NASA’s diagram thus not only proves CO2 isn’t a well mixed gas but also demonstrates that there is no link between regions of highest CO2 concentration and areas of highest human industrial emissions.
The Southern Hemisphere does not source CO2 from the Northern Hemisphere to balance everything out.
Previously, scientists believed that the Intertropical Convergence Zone (ITCZ) formed the boundary between the polluted air of the Northern Hemisphere and the cleaner air of the Southern Hemisphere. The ITCZ is a cloudy region circling the globe where the trade winds from each hemisphere meet. It is characterised by rapid vertical uplift and heavy rainfall, and acts as a meteorological barrier to pollutant transport between the hemispheres.
But the new research, to be published in the Journal of Geophysical Research - Atmospheres, found huge differences in air quality on either side of the chemical equator, which was 50 km wide and well to the north of the ITCZ. The study revealed that carbon monoxide, a tracer of combustion, increased from 40 parts per billion to the south, to 160 parts per billion in the north. The difference in pollutant levels was increased by extensive forest fires to the north of the boundary and very clean air south of the chemical equator being pulled north from the Southern Indian Ocean by a land based cyclone in northern Australia.
