Change In Earth’s Rotation May Have Caused Ancient Global Warming
Scientists and geology experts have found out that changes in the tilt of the Earth’s axis may have caused a heat wave millions of years ago. The poles melted and released carbon dioxide into the atmosphere, causing it to warm up.
About 55 million years ago the Earth’s temperature went up by about 5 degrees Celsius. After a short time, temperatures went down again but two more, smaller heat waves followed.
A team of scientists have now concluded that the permafrost in the polar region melted and set carbon free. Thus, sunlight came into the atmosphere but was blocked from getting out, similar to what the greenhouse effect causes today.
In an earlier theory scientists assumed that carbon trapped in ocean sediments was responsible for the warming of the atmosphere during this period. But now experts think that not enough carbon could have been released from the oceans to cause a heat wave of such a magnitude.
The path of the Earth around the sun varies in cycles. About 55 million years ago the Earth probably was tilted more towards the sun and polar regions melted. These regions endured longer and warmer summers. The warming period lasted about ten thousand years with two more warming phases occurring about one million years later.
Although a five degree change in temperature is rather big, scientists say that global warming today is continuing at a more rapid pace.
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Words
- although = while
- assume = think
- axis = the line around which the Earth turns or rotates
- block out = to keep from getting in
- carbon = chemical substance that exists as diamonds in its pure form; element that is also in coal
- carbon dioxide = gas which animals and people breathe out or when carbon is burned in the air
- cause = lead to
- conclude = to come to a final result
- cycle = phase
- endure = here: experience
- follow = come after
- geology = the study of rocks that make up the Earth
- greenhouse effect = the slow warming of the Earth’s atmosphere
- heat wave = a very hot period of time
- magnitude = size, greatness
- melt = to turn from ice to water
- occur = happen
- pace = speed
- path = route
- permafrost = layer of soil that is always frozen in very cold countries
- rapid = fast
- release = set free
- responsible = cause
- scientist = a person who is trained in science and works in a laboratory
- sediment = solid material that sinks down to the ocean floor
- similar = like
- thus = that is why
- tilt = to move to the side
- trap = not be able to escape
- vary = to be different; not always the same