Hailed as ‘the last piece of the puzzle’ in codifying our understanding of the mechanism(s) that cause climate changes, scientists are increasingly turning to Sun-modulated cosmic ray flux and cloud cover variations as the explanation for decadal- and centennial-scale global warming and cooling. In other words, climate changes are increasingly being attributed to natural variability, not anthropogenic activity.
Image Source: Sciencedaily.com and Climate4you.com
Fewer sunspots leads to low solar activity and more low-level cloud cover that reflects rather than absorbs the incoming solar heat. The result is colder climates. Higher solar activity leads to fewer low clouds and warmer climates, consistent with what has occurred in recent decades. The Modern Grand Maximum of very high solar activity (1940-2015) recently ended.
Periods with few sunspots are associated with low solar activity and cold climate periods. Periods with many sunspots are associated with high solar activity and warm climate periods. … Deterministic models based on the stationary periods confirm the results through a close relation to known long solar minima since 1000 A.D. and suggest a modern maximum period from 1940 to 2015. The conclusion is that the activity level of the Modern Maximum (1940–2000) is a relatively rare event, with the previous similarly high levels of solar activity observed 4 and 8 millennia ago (Usoskin et al., 2003).
With fewer clouds, more solar radiation can be absorbed by the oceans rather than reflected back to space; this, in turn, leads to warming.
Therefore, cloud cover changes and the concomitant alteration of surface solar heat absorption can explain the 1980s to 2000s warming via the increase in absorbed solar radiation (Pinker et al., 2005; Pallé et al., 2004; Herman et al., 2013; Wang et al., 2012; Calbó et al., 2016; Kauppinen et al, 2014; McLean, 2014).
There has recently been a scientific “breakthrough” in understanding the “missing link” between the Sun’s modulation of cosmic rays and thus cloud cover, supported by real-world observational evidence (3,100 hours of data sampling and controlled experimentation). More and more papers detailing the Sun-Climate connection are being published in scientific journals.
The following is an abbreviated list of scientific papers supporting the Sunspot Activity→Cosmic Ray Flux→Cloud Cover Changes→Climate Changes conceptualization published within the last year.
The missing link between exploding stars, clouds, and climate on Earth
Breakthrough in understanding of how cosmic rays from supernovae can influence Earth’s cloud cover and thereby climate
The new results reveal, both theoretically and experimentally, how interactions between ions and aerosols can accelerate the growth by adding material to the small aerosols and thereby help them survive to become cloud condensation nuclei. It gives a physical foundation to the large body of empirical evidence showing that Solar activity plays a role in variations in Earth’s climate. For example, the Medieval Warm Period around year 1000 AD and the cold period in the Little Ice Age 1300-1900 AD both fits with changes in Solar activity.
“‘Finally we have the last piece of the puzzle explaining how particles from space affect climate on Earth. It gives an understanding of how changes caused by Solar activity or by super nova activity can change climate.’ says Henrik Svensmark, from DTU Space at the Technical University of Denmark, lead author of the study.
Data was taken over a period of 2 years with total 3100 hours of data sampling. The results of the experiments agreed with the theoretical predictions.
• Low clouds made with liquid water droplets cool the Earth’s surface.
•Variations in the Sun’s magnetic activity alter the influx of cosmic rays to the Earth.
•When the Sun is lazy, magnetically speaking, there are more cosmic rays and more low clouds, and the world is cooler.
•When the Sun is active fewer cosmic rays reach the Earth and, with fewer low clouds, the world warms up.
The implications of the study suggests that the mechanism can have affected:
• The climate changes observed during the 20th century
• The coolings and warmings of around 2°C that have occurred repeatedly over the past 10,000 years, as the Sun’s activity and the cosmic ray influx have varied.
• The much larger variations of up to 10°C occuring as the Sun and Earth travel through the Galaxy visiting regions with varying numbers of exploding stars.
