Scientific Assessment of Ozone Depletion: 2014

Assessment for Decision-Makers

2014 Ozone Assessment Assessment for Decision-Makers cover
Assessment for Decision-Makers

Executive Summary

This is the Executive Summary of the ADM of the 2014 Ozone Assessment. It contains the policy-relevant major findings of the Assessment's five scientific chapters.

Actions taken under the Montreal Protocol have led to decreases in the atmospheric abundance of controlled ozone-depleting substances (ODSs), and are enabling the return of the ozone layer toward 1980 levels.
The Antarctic ozone hole has caused significant changes in Southern Hemisphere surface climate in the summer.
Changes in CO2, N2O, and CH4 will have an increasing influence on the ozone layer as ODSs decline.
The climate benefits of the Montreal Protocol could be significantly offset by projected emissions of HFCs used to replace ODSs.

The Montreal Protocol and its Amendments and adjustments have made large contributions toward reducing global greenhouse gas emissions. In 2010, the decrease of annual ODS emissions under the Montreal Protocol is estimated to be about 10 gigatonnes of avoided CO2-equivalent emissions per year, which is about five times larger than the annual emissions reduction target for the first commitment period (2008-2012) of the Kyoto Protocol (from the Executive Summary of the Scientific Assessment of Ozone Depletion: 2010)[3].

Additional important issues relevant to the Parties to the Montreal Protocol and other decision-makers have been assessed.
While past actions taken under the Montreal Protocol have substantially reduced ODS production and consumption, additional, but limited, options are available to reduce future ozone depletion.
options to accelerate recovery

Emissions from the current banks are projected to contribute more to future ozone depletion than those caused by future ODS production, assuming compliance with the Protocol.

[3] GWP-weighted emissions, also known as CO2-equivalent emissions, are defined as the amount of gas emitted multiplied by its 100-year Global Warming Potential (GWP). Part of the effect of ODSs as greenhouse gases is offset by the cooling due to changes in ozone.

[4] This is equivalent to about 45% of the fossil fuel and cement emissions of CO2 in the late 1980s.