The Change of Green House Gas Emissions
During the Industrial Revolution (1760 - 1830), the concentration of greenhouse gases in the atmosphere seemed to be steady,. However, greenhouse gasses are affected by human activity and have been increasing steadily since that time.
The concentration of CO2 increased 31% from about 280ppmv late in the 18th century to 367ppmv in 1999. The reason for the increase of observed CO2 is mainly due to the combustion of fossil fuels and the oxidation of carbon organic matter resulting from the destruction of forests. After 1980, the rate of annual average increase rate of CO2 has been 0.4%. The main factor for the last 20years has been the combustion of fossil fuels. The rest (10~30 %), is mostly due to the change of land use, especially, the desolation of forests.
The six suggested scenarios from the IPCC are used many times in order to predict the released amount of CO2 in the future.
These scenarios assume that the population of the world will decreased increase from 6 billion to 8.6 billion in 2050 and will further increase to 7.1 billion in 2100. Though GDP assumes that the rate of economic growth will grow rapidly from $21 trillion in 1990 to $525-550 trillion consistently, there is a big difference about the assumption of energy producing systems. This scenario assumes that 85% of major energy will be produced by non-fossil fuels at maximum and 31% at minimum. Based on this assumption, total global CO2 emissions from the combustion of the fossil fuels are predicted to change from the 6GT/yr in 1990 to 30.3GT/yr in 2100. The lowest predicted emissions are 4.3GT/yr. The mean value of emissions will rise to about 13GT/yr by 2100.
All scenarios imply a higher concentration for the next century. The IPCC scenario forecasts CO2 emissions of 540~970ppm for 2100 which is a 90~250% higher concentration than that of the late 1700s. The recent CO2 rate of 370ppm is 95ppm higher than before the Industrial Revolution. This means that human activity has increased the CO2 concentration 5 ~ 10 times more than that of the past century.
Methane in the atmosphere increased about 150% after 1750. Hereafter, the increase of emissions did not rise faster than CO2. Arable land is the major cause and there is a limitation to how many regions can be additionally used for cultivation. According to the IPCC scenario, it is expected that methane emissions will go from 310 million tons in 1990 to 236 ~ 889 tons in 2100. When the exhausted amount range of the scenario is the foundation, it can be produced from 1570ppb to 3730ppb by 2100. Base. Based on this scenario, there will be 1570~3730 ppb of methane in the atmosphere by 2100.
The concentration of nitrous oxide in the atmosphere has increased continually since the Industrial Revolution and it has become 16% (46ppb) higher than the 1970 value. The concentration in the atmosphere of N2O has increased continually at a rate of 0.25%/yr (1980~1998). The amount of N2O from fertilizers and human activity in 2100 could possibly increase 150% from the 20% decrement of present emissions. The present concentration level of 316ppb is much higher than the 40ppb before the Industrial Revolution. The IPCC is 354-460ppb in 2100 that is 80-186ppb higher. The IPCC 2100 prediction is 354~460 ppb which is an increase of 80~460ppb. Therefore, in the next century, the greenhouse effect of N2O will increase 1.4 times more than that of the past century.