

The Sun’s activity rises and falls in an 11-year cycle. The forecast for the next solar cycle says it will be the weakest of the last 200 years. (Emphasis added) The maximum of this next cycle – measured in terms of sunspot number, a standard measure of solar activity level – could be 30 to 50% lower than the most recent one. The results show that the next cycle will start in 2020 and reach its maximum in 2025.

Sunspots are regions on the Sun with magnetic fields thousands of times stronger than the Earth’s. Fewer of them at the point of maximum solar activity means fewer dangerous blasts of radiation.

The new research was led by Irina Kitiashvili, a researcher with the Bay Area Environmental Research Institute at NASA’s Ames Research Center, in California’s Silicon Valley. It combined observations from two NASA space missions – the Solar and Heliospheric Observatory and the Solar Dynamics Observatory – with data collected since 1976 from the ground-based National Solar Observatory.

In admitting that solar activity during sunspot-cycle 25 could be the weakest in 200 years, NASA was effectively forecasting a return to Dalton Minimum (1790-1830) conditions. But the release gives no mention of the ferocious cold, no mention of the disastrous crop losses, no mention of the ensuing starvation and famine, no mention of the wars over food, no mention of the powerful earthquakes, no mention of the catastrophic volcanic eruptions during the Dalton Minimum.

NASA Paper is HERE

Some people consider the low solar activity a trigger for other catastrophic events such as the 1811-1812 New Madrid Fault Earth Quakes and 1815 eruption of Mount Tamboura.  As you can see from this chart global cooling produced some strong eruption.

Volcanic activity

I have done some investigation of the cooling triggering earthquakes and significant eruptions but could not find any smoking-gun evidence.  [Your thoughts?]

The said the real issue is global cooling, as  1-2 degrees C of cooling shortens the growing seasons and disrupts the food supply. This is a problem for a planet with more mouths to feed with every passing year.  Modern transportation can mitigate the distribution issues that plagued other grand minimum populations, but you first have to have agricultural output to distribute.  This year the growing season is going to be much shorter than last year. Your thoughts?

The Next Great Extinction Event Will Not Be Global Warming – It Will Be Global Cooling

By Allan M. R. MacRae, B.A.Sc., M.Eng., August 2019

CATASTROPHIC GLOBAL WARMING IS A FALSE CRISIS – THE NEXT GREAT EXTINCTION WILL BE GLOBAL COOLING

Forget all those falsehoods about scary global warming, deceptions contrived by wolves to stampede the sheep. The next great extinction event will not be global warming, it will be global cooling. Future extinction events are preponderantly cold: a glacial period, medium-size asteroid strike or supervolcano. Humanity barely survived the last glacial period that ended only 11,500 years ago, the blink-of–an-eye in geologic time.

Cold, not heat, is by far the greater killer of humanity. Today, cool and cold weather kills about 20 times as many people as warm and hot weather. Excess Winter Deaths, defined as more deaths in the four winter months than equivalent non-winter months, total over two million souls per year, in both cold and warm climates. Earth is colder-than-optimum for humanity, and currently-observed moderate global warming increases life spans.

I am not in agreement with all the author’s points, but it is an interesting read. Grand minimums are referenced. Some of the comments give some perspective to the author’s claims of rapid cooling.

The full post is HERE.

The strongest summer jet stream ever observed over the Pacific Northwest.

Reposted from the  Cliff Mass Weather and Climate Blog

An extraordinary weather event has been occurring above our heads during the past 24-hour.   A record that was not only broken, but shattered to little pieces.

The strongest summer jet stream ever observed over the Pacific Northwest.  

The jet stream is a narrow current of strong winds in the upper troposphere (roughly 25,000 ft to 35,000 ft above sea level).   It is often the conduit for storms and is associated with a large temperature gradient (change in temperature with horizontal distance) in the middle and lower troposphere.   Winds in the jet stream are westerly (from the west) and aircraft like to fly in the jet stream going east, while avoiding it going west.   You are now Jet Steam certified!

The ECMWF 12-h forecast for 5 AM this morning for the wind speed at the 250 hPa pressure level (about 35,000 ft) clearly shows the jet stream, with the orange/red colors being the strongest winds.

This is a HUGE and very zonal (east-west oriented) jet stream…as shown by the next map at the same time.  This looks like January, not July.

But now I will really impress you. 

The wind this morning at the radiosonde site at Quillayute (UIL) was 140 knots (161 mph) at the 250 hPa level (again around 35,000 ft).   This is amazingly fast for this time of the year.

