A large igneous province is a continent-scale volcanic outburst. Why abrupt extinctions?

Answer: A short gas-release pulse

Total lava area alone — Total area is a tempting but blunt metric. A province can be vast and still release gases too slowly, or in the wrong rocks, to make an extinction-level shock. PNAS work on LIPs argues that volume and rate of CO2 emissions help separate mild crises from catastrophic ones. Tempo turns geology into biology.

A short gas-release pulse ✓ — Right. Ecosystems respond to how fast climate and ocean chemistry are pushed, not only to how much basalt eventually exists. USGS makes the same logic for the end-Permian: a shorter subinterval of Siberian magmatism, not the whole long event, matched the extinction trigger. The rate is the weapon.

A steady gas trickle — A steady trickle is less likely to shock ecosystems than a pulse. Slow degassing gives weathering, ocean mixing, and biological turnover more time to buffer change. The useful diagnostic is timing: did CO2, sulfur, methane, or halogens enter air and ocean faster than Earth systems could absorb them?