The news about the environment is often extremely demoralizing. Today, at last, we have a breath of fresh air: the hole in the ozone layer will completely ‘heal’ very soon. Thus, ozone-depleting substances continue to decline years after a major international agreement phased out their production, leading to a full recovery of the ozone layer by 2060, according to a UN-backed report .
The latest United Nations Scientific Assessment of Ozone Depletion report shows that actions taken under the Montreal Protocol are working and have led to long-term decreases in the atmospheric abundance of these ozone-depleting substances. It is an inspiring (and timely) reminder of how international cooperation and diplomacy can bring about meaningful positive change.
The Montreal Protocol was negotiated in 1987 in response to the realization that many of the chemicals used in aerosols, air conditioning systems, refrigerators, and industrial solvents were eroding the planet’s stratosphere, creating a hole and allowing harmful levels of ultraviolet radiation. will seep through the ozone layer. The international agreement forced the world community to begin the phase-out of ozone-depleting substances, such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and halons.
Every four years, a report like this is published, documenting the recovery of the ozone layer. The 2018 edition shows that ozone levels in sections of the stratosphere have been recovering at rates of 1-3% since 2000. And if recovery rates continue as planned, the report states that the hemisphere North and mid-latitude ozone will fully recover by the 2030s, followed by the southern hemisphere in the 2050s and the polar regions in 2060.
“The Montreal Protocol is one of the most successful multilateral agreements in history for a reason,” said Erik Solheim, UN Chief of Environment. “
Former UN Secretary General Kofi Annan, who passed away in August 2018, also agreed that the Montreal Protocol is one of the most successful international agreements ever seen.
Several decades later, as we see, it is difficult to disagree.
Concentrations of both total tropospheric chlorine and total tropospheric bromine have declined since the 2014 assessment. That massive hole we were concerned about also continues to thicken. What this means is that we can expect that the ozone layer that covers the mid-latitude of the Northern Hemisphere will return to the levels of the 80s sometime in the 2030s and the South Pole hole will more or less disappear by the decade. of 2060.
This does not mean that we can close the issue. Those efforts still require careful monitoring, especially in the face of the occasional illegal production of ozone-depleting pollutants, and there are still more issues we need to address.
Closing the hole in the ozone layer has been a warm-up exercise. The real test is yet to come (if we are to have any hope of limiting global warming to just 1.5 degrees Celsius, it will require unprecedented change) and failure is not an option.
Reference: UN Environment http://conf.montreal-protocol.org/meeting/mop/mop30/presession/Background-Documents/SAP-2018-Assessment-ES-October2018.pdf
