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Geomagnetic Field Effects on Living Systems

fuid fow is induced in the liquid outer core due to the “Coriolis force” efect caused by the rotation of

the Earth (Kageyama and Sato, 1997). Tat is, due to the Coriolis force, fuid motion and convection

currents are organized in columns along the rotation axis (Kageyama and Sato, 1997). Tus, the spiral

fow of conducting fuid is created by the combination of convection currents and the Coriolis force.

Te GMF varies depending on the region. Tis is because the GMF increases in strength due to the

increased density of MF lines at the north (N) and south (S) magnetic poles, and weakens in the sparse

equatorial region of MF lines. Tis indicates that the shape of the GMF is a dipole MF. Te main GMF

is a dipole generated in the Earth’s outer core (Elsasser, 1950). Te dipole feld constitutes ~90% of the

main GMF. However, since the GMF has partially non-dipole MF components, spatial variations are

magnifed. Tese variations in GMF strength are particularly remarkable in areas where the GMF in

the South Atlantic Ocean is extremely weak. Tese areas are the “South Atlantic Anomaly” shown as

the patch (ESA, 2012).

Te variation of ionospheric plasma is strongly correlated with solar radiation and geomagnetic

activity (Datta and Das, 2020). However, some other reports have pointed out that extreme tropospheric

events such as thunderstorms and heavy lightning can also change the ionospheric total electron content

distribution (Lay et al., 2013). Lightning which is the discharge between separated positively charged ice

particles and negatively charged small other particles generates huge energy and couples through a

quasi-electrostatic or electric feld (EF) and electromagnetic (EM) pulsed feld (Datta and Das, 2020).

Tis generated energy then reaches to lower ionosphere and produces reionization by heating up this

medium (Datta and Das, 2020).

Xiong et al. (2016) addressed the close relationship between ionospheric plasma irregularities, i.e.,

“ionospheric thunderstorms” and Global Positioning System (GPS) signal total interruption of Swarm

satellites mainly at the satellite altitude of ~500 km. Tus, GPS navigation systems on low-orbiting sat­

ellites sometimes black out when they fy over the equator between Africa and South America (ESA,

2016a). According to an ESA announcement (ESA, 2016a), the GPS link was broken 166 times during

the frst 2 years of Swarm project since 2013, of which 161 coincided with ionospheric thunderstorms.

Te high-resolution observations from the satellite helped to link these outages to ionospheric thunder­

storms 300–600 km in the Earth’s atmosphere (DTU Space, 2016). Surprisingly, the area where satellite

failures such as GPS losses are concentrated is in perfect coincidence with South Atlantic Anomaly

(ESA, 2012).

According to Tarduno et al. (2010), MF and stronger solar wind strengths suggest important modi­

fcations during the frst billion years of Earth evolution. Studies of the evolution of solar-type stars

suggest that the Sun could emit high-energy fux (X-rays to UV-rays) up to 1,000 times stronger than the

present fux during the early stages, gradually decreasing to 6 times 3.5 Ga, and to 2.5 times 2.5 Ga (Ribas

et al., 2005, 2010). Terefore, besides the shielding efect of the Earth’s magnetosphere, the Earth was hit

by a much stronger ionizing fux in the past, which could have inhibited the evolution of “surface life”

during the earlier stages of the Earth’s history (Doglioni et al., 2016).

Te evolution of life is afected by fuctuations and variations of the GMF intensity together with

atmospheric oxygen (O2) level and UV radiation (Meert et al., 2016). More recently, it has been suggested

that under the condition of the GMF intensity minima, UV radiation reaching to Earth’s surface could

infuence mammalian evolution with the loci of extinction controlled by the geometry of stratospheric

ozone (O3) depletion (Channell and Vigliotti, 2019). It has been reported that when the GMF reverses,

the GMF is estimated to weaken (Brown et al., 2007; Valet and Plenier, 2008; Ferk and Leonhardt, 2009)

and the changes in the last 200 years have been potentially diminishing declines. Te magnetic poles

are also moving, and it is estimated that the N pole has moved 1,100 km over 170 years, but it is not fully

understood how much harmful charged particles and GCRs will radiate to the Earth. Terefore, it is

unclear whether the GMF reversals will cause the mass extinction of living organisms on Earth.

Many living organisms can perceive and respond to the GMF. Several animals use the GMF as a

magnetic compass (reviewed by R. Wiltschko and Wiltschko, 2012, 2021) and plants use the GMF as

a physiological modulator (reviewed by Mafei, 2014). Furthermore, it has been reported that human