DOI: 10.1201/9781003181354-6

215

6.1  Introduction

The existence of the Earth’s magnetic field (geomagnetic field, GMF) is indispensable for the origin

and evolution of life. This is because when a constant stream of potentially harmful charged particles

(mainly protons and electrons), which have reached the Earth blown by the solar wind, and galactic

cosmic rays (GCRs), including ultraviolet (UV)-, X-, and γ-rays, is shielded and protected by the barrier

of the Earth’s magnetosphere (geomagnetosphere) (see ESA, 2016b), living organisms can only survive.

In an environment where damaging charged particles and GCRs could reach, their genes were damaged

and they could not survive and proliferate. It is inferred that primitive organisms such as cyanobacteria

could survive even in an environment near the sea surface where light reaches. So when and how was

the GMF to protect living organisms against harmful radiations generated?

The GMF intensity was about half of the current one 4.2 billion years ago (Ga = giga-annum = 10⁹years),

but it became about the current intensity 4.1–4.0 Ga, and again about half the current one 3.9–3.3 Ga,

and since about 2.7–2.1 Ga, it remains as large as the present intensity (Tarduno et al., 2007, 2010). The

magnetosphere is the region above the ionosphere that is defined by the extent of the GMF in space. It

extends several tens of thousands of kilometers into space, protecting the Earth from the charged par-

ticles of the solar wind and GCRs that would otherwise strip away the upper atmosphere, including the

ozone layer that protects the Earth from the potentially harmful UV-B (280–315 nm) radiation. The ion-

osphere is the ionized part of Earth’s upper atmosphere, from about 48 to 965 km altitude (Zell, 2020).

The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and

6

Geomagnetic Field Effects

on Living Systems

Hideyuki Okano

Shoogo Ueno

6.1

Introduction....................................................................................... 215

6.2

Magnetic Sense................................................................................... 218

Primitive Magnetic Sense  •  Magnetic Sense of Animals 

•  Magnetic Sense of Plants  •  Magnetic Sense of Humans

6.3

Change of the Geomagnetic Field...................................................233

Pole Shift  •  Chibanian  •  Superchron  •  Decrease of Geomagnetic

Field •  The Extinction of Neanderthals  •  Mass Extinctions of Life on

Earth  •  The Cambrian Explosion of Life on Earth

6.4

Health Effects of the Geomagnetic Field (GMF)..........................254

Magnetic Field Deficiency Syndrome  •  Magnetic Storm and Its

Related Diseases  •  Schumann Resonance  •  The Effects of the Solar

Cycles and the Geomagnetic Field on Infectious Diseases and

Human Health

6.5

Discussion and Conclusions............................................................ 271

References.......................................................................................................275