WMO report finds evidence of healing ozone layer

The World Meteorological Organization’s (WMO) latest scientific assessment on ozone depletion has revealed further evidence pointing to a healing ozone layer. The quadrennial Scientific Assessment of Ozone Depletion has confirmed that actions taken under the Montreal Protocol in 1987 have led to long-term decreases in the atmospheric abundance of controlled ozone-depleting substances (ODSs) and the ongoing recovery of stratospheric ozone. Evidence presented by the authors shows that the ozone layer in parts of the stratosphere has recovered at a rate of 1-3% per decade since 2000. At the projected rates, the northern hemisphere and mid-latitude ozone is scheduled to heal completely by the 2030s, followed by the southern hemisphere in the 2050s and polar regions by 2060. The WMO says that the report is further evidence of the success of the environmental treaty now entering its fourth decade. The report also offers a view of the role that the protocol must have in decades to come. Erik Solheim, head of UN Environment, said, “The Montreal Protocol is one of the most successful multilateral agreements in history for a reason. The careful mix of authoritative science and collaborative action that has defined the Protocol for more than 30 years and was set to heal our ozone layer is precisely why the Kigali Amendment holds such promise for climate action in future.” Set to come into force on January 1, 2019, the Kigali Amendment calls for slashing the future use of powerful climate-warming gases in refrigerators, air conditioners and related products. Nations that ratify the Kigali Amendment are committing to cutting the projected production and consumption of these gases, known as hydrofluorocarbons (HFCs), by more than 80%. So far, 58 parties have done so. Authors of the assessment found the world can avoid up to 0.4°C of global warming this century through implementation of the Kigali Amendment, affirming its critical role in keeping global temperature rise below the 2°C mark. Full compliance would reduce future global warming due to HFCs by about 50% between now and 2050 compared with a scenario without any HFC controls. The findings come at a time when the world is still grappling with the message from the Intergovernmental Panel on Climate Change (IPCC) which found just 12 years remain to limit global warming to 1.5°C, beyond which, the impacts of a further rise in global temperatures will begin to have an increasingly extreme impact on human society and ecosystems. The IPCC report offered the clearest evidence to date of the drastic difference between the 1.5°C and 2°C scenarios. Petteri Taalas, secretary-general, WMO, said, “Carbon dioxide emissions remain by far the most important greenhouse gases which are driving global warming. But we can also help tackle climate change by reducing our commitment to other gases including HFCs. Every bit of warming matters.” To read the full Scientific Assessment of Ozone Depletion, click here.