We present observations defining (i) the frequency and depth of convective penetration of water into the stratosphere over the United States in summer using the Next-Generation Radar system; (ii) the altitude-dependent distribution of inorganic chlorine established in the same coordinate system as the radar observations; (iii) the high resolution temperature structure in the stratosphere over the United States in summer that resolves spatial and structural variability, including the impact of gravity waves; and (iv) the resulting amplification in the catalytic loss rates of ozone for the dominant halogen, hydrogen, and nitrogen catalytic cycles.

Background material for the workshop on safety standards relevant to the safe use of low global-warming-potential (GWP) alternatives to be held in Bangkok on 10th July 2017. Briefing note 3 provides an overall picture of safety related standards that apply during the lifetime of RACHP equipment. It provides indicative examples of RACHP equipment as well as the stakeholders who may be responsible for applying them.

Background material for the workshop on safety standards relevant to the safe use of low global-warming-potential (GWP) alternatives to be held in Bangkok on 10th July 2017. Brie ng note 1 covers the safety standards that are relevant to refrigeration, air-conditioning and heat pump (RACHP) equipment.

Background material for the workshop on safety standards relevant to the safe use of low-GWP alternatives to be held in Bangkok on 10th July 2017. Brie ng note 2 describes the process for writing new international standards or updating existing safety standards for the refrigeration, air-conditioning and heat pump (RACHP) equipment. It includes a summary of the current activities related to the updating of various RACHP safety standards.

This primer is intended to provide participants, especially new delegates, attending the meetings of the Conference of the Parties to the Vienna Convention for the Protection of the Ozone Layer (the Vienna Convention), the Meetings of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol) and meetings of the Open-ended Working Group of the Montreal Protocol, with the necessary information to understand the procedures of those bodies and to enable them to effectively participate in those meetings.

On 15 October 2016, in Kigali, the parties to the Mon- treal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol) reached agreement at their 28th Meeting to phase down consumption and production of hydrofluorocarbons (HFCs). They adopted an amendment (the Kigali Amendment) in Decision XXVIII/1. This briefing note has been prepared by the Secretar- iat of the Montreal Protocol to help Parties to the Pro- tocol prepare for ratification, acceptance, or approval of the Kigali Amendment.

The Protocol, along with the Vienna Convention, achieved universal participation on 16 September 2009 – the first treaties of any kind in the history of the United Nations system to achieve that aspiration.

This edition has been updated to include all relevant information from 1989 to date.