The Earth's global magnetic field generated by an internal dynamo mechanism has been continuously changing at different time scales since its formation. Paleodata indicate that relatively long periods of evolutionary changes can be replaced by quick magnetic inversions. Based on observations, the Earth's magnetic field is currently weakening and the magnetic poles are shifting, possibly indicating the beginning of the inversion process. This paper uses the Gauss coefficients to approximate the behavior of the Earth's magnetic field components over the past 100’years. Using the extrapolation method, it is shown that the magnetic dipole component will vanish by the year 3600 and that at that time the geomagnetic field will be determined by the smaller value of a quadrupole magnetic component. A numerical model is developed which allows one to evaluate and compare both galactic and solar cosmic ray fluxes in the Earth's magnetosphere and on its surface during the periods of dipole or quadrupole domination. The role of atmosphere in absorbing particles of cosmic rays is taken into account. An estimate of radiation danger to humans is obtained for the ground level and for the International Space Station altitude of ~400 km. It is shown that in the most unfavorable, minimum field, part of the inversion process the galactic cosmic ray flux increases by no more than a factor of three, implying that the radiation danger does not exceed the maximum permissible dose. Thus, the danger of the magnetic inversion periods for humans and nature generally should not have fatal consequences for humans and nature despite dramatically changing the structure of the Earth's magnetosphere.

Keywords: geomagnetic dynamo, magnetic field inversion, geomagnetic field, modeling, galactic cosmic rays, solar cosmic rays, radiation security PACS: 91.25.Cw, 91.25.Mf, 94.20.wq (all) DOI: 10.3367/UFNe.2017.07.038190 URL: https://ufn.ru/en/articles/2018/2/d/ 000435333700004 2-s2.0-85047548826 2018PhyU...61..191T Citation: Tsareva O O, Zelenyi L M, Malova H V, Podlozko M V, Popova E P, Popov V Yu "What expects humankind during the inversion of the Earth's magnetic field: threats imagined and real" Phys. Usp. 61 191–202 (2018) BibTexBibNote ® (generic)BibNote ® (RIS)MedlineRefWorks Received: 27th, June 2017, revised: 27th, July 2017, accepted: 28th, July 2017 Оригинал: Царёва О О, Зелёный Л М, Малова Х В, Подзолко М В, Попова Е П, Попов В Ю «Что ожидает человечество при инверсии магнитного поля Земли: угрозы мнимые и подлинные» УФН 188 207–220 (2018); DOI: 10.3367/UFNr.2017.07.038190