Mount Pinatubo in 1991 injected sulfur aerosols into the stratosphere and cooled global temperatures roughly 0.5C for a year. That natural experiment shows solar geoengineering can work fast. My opponent will likely argue risk, but doing nothing is also a risk. I would pair aggressive emissions cuts with a tightly monitored, reversible cooling effort, treating it like a thermostat, not a substitute for decarbonization. Refusing even research guarantees we have no lever if tipping points hit.

Fair point on acidification: dimming the sun does not touch ocean chemistry, and I will not pretend otherwise. But that argues for pairing it with carbon removal, not for banning research. Here is the practical consequence the other side skips: if a tipping point hits, say West Antarctic collapse or Amazon dieback, emissions cuts already underway cannot reverse it in time. A reversible thermostat buys decades while decarbonization scales. Termination shock is a real design constraint, so ramp down slowly instead of cutting the spray abruptly. Nobody is choosing geoengineering over renewables; the choice is having a lever or not.

Consider the Montreal Protocol: we did not ban CFCs overnight; we phased them down while substitutes scaled, and the ozone layer is recovering. That is the model for solar geoengineering: monitor, adjust, ramp down slowly. My opponent is right that Pinatubo thinned ozone and weakened monsoons. But that argues for targeted research, not a ban. A reversible thermostat paired with carbon removal buys time if a tipping point hits. Renewables alone cannot cool the planet within a decade. The choice is a managed lever or bare handed hope.