does anyone have an opinion about the source's validity?
Temperature (Austin). 2020; 7(3): 217–222.
Published online 2020 Aug 4.
Modern Grand Solar Minimum will lead to terrestrial cooling
Valentina Zharkova
In this editorial I will demonstrate with newly discovered solar activity proxy-
magnetic field that the Sun has entered into the modern Grand Solar
Minimum (2020–2053) that will lead to a significant reduction of solar
magnetic field and activity like during Maunder minimum leading to
noticeable reduction of terrestrial temperature.
Sun is the main source of energy for all planets of the solar system. This
energy is delivered to Earth in a form of solar radiation in different
wavelengths, called total solar irradiance. Variations of solar irradiance lead
to heating of upper planetary atmosphere and complex processes of solar
energy transport toward a planetary surface.
The signs of solar activity are seen in cyclic 11-year variations of a number of
sunspots on the solar surface using averaged monthly sunspot numbers as
a proxy of solar activity for the past 150 years. Solar cycles were described
by the action of solar dynamo mechanism in the solar interior generating
magnetic ropes at the bottom of solar convective zone.
These magnetic ropes travel through the solar interior appearing on the
solar surface, or photosphere, as sunspots indicating the footpoints where
these magnetic ropes are embedded into the photosphere.
Magnetic field of sunspots forms toroidal field while solar background
magnetic field forms poloidal field. Solar dynamo cyclically converts poloidal
field into toroidal one reaching its maximum at a solar cycle maximum and
then the toroidal field back to the poloidal one toward a solar minimum. It is
evident that for the same leading polarity of the magnetic field in sunspots in
the same hemisphere the solar cycle length should be extended to 22 years.
Despite understanding the general picture of a solar cycle, it was rather
difficult to match the observed sunspot numbers with the modeled ones
unless the cycle is well progressed. This difficulty is a clear indication of
some missing points in the definition of solar activity by sunspot numbers
that turned our attention to the research of solar (poloidal) background
magnetic field (SBMF) [1].
By applying Principal Component Analysis (PCA) to the low-resolution full
disk magnetograms captured in cycles 21–23 by the Wilcox Solar
Observatory, we discovered not one but two principal components of this
solar background magnetic field (see Figure 1, top plot) associated with two
magnetic waves marked by red and blue lines. The authors derived
mathematical formulae for these two waves fitting principal components
from the data of cycles 21–23 with the series of periodic functions and used
these formulae to predict these waves for cycles 24–26. These two
waves are found generated in different layers of the solar interior gaining
close but not equal frequencies [1]. The summary curve of these two
magnetic waves (Figure 1, bottom plot) reveals the interference of these
waves forming maxima and minima of solar cycles.
Figure 1.
Top plot: two principal components (PCs) of solar background magnetic
field (blue and green curves, arbitrary numbers) obtained for cycles 21–23
(historic data) and predicted for cycles 24–26 using the mathematical
formulae derived from the historical data (from the data by Zharkova et al.
[1]). The bottom plot: The summary curve derived from the two PCs above
for the “historical” data (cycles 21–23) and predicted for solar cycle 24
(2008–2019), cycle 25 (2020–2031), cycle 26 (2031–2042) (from the data
by Zharkova et al. [1]).
The summary curve of two magnetic waves explains many features of 11-
year cycles, like double maxima in some cycles, or asymmetry of the solar
activity in the opposite hemispheres during different cycles. Zharkova et al.
[1] linked the modulus summary curve to the averaged sunspot numbers for
cycles 21–23 as shown in Figure 2 (top plot) and extended this curve to
cycles 24–26 as shown in Figure 2 (bottom plot). It appears that the
amplitude of the summary solar magnetic field shown in the summary curve
is reducing toward cycles 24–25 becoming nearly zero in cycle 26.
Figure 2.
Top plot: The modulus summary curve (black curve) obtained from the
summary curve (Figure 1, bottom plot) versus the averaged sunspot
numbers (red curve) for the historical data (cycles 21–23). Bottom plot: The
modulus summary curve associated with the sunspot numbers derived for
cycles 21–23 (and calculated for cycles 24–26 (built from the data obtained
by Zharkova et al. [1])).
Zharkova et al. [1] suggested to use the summary curve as a new proxy of
solar activity, which utilizes not only amplitude of a solar cycle but also its
leading magnetic polarity of solar magnetic field.
