Climate Science

Sources and Emissions

The purpose of this slide is to show what is causing climate change. In particular, this slide depicts long-term greenhouse gas (GHG) records, which show a rapid increase since the Industrial Age. The top quadrant of the graph depicts increases in Carbon dioxide (CO2), with the explanation that these increases are due primarily to fossil fuel use, with additional contribution from land use change. The middle and bottom quadrants of the graph depict increases in methane (CH4) and Nitrous oxide (N2O), which are primarily due to agriculture. The slide also explains that GHGs like CO2 are well mixed and long-lived, and their effects are global. The data in these graphs has been obtained from atmospheric concentrations of GHGs from direct measurements starting in the mid-20th century, and from air bubbles trapped in glacial ice prior to that. This figure on the right is from the IPCC AR5 report. (http://ec.gc.ca/sc-cs/Default.asp?lang=En&n=A5F83C26-1)