The plot below shows the climatology of the winds at this level throughout the year at this location, with the red lines being the all-time record for each date (the black lines are average winds for the date, blue lines, the record low winds).   Vertical soundings at Quillayute go back to the late 1960s…so we are talking about a half-century of observations.   The previous record was around 110 knots…so the 140 knots observed today absolutely shattered the record.     In fact, the wind over us right now is greater then the records for any date from April 1 to mid-October.

Record, but lesser winds, are being observed at the next upper air station to the south:  Salem, Oregon (see below)

A truly unusual event.   And one that should not be pinned on global warming.  In fact, several of the global warming jet stream papers (e.g., by Jennifer Francis and others) suggest that global warming will bring a weak and wavy jet stream.  This is just the opposite.

===========================
Reading climate history during Grand Minimums, there is a plethora of stories, journal entries and letters written about unusual climate activity.  This could just another example.  We just have better detection tools today, than the speed of the clouds moving over head.

The Next Grand Solar Minimum is Approaching

Oscillations of the baseline of solar magnetic field and solar irradiance on a millennial timescale

Another paper by V. V. Zharkova, S. J. Shepherd, S. I. Zharkov & E. Popova 

Abstract

Recently discovered long-term oscillations of the solar background magnetic field associated with double dynamo waves generated in inner and outer layers of the Sun indicate that the solar activity is heading in the next three decades (2019–2055) to a Modern grand minimum similar to Maunder one. On the other hand, a reconstruction of solar total irradiance suggests that since the Maunder minimum there is an increase in the cycle-averaged total solar irradiance (TSI) by a value of about 1–1.5 Wm−2 closely correlated with an increase of the baseline (average) terrestrial temperature. In order to understand these two opposite trends, we calculated the double dynamo summary curve of magnetic field variations backward one hundred thousand years allowing us to confirm strong oscillations of solar activity in regular (11 year) and recently reported grand (350–400 year) solar cycles caused by actions of the double solar dynamo. In addition, oscillations of the baseline (zero-line) of magnetic field with a period of 1950 ± 95 years (a super-grand cycle) are discovered by applying a running averaging filter to suppress large-scale oscillations of 11 year cycles. Latest minimum of the baseline oscillations is found to coincide with the grand solar minimum (the Maunder minimum) occurred before the current super-grand cycle start. Since then the baseline magnitude became slowly increasing towards its maximum at 2600 to be followed by its decrease and minimum at ~3700. These oscillations of the baseline solar magnetic field are found associated with a long-term solar inertial motion about the barycenter of the solar system and closely linked to an increase of solar irradiance and terrestrial temperature in the past two centuries. This trend is anticipated to continue in the next six centuries that can lead to a further natural increase of the terrestrial temperature by more than 2.5 °C by 2600.

Conclusions

Until recently, solar activity was accepted to be one of the important factors defining the temperature on Earth and other planets. In this paper we reproduced the summary curve of the solar magnetic field associated with solar activity5,6 for the one hundred thousand years backward by using the formulas describing the sum of the two principal components found from the full disk solar magnetograms. In the past 3000 years the summary curve shows the solar activity for every 11 years and occurrence of 9 grand solar cycles of 350–400 years, which are caused by the beating effects of two magnetic waves generated by solar dynamo at the inner and outer layers inside the solar interior with close but not equal frequencies6.

The resulting summary curve reveals a remarkable resemblance to the sunspot and terrestrial activity reported in the past millennia including the significant grand solar minima: Maunder Minimum (1645–1715), Wolf minimum (1200), Oort minimum (1010–1050), Homer minimum (800–900 BC) combined with the grand solar maxima: the medieval warm period (900–1200), the Roman warm period (400–10BC) etc. It also predicts the upcoming grand solar minimum, similar to Maunder Minimum, which starts in 2020 and will last until 2055.

A reconstruction of solar total irradiance suggests that there is an increase in the cycle-averaged total solar irradiance (TSI) since the Maunder minimum by a value of about 1–1.5 Wm−2 27. This increase is closely correlated with the similar increase of the average terrestrial temperature26,43. Moreover, from the summary curve for the past 100 thousand years we found the similar oscillations of the baseline of magnetic field with a period of 1950 ± 95 years (a super-grand solar cycle) by filtering out the large-scale oscillations in 11 year cycles. The last minimum of a super-grand cycle occurred at the beginning of Maunder minimum. Currently, the baseline magnetic field (and solar irradiance) are increasing to reach its maximum at 2600, after which the baseline magnetic field become decreasing for another 1000 years.

