This is a continuing series of posts on the “Representative Concentration Pathways” (RCPs), presented by the Intergovernmental Panel on Climate Change as possible trajectories of atmospheric concentrations of green house gases (GHGs) over the next century. The RCPs start with a target GHG concentration, on the basis of which they estimate global temperature over various time periods. The scariest is RCP8.5, which projects a mean global temperature rise of 3.7°C by 2100. The story line of RCP8.5 has been described as  a "conservative business as usual" scenario that assumes “a 10 fold increase in the use of coal as a power source and a move away from natural gas as an energy source”. “Business as usual” usually means the way things are expected to be if current trends continue. So, is the global use of coal on the upswing? Here is what the  International Energy Agency has to say:

“Coal is the slowest-growing energy source in the IEO2016 Reference case, with 0.6%/year average increases in total world coal consumption from 2012 to 2040, considerably slower than the 2.2%/year average over the past 30 years. The EIA forecasts declines from 40% of total generation in 2012 to 29% in 2040.”

Here’s what a recent Goldman Sacks analysis concludes:

“Unlike most other commodities, thermal coal is unlikely to experience another period of tightness ever again because investment in new coal-fired generation is becoming less common and the implied decline in long-term demand appears to be irreversible."

And here is what David Rutledge, Professor of Engineering and Applied Science at the California Institute of Technology, predicts:

“If the current trends continue, 90% of the coal would be produced by 2067.”

Once again, in the case of coal, there is no way RCP8.5 represents a plausible “business as usual” trajectory.

That completes this series on RCP8.5. I suspect that many people would say the plausibility of climate change scenarios is beside the point, and that the point is: unless you scare people shitless, they won’t take sufficient action, and if they don’t act now, and act decisively, the future of the biosphere – including humanity -  is going to be very, very bleak.


Next up: really?