Please explain charging of the earth by thunderstorms ??

Atmospheric electricity is the pattern of electrical charges in the Earth's atmosphere (or less commonly, that of another planet). The normal movement of electric charges among the Earth's surface, the various layers of the atmosphere, and especially the ionosphere, taken together, are known as the global atmospheric electrical circuit. Much of the reasoning required to explain these currents lies within the field of electrostatics, but also requires understanding of other disciplines within Earth science. Eliminating, for the moment, consideration of the extremely dense charge populations that exist in the upper reaches of the atmosphere, a region called the ionosphere, filled with dense, plasma gas whose ions give the ionosphere its name, we note that there is always some amount of unbound positive and negative, but net positive, electric charge in the atmosphere closest to the surface of the negatively charged Earth on a 'fine day'. When days are not so 'fine', the net unbound charge that exists in the clouds of thunderstorms can be exceedingly negative. The 'fine day' net positive charge sets up an electric field between the negative Earth and the net positive charge in the air, and this electric field stores electrical energy. The positive charge acts by induction on the earth and electromagnetic devices read less

Lightning is a sign that charge separation is being discharged.There is an electrical balance between the earth and the atmosphere. Lightning is constantly charging the earth, and the earth is constantly discharging to the atmosphere. The electrical resistivity of the atmosphere decreases with height. From the point of view of atmospheric electricity, the resistivity is sufficiently low at an altitude of about 30 miles that the voltage does not vary much above that point. The earth is recharged by thunderstorms. Thunderstorms deliver a net negative charge to earth as a result of the sum of the effects of the following processes: (1) negative charge carried from cloud to earth by lightning, (2) positive charge carried from cloud to ground by rain and (3) positive charge carried upward (the equivalent of negative charge carried downward) through the air beneath and above a thunderstorm read less