Neues vom Svensmark-Solarverstärker: Zwei Schritte vor, ein Schritt zurück

Am 15. Juli 2019 brachte die Tageszeitung The Australian einen ausgewogenen Artikel zur klimatischen Wirkung von solaren Aktivitätsschwankungen:

Climate change: Clouds, solar cycles play a part

Sand deposits near the Gobi Desert in China may seem a strange place to look for evidence that cosmic rays can control how clouds are formed and the impact they have on Earth’s climate. But Japanese scientists have measured the size of sand grains and the distance they travelled 780,000 years ago to add a new level of understanding to one of the questions that continues to baffle climate science: clouds.

The findings, published in Nature, point to big trends in natural variation of past and future climate that operate apart from greenhouse gas levels. The study adds weight to a contentious theory by Danish researcher Henrik Svensmark, of the Danish National Space Institute in Copenhagen, which uses cosmic rays and clouds to question the sensitivity of climate to carbon dioxide in the atmosphere.

Weiterlesen in The Australian

Der Artikel gibt uns einen guten Anlass nachzuschauen, was es Neues zu Svensmarks Solarverstärkermodell gibt. Allen Einsteigern in die Thematik sei zunächst der Dokufilm zur Theorie empfohlen:

Hier etwas ganz Verrücktes: Noch vor 15 Jahren konnte sich sogar Harald Lesch für Svensmark und die Sonnenflecken begeistern. Heute ist Lesch Vollblut-Aktivist auf der CO2-Seite, wird sich sicher nicht gerne an diese Zeit zurück erinnern. Ab Minute 10 schauen:

Beginnen wir mit dem Projekt CLOUD, welches das Svensmark-Modell „mit schwerem Gerät“ nachprüfen sollte. Der Beginn war vielversprechend, dann wurde es jedoch ziemlich politisch. Svensmark verließ das Projekt. Am Ende kam etwas heraus, was vielen nur allzurecht war: Der Mechanismus wäre viel zu unbedeutend, um im globalen Klimageschehen eine wichtige Rolle zu spielen. Das meinte man jedenfalls gefunden zu haben. Tief durchatmen, case closed. Ein Glück, alles andere hätte dem IPCC viel Ärger eingebracht. Pierce (2017), veröffentlicht am 2.8.2017 in JGR Atmospheres:

Cosmic rays, aerosols, clouds, and climate: Recent findings from the CLOUD experiment

The Cosmics Leaving OUtdoor Droplets (CLOUD) experiment was created to systematically test the link between galactic cosmic rays (GCR) and climate, specifically, the connection of ions from GCR to aerosol nucleation and cloud condensation nuclei (CCN), the particles on which cloud droplets form. The CLOUD experiment subsequently unlocked many of the mysteries of nucleation and growth in our atmosphere, and it has improved our understanding of human influences on climate. Their most recent publication (Gordon et al. 2017, https://doi.org/10.1002/2017JD026844) provides their first estimate of the GCR‐CCN connection, and they show that CCN respond too weakly to changes in GCR to yield a significant influence on clouds and climate.

Man gab sogar das Geld aus, um den Artikel für alle frei zugänglich zu machen. Etliche der Editoren der Zeitschrift wirken übrigens beim IPCC mit.

Allerdings hatte Kilifarska 2015 etwas ganz anderes gefunden. Nach dieser Studie wird das Sonnensignal über energetische Partikel aus der Höhe bis in die untere Atmosphäre weitergeleitet:

Bi-decadal solar influence on climate, mediated by near tropopause ozone

The Sun’s contribution to climate variations was highly questioned recently. In this paper we show that bi-decadal variability of solar magnetic field, modulating the intensity of galactic cosmic ray (GCR) at the outer boundary of heliosphere, could be easily tracked down to the Earth’s surface. The mediator of this influence is the lower stratospheric ozone, while the mechanism of signal translation consists of: (i) GCR impact on the lower stratospheric ozone balance; (ii) modulation of temperature and humidity near the tropopause by the ozone variations; (iii) increase or decrease of the greenhouse effect, depending on the sign of the humidity changes. The efficiency of such a mechanism depends critically on the level of maximum secondary ionisation created by GCR (i.e. the Pfotzer maximum) – determined in turn by heterogeneous Earth’s magnetic field. Thus, the positioning of the Pfotzer max in the driest lowermost stratosphere favours autocatalytic ozone production in the extra-tropical Northern Hemisphere (NH), while in the SH– no suitable conditions for activation of this mechanism exist. Consequently, the geomagnetic modulation of precipitating energetic particles – heterogeneously distributed over the globe – is imprinted on the relation between ozone and humidity in the lower stratosphere (LS). The applied test for causality reveals that during the examined period 1957–2012 there are two main centres of action in the winter NH, with tight and almost stationary winter ozone control on the near tropopause humidity. Being indirectly influenced by the solar protons, the variability of the SH lower stratospheric ozone, however, is much weaker. As a consequence, the causality test detects that the ozone dominates in the interplay with ULTS humidity only in the summer extra-tropics.

