Intentional Stratospheric Aerosol Injection (SAI) offers a dial that accidental sulfate shields lack. A massive volcanic eruption cools the planet blindly. It might save some regions from heat while triggering droughts in others.
SAI allows for theoretical precision. However, this control creates a power imbalance. A few wealthy nations could set the global thermostat to suit their own crops, potentially ignoring the specific needs of the Global South. There is also the risk of termination shock. If an intentional system fails or is sabotaged, temperatures would spike violently.
Accidental shields are disasters, but they don't carry the burden of political choice. Intentional deployment shifts the problem from geology to governance. It does not stop ocean acidification. It just hides the sun. Choosing SAI means betting that humans can manage a planetary thermostat without crashing the biosphere.
