Ozone and Climate: A Review of Interconnections Coordinating Lead Authors

EXECUTIVE SUMMARY 85 1.1 Introduction 87 1.1.1 Purpose and scope of this chapter 87 1.1.2 Ozone in the atmosphere and its role in climate 87 1.1.3 Chapter outline 93 1.2 Observed changes in the stratosphere 93 1.2.1 Observed changes in stratospheric ozone 93 1.2.2 Observed changes in ODSs 96 1.2.3 Observed changes in stratospheric aerosols, water vapour, methane and nitrous oxide 96 1.2.4 Observed temperature changes in the stratosphere 98 1.3 Stratospheric ozone and climate feedback processes 99 1.3.1 Impact of ODSs on stratospheric ozone 101 1.3.2 Impact of temperature changes on ozone chemistry 102 1.3.3 Impact of methane and water vapour changes on ozone chemistry 104 1.3.4 The role of transport for ozone changes 105 1.3.5 Stratosphere-troposphere dynamical coupling 107 1.3.6 Possible dynamical feedbacks of ozone changes 108 1.4 Past and future stratospheric ozone changes (attribution and prediction) 110 1.4.1 Current understanding of past ozone changes 110 1.4.2 The Montreal Protocol, future ozone changes and their links to climate 117