Figure 3 presents the summary curve calculated with the derived
mathematical formulae forwards for 1200 years and backwards 800 years.
This curve reveals appearance of Grand Solar Cycles of 350–400 years
caused by the interference of two magnetic waves. These grand cycles are
separated by the grand solar minima, or the periods of very low solar activity
[1]. The previous grand solar minimum was Maunder minimum (1645–1710),
and the other one before named Wolf minimum (1270–1350). As seen in
Figure 3 from prediction by Zharkova et al. [1], in the next 500 years there
are two modern grand solar minima approaching in the Sun: the modern one
in the 21st century (2020–2053) and the second one in the 24th century
(2370–2415).
Figure 3.
Solar activity (summary) curve restored for 1200–3300 AD (built from the
data obtained by Zharkova et al. [1]).
The observational properties of the two magnetic waves and their summary
curve were closely fit by double dynamo waves generated by dipole
magnetic sources in two layers of the solar interior: inner and outer layers
[1], while other three pairs of magnetic waves can be produced by
quadruple, sextuple, and octuple magnetic sources altogether with dipole
source defining the visible appearance of solar activity on the surface.
Currently, the Sun has completed solar cycle 24 – the weakest cycle of the
past 100+ years – and in 2020, has started cycle 25. During the periods of
low solar activity, such as the modern grand solar minimum, the Sun will
often be devoid of sunspots. This is what is observed now at the start of this
minimum, because in 2020 the Sun has seen, in total, 115 spotless days (or
78%), meaning 2020 is on track to surpass the space-age record of 281
spotless days (or 77%) observed in 2019. However, the cycle 25 start is still
slow in firing active regions and flares, so with every extra day/week/month
that passes, the null in solar activity is extended marking a start of grand
solar minimum. What are the consequences for Earth of this decrease of
solar activity?
Go to:
Total solar irradiance (TSI) reduction during Maunder Minimum
Let us explore what has happened with the solar irradiance during the
previous grand solar minimum – Maunder Minimum. During this period, very
few sunspots appeared on the surface of the Sun, and the overall brightness
of the Sun was slightly decreased.
The reconstruction of the cycle-averaged solar total irradiance back to 1610
(Figure 4, top plot) suggests a decrease of the solar irradiance during
Maunder minimum by a value of about 3 W/m2 [2], or about 0.22% of the
total solar irradiance in 1710, after the Maunder minimum was over.
Figure 4.
Top plot: restored total solar irradiance from 1600 until 2014 by Lean et al.
[2]. Modified by Easterbrook [3], from Lean, Beer, Bradley [2]. Bottom plot:
Central England temperatures (CET) recorded continuously since 1658. Blue
areas are reoccurring cool periods; red areas are warm periods. All times of
solar minima were coincident with cool periods in central England. Adopted
from Easterbrook [3], with the Elsevier publisher permissions.
Go to:
Temperature decrease during Maunder minimum
From 1645 to 1710, the temperatures across much of the Northern
Hemisphere of the Earth plunged when the Sun entered a quiet phase now
called the Maunder Minimum. This likely occurred because the total solar
irradiance was reduced by 0.22%, shown in Figure 4 (top plot) [2], that led
to a decrease of the average terrestrial temperature measured mainly in the
Northern hemisphere in Europe by 1.0–1.5°C as shown in Figure 4 (bottom
plot) [3]. This seemingly small decrease of the average temperature in the
Northern hemisphere led to frozen rivers, cold long winters, and cold
summers.
The surface temperature of the Earth was reduced all over the Globe (see
Figure 1 in [4]), especially, in the countries of Northern hemisphere. Europe
and North America went into a deep freeze: alpine glaciers extended over
valley farmland; sea ice crept south from the Arctic; Dunab and Thames
rivers froze regularly during these years as well as the famous canals in the
Netherlands.
Shindell et al. [4] have shown that the drop in the temperature was related to
dropped abundances of ozone created by solar ultra-violate light in the
stratosphere, the layer of the atmosphere located between 10 and 50
kilometers from the Earth’s surface. Since during the Maunder Minimum the
Sun emitted less radiation, in total, including strong ultraviolet emission, less
ozone was formed affecting planetary atmosphere waves, the giant wiggles
in the jet stream.
Shindell et al. [4] in p. 2150 suggest that “a change to the planetary waves
during the Maunder Minimum kicked the North Atlantic Oscillation (NAO) –
the balance between a permanent low-pressure system near Greenland and
a permanent high-pressure system to its south – into a negative phase, that
led to Europe to remain unusually cold during the MM.”
