Effects of Geomagnetic Variations on System Earth

Vogt, Joachim; Sinnhuber, Miriam; Kallenrode, May-Britt

doi:10.1007/978-3-540-76939-2_5

Cited by 10 publications

(7 citation statements)

References 83 publications

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“…Son et al (2008), for example, have shown that the southward shift of the westerlies observed during recent decades can likely be attributed to the anthropogenic destruction of stratospheric ozone and related changes in temperature gradients. Provided that the Laschamp event also caused an ozone hole (Valet and Valladas, 2010;Vogt et al, 2009), one might analogously expect a southward shift of the westerlies at ∼39 ka. This, taken at face value, is the opposite of what one would expect from the apparent correlation between strong cosmic ray fluxes and northward shifts of the westerlies/glacial advances ( Fig.…”

Section: Discussion Of the Forcings Of The Westerliesmentioning

confidence: 99%

Early last glacial maximum in the southern Central Andes reveals northward shift of the westerlies at ~39 ka

Zech

Kull

et al. 2011

Clim. Past

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The latitudinal position of the southern westerlies has been suggested to be a key parameter for the climate on Earth. According to the general notion, the southern westerlies were shifted equatorward during the global Last Glacial Maximum (LGM: ~24–18 ka), resulting in reduced deep ocean ventilation, accumulation of old dissolved carbon, and low atmospheric CO<sub>2</sub> concentrations. In order to test this notion, we applied surface exposure dating on moraines in the southern Central Andes, where glacial mass balances are particularly sensitive to changes in precipitation, i.e. to the latitudinal position of the westerlies. Our results provide robust evidence that the maximum glaciation occurred already at ~39 ka, significantly predating the global LGM. This questions the role of the westerlies for atmospheric CO<sub>2</sub>, and it highlights our limited understanding of the forcings of atmospheric circulation

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Section: Discussion Of the Forcings Of The Westerliesmentioning

confidence: 99%

Early last glacial maximum in the southern Central Andes reveals northward shift of the westerlies at ~39 ka

Zech

Kull

et al. 2011

Clim. Past

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“…Since most of the ozone layer is located in the mid-stratosphere nitric oxide is more effective for ozone loss than OH which is found in the upper and lowermost stratosphere. Presently the loss of stratospheric ozone induced by major solar events does not exceed a few percents, but the simulations show that in the magnetosphere of a strongly reduced dipole moment, solar protons of several tens of MeV access the atmosphere even at midlatitudes (Vogt et al, 2007(Vogt et al, , 2009. In the extreme case of a vanishing field leaving the atmosphere entirely exposed to energetic particles, the simulations (Sinnhuber et al, 2003) show that the total ozone loss would reach 40% in the northern atmosphere after a typical series of three solar events.…”

Section: What Did Happen During the Laschamp Event?mentioning

confidence: 98%

“…The penetration is much larger at one of the poles depending on the respective signs of the two components, but ozone loss can reach up to 20e40% at latitudes of 45e50 ( Fig. 5) and persists several years after the solar events (Vogt et al, 2007(Vogt et al, , 2009. Thus, both the reduced field strength and complex magnetosphere which prevailed during the Laschamp favoured a significant depletion of ozone during many episodes of intense solar activity.…”

Section: What Did Happen During the Laschamp Event?mentioning

confidence: 99%

The Laschamp-Mono lake geomagnetic events and the extinction of Neanderthal: a causal link or a coincidence?

Valet

Valladas

2010

Quaternary Science Reviews

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The causes of Neanderthal extinction and the transition with the modern man in Europe and Near East remain largely uncertain. The two main factors currently proposed are the arrival of a modern human competitor and/or the aptitude of the Neanderthals to survive rapidly changing climatic conditions. None of these hypotheses is fully satisfactory because the Neanderthals experienced other large climatic changes and the duration of overlap of the two populations remains largely unknown and even uncertain. No special attention has been given to the geomagnetic excursions of Laschamp and Mono Lake which are synchroneous with the extinction and were the most dramatic events encountered by the Neanderthals over the past 250 thousand years of their existence. During this period the geomagnetic field strength was considerably reduced and the shielding efficiency of the magnetosphere lowered, leaving energetic particles reach latitudes as low as 30. The enhanced flux of high-energy protons (linked to solar activity) into the atmosphere yielded significant ozone depletion down to latitudes of 40 e45. A direct consequence was an increase of the UV-B radiations at the surface which might have reached at least 15e20% in Europe with significant impacts on health of human populations. We suggest that these conditions, added to some other factors, contributed to the demise of Neanderthal population.

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“…The model furthermore allows to determine the loss of total ozone in the atmosphere and the surface UV-B radiation. For details reference is made to Sinnhuber et al (2003), Winkler et al (2008), and Vogt et al (2009).…”

Section: Polarity Transitions and Uv-b Radiation Enhancementsmentioning

confidence: 99%

Magnetic Polarity Transitions and Biospheric Effects

Glaßmeier

Vogt

2010

Space Sci Rev

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This review addresses possible biospheric effects of geomagnetic polarity transitions. During a transition the magnetic field at the surface of the Earth decreases to about 10% of its current value. If the geomagnetic field is a shield against energetic particles of solar or cosmic origin then biospheric effects can be expected. We review the early speculations on the problem and discuss in more detail its current status. We conclude that no clear picture of a geomagnetic link, a causal relation between secular magnetic field variations and the evolution of life on our planet can be drawn.

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Effects of Geomagnetic Variations on System Earth

Cited by 10 publications

References 83 publications

Early last glacial maximum in the southern Central Andes reveals northward shift of the westerlies at ~39 ka

Early last glacial maximum in the southern Central Andes reveals northward shift of the westerlies at ~39 ka

The Laschamp-Mono lake geomagnetic events and the extinction of Neanderthal: a causal link or a coincidence?

Magnetic Polarity Transitions and Biospheric Effects

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