Weegy: fluctuated between hot and cold periods User: Scientists think the earth is approximately _____ years old. 2 billion 3 billion 4 ½ billion 6 ½ billion Weegy: Earth is approximately 4 1/2 billion years old. User: no it not true User: no the earth is not 4 1/2 million or billion it. the earth is 7000 thousnd Weegy: The earth's climate has always changed through history due to natural cycles. Earth's climate has been volatile throughout history, as the graph demonstrates to the right. This is due to naturally forcing, and, [ given that changes in the Earth's climate are on a hundred-thousand-year cycle, it would appear that the cause must be inter-planetary (involving a slight wobble in the orbit of the Earth around the sun over these many centuries). In any event, our changes today, must be placed in the context of this constant natural change. We are now in a warming period before entering the next ice-age. This means that much of our current warming experience must be appropriately attributed to these natural, cyclical forces. ] (More)