The following terms have been used to indicate the assessed likelihood of an outcome or result: virtually certain 
99–100% probability; very likely 90–100%; likely 66–100%; more likely than not >50-100%; about as likely as not 33–66%; unlikely 0–33%; very unlikely 0–10%; and 
exceptionally unlikely 0–1%. Additional terms (extremely likely 95–100%  and extremely unlikely 0–5%) are also used when appropriate. Assessed likelihood also is typeset in 
italics: for example, very likely. This is consistent with AR5. In this Report, unless stated otherwise, square brackets [x to y] are used to provide the assessed very likely range, or 
90% interval.
futures. It considers long-term characteristics, impacts, risks and costs 
in adaptation and mitigation pathways in the context of sustainable 
development. Section 4, ‘Near- Term Responses in a Changing Climate’, 
assesses opportunities for scaling up effective action in the period up 
to 2040, in the context of climate pledges, and commitments, and the 
pursuit of sustainable development.
Based on scientiﬁc understanding, key ﬁndings can be formulated as 
statements of fact or associated with an assessed level of conﬁdence 
using the IPCC calibrated language62. The scientiﬁc ﬁndings are 
drawn from the underlying reports and arise from their Summary for 
Policymakers (hereafter SPM), Technical Summary (hereafter TS), and 
underlying chapters and are indicated by {} brackets. Figure 1.1 shows 
the Synthesis Report Figures Key, a guide to visual icons that are used 
across multiple ﬁgures within this report.
1. Introduction