Highlights der Studie:

  • Solar modulation of GCR [Galactic Cosmic Rays] is translated down to the Earth climate.
  • The mediator of solar influence are energetic particles.
  • GCR impacts the O3 [ozone] budget in the lower stratosphere.
  • O3 influences the temperature and humidity near tropopause, and greenhouse effect.
  • Effectiveness of this mechanism depends on geomagnetic field intensity.

Svensmark selber ließ sich von den CLOUD-Ergebnissen nicht entmutigen und hielt im März 2018 in London einen Übersichtsvortrag zum Thema mit neuen Ergebnissen. Die Vortragsfolien können Sie bei der GWPF herunterladen.

Die GWPF brachte seinerzeit auch einen 25-minütigen Youtube-Beitrag:

Hören Sie auch ein Svensmark-Interview, das aus dem Mai 2019 stammt.

Bestätigung erhielt Svensmark durch Ogurtsov and Veretenenko 2017:

Possible Contribution of Variations in the Galactic Cosmic Ray Flux to the Global Temperature Rise in Recent Decades

The field area of the Earth’s lower (<3.2 km) clouds is shown to correlate significantly with the intensity of galactic cosmic rays in 1983–2010, with the sign of correlation reversing in 2003. The same effect is discovered in the correlation between air temperatures in various regions of the Earth and the relativistic electron fluxes with energies of 30–300 KeV that precipitate in winter (December–February). An energy-balance climate model is used to estimate the possible contribution of lower clouds to the globally averaged temperature in the indicated period. It is shown that the consideration of lower clouds as a radiative forcing allows one to explain the global warming of the last 30 years without employing the hypothesis of anthropogenic greenhouse heating.

Im August 2018 erschien ein weiteres Paper der Gruppe, Veretenenko et al 2018, auf Intechopen:

Galactic Cosmic Rays and Low Clouds: Possible Reasons for Correlation Reversal

Influence of galactic cosmic rays (GCRs) on cloud formation is suggested to be an important part of the mechanism of solar activity influence on weather and climate. A high positive correlation between low cloud amount and GCR fluxes was observed in the 1980s–1990s; however, in the early 2000s, it was violated. In this work, we consider a nature of long-term correlation links between cloud cover at middle latitudes and GCRs, as well as possible reasons for this correlation reversal. It was shown that the GCR-cloud links observed on the decadal time scale are indirect and caused by GCR effects on cyclonic activity which depend on epochs of the large-scale atmospheric circulation. The reversal of GCR-cloud correlation in the 2000s seems to be due to a sharp weakening of the Arctic and Antarctic stratospheric polar vortices, which results in the change of the troposphere-stratosphere coupling and, then, of GCR contribution to the development of extratropical cyclogenesis.

In der Arbeit gehen die Autoren auf eine wichtige Schwäche des Svensmark-Modells ein, nämlich die Tatsache, dass die schöne Korrelation zwischen Sonnenaktivität und Wolken in den frühen 2000er Jahren zusammenbrach. Veretenenko und Kollegen nehmen eine Phasenumkehr an und beschreiben einen indirekten Mechanismus im Sonne-Wolken-Wechselspiel über die Bildung von Tiefdruckgebieten.

