Ozone Layer Hole

Tropics Suffer 7-times Larger ‘Ozone Hole’ All Year Round

According to a Canadian researcher, an ozone hole seven times bigger than the Antarctic ozone hole has been present across tropical regions since the 1980s.

Qing-Bin Lu, a scientist from the University of Waterloo in Ontario, Canada, discovered a large, all-season hole — defined as an area of ozone loss greater than 25% compared to the undisturbed atmosphere — in the lower stratosphere over the tropics comparable in depth to the well-known springtime Antarctic hole, but seven times larger in area.

The tropics cover half of the planet’s land area and are home to around half of the world’s inhabitants. The presence of the tropical hole generated widespread alarm across the world.

Changes in % of the O3 climatology in the season SON of the 1980s–2010s relative to those in the 1960s.

The depletion of the layer can lead to increased ground-level UV radiation, which can raise the risk of skin cancer and cataracts in people, as well as weaken human immune systems, reduce agricultural output, and severely impact sensitive aquatic creatures and ecosystems. As with the polar hole, approximately 80% of the normal ozone value is found to be depleted at the center of the tropical ozone hole.

(a)–(c) Time-series decadal mean O3 changes in % with respect to those in the 1960s at the lower stratosphere of 14–21 km of the Antarctic in SON, the Arctic in MAM, and the annual tropical (solid lines in black) and sum of measured concentrations of main ODSs (CFCs and CCl4) (solid circles in red) over the period 1960–2010. (d) Zonal mean latitude–altitude distribution of the CF2Cl2 (CFC-12) concentration in 1992 obtained from the NASA UARS’s CLEAS dataset, where the dashed square shows the zone of most significant CFC destruction. (e) Difference in % of the annual O3 climatology in the 1990s with respect to that in the 1960s. (f) Decadal mean zonal mean latitude–altitude distribution of the temperature climatology averaged over seasons in the 2000s.

The tropical and polar holes play an important role in lowering and controlling stratospheric temperatures, mimicking the emergence of three worldwide stratospheric “temperature holes.” This discovery might be critical to better comprehending global climate change.

Reference- Journal AIP Advances, Clean Technica, NOAA, Business Standard, Independent, CNBC