The spectral analysis of the sedimentological parameters reveals the significant periodicities (>95% significance) centering at ∼1067, ∼907, and ∼824 years. The long-term trends in the data suggest the possible fluctuation of Antarctic ice-sheet superimposed on global climatic fluctuations due to solar activity. … The curiosity of climate scientists arises on the mechanism of reaction of the climate system in response to the changes in solar forcing. There are two possible mechanisms proposed which work through the atmospheric processes. The first mechanism includes the action of the ozone layer by increasing more UV radiations with increased solar activity. It must have raised the temperature in the stratosphere which produces stronger winds in lower stratosphere and troposphere. These strong winds in the troposphere result in the relocation of pressure cells and storm tracks which ultimately disturbs the climate system (Schindell et al., 1999; Crosta et al., 2007). The second proposed mechanism considers the cosmic rays and cloud cover responsible for amplifying the climate forcing (Svensmark, 2000). High solar activity is believed to be responsible for less cooling of the lower atmosphere due to reduced cloud cover (Marsh and Svensmar, 2000). Conversely, low solar activity is believed to provide additional cooling of the lower atmosphere. These two feedback mechanisms responsible for the climatic forcing due to solar activity may work alone or in conjugation and are also superposed to other climate forcing as well as variability of internal cycling (Rind, 2002). Further, the periodic increase in solar activity results in increased temperature in the lower atmosphere which causes melting of ice-sheets in the Antarctic region. It may further provide the periodicity in freshwater discharge in the Schirmacher lakes and hence regulates the depositional environment of the studies lake.
A similar result was also found for the relationship between solar activity and cosmic ray flux with a negative correlation, i.e. 0.69/year. When solar activities decrease, the clouds cover rate increase due-0.61/month and – to secondary ions produced by cosmic rays. The increase in the cloud cover rate causes the decrease in solar constant value and solar radiation on the earth’s surface. … The increase in the formation rate of cloud would affect the decrease in the intensity of solar radiation reaching the Earth’s surface. The relationship between cosmic rays and solar constant is an “opposite” relationship because of the negative correlation type (r < 0). The phenomenon of “opposite” is in a good agreement with the result by Svensmark (1997) who found a correlation between temperature and global cloud coverage with the cosmic rays… [T]he climate also depends on variations in the flux of solar energy received by the earth’s surface. Variation in the solar energy flux is caused by variations in solar activity cycle. Thus the climate is a manifestation of how solar radiation is absorbed, redistributed by the atmosphere, land and oceans, and ultimately radiated back into space. Every variation of solar energy received at the earth’s surface and reradiated by the earth into space will have a direct impact on climate change on Earth.
Secondary aerosol particles, which are formed by nucleation processes in the atmosphere, play an important role in atmospheric chemistry and in the Earth’s climate system. They affect the Earth’s radiation balance by scattering solar radiation back to space and can also act as cloud condensation nuclei (CCN) and thereby affect the amount of cloud and its radiative properties. Clouds have a net cooling effect on the Earth’s radiation budget of about −27.7 W m−2 (Hartmann, 1993). Thus, a small change in cloud properties can have significant effect on the climate system. Results by Merikanto et al. (2009) and Yu and Luo (2009) have shown that a significant fraction (ranging between 31 and 70 %) of cloud-forming aerosol particles in the atmosphere are secondary particles that originate from nucleation. Therefore, understanding nucleation is crucial in order to fully understand the atmospheric and climatic effects of aerosols.
The weakening of the geomagnetic field causes an increase in galactic cosmic ray (GCR) flux. Some researchers argue that enhanced GCR flux might lead to a climatic cooling by increasing low cloud formation, which enhances albedo (umbrella effect). Recent studies have reported geological evidence for a link between weakened geomagnetic field and climatic cooling. … Greater terrestrial cooling indicates that a reduction of insolation [solar radiation reaching the surface] is playing a key role in the link between the weakening of the geomagnetic field and climatic cooling. The most likely candidate for the mechanism seems to be the increased albedo of the umbrella effect.
In this work, we investigate the relationship between the ∼ 11-year and ∼ 22-year cycles that are related to solar activity and GCRs [galactic cosmic rays] and the annual average temperature recorded between 1936 and 2014 at two weather stations, both located near a latitude of 26◦ S but at different longitudes. … Sunspot data and the solar modulation potential for cosmic rays were used as proxies for the solar activity and the GCRs, respectively. Our investigation of the influence of decadal and bidecadal cycles in temperature data was carried out using the wavelet transform coherence (WTC) spectrum. The results indicate that periodicities of 11 years may have continuously modulated the climate at TOR [Torres, Brazil] via a nonlinear mechanism … The obtained results offer indirect mathematical evidence that solar activity and GCR variations contributed to climatic changes in southern Brazil during the last century. The contribution of other mechanisms also related to solar activity cannot be excluded.
The effects of total solar irradiance (TSI) and volcanic activity on long-term global temperature variations during solar cycles 19–23 [1954-2008] were studied. It was shown that a large proportion of climate variations can be explained by the mechanism of action of TSI [total solar irradiance] and cosmic rays (CRs) on the state of the lower atmosphere and other meteorological parameters. … Recent studies by Pudovkin and Raspopov, Tinsley, and Swensmark have shown that the Earth’s cloud coverage is strongly influenced by cosmic ray intensity. Conditions in interplanetary space, which can influence GCRs and climate change, have been studied in numerous works. As has been demonstrated by Biktash, the long-term CR count rate and global temperature variations in 20–23 solar cycles are modulated by solar activity and by the IMF (interplanetary magnetic field). A possible geophysical factor which is able to affect the influence of solar activity on the Earth’s climate is volcanism. The effects of volcanism can lead to serious consequences in the atmosphere and the climate.