Im August 2019 erschien im Journal of Atmospheric and Solar-Terrestrial Physics ein Paper von Christodoulakis und Kollegen, das die Hoffnung auf einen Svensmark-Mechanismus wieder dämpft:

On the link between atmospheric cloud parameters and cosmic rays

We investigate the cosmic rays behavior with respect to the scaling features of their temporal evolution. Our analysis is based on cosmic rays measurements by three neutron monitor stations in Athens (Greece), Jungfraujoch (Switzerland) and Oulu (Finland), for the period 2000 to early 2017. Each of these datasets was analyzed by using the Detrended Fluctuation Analysis (DFA) and Multifractal Detrended Fluctuation Analysis (MF-DFA) in order to investigate intrinsic properties, like self-similarity and the spectrum of singularities. The main result obtained is that the cosmic rays time series as recorded by the aforementioned neutron monitor stations exhibit positive long-range correlations of 1/f type with multifractal behavior meaning that this behavior is characteristic for cosmic rays at North Hemisphere. In addition, we investigate the possible similar scaling features in the temporal evolution of meteorological parameters that are closely associated with the cosmic rays, such as physical properties of clouds. The main conclusions drawn from the latter investigation are that positive long-range correlations are observed in cloud optical thickness liquid mean and cirrus reflectance mean, while both of them do not present statistically significant correlation with cosmic rays, which is in agreement with earlier studies.

Bestätigung erfuhr Svensmark hingegen durch die University of Kobe, die am 3. Juli 2019 per Pressemitteilung bekanntgab:

Winter monsoons became stronger during geomagnetic reversal

Revealing the impact of cosmic rays on the Earth’s climate

New evidence suggests that high-energy particles from space known as galactic cosmic rays affect the Earth’s climate by increasing cloud cover, causing an “umbrella effect”.

When galactic cosmic rays increased during the Earth’s last geomagnetic reversal transition 780,000 years ago, the umbrella effect of low-cloud cover led to high atmospheric pressure in Siberia, causing the East Asian winter monsoon to become stronger. This is evidence that galactic cosmic rays influence changes in the Earth’s climate. The findings were made by a research team led by Professor Masayuki Hyodo (Research Center for Inland Seas, Kobe University) and published on June 28 in the online edition of Scientific Reports.

The Svensmark Effect is a hypothesis that galactic cosmic rays induce low cloud formation and influence the Earth’s climate. Tests based on recent meteorological observation data only show minute changes in the amounts of galactic cosmic rays and cloud cover, making it hard to prove this theory. However, during the last geomagnetic reversal transition, when the amount of galactic cosmic rays increased dramatically, there was also a large increase in cloud cover, so it should be possible to detect the impact of cosmic rays on climate at a higher sensitivity.

In the Chinese Loess Plateau, just south of the Gobi Desert near the border of Mongolia, dust has been transported for 2.6 million years to form loess layers – sediment created by the accumulation of wind-blown silt – that can reach up to 200 meters in thickness. If the wind gets stronger, the coarse particles are carried further, and larger amounts are transported. Focusing on this phenomenon, the research team proposed that winter monsoons became stronger under the umbrella effect of increased cloud cover during the geomagnetic reversal. They investigated changes in particle size and accumulation speed of loess layer dust in two Loess Plateau locations.

In both locations, for about 5000 years during the geomagnetic reversal 780,000 years ago, they discovered evidence of stronger winter monsoons: particles became coarser, and accumulation speeds were up to > 3 times faster. These strong winter monsoons coincide with the period during the geomagnetic reversal when the Earth’s magnetic strength fell to less than ¼, and galactic cosmic rays increased by over 50%. This suggests that the increase in cosmic rays was accompanied by an increase in low-cloud cover, the umbrella effect of the clouds cooled the continent, and Siberian high atmospheric pressure became stronger. Added to other phenomena during the geomagnetic reversal – evidence of an annual average temperature drop of 2-3 degrees Celsius, and an increase in annual temperature ranges from the sediment in Osaka Bay – this new discovery about winter monsoons provides further proof that the climate changes are caused by the cloud umbrella effect.

“The Intergovernmental Panel on Climate Change (IPCC) has discussed the impact of cloud cover on climate in their evaluations, but this phenomenon has never been considered in climate predictions due to the insufficient physical understanding of it”, comments Professor Hyodo. “This study provides an opportunity to rethink the impact of clouds on climate. When galactic cosmic rays increase, so do low clouds, and when cosmic rays decrease clouds do as well, so climate warming may be caused by an opposite-umbrella effect. The umbrella effect caused by galactic cosmic rays is important when thinking about current global warming as well as the warm period of the medieval era.”

Paper: Ueno et al. 2019. “Intensified East Asian winter monsoon during the last geomagnetic reversal transition” DOI:10.1038/s41598-019-45466-8

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