Go to:
Role of magnetic field in terrestrial cooling in Grand Solar Minima
However, not only solar radiation was changed during Maunder minimum.
There is another contributor to the reduction of terrestrial temperature
during Maunder minimum – this is the solar background magnetic field,
whose role has been overlooked so far. After the discovery [1] of a
significant reduction of magnetic field in the upcoming modern grand solar
minimum and during Maunder minimum, the solar magnetic field was
recognized to control the level of cosmic rays reaching planetary
atmospheres of the solar system, including the Earth. A significant reduction
of the solar magnetic field during grand solar minima will undoubtedly lead
to the increase of intensity of galactic and extra-galactic cosmic rays, which,
in turn, lead to a formation of high clouds in the terrestrial atmospheres and
assist to atmospheric cooling as shown by Svensmark et al. [5].
In the previous solar minimum between cycles 23 and 24, the cosmic ray
intensity increased by 19%. Currently, solar magnetic field predicted in
Figure 1 by Zharkova et al. [1] is radically dropping in the sun that, in turn,
leads to a sharp decline in the sun’s interplanetary magnetic field down to
only 4 nanoTesla (nT) from typical values of 6 to 8 nT. This decrease of
interplanetary magnetic field naturally leads to a significant increase of the
intensity of cosmic rays passing to the planet’s atmospheres as reported by
the recent space missions [6]. Hence, this process of solar magnetic field
reduction is progressing as predicted by Zharkova et al. [1], and its
contribution will be absorbed by the planetary atmospheres including Earth.
This can decrease the terrestrial temperature during the modern grand solar
minimum that has already started in 2020.
Go to:
Expected reduction of terrestrial temperature in modern Grand Solar Minima
This summary curve also indicated the upcoming modern grand solar
minimum 1 in cycles 25–27 (2020–2053) and modern grand solar minimum
2 (2370–2415). This will bring to the modern times the unique low activity
conditions of the Sun, which occurred during Maunder minimum. It is
expected that during the modern grand solar minimum, the solar activity will
be reduced significantly as this happened during Maunder minimum (Figure
4, bottom plot). Similarly to Maunder Minimum, as discussed above, the
reduction of solar magnetic field will cause a decrease of solar irradiance by
about 0.22% for a duration of three solar cycles (25–27) for the first modern
grand minimum (2020–2053) and four solar cycles from the second modern
grand minimum (2370–2415).
This, in turn, can lead to a drop of the terrestrial temperature by up to 1.0°C
from the current temperature during the next three cycles (25–27) of grand
minimum 1. The largest temperature drops will be approaching during the
local minima between cycles 25 − 26 and cycles 26–27 when the lowest
solar activity level is achieved using the estimations in Figure 2 (bottom plot)
and Figure 3. Therefore, the average temperature in the Northern
hemisphere can be reduced by up to 1.0°C from the current temperature,
which was increased by 1.4°C since Maunder minimum. This will result in the
average temperature to become lower than the current one to be only 0.4°C
higher than the temperature measured in 1710. Then, after the modern
grand solar minimum 1 is over, the solar activity in cycle 28 will be restored
to normal in the rather short but powerful grand solar cycle lasting between
2053 and 2370, as shown in Figure 3, before it approaches the next grand
solar minimum 2 in 2370.
Conclusions
In this editorial, I have demonstrated that the recent progress with
understanding a role of the solar background magnetic field in defining solar
activity and with quantifying the observed magnitudes of magnetic field at
different times allowed us to enable reliable long-term prediction of solar
activity on a millennium timescale. This approach revealed a presence of not
only 11-year solar cycles but also of grand solar cycles with duration of 350–
400 years. We demonstrated that these grand cycles are formed by the
interferences of two magnetic waves with close but not equal frequencies
produced by the double solar dynamo action at different depths of the solar
interior. These grand cycles are always separated by grand solar minima of
Maunder minimum type, which regularly occurred in the past forming well-
known Maunder, Wolf, Oort, Homeric, and other grand minima.
During these grand solar minima, there is a significant reduction of solar
magnetic field and solar irradiance, which impose the reduction of terrestrial
temperatures derived for these periods from the analysis of terrestrial
biomass during the past 12,000 or more years. The most recent grand solar
minimum occurred during Maunder Minimum (1645–1710), which led to
reduction of solar irradiance by 0.22% from the modern one and a decrease
of the average terrestrial temperature by 1.0–1.5°C.
