Post by Admin on Oct 8, 2012 11:40:10 GMT -5
Scientists believe that earth was formed 4.5 billion years ago. When earth was formed, It had no atmosphere.
Scientists also believe that there was a lot of volcanic activity in earth's first billion years. The early atmosphere was probably formed from the gases given out by volcanoes. The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. There were smaller proportions of water vapour, ammonia and methane. As the Earth cooled down, most of the water vapour condensed and formed the oceans.
The proportion of oxygen went up because of photosynthesis by plants.
While the Proportion of the carbon dioxide went down because :
it was locked up in sedimentary rocks such as limestone, and in fossil fuels.
it was absorbed by plants for photosynthesis.
it dissolved in the oceans.
But ,The burning of fossil fuels is adding carbon dioxide to the atmosphere faster than it can be removed. This means that the level of carbon dioxide in the atmosphere is increasing.
Scientists also believe that there was a lot of volcanic activity in earth's first billion years. The early atmosphere was probably formed from the gases given out by volcanoes. The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. There were smaller proportions of water vapour, ammonia and methane. As the Earth cooled down, most of the water vapour condensed and formed the oceans.
The proportion of oxygen went up because of photosynthesis by plants.
While the Proportion of the carbon dioxide went down because :
it was locked up in sedimentary rocks such as limestone, and in fossil fuels.
it was absorbed by plants for photosynthesis.
it dissolved in the oceans.
But ,The burning of fossil fuels is adding carbon dioxide to the atmosphere faster than it can be removed. This means that the level of carbon dioxide in the atmosphere is increasing.