Short-lived halogens: The Critical Flaw in Climate Modelling

Global climate models are running on incomplete data. They systematically exclude short-lived halogens (SLHs), creating a significant blind spot in our understanding of atmospheric chemistry. These compounds—comprising chlorine, bromine, and iodine with lifespans under six months—are not merely background noise. They are active agents determining the fate of ozone and methane in the atmosphere.

The Anthropogenic Multiplier

SLHs originate primarily from natural sources: oceans, volcanoes, salt lakes, and the cryosphere. However, the narrative that these are purely natural phenomena is false. Unregulated anthropogenic sources are rising. Furthermore, human pollution is forcing nature’s hand. The deposition of ozone on the sea surface, a by-product of pollution, triggers increased oceanic iodine emissions. We are not just adding new chemicals; we are destabilising existing natural cycles.

Why Short-lived Halogens Matter

This is an issue of predictive accuracy. SLHs aggressively interact with methane and ozone. Methane drives heating; ozone affects both temperature and air quality. By ignoring the chemical drivers that break down or sustain these gases, current international assessments produce skewed results. The models assume a chemical stability that does not exist.

Correcting the Course

Future assessments must integrate comprehensive SLH chemistry. Continuing to omit these compounds renders air-quality forecasts and climate projections unreliable. We must identify the gaps in emission data and chemical interactions immediately. Policy built on partial science is policy destined to fail.