Global action to combat climate change may seem elusive, after the failure of the latest United Nations climate summit to reconcile differences over further cuts in fossil fuel emissions. News to restore faith in the UN ideal of cooperation in the interests of all mankind is welcome. It comes in a report that the man-made hole in the ozone layer in the stratosphere that shields life on Earth from harmful ultraviolet radiation from the sun is shrinking. Moreover, it is shrinking as a result of cooperative action organised under the UN. It may be happening slowly, but the worst hole – over Antarctica – could be back to 1980 pre-thinning levels by 2066. Scientists and environmental activists call it one of humanity’s biggest ecological victories. The news comes 35 years after a UN conference agreed unanimously to stop producing a class of gases, chlorofluorocarbons (CFCs), used in aerosols, air conditioning units and refrigerators, which were found to be creating a gaping hole in the ozone layer above the South Pole. UN says ozone layer slowly healing, hole to mend by 2066 The Montreal Protocol, as the agreement is called after the venue of the conference, remains the only UN treaty that has been ratified by all 198 UN member states. As a result, CFCs have almost been completely phased out, the use of other ozone depleting gases has been reduced significantly and work is under way to go further. A new UN report following a four-yearly assessment confirms recovery of the ozone layer is in progress. “In the upper stratosphere and in the ozone hole we see things getting better,” says Paul Newman, chief scientist for Earth Sciences at Nasa’s Goddard Space Flight Centre and chairman of the scientific assessment. The United Nations Environment Programme (UNEP) says: “Without the Montreal treaty, ozone depletion would have increased tenfold by 2050 compared with current levels, and resulted in millions of additional cases of melanoma, other cancers and eye cataracts. It has been estimated that the Montreal Protocol is saving an estimated 2 million people each year by 2030 from skin cancer.” The huge reduction in the release of ozone-depleting substances is also helping to reduce global temperature rise by 0.5 degrees Celsius by 2100, according to UNEP. The latest assessment shows international cooperation can really make a difference and points the way forward to tackle the threat of climate change. Little wonder that scientists have cited ozone action as a precedent for transitioning away from fossil fuels, reducing greenhouse gases and limiting temperature increase. The developed and developing worlds must redouble their efforts to reconcile competing goals and historical responsibility for global warming.