Global Temperature and Atmospheric Carbon Dioxide Concentration

Abstract

The solar energy absorbed by lands, oceans and the atmosphere is released in the form of infrared thermal radiation into space. Greenhouse gases absorb the infrared radiation and maintain stable climate. Among greenhouse gases carbon dioxide had been kept almost constant at about 280 ppm by a balance in biogeochemical carbon cycle before industrial revolution. After industrial revolution it became higher than 290 ppm for about 100 years. During subsequent 100 years from the 1870s the industrial development of the world led to its constant increase at about 0.28 ppm every year. After 1970, the carbon dioxide emissions were too much to be treated on our planet. Carbon dioxide was accumulating in the atmosphere with an increase in rate and its atmospheric concentration exceeded 400 ppm. It has been said in 2007 that the atmospheric carbon dioxide concentration reached the level in 3.5 million years ago, in spite of the fact that our Homo Sapiens appeared only 200 thousand years ago. It has been known that in 3.5 million years ago the atmospheric carbon dioxide concentration was between 360 to 400 ppm and that the mean global temperature and sea level were 2--3 {\textdegree}C and 15--25 m higher than the pre-industrial levels, respectively. Our planet spent 2.5 million years to decrease it to the preindustrial level by forming carbonate solids due to chemical weathering of the Himalayas. It is clear how the current level is hazardous, and we need to avoid the carbon dioxide emissions higher than the pre-industrial level.