We Calculate: You Decide
By David Henderson
Patrick J. Michaels and Paul C. “Chip” Knappenberger have figured out a marvelously clever way of showing the effects of various levels of carbon reduction on the temperature 2050 and by 2100.
They use a term called “climate sensitivity” and explain:
the climate sensitivity (how much you think the global average temperature will increase as a result of a doubling of the pre-industrial atmospheric carbon dioxide concentration). The United Nation’s Intergovernmental Panel on Climate Change’s (IPCC) modestly-educated guess is 3.0°C, but a collection of reports from the recent scientific literature puts the value around 2.0°C, and based on recent global temperature behavior, a value of 1.5°C may be most appropriate. Not wanting to leave firebrands like former NASA employee James Hansen out of the fun, we include the option of selecting an extremely high climate sensitivity value of 4.5°C.
They start by asking you to key in whether you apply a reduction in carbon just to the United States or more broadly. Then they ask you to choose by how much to reduce carbon. Finally, they give you the option of a range of climate sensitivities. Voila. Out pops the answer. I don’t want to spoil your fun, so have at it.
Update: The above was corrected based on a correction provided to me by Bob Murphy.