2 Comments

That was helpful, thanks. Another dimension I’m curious about is the global temperature goals for SRM, as in what are the various options being considered and their plausibility. I’m guessing the most discussed targets are between 1.5 and 2C above preindustrial.

Expand full comment

Dear Pete

Dr Stephen Salter has shared the following comment with map at https://groups.google.com/g/geoengineering/c/dw6Iyothm_0/m/1hnBoZCQBQAJ

Regards, Robert Tulip

Pete Irvine

You put maximum potential radiative forcing at the top of your list. This might be useful to rule out methods with very low cooling but there is no need to consider it for methods that could cool more than the excess heating since preindustrial times.

You mention patchiness in connection with marine cloud brightening. This is true for any instant but of less concern if the patches move to spread their effects and if we can learn how to forecast their movement. The world’s oceans are a very large integrator of thermal energy variations and are provided free. Weather forecasts are now very good and getting better. The high speed and agility and instant response to spray commands of spray vessels allow us to respond tactically to random events such as not cooling during winter cold spells.

You mention large shifts in rain patterns caused by marine cloud brightening. Below is a map by Stjern et al from the Norwegian Cicero labs showing the change in precipitation resulting from a 50% increase in the concentration of condensation nuclei in ocean regions of low cloud. Blue-green shows increases up to 20%.

There are indeed shifts in rain patterns but valuable increases in drought stricken regions. The brown reductions are all over the sea. This is quite a gentle dose and I am sure that Norwegians could learn a more sophisticated strategy.

Perhaps your list could have included energy required for operation, zero for wind driven vessels, phase lag and frequency response desirable for control systems. While we are learning how to drive a climate control system we might be very glad to be able to stop an experiment with a single mouse click.

Stephen

Expand full comment