The 
following
 supplementary
 material
 provides
 additional
 details
 about
 our
 ozone
 depletion
potential,
 ODP, calculations,
 factors
 affecting
 the
 ODP 
of
 N₂O,
 uncertainties
 unique
 to 
the
 calculation
 of
 the
 ODP
 of
 N₂O,
 our
method
 of
 inferring 
N₂O
 emissions,
 and
 a
comparison
 of 
the
 contributions
 of
 the
 sectoral 
N₂O 
emissions
 with
 the
  emissions
 of
 methyl
 bromide.

The consumption and emissions of hydrofluorocarbons (HFCs) are projected to increase substantially in the coming decades in response to regulation of ozone depleting gases under the Montreal Protocol. The projected increases result primarily from sustained growth in demand for refrigeration, air-conditioning (AC) and insulating foam products in developing countries assuming no new regulation of HFC consumption or emissions. New HFC scenarios are presented based on current hydrochlorofluorocarbon (HCFC) consumption in leading applications, patterns of replacements of HCFCs by HFCs in developed countries, and gross domestic product (GDP) growth.

This edition comes at a time when further steps taken by the Parties to develop interlinkages with other multilateral environmental agreements are coming to fruition.

The Montreal Protocol has reduced the global consumption of chlorofluorocarbons (CFCs) by more than 95% from its peak value. CFCs are principal ozone depleting substances (ODSs). As a result, the consumption of HCFCs as substitute compounds has increased. In developing countries the increase is 20% yr-1 (in agreement with new observations).

This edition contains the full text of the Vienna Convention for the Protection of the Ozone Layer (1985) in Section 1. Section 2 updates the text of the decisions of the Conferences of the Parties by incorporating the decisions adopted at the Eighth Conference of the Parties in Doha, Qatar, in November 2008. The decisions are presented in sub-sections relating to each article of the Convention.

The Handbook is published shortly after the Protocol, along with the Vienna Convention, achieved universal participation, by 196 Parties, on 16 September 2009 – the first treaties of any kind in the history of the United Nations system to achieve that aspiration. The universal ratification of the Vienna Convention and the Montreal Protocol is the culmination of more than twenty-two years of efforts by the international community to ensure that the ozone protection treaties achieved global support and implementation. 

The Handbook describes the nomination process for essential use exemptions as it has evolved through Articles of the Protocol and Decisions of the Parties; the procedures followed under the Protocol; and the experience of the Panel and its Technical Options Committees in managing the process to date. The Handbook contains three sections: review of the essential use process; instructions for the completion of essential use nominations; and appendices. The appendices contain provisions of the Montreal Protocol, decisions of the Parties to the Protocol and an essential use nomination form.

For this first issue, we have undertaken to include articles that provide an overview of some potentially positive aspects of interlinkages, and some concerns as they relate to our system of international environmental agreements. We have also invited articles from some of the global implementing agencies and MEAs on the interlinkages that they see in their daily work.

The Handbook contains four sections: (1) an outline of the critical-use process, (2) suggested forms and notes for the submission of critical-use nominations, (3) reporting accounting framework and (4) appendices. The appendices contain provisions of the Montreal Protocol relating to critical-use exemptions for methyl bromide, relevant decisions of the Parties to the Protocol, and extracts from meeting reports of the Parties relevant to critical uses.