Holy Fucking Shit of the Day (Climate Change Edition)
I just had to pick my jaw up off the floor upon reading this post by Dave Rutledge at Caltech, whose main area of research is fuel reserves and climate change. It's a bit dense, but I'll distill the point that blew my mind. If you're like me, you've been following the debates about climate change with just enough interest to have developed an acute awareness of how complicated it all is, and thus were willing to take the IPCC's report at face value simply because you didn't have any other rational alternative given your priorities. If you're like me, you assumed all the numerical ranges they assigned to the variables in their models were all based on the best known estimates.
Rookie mistake. According to Rutledge, turns out that they never actually bothered to base their carbon emission values on the best estimates of world fossil fuel reserves; they just plugged in a range of values that seemed reasonable based on current and past usage trends. They ran the numbers for 40 different scenarios up to the year 2100, all of which assumed more fuel would be burned than we appear to have. More specifically, he says the IPCC is assuming 11-15 trillion boe of oil and about 18 trillion boe of coal is available to be burned in the IPCC scenarios, while the numbers he comes up with are 3.2 and 3.5 Tboe, respectively.
He ran his own plot of cumulative fossil fuel emissions alongside the IPCC scenarios and this was the result:
That line at the bottom is the one using his numbers. When you run them through a simulation like the one IPCC used, atmospheric carbon is expected to peak at 460 ppm around the year 2070, which would lead to a temperature increase peaking at 1.8 degrees Celsius around 2150, which is at the extreme low end of the IPCC estimates. (The range they give as most likely is 3-4 degrees, which by their calculations would result in 1-5% of global GDP being lost.) If this is even close to being correct, then the entire climate change debate is being conducted under an incorrect assumption and the models need to be revised downward considerably.
I told colinmarshall a little while back that I kept a list of five large-scale trends I allow myself to worry about, with climate change clocking in at #4. The fifth was "medium-term drastic increases in transportation costs as oil prices continue to rise, before we can get this whole alternative energy source thing worked out". Since I'm now more worried about fossil fuel supplies than climate change, the two have now swapped places.
Rookie mistake. According to Rutledge, turns out that they never actually bothered to base their carbon emission values on the best estimates of world fossil fuel reserves; they just plugged in a range of values that seemed reasonable based on current and past usage trends. They ran the numbers for 40 different scenarios up to the year 2100, all of which assumed more fuel would be burned than we appear to have. More specifically, he says the IPCC is assuming 11-15 trillion boe of oil and about 18 trillion boe of coal is available to be burned in the IPCC scenarios, while the numbers he comes up with are 3.2 and 3.5 Tboe, respectively.
He ran his own plot of cumulative fossil fuel emissions alongside the IPCC scenarios and this was the result:
That line at the bottom is the one using his numbers. When you run them through a simulation like the one IPCC used, atmospheric carbon is expected to peak at 460 ppm around the year 2070, which would lead to a temperature increase peaking at 1.8 degrees Celsius around 2150, which is at the extreme low end of the IPCC estimates. (The range they give as most likely is 3-4 degrees, which by their calculations would result in 1-5% of global GDP being lost.) If this is even close to being correct, then the entire climate change debate is being conducted under an incorrect assumption and the models need to be revised downward considerably.
I told colinmarshall a little while back that I kept a list of five large-scale trends I allow myself to worry about, with climate change clocking in at #4. The fifth was "medium-term drastic increases in transportation costs as oil prices continue to rise, before we can get this whole alternative energy source thing worked out". Since I'm now more worried about fossil fuel supplies than climate change, the two have now swapped places.