Climate Change: Cutting Carbon

Sue Van Hattum got wondering about this claim: "We must immediately commence carbon emissions reductions of 6% each year until the end of the century. Timing is crucial. If we wait until 2020 to begin emissions reductions the annual requirement is 15% per year." From: http://cascadiaplanet.blogspot.com.br/2015/08/the-kids-call-us-out-filing-lawsuits.html In this sketch you can change the numbers: S, when we start to cut, G, the current growth rate of emissions, and the amount we cut by now and later. If this is 2015, the dotted line is for the end of the century. To me, the claim looks very reasonable.
More GeoGebra at bit.ly/mh-ggb