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WMO No. 898



Geneva/Nairobi, 16 September 2010 – International efforts to protect the ozone layer—the

shield that protects life on Earth from harmful levels of ultraviolet rays—are a success and

have stopped additional ozone losses and contributed to mitigating the greenhouse effect,

according to a new report.

The executive summary of the Scientific Assessment of Ozone Depletion 2010 provides new

information about the effects of climate change on the ozone layer, as well as the impact of ozone

changes on the Earth’s climate.

The report was written and reviewed by some 300 scientists and launched on the UN International

Day for the Preservation of the Ozone Layer. It is the first comprehensive update in four years.

The report reaffirms that the Montreal Protocol is working. “It has protected the stratospheric ozone

layer from much higher levels of depletion by phasing out production and consumption of ozone

depleting substances.”

Given that many substances that deplete the ozone layer are also potent greenhouse gases, the

report says that the Montreal Protocol has “provided substantial co-benefits by reducing climate

change.” In 2010, the reduction of ozone depleting substances as a result of the Montreal Protocol,

expressed in CO2-equivalent emissions (about 10 Gigatonnes per year), were five times larger

than those targeted by the first commitment period (2008-2012) of the Kyoto Protocol, the

greenhouse emissions reduction treaty.

The report published by the World Meteorological Organization (WMO) and the United Nations

Environment Programme (UNEP) says that an important remaining scientific challenge is to project

future ozone abundance based on an understanding of the complex linkages between ozone and

climate change.

Changes in climate are expected to have an increasing influence on stratospheric ozone in the

coming decades, it says. “These changes derive principally from the emissions of long-lived

greenhouse gases, mainly carbon dioxide, associated with human activities.”

Key findings on the ozone layer:

Over the past decade, global ozone and ozone in the Arctic and Antarctic regions is no

longer decreasing but is not yet increasing.

As a result of the phase-out of ozone depleting substances under the Montreal Protocol,

the ozone layer outside the Polar regions is projected to recover to its pre-1980 levels some

time before the middle of this century. The recovery might be speeded up by greenhouse

gas-induced cooling of the upper stratosphere.

In contrast, the springtime ozone hole over the Antarctic is expected to recover much later.

The impact of the Antarctic ozone hole on surface climate is becoming evident, leading to

important changes in surface temperature and wind patterns.

It is reaffirmed that at mid-latitudes, surface UV radiation has been about constant over the

last decade.

In Antarctica large UV levels continue to be seen when the springtime ozone hole is large.

Key findings on ozone depleting substances and substitutes:

Many ozone depleting chemicals, such as CFCs (chlorofluorocarbons), once present in products

such as refrigerators and spray cans, have been phased out. Demand for replacement substances

called HCFCs (hydrochlorofluorocarbons) and HFCs (hydrofluorocarbons) has increased. Many of

these are powerful greenhouse gases.

Total emissions of HCFCs are projected to begin to decline in the coming decade due to

measures agreed under the Montreal Protocol in 2007. But they are currently increasing

faster than four years ago. The most abundant one, HCFC-22, increased more than 50%

faster in 2007-2008 than in 2003-2004.

Abundances and emissions of HFCs are increasing at about 8% per year. HFC-23 is a

byproduct of HCFC-22 production. Although it has no impact on the ozone layer it is more

than 14,000 times more powerful as a greenhouse gas than CO2.

Achim Steiner, UN Under-Secretary General and UNEP Executive Director said: "This represents

a further potential area for action within the overall climate change challenge. An international

group of modellers working with UNEP recently concluded that current commitments and pledges

linked with the Copenhagen Accord are unlikely to keep a global temperature rise to under 2°C by

2050. The gap between scientific reality and ambition is estimated to average around 4.7

Gigatonnes of CO2 equivalent per year--a gap that needs to be urgently bridged over the next

decade or so if the 2°C target is to be met."

Commenting on the International Day for the Preservation of the Ozone Layer, he added: "Today's

report underlines that action to protect the ozone layer has not only been a success, but continues

to deliver multiple benefits to economies including on efforts to meet the Millennium Development

Goals. The contribution to combating climate change is one, but so are the direct benefits to public

health. For without the Montreal Protocol and its associated Vienna Convention atmospheric levels

of ozone-depleting substances could have increased tenfold by 2050. This in turn could have led to

up to 20 million more cases of skin cancer and 130 million more cases of eye cataracts, not to

speak of damage to human immune systems, wildlife and agriculture.”

“The ozone-hole issue demonstrates the importance of long-term atmospheric monitoring and

research, without which ozone destruction would have continued unabated and might not have

been detected until more serious damage was evident,” said WMO Secretary-General Michel

Jarraud. “The Montreal Protocol is an outstanding example of collaboration among scientists and

decision-makers that has resulted in the successful mitigation of a serious environmental and

societal threat.’’

“Human activities will continue to change the composition of the atmosphere. WMO’s Global

Atmosphere Watch programme will therefore continue its crucial monitoring, research and

assessment activities to provide scientific data needed to understand and ultimately predict

environmental changes on both regional and global scales,” said Mr Jarraud.

The Scientific Assessment Panel will present the Executive Summary of the new report at the next

annual Meeting of the Parties to the Montreal Protocol, to be held in Kampala, Uganda, from 8 to

12 November 2010.

The full body of the report will be available in early 2011.

The International Day for the Preservation of the Ozone Layer 16 September marks the signature

date, in 1987, of the Montreal Protocol on Substances that Deplete the Ozone Layer.

For more information, please contact:


Carine Richard-Van Maele, Chief, Communications and Public Affairs, Tel: +(41 22) 730 8315;

+(41 79) 406 47 30 (cell); e-mail:

Clare Nullis, Press Officer, Communications and Public Affairs, Tel: +(41 22) 730 8478; e-mail:

WMO website:


Nick Nuttall, UNEP Spokesperson/Head of Media, Tel: +254 207 62 30 84, +254 (0) 733 632755

(cell); e-mail

Relevant links include and