This discovery of double dynamo action in the Sun brought us a timely
warning about the upcoming grand solar minimum 1, when solar magnetic
field and its magnetic activity will be reduced by 70%. This period has
started in the Sun in 2020 and will last until 2053. During this modern grand
minimum, one would expect to see a reduction of the average terrestrial
temperature by up to 1.0°C, especially, during the periods of solar minima
between the cycles 25–26 and 26–27, e.g. in the decade 2031–2043.
The reduction of a terrestrial temperature during the next 30 years can have
important implications for different parts of the planet on growing
vegetation, agriculture, food supplies, and heating needs in both Northern
and Southern hemispheres. This global cooling during the upcoming grand
solar minimum 1 (2020–2053) can offset for three decades any signs of
global warming and would require inter-government efforts to tackle
problems with heat and food supplies for the whole population of the
Earth
Go to:
References
[1] Zharkova VV, Shepherd SJ, Popova E, et al. Heartbeat of the sun from
principal component analysis and prediction of solar activity on a millennium
timescale. Sci Rep. 2015;5:15689. Available from:
https://www.nature.com/articles/srep15689 [PMC free article] [PubMed]
[Google Scholar]
[2] Lean JL, Beer J, Bradley R.. Reconstruction of solar irradiance since
1610: implications for climatic change. Geophys Res Lett. 1995;22:3195–
3198. [Google Scholar]
[3] Easterbrook DJ. Cause of global climate changes. In: Evidence-based
climate science. 2nd ed. Elsevier Inc.; 2016. p. 245–262. [Google Scholar]
[4] Shindell DT, Schmidt GA, Mann ME, et al. Solar forcing of regional
climate change during the Maunder minimum. Science. 2001;294:2149.
[PubMed] [Google Scholar]
[5] Svensmark H, Enghoff MB, Shaviv NJ, et al. Increased ionization
supports growth of aerosols into cloud condensation nuclei. Nat Comms.
2017;8:2199. [PMC free article] [PubMed] [Google Scholar]
[6] Schwadron NA, Rahmanifard F, Wilson J, et al. Update on the worsening
particle radiation environment observed by CRaTER and implications for
future human deep-space exploration. Space Weather. 2018;16:289–303.
[Google Scholar]
|
|
I'm no scientist, but that sounds implausible.
ASK NASA CLIMATE | February 13, 2020
There Is No Impending 'Mini Ice Age'
By NASA Global Climate Change
"Pink elephant in the room" time: There is no impending “ice age” or "mini
ice age" if there's a reduction in the Sun’s energy output in the next several
decades.
Through its lifetime, the Sun naturally goes through changes in energy
output. Some of these occur over a regular 11-year period of peak (many
sunspots) and low activity (fewer sunspots), which are quite predictable.
Temperature vs Solar Activity 2020
The above graph compares global surface temperature changes (red line)
and the Sun's energy that Earth receives (yellow line) in watts per square
meter since 1880. The lighter/thinner lines show the yearly levels while the
heavier/thicker lines show the 11-year average trends. Eleven-year averages
are used to reduce the year-to-year natural noise in the data, making the
underlying trends more obvious.
The amount of solar energy that Earth receives has followed the Sun’s
natural 11-year cycle of small ups and downs with no net increase since the
1950s. Over the same period, global temperature has risen markedly. It is
therefore extremely unlikely that the Sun has caused the observed global
temperature warming trend over the past half-century. Credit: NASA/JPL-
Caltech
But every so often, the Sun becomes quieter for longer periods of time,
experiencing much fewer sunspots and giving off less energy. This is called
a "Grand Solar Minimum," and the last time this happened, it coincided with
a period called the "Little Ice Age" (a period of extremely low solar activity
from approximately AD 1650 to 1715 in the Northern Hemisphere, when a
combination of cooling from volcanic aerosols and low solar activity
produced lower surface temperatures).
Anomalous periods like a Grand Solar Minimum show that magnetic activity
and energy output from the Sun can vary over decades, although the space-
based observations of the last 35 years have seen little change from one
cycle to the next in terms of total irradiance. Solar Cycle 24, which began in
December 2008 and is likely to end in 2020, was smaller in magnitude than
the previous two cycles.
On occasion, researchers have predicted that coming solar cycles may also
exhibit extended periods of minimal activity. The models for such
predictions, however, are still not as robust as models for our weather and
are not considered conclusive.
But if such a Grand Solar Minimum occurred, how big of an effect might it
have? In terms of climate forcing – a factor that could push the climate in a
particular direction – solar scientists estimate it would be about -0.1 W/m2,
the same impact of about three years of current carbon dioxide (CO2)
concentration growth.
Thus, a new Grand Solar Minimum would only serve to offset a few years of
warming caused by human activities.
What does this mean? The warming caused by the greenhouse gas
emissions from the human burning of fossil fuels is six times greater than
the possible decades-long cooling from a prolonged Grand Solar Minimum.
Even if a Grand Solar Minimum were to last a century, global temperatures
would continue to warm. The reason for this is because more factors than
just variations in the Sun’s output change global temperatures on Earth, the
most dominant of those today is the warming coming from human-induced
greenhouse gas emissions.
Related post: What Is the Sun's Role in Climate Change?
The Sun powers life on Earth; it helps keep the planet warm enough for us to
survive. It also influences Earth’s climate: We know subtle changes in Earth’s
orbit around the Sun are responsible for the comings and goings of the past
ice ages. But the warming we’ve seen over the last few decades is too rapid
to be linked to changes in Earth’s orbit, and too large to be caused by solar
activity.
The Sun doesn’t always shine at the same level of brightness; it brightens
and dims slightly, taking approximately 11 years to complete one solar cycle.
During each cycle, the Sun undergoes various changes in its activity and
appearance. Levels of solar radiation go up or down, as does the amount of
material the Sun ejects into space and the size and number of sunspots and
solar flares. These changes have a variety of effects in space, in Earth’s
atmosphere and on Earth’s surface.
The current solar cycle, Solar Cycle 24, began in December 2008 and is less
active than the previous two. It’s expected to end sometime in 2020.
Scientists don’t yet know with confidence how strong the next solar cycle
may be.
What Effect Do Solar Cycles Have on Earth’s Climate?
According to the United Nations’ Intergovernmental Panel on Climate
Change (IPCC), the current scientific consensus is that long and short-term
variations in solar activity play only a very small role in Earth’s climate.
Warming from increased levels of human-produced greenhouse gases is
actually many times stronger than any effects due to recent variations in
solar activity.
For more than 40 years, satellites have observed the Sun's energy output,
which has gone up or down by less than 0.1 percent during that period.
Since 1750, the warming driven by greenhouse gases coming from the
human burning of fossil fuels is over 50 times greater than the slight extra
warming coming from the Sun itself over that same time interval.
Are We Headed for a ‘Grand Solar Minimum’? (And Will It Slow Down Global
Warming?)
As mentioned, the Sun is currently experiencing a lower level of sunspot
activity. Some scientists speculate that this may be the beginning of a Grand
Solar Minimum — a decades-to-centuries-long period of low solar activity —
while others say there is insufficient evidence to support that position.
During a grand minimum, solar magnetism diminishes, sunspots appear
infrequently and less ultraviolet radiation reaches Earth.
The largest recent event -- the “Maunder Minimum,” which lasted from 1645
and 1715 — overlapped with the “Little Ice Age” (13th to mid-19th century).
While scientists continue to research whether an extended solar minimum
could have contributed to cooling the climate, there is little evidence that the
Maunder Minimum sparked the Little Ice Age, or at least not entirely by itself
(notably, the Little Ice Age began before the Maunder Minimum). Current
theories on what caused the Little Ice Age consider that a variety of events
could have contributed, with natural fluctuations in ocean circulation,
changes in land use by humans and cooling from a less active sun
also playing roles; overall, cooling caused by volcanic aerosols likely played
the title role.
Several studies in recent years have looked at the effects that another Grand
Solar Minimum might have on global surface temperatures. These studies
have suggested that while a grand minimum might cool the planet as much
as 0.3 degrees C, this would, at best, slow down but not reverse human-
caused global warming. There would be a small decline of energy reaching
Earth; however, just three years of current carbon dioxide concentration
growth would make up for it. In addition, the Grand Solar Minimum would be
modest and temporary, with global temperatures quickly rebounding once
the event concluded.
Moreover, even a prolonged Grand Solar Minimum or Maunder Minimum
would only briefly and minimally offset human-caused warming.
More about solar cycles:
https://scijinks.gov/solar-cycle/
|
|