"Who says it is warming catastrophically?
Humans have only been trying to measure the temperature fairly consistently since about 1880, during which time we think the world may have warmed by about +0.6 °C ± 0.2 °C. As we've already pointed out, the estimate of warming is less than the error margin on our ability to take the Earth's temperature, generally given as 14 °C ± 0.7 °C for the average 1961-1990 while the National Climatic Data Center (NCDC) suggest 13.9 °C for their average 1880-2004.
We are pretty sure it was cold before the 1880 commencement of record and we would probably not handle the situation too well if such conditions returned but there has been no demonstrable catastrophic warming while people have been trying to measure the planet's temperature.
If we have really been measuring a warming episode as we think we have, then setting new records for "hottest ever in recorded history" should happen just about every year -- although half a degree over a century is hardly something to write home about -- so there's really nothing exciting about scoring the highest number when looking at such a short history."
Also, did you know:
- Water vapor and carbon dioxide are major greenhouse gases.
Water vapor accounts for about 70% of the greenhouse effect, carbon dioxide somewhere between 4.2% and 8.4%.
Much of the wavelength bands where carbon dioxide is active are either at or near saturation.
Water vapor absorbs infrared over much the same range as carbon dioxide and more besides.
Clouds are not composed of greenhouse gas -- they are mostly water droplets -- but absorb about one-fifth of the longwave radiation emitted by Earth.
Clouds can briefly saturate the atmospheric radiation window (8-13µm) through which some Earth radiation passes directly to space (those hot and sticky overcast nights produce this effect - that is greenhouse but has nothing to do with carbon dioxide).
Greenhouse gases can not obstruct this window although ozone absorbs in a narrow slice at 9.6µm.
- Adding more greenhouse gases which absorb in already saturated bandwidths has no net effect.
- Adding them in near-saturated bands has little additional effect.