A3.7 Continued…

The graph below provides an illustration of the rapid increase in emissions of greenhouse gases, which coincidentally matches the industrial revolution. The data is shown in concentration units of parts per million (ppm) or parts per billion (ppb), indicating the number of molecules of the greenhouse gas per million or billion air molecules, respectively, in an atmospheric sample.

Source: IPCC (Intergovernmental Panel on Climate Change); 2007, Cambridge University Press “Climate Change: The Physical Sciences Bases” available via http:www.ipcc.ch