Green House Effect - Current Scenario
Since the beginning of the Industrial Revolution, the concentrations of most of the greenhouse gases have increased. For example, the concentration of carbon dixode has increased by about 36% to 380 ppmv, or 100 ppmv over modern pre-industrial levels. The first 50 ppmv increase took place in about 200 years, from the start of the Industrial Revolution to around 1973; however the next 50 ppm increase took place in about 33 years, from 1973 to 2006.
Recent data also shows the concentration is increasing at a higher rate. In the 1960s, the average annual increase was only 37% of what it was in 2000 through 2007.
The other greenhouse gases produced from human activity show similar increases in both amount and rate of increase. Many observations are available online in a variety of Atmospheric Chemistry Observational Databases.Relevant to radiative forcing
| Gas |
Current (1998) Amount by volume |
Increase over pre-industrial (1750) |
Percentage increase |
Radiative forcing (W/m²) |
| Carbon dioxide |
365 ppm {383 ppm(2007.01)} |
87 ppm {105 ppm(2007.01)} |
31% {37.77%(2007.01)} |
1.46 {~1.532 (2007.01)} |
| Methane |
1,745 ppb |
1,045 ppb |
150% |
0.48 |
| Nitrous oxide |
314 ppb |
44 ppb |
16% |
0.15 |
Relevant to both radiative forcing and ozone depletion; all of the following have no natural sources and hence zero amounts pre-industrial
(Source: IPCC radiative forcing report 1994 updated (to 1998) by IPCC TAR table 6.1)
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