PPI's Trade Fact of the Week: 'Total Column Ozone Counts' are Rising

FACT: 'Total column ozone counts' are rising.

THE NUMBERS: World ozone-depleting substance consumption* –

1989 1.32 million tons

2005 0.25 million tons

2010 0.10 million tons

2015 0.01 million tons

2022 ~0.0 million tons

* Includes chlorofluorocarbons, hydrochlorofluorocarbons, methyl bromide, carbon tetrachloride, halons, and methyl chloroform. (Our World in Data)

What They Mean:

Here is a success story:

Chlorofluorocarbons, known for pronunciation's sake as “CFCs,” are strings of carbon atoms joined with the halide elements fluorine and chlorine rather than their more common hydrogen-ion partners. First synthesized in 1928 by American refrigerator-makers, they were used worldwide as coolants and industrial solvents from the 1930s to the 1990s by manufacturers, building superintendents, food-service professionals, and home-owners, all of them unaware that CFCs react easily with ozone, and that this, in turn, could have large consequences.

Via eleventh-grade chemistry, meanwhile, ozone is a pungent form of oxygen arranged chemically as “O3,” as distinct from breathable oxygen “O2.” Floating in a “layer” 15-35 kilometers above the earth, ozone absorbs ultraviolet light and in doing so reduces the risk of skin cancer to people, cools lower-atmosphere temperatures, and facilitates photosynthesis in land plants and oceanic phytoplankton. CFCs are fairly stable molecules that float around for a long time — depending on the particular molecule, they can last from 100 to 200 years before breaking up and raining down out of the sky — and react quickly with ozone. Thus their release from buildings and refrigerators began an era of high-atmosphere chemical reactions, which scientists predicted in the 1970s and then detected as a fall in the atmosphere’s “total column ozone” count by 1985. This eased ultraviolet light passage to the earth, with especially large effects over Antarctica where a large “hole” of missing ozone appeared in the early 1980s, first at about 5 million square km and reaching 28 million square km by 2000.

How to respond? The Montreal Protocol, a monument of Reagan-administration and international environmental diplomacy, banned the production and use of CFCs in 1987, and has since been ratified and implemented by 196 countries and territories. Over the ensuing 35 years, production and industrial consumption of CFCs has dropped by about 100%, from 1.1 million tons in 1986 to 43,000 tons in 2005, then to a tiny 63 tons in 2010, and since then oscillating around zero. (“About 100%” and “oscillating” because sometimes discovery and destruction of unused CFC stocks create a negative output; alternatively, sometimes destruction of old buildings inadvertently releases old “banks” of CFC-containing insulation for a small positive output.)

The “Kigali Amendment” negotiated under the Obama administration in 2016 added a ban on hydrofluorocarbons — a temporary replacement for CFCs which are less potent ozone-depleters but have strong greenhouse effects — and made the sale of the next generation of chemicals conditional on participation. This went into effect in 2019, with Senate ratification last fall. The HFCs are supposed to be gone by 2030.

Two results of all this:

(1) CFC atmospheric concentration down: Near zero in 1920, the level of chlorine in the Antarctic stratosphere hit 2.2 parts per billion in 1980 and peaked at 4.7 parts per billion in the mid-1990s. Since then it has been falling by 0.4% to 0.8% per year, with NOAA charts showing “CFC-11” down from 540 points per trillion to 490 ppt since the late 1990s, “CFC-12” from 270 ppt to 220 ppt, and “CFC-113” from 84 ppt to 68 ppt. The current CFC level is about 3.5 parts per billion, and though CFCs degrade only slowly, NOAA’s projections show a return to 1980 levels by the 2070s.

(2) Ozone layer slowly recovering: As CFC levels drop, ozone levels have stabilized. UNEP believes “total column ozone” is rising by about 1% to 3% per year, and the “ozone hole” above Antarctica now oscillates in a range between 16 million square km in 2019 and 24.5 million square km in 2022. The UN Environmental Programme’s 2022 ozone assessment tentatively projects that atmospheric ozone will return to its 1980 levels sometime around the year 2040 worldwide, and in the 2060s for the Antarctic. The reduced emissions of CFC and related gases, meanwhile, appear to have averted a rise of 0.5 to 1 degree Celsius in average global temperatures; and the Kigali Amendment is likely to prevent another 0.5-degree rise.

So altogether: With good scientific evidence, commitment by governments of quite different political outlooks, implementation by bureaucracies and businesses, and some modest temporary sacrifice for the common good, policy can achieve a lot.