After running across some resources again recently, I thought it would be a good idea to put some posts together that showed the background of many of the common facts I discuss. In this first post, I wanted to show the relationship between greenhouse gases, radiative forcing and temperatures. In doing, I will use graphics from the IPCC’s 4th Assessment Report Technical Summary.
First, here is a graphic of changes in greenhouse gases from ice core and modern observational data, spanning the time period of 20,000 years ago through current:
The portion of this graph I’d like to focus on is the upper left quadrant displaying the time series of atmospheric carbon dioxide concentration. First, note is the transition from ~180ppm 20,000 years ago to between 260 and 280ppm. This transition helped bring the last interglacial period to an end. Of greater import is the more recent transition from 280ppm to 380ppm (as of ~2005; current concentrations are ~390ppm).