CO2 and SO2 can both leave big eruptions. Why do their climate effects split?

Answer: Different lifetimes in air

Different lifetimes in air ✓ — Right. SO2 can become sulfate aerosols that reflect sunlight and cool the lower atmosphere for a short window, while CO2 is a greenhouse gas that can push longer warming. USGS puts the contrast plainly: sulfur dioxide can cause cooling, carbon dioxide can promote warming. Same eruption, opposite time signatures.

Only carbon matters — Carbon matters a lot, but sulfur is not a side note. SO2 can form sulfate aerosols that reflect sunlight, while carbon dioxide traps heat over longer intervals. The surprise is that a carbon-only story misses the short cooling swings that can sit inside a broader greenhouse crisis.

All gases cool equally — Common myth, but gases do not share one climate sign. SO2 can cool by making reflective aerosols; CO2 warms by trapping infrared radiation, and halogens can add ozone stress. A volcanic crisis can therefore jitter cold and hot before the longer carbon signal dominates.