The oscillations of the baseline of solar magnetic field are likely to be caused by the solar inertial motion about the barycentre of the solar system caused by large planets. This, in turn, is closely linked to an increase of solar irradiance caused by the positions of the Sun either closer to aphelion and autumn equinox or perihelion and spring equinox. Therefore, the oscillations of the baseline define the global trend of solar magnetic field and solar irradiance over a period of about 2100 years. In the current millennium since Maunder minimum we have the increase of the baseline magnetic field and solar irradiance for another 580 years. This increase leads to the terrestrial temperature increase as noted by Akasofu26 during the past two hundred years. Based on the growth rate of 0.5 C per 100 years26 for the terrestrial temperature since Maunder minimum, one can anticipate that the increase of the solar baseline magnetic field expected to occure up to 2600 because of SIM will lead, in turn, to the increase of the terrestrial baseline temperature since MM by 1.3 °C (in 2100) and, at least, by 2.5–3.0 °C (in 2600).

Naturally, on top of this increase of the baseline terrestrial temperature, there are imposed much larger temperature oscillations caused by standard solar activity cycles of 11 and 350–400 years and terrestrial causes. The terrestrial temperature is expected to grow during maxima of 11 year solar cycles and to decrease during their minima. Furthermore, the substantial temperature decreases are expected during the two grand minima47 to occur in 2020–2055 and 2370–24156, whose magnitudes cannot be yet predicted and need further investigation. These oscillations of the estimated terrestrial temperature do not include any human-induced factors, which were outside the scope of the current paper.

Continue reading HERE

Keep your warm coat handy the climate is about to get interesting.

The Setup is like 1315

Guest Commentary by David Archibald at Watts Up With That

The area planted for corn and soybeans this season is well below historic averages. This was mostly due to waterlogged fields and flooding which precluded planting. The planting windows for corn and soybeans are now closed. The USDA crop progress reports provide weekly updates by state. For example this is the state of the corn crop in Indiana to Monday June 17:

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Figure 1: Indiana corn crop progress to Monday June 17.

The emerged crop is one month behind where it was in 2018. Which means that maturity will be one month later at best, assuming that the rest of the summer isn’t abnormally cold.

Figure 2 shows that the same situation in soybeans in Indiana:

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Figure 2: Indiana soybean crop progress to Monday June 17.

The current expectation is that the US corn crop will be down 30% on 2018 which will push the price to about $9.00 per bushel at harvest. What could make the situation a lot worse is an early frost. The Corn Belt did warm slightly over the last 100 years due to the high solar activity of the second half of the 20th century. This is shown by the cumulative growing degree days (GDD) of the first decade of the 20th century (blue lines) compared to the first decade of the 21st century (red lines) in Figure 3 for Whitestown, Indiana:

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Figure 3: Cumulative GDD for Whitestown, Indiana

Normally, for the 21st century, the corn crop is in the ground by April 27 and the crop has reached maturity with 2,500 GDD well before the normal first frost date for Whitestown of October 10. The earliest recorded date for Whitestown is September 3. That was in 1908. If that is repeated in 2019 the crop will be only 80% through its growth cycle. Yield and quality will be well down and the total crop may be 50% or less of the 2018 level.

The US will be able to feed itself but at much higher prices. Currently some 40% of the corn crop goes to ethanol production and this could be redirected to animal feed without too much trouble. But protein production would still be well down. Each 56 lb bushel of corn used in ethanol production results in 18 lbs of dried distillers grains (DDG) containing the protein. This is used as a feed supplement to pigs, chickens and cattle. Both pigs and chickens have a 25% conversion efficiency of vegetable protein to animal protein. The global warmers want us to adopt vegetarianism in order to save the planet. The public is going to get a taste of that future coming up soon. However animal fat is essential for infant neurological development and brain function so we can’t go completely vegetarian.

What is happening in the Corn Belt is a mini version of the transition from the Medieval Warm Period to the Little Ice Age. The population of Europe exploded in benign conditions of the Medieval Warm Period from 1000 AD to 1300 AD, reaching population levels that weren’t matched again until the 19th century. In fact parts of rural France have less population today than at the beginning of the 14th century.

The breakover from the Medieval Warm Period to the Little Ice Age in Europe had sustained periods of bad weather characterised by severe winters and rainy and cold summers. The Great Famine of 1315 – 1317 started with bad weather in the spring of 1315. Crop failures lasted through 1316 until the summer of 1317. The population decline over the two years is thought to be about 10%, associated with “extreme levels of crime, disease, mass death, cannibalism and infanticide.” These conditions may be less in the Mormons amongst us who are instructed to keep one year’s worth of food in stock.

The Modern Warm Period ended in 2006. Current solar activity is back to levels of the Little Ice Age. To paraphrase Santayana, those who don’t remember history are condemned to being surprised and unprepared when it repeats itself.

