Adding up the Greenhouse Effect: Attributing the contributions

For most people who study global warming only casually it is well known that the greenhouse effect acts to increase the surface temperature of the planet (currently) by about 33 K (or 60 F) above the so-called “effective temperature”; this is the temperature value that a planet would need to have in order for the infrared energy it emits to space to balance the energy it absorbs from the sun (assuming the sun is the only important source of energy, which is true enough for Earth and neighboring planets like Venus and Mars). This is simple enough, yet there are still many popular misconceptions out there concerning the relative roles of individual greenhouse gases and the total mean climatology of the greenhouse effect, and some of these confusions have admittedly not been explicitly corrected in the literature very well.

A matter of curiosity from this point is to decide how much of the total greenhouse effect is partitioned between various radiatively active substances in our atmosphere. That is, how much of the natural greenhouse effect is fractionally supported by water vapor, by CO2, etc

Advertisement

Climate Feedbacks: Part 1

Update: I have recently done a guest post on feedbacks at RealClimate. Part 1 is similar, but not the same as this post. I will not be doing a Part two on this site, instead it will be over at RC.

In light of recent attempts to describe the physics of climate change from first principles and in an accessible way (see Rasmus’ recent posts at RealClimate on the greenhouse effect and the troposphere) (also , here and here) it is worthwhile reviewing one of the greatest uncertainties surrounding climate change science and future predictions in a similar fashion: climate sensitivity and feedbacks. Feedbacks can behave in odd and counter-intuitive ways, some of which require some mathematics to really appreciate. In order to help facilitate an understanding for those who receive information at different levels of understanding, this will be a 2-part endeavor, where part 2 will be the more ‘technical version’ which may not necessarily be for everyone but will help demonstrate claims in part 1 quantitatively.