How well can ISA application be localised or regionalised?
Atmospheric mixing happens far more around a given latitude than between the northern and southern hemispheres, and the highest methane concentration is over the north pole and its sub-polar regions. The biggest ocean region of high nutrient, low chlorophyll (i.e. highest potential for CO2 draw down by addition of iron) is the Southern Ocean, encircling Antarctica. In addition, both poles need to be cooled.
ISA can be exploited for all three cases: methane depletion, CO2 sequestration and marine cloud cooling. These effects can be maximised for a given ISA emission volume if application is at the location of highest utilisation, therefore we propose applying ISA plumes in the following regions:
- where substantial areas of permafrost are melting
- north and south poles, and sub-polar regions
- the Southern Ocean.
We would expect the reduced greenhouse gas levels to balance out between northern and southern hemispheres within 1-2 years.