A large and increasing number of nations are feeding their population growth with imported grain. That is going to be become more expensive to continue, with or without an early frost in the Corn Belt. Global warming hysteria has been a consequence of very benign conditions for the OECD countries where it is concentrated. That angst will be supplanted by more basic concerns.

David Archibald is the author of American Gripen: The Solution to the F-35 Nightmare

I am going to create a Google Alert to track early frost reports. I will share the results.

When will people realize that. . .

 

Ed Hoskins

  1. The modern short pulse of beneficial Global warming stopped 20 years ago and recent global temperatures are now stable or declining.
  2. The last millennium 1000 – 2000 AD was the coldest of our current Holocene interglacial and the world has already been cooling quite rapidly for the last 3000 years.
  3. At 11,000 years our Holocene interglacial, responsible for all man-kind’s advances, is reaching its end.
  4. The weather gets worse in colder times.
  5. The world will very soon (in geological time), revert to a true glaciation, again resulting in mile high ice sheets over New York.

Our current beneficial, warm Holocene interglacial has been the enabler of mankind’s civilization for the last 10,000 years.

The congenial climate of the Holocene epoch spans from mankind’s earliest farming to the scientific and technological advances of the last 100 years.

screen-shot-2018-10-08-at-15.49.41

However all the Northern Hemisphere Ice Core records  from Greenland show:

  • the last millennium 1000AD – 2000AD has been the coldest millennium of the entire Holocene interglacial.
  • each of the notable high points in the Holocene temperature record, (Holocene Climate Optimum – Minoan – Roman – Medieval – Modern), have been progressively colder than the previous high point.
  • for its first 7-8000 years the early Holocene, including its high point “climate optimum”, had virtually flat temperatures, an average drop of only ~0.007 °C per millennium.
  • but the more recent Holocene, since a “tipping point” at ~1000BC, has seen a temperature diminution at more than 20 times that earlier rate at about 0.14 °C per millennium.
  • the Holocene interglacial is already 10 – 11,000 years old and judging from the length of previous interglacials the Holocene epoch should be drawing to its close: in this century, the next century or this millennium.
  • the beneficial warming at the end of the 20th century to the Modern high point has been transmuted into the “Great Man-made Global Warming Alarm”.
  • eventually, this late 20th-century temperature blip will come to be seen as just noise in the system in the longer term progress of comparatively rapid cooling over the last 3000+ years.
  • other published Greenland Ice Core records as well as GISP2, (NGRIP1, GRIP) corroborate this finding. They also exhibit the same pattern of a prolonged relatively stable early Holocene period followed by a subsequent much more rapid decline in the more recent (3000 years) past.

When considering the scale of temperature changes that alarmists anticipate because of Man-made Global Warming and their view of the disastrous effects of additional Man-made Carbon Dioxide emissions in this century, it is useful to look at climate change from a longer term, century by century and even on a millennial perspective.

The much vaunted and much feared “fatal” tipping point of +2°C would only bring Global temperatures close to the level of the very congenial climate of “the Roman warm period”.

If it were possible to reach the “horrendous” level of +4°C postulated by Warmists, that extreme level of warming would still only bring temperatures to about the level of the previous Eemian maximum, a warm and abundant epoch when hippopotami thrived in the Rhine delta.

screen-shot-2015-06-06-at-12-34-16

Read the full paper HERE

The Little Ice Age: What Happened Around the World

Between 1300 and 1850, the Earth experienced a Little Ice Age whose cause to this day is not known.

A blog post at Interesting Engineering has more details including the consequences and some paintings from the period. The causes listed are interesting:

Causes

The causes of the LIA are still not known, while potential candidates are reduced solar output, changes in atmospheric circulation, and volcanism.

Low sunspot activity is associated with lower solar output, and two periods of unusually low sunspot activity occurred during the Little Ice Age: the Spörer Minimum (1450–1540) and the Maunder Minimum (1645–1715), which is named for astronomer E.W. Maunder who discovered the absence of sunspots during that period. Both of these coincide with the coldest years of the LIA in parts of Europe.

Another possible candidate is a reversal of the North Atlantic Oscillation (NAO). This is a large-scale atmospheric-circulation pattern over the North Atlantic and adjacent areas. During its “positive” phase, the track of North Atlantic storms is centered over the British Isles and Northern Europe. During its “negative” phase, cold Arctic air from Russia moves over northern Europe.

A final candidate is volcanic eruptions which propel gases and ash into the stratosphere, where they reflect incoming sunlight. In 1783, Iceland’s Laki volcano erupted, and in 1815, the Tambora volcano on Sumbawa Island erupted.

I am voting for low sunspot activity.  Your thoughts?