Ozone layer to recover by mid-century, say scientists

Campaigners renew calls for HFC phase-out to build on ozone success and tackle climate change

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By Megan Darby

The ozone layer is well on the road to recovery after an international crackdown on damaging substances, according to an assessment by 300 scientists.

A phase-out of CFCs and other ozone-depleting substances under the Montreal Protocol is having the desired effect, they say.

However, many of the substitutes for CFCs in applications such as fridges and air conditioners are potent warming gases, posing a new set of problems.

Achim Steiner, the UN environment chief, called for the same global cooperation to tackle climate change.

“There are positive indications that the ozone layer is on track to recovery towards the middle of the century,” said Steiner.

“However, the challenges that we face are still huge. The success of the Montreal Protocol should encourage further action not only on the protection and recovery of the ozone layer but also on climate.”

Heads of state meeting in New York for Ban Ki-moon’s climate summit on 23 September can take inspiration from the Montreal Protocol’s success, he added.

In the first comprehensive review of the science in four years, the World Meteorological Organization (WMO) and the UN Environment Programme noted improvements in the state of stratospheric ozone.

This gaseous layer, high up in the atmosphere, protects the earth from the sun’s UV rays. CFCs caused that layer to thin, raising the risk of skin cancers and crop damage.

Scientists project stratospheric ozone will return to 1980 benchmark levels by mid-century over the Arctic and middle latitudes, and by 2060 over the Antarctic.

“International action on the ozone layer is a major environmental success story,” said WMO secretary general Michel Jarraud.

“This should encourage us to display the same level of urgency and unity to tackle the even greater challenge of climate change.

“This latest assessment provides solid science to policy-makers about the intricate relationship between ozone and climate and the need for mutually-supportive measures to protect life on earth for future generations.”

Many ozone-depleting substances also had a warming effect on the atmosphere, so their phase-out is benefitting the climate.

In 1987, the report says, emissions of these substances had an impact equivalent to 10 gigatonnes of carbon dioxide.

Those emissions have since been slashed by over 90%, more than five times the savings delivered by the Kyoto Protocol on climate change.

However, the scientists warn, the substitution of HFCs risk undermining those climate benefits.

HFCs do not harm the ozone layer but are potent greenhouse gases. They contribute some 0.5 gigatonnes of carbon dioxide equivalent and rising.

Campaigners are calling for the Montreal Protocol to be used to phase out HFCs in the same way – and see the Ban Ki-moon summit as an opportunity to get global support.

The Institute for Governance and Sustainable Development (IGSD) estimates between 100 and 200 billion tonnes of CO2 equivalent can be avoided by 2050.

The US, Canada and Mexico have backed such a move, but some nations have resisted in order to protect their chemical industries or avoid costs.

Durwood Zaelke, president of the IGSD, said: “The world owes the Montreal Protocol a debt of gratitude for doing so much to protect both the climate and the stratospheric ozone layer.

“It’s now time to finish the HFC amendment, and take another big bite out of the climate problem.”

Natasha Hurley, climate campaigner at the Environmental Investigation Agency, agreed.

“We expect leaders at the UN secretary general’s climate summit to put forward real and rapidly deployable initiatives leading to a drastic fall in emissions in the very near term,” she said.

“Action on HFCs stands out as one of the most straightforward and cost-effective options on the table and has the overwhelming support of governments and business leaders alike. Simply put, it’s a no-brainer.”

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