Our efforts at reducing global warming so far are totally ineffectual. There are many reasons for this, but one of the most important is that we are starting out with the wrong idea. There is much discussion about “safe levels” of Carbon Dioxide (equivalent) in the atmosphere, but nobody knows if they are actually safe. In any case, they are not relevant at all in our present situation, but will become relevant later, after we have achieved climate stability.
I think the best way to explain this is to liken the Earth to a ship coming into dock in a harbour. It is no use for the ship’s captain to gradually reduce power to the engines, and hope that the ship will lose enough speed to stop it crashing into the wharf – he has to go to “Full Astern” to take way off the vessel in time. If he makes an error of judgement, he either makes a hard contact with the wharf, or has to go to “Slow Ahead” to counter the excess reverse thrust.
Why is it that difficult? Because of the ships “Momentum”, which is dependent on both its speed and its mass – and ships don’t have brakes.
With the Earth, we have a similar problem, although we are not trying to dock it anywhere. Over the last 200 hundred years or so, we have been steadily winding up the overheating process, (increasing speed), by pumping more and more greenhouse gas into the atmosphere, but it took a long time before the effects became visible, and even longer before we would accept that it was us that was causing it.
What we have now is the equivalent of the ship approaching the wharf at too high a speed, and our engines are still at “Full Ahead”. What is worse, is that we cannot immediately switch our engines to “Full Astern” because it doesn’t work that way. What is worse still, is that nobody is even considering switching to “Full Astern” yet, and to make it yet more severe, we are actually increasing power in the forward direction.
To get to “Full Astern” in the shortest time possible – (for the time is critical) – we need to do two things:-
1 Drastically reduce our output of all greenhouse gases, not just Carbon Dioxide
2 Sequester Carbon Dioxide as fast as we possibly can.
Our aiming point must be 200 ppm of CO2 or lower, to ensure that “Full Astern” is applied!
Once we have reached that point, we must wait until the climate moves towards stabilisation again, and then release enough CO2 from storage to maintain the equilibrium. This will have to be done empirically, and will not be an easy matter, as the Earth’s Thermal Inertia will mask immediate effects as usual. If we are successful, however, we then have the possibility of keeping the planet in its “Inter-Glacial” state, by either sequestration or release of Carbon Dioxide, thus maintaining our compatible environment indefinitely, in spite of periodic external influences.
It occurs to me that our analogy is incomplete, which presents a further difficulty:-
Where, and who, is the captain?