The fact that the periods of eight out of nine of the most prominent peaks in the lunar alignment spectrum (highlighted column 3 of Table 2) closely match those in the spectra of ϕm [solar modulation potentional] and Tm [maximum daily temperature], strongly supports the contention that all three of these phenomena are closely related to one another. … principal component analyses of the 10Be and 14C records show that, on multi-decadal to centennial time scales, the radionuclide production signal accounts for 76% of the total variance in the data [18,19]. This would imply that there is a causal link between Tm [maximum daily temperature] and near-Earth GCR flux, with a factor related to the latter driving the former. … An implicit assumption that is used by those who reject GCR [galactic cosmic rays]-cloud models is that the GCR flux hitting the Earth needs to produce changes in the total amount of cloud cover over the majority of the globe in order to significantly affect the world mean temperature. However, this assumption ignores the possibility that regional changes in the amount of cloud cover could influence the rate at which the Earth’s climate system warms or cools. Of course, for this to be true there would have to be observational evidence that shows that the GCR flux can affect the level of cloud cover on a regional scale. Support for this hypothesis is provided  who claim that existing multi-decadal ground-based datasets for clouds show that there is a weak but significant correlation between the amounts of regional cloud cover and the overall level of GCR fluxes. In addition, Larken et al.  find that there is a strong and robust positive correlation between statistically significant variations in the short-term (daily) GCR ray flux and the most rapid decreases in cloud cover over the mid-latitudes (30° – 60° N/S). Moreover, Larken et al.  find that there is a direct causal link between the observed cloud changes and changes in the sea level atmospheric temperature, over similar time periods.Hence, the solar connection between Tm and ϕm can be summarized using a heuristic luni-solar model like that shown in Figure 6. Firstly, the model proposes that there must be some, as yet, unknown factor associated with the level of solar activity on the Sun (e.g. possibly the overall level GCR hitting the Earth) that is producing long-term systematic changes in the amount and/or type of regional cloud cover. Secondly, the model proposes that the resulting changes in regional cloud cover lead to variations in the temperature differences between the tropics and the poles which, in turn, result in changes to the peak strength of the zonal tropical winds. Thirdly, the model further proposes that it is the long-term changes in the amount and/or type of regional cloud cover, combined with the variations in the temperature differences between the tropics and the poles that lead to the long-term changes in the poleward energy and momentum flux. And finally, the model proposes that it is this flux which governs the rate at which the Earth warms and cools, and hence, determines the long-term changes in the world mean temperature.
Galactic cosmic rays (GCRs) are the main source of ionizing radiation in the lower troposphere, in which secondary products can penetrate the ground and underground layers. GCRs affect the physical–chemical properties of the terrestrial atmosphere, as well as the biosphere. GCRs are modulated by solar activity and latitudinal geomagnetic field distribution.
Variations of charged particles of galactic cosmic rays (GCRs), which are caused by variations in the Earth’s magnetic field, are one of most significant among the variety of phenomena that influence the near-Earth medium and, consequently, the Earth’s climate and weather. Being the main sources of atmospheric ionization, they influence the atmosphere transparency and play the key role in formation of clouds, thunderstorms, and lightnings (Dorman, 2009).
The 11 yr solar cycle, also known as Schwabe cycle, represents the smallest-scaled solar cyclicity and is traced back to sunspot activity (Douglass, 1928; Lean, 2000), which has a measurable effect on the Earth’s climate, as indicated by the Maunder minimum (Usoskin et al., 2015). Global climate feedback reactions to solar irradiance variations caused by sunspots are complex and hypothesized to be triggered by (1) variation in total energy input (Cubasch and Voss, 2000), (2) the influence of ultraviolet light intensity variation on composition of the stratosphere (Lean and Rind, 2001), (3) the effect of cosmic rays on cloud formation (Marsh and Svensmark, 2000; Sun and Bradley, 2002), and/or (4) the effect of high-energy particles on the strato- and mesosphere (Jackman et al., 2005). … [L]ike today, sunspot activity caused fluctuations of cosmic radiation input to the atmosphere, affecting cloud formation and annual rates of precipitation.
May 21, 2018 at 08:09AM