Last month, researchers published a study showing that the hole in the ozone layer had started to close. It found that the size of the ozone layer hole is now 4 million square kilometres smaller than in 2000. Moreover, their analysis showed that this can be directly attributed to the reduction in chlorofluorocarbons (CFCs) in the atmosphere.
With this news, the danger from one of the greatest environmental challenges of the 1980s and 1990s seems to be receding. This blog will briefly examine the environmental problem, the political solution that was devised to address it, and the policy lessons for tackling other global environmental challenges.
The ozone layer protects the Earth’s surface from harmful ultraviolet rays from the sun. In 1985, scientists discovered conclusive evidence of a hole in the ozone layer above Antarctica. It was also found that this phenomenon was being caused by manmade ozone-destroying chemicals, such as CFCs, which were found in aerosols and refrigerators.
Depletion of the ozone layer has been shown to lead to adverse health and environmental outcomes. It increases incidence of skin cancer and cataracts, as well as a harming plant growth and the production of phytoplankton, which is vital to marine ecosystems.
The international response to this scientific consensus was rapid and decisive. In 1985, the Vienna Convention was agreed, which established a framework for international cooperation on research and monitoring. This led to the signing of the 1987 Montreal Protocol, which was championed by green conservatives Margaret Thatcher and Ronald Reagan. Now hailed as the most successful international environmental agreement ever signed, it imposed legally binding controls on the production and consumption of ozone-depleting materials. It has now been ratified by every country in the world, making it the only international environmental treaty to enjoy such a status.
The seminal agreement has already had a major impact on human health. Research by Cambridge University in 2012 found that the Montreal Protocol had prevented 2 million cases of skin cancer per year around the world, which represents 14% fewer skin cancer cases per year.
The environmental benefits are already being felt. Chipperfield et al. published a study in 2013 showing that, without the Montreal Protocol, the ozone hole over the Antarctic would have been 40% bigger and a new ozone hole over the Arctic would have formed.
CFCs have a long lifetime in the atmosphere, and so scientists do not expect the hole to close up completely until 2050 at the earliest. Moreover, some of the chemicals, such as fluorinated gases (F-gases), devised to replace ozone depleting substances, are potent greenhouse gases. However, last month’s research shows positive signs that not only has the depletion been halted, but the environmental damage is starting to be reversed.
Caution is required before seeking to apply the policy lessons of the Montreal Protocol to other global environmental issues like climate change. The reliance of the global economy on carbon-intensive fossil fuels is much greater than it was on ozone depleting substances. The scale of the clean energy transition, and the disruption it will cause, is therefore of a different order of magnitude to the phasing out of CFCs.
However, one important lesson that can be applied is that international agreements on the environment require broad political consensus, forged by strong leadership. Margaret Thatcher and Ronald Reagan were both free-market conservatives. Yet they led the international community in imposing these environmental regulations on businesses. Unlike with ozone depleting substances, there has been a consistent failure to align the negotiating interests and priorities of the major carbon polluting nations, which has limited the effectiveness of international climate agreements to date.
As Bright Blue has argued previously, concern for the environment should not be confined to either the political left or right. Widespread political cooperation on tackling these challenges is vital if international agreements are to have a real impact. The success of the Montreal Protocol is testament to the power of evidence-led, political consensus on environmental threats.