Finally let's return to the issue of Carbon Stabilization (either through reduced emissions of sequestration). This is basically where the economics have to apply, either through investments in CCS or Carbon taxation to reduce emissions.

In terms of stablization, its again highly useful to look at probabilities:

The challenge of stablization:

1. If carbon absorption were to weaken (because of ocean saturation that we will get to later), future emissions would need to be cut even more rapidly to hit any given stabilisation target for atmospheric concentration.

2. Energy systems are subject to very significant inertia. It is important to avoid getting locked into long-lived high carbon technologies, and to invest early in low carbon alternatives. We are not doing this on anywhere near the scale that needs to be done. Remember in the US we have 450,000 MW electric of coal power (increasing very year) and we are adding wind capacity at the rate of only around 8-10,000 MW per year; solar additions are much lower.

3. Stabilising at 550 ppm CO2e (around 440 - 500 ppm CO2 only) would require global emissions to peak in the next 10 - 20 years, and then fall at a rate of at least 1 - 3% per year. By 2050, global emissions would need to be around 25% below current levels. These cuts will have to be made in the context of a world economy in 2050 that may be three to four times larger than today: so emissions per unit of GDP would need to be just one quarter of current levels by 2050.

4. To stabilise at 450 ppm CO2e, without overshooting, global emissions would need to peak in the next 10 years and then fall at more than 5% per year, reaching 70% below current levels by 2050. This is likely to be unachievable with current and foreseeable technologies.

5. Any overshoots of peak trajectories require severe post peak reductions.

The above points are effectively summarized in the figure below: