A central mistake that all too many people are making:
The black line is carbon emissions to date. The red line is the status quo — a projection of where emissions will go if no new substantial policy is passed to restrain greenhouse gas emissions.
This is not true. The red line is RCP 8.5. and that is “a” business as usual projection, yes. But then so are the other three RCPs “business as usual projections”. All are possible (however unlikley) emissions paths based upon demographics, energy mix, wealth or GDP and the effects of emissions upon temperatures.
By design (yes, by design, so this point is not arguable) they all assume no policy responses. These are the possibilities without mitigation policies.
And we need to be honest about this. RCP 8.5 just ain’t gonna happen:
For a start, this is a world of “continuously increasing global population” so that there are 12 billion on the planet. This is more than a billion more than the United Nations expects, and flies in the face of the fact that the world population growth rate has been falling for 50 years and is on course to reach zero – i.e., stable population – in around 2070. More people mean more emissions.
Second, the world is assumed in the RCP8.5 scenario to be burning an astonishing 10 times as much coal as today, producing 50% of its primary energy from coal, compared with about 30% today. Indeed, because oil is assumed to have become scarce, a lot of liquid fuel would then be derived from coal. Nuclear and renewable technologies contribute little, because of a “slow pace of innovation” and hence “fossil fuel technologies continue to dominate the primary energy portfolio over the entire time horizon of the RCP8.5 scenario.” Energy efficiency has improved very little.
We’ve already invented solar panels. Cheaper than coal (even without coal paying for its emissions) in 5…4..3… years or so. It’s just Not. Going. To. Happen.