Editing IPCC:AR6/Glossary (section)

=== <span class="glossary-term">Emergence</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI; WGII</div>

<div class="glossary-longer-term">'''Full term:''' Emergence (of the climate signal)</div>

<div class="glossary-definition">'''Definition:''' Emergence of a climate change signal or trend refers to when a change in climate (the ‘signal’) becomes larger than the amplitude of natural or internal variations (defining the ‘noise’), This concept is often expressed as a ‘signal-to-noise’ ratio and emergence occurs at a defined threshold of this ratio (e.g., S/N > 1 or 2). Emergence can refer to changes relative to a historical or modern baseline (usually at least 20 years long) and can also be expressed in terms of time (time of emergence) or in terms of a global warming level. Emergence is also used to refer to a time when we can expect to see a response to reducing greenhouse gas (GHG) emissions (emergence with respect to mitigation). Emergence can be estimated using observations and/or model simulations.</div>
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