Editing IPCC:AR6/WGI/Chapter-1 (section)

==== 1.2.3.1 Climate Change Understanding, Communication and Uncertainties ====

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Responses to climate change are facilitated when leaders, policymakers, resource managers and their constituencies share a basic understanding of the causes, effects, and possible future course of climate change (SR1.5, [[#IPCC--2018|IPCC, 2018]]; SRCCL, [[#IPCC--2019a|IPCC, 2019a]]). Achieving shared understanding is complicated, since scientific knowledge interacts with pre-existing conceptions of weather and climate that have built up in diverse world cultures over centuries, and which are often embedded in strongly held values and beliefs stemming from ethnic or national identities, traditions, religions, and lived relationships to weather, land and sea (Van Asselt and Rotmans, 1996; [[#Rayner--1998|Rayner and Malone, 1998]]; [[#Hulme--2009|Hulme, 2009]], 2018; [[#Green--2010|Green et al., 2010]]; [[#Jasanoff--2010|Jasanoff, 2010]]; [[#Orlove--2010|Orlove et al., 2010]]; [[#Nakashima--2012|Nakashima et al., 2012]]; [[#Shepherd--2020|Shepherd and Sobel, 2020]]).These diverse, more local understandings can both contrast with and enrich the planetary-scale analyses of global climate science (''hi'' ''gh confidence'').

Political cultures also give rise to variation in how climate science knowledge is interpreted, used and challenged ([[#Leiserowitz--2006|Leiserowitz, 2006]]; [[#Oreskes--2010|Oreskes and Conway, 2010]]; [[#Brulle--2012|Brulle et al., 2012]]; [[#Dunlap--2013|Dunlap and Jacques, 2013]]; [[#Mahony--2014|Mahony, 2014]], 2015; [[#Brulle--2019|Brulle, 2019]]). A meta-analysis of 87 studies carried out between 1998 and 2016 (62 USA national, 16 non-USA national, 9 cross-national) found that political orientation and political party identification were the second most important predictors of views on climate change after environmental values (McCright et al. 2016). [[#Ruiz--2020|Ruiz et al. (2020)]] systematically reviewed 34 studies of non-US nations or clusters of nations and 30 studies of the USA alone. They found that in the non-US studies, ‘changed weather’ and ‘socio-altruistic values’ were the most important drivers of public attitudes. For the USA case, by contrast, political affiliation and the influence of corporations were most important. Widely varying media treatment of climate issues also affects public responses ([[#1.2.3.4|Section 1.2.3.4]]). In summary, environmental and socio-altruistic values are the most significant influences on public opinion about climate change globally, while political views, political party affiliation, and corporate influence also had strong effects, especially in the USA (''hi'' ''gh confidence'').

Furthermore, climate change itself is not uniform. Some regions face steady, readily observable change, while others experience high variability that masks underlying trends ([[#1.4.1|Section 1.4.1]]); mostregions are subject to hazards, but some may also experience benefits, at least temporarily (Chapters 11, 12 and Atlas). This non-uniformity may lead to wide variation in public climate change awareness and risk perceptions at multiple scales ([[#Howe--2015|Howe et al., 2015]]; [[#Lee--2015|Lee et al., 2015]]). For example, short-term temperature trends, such as cold spells or warm days, have been shown to influence public concern ([[#Hamilton--2013|Hamilton and Stampone, 2013]]; [[#Zaval--2014|Zaval et al., 2014]]; [[#Bohr--2017|Bohr, 2017]]).

Given these manifold influences and the highly varied contexts of climate change communication, special care is required when expressing findings and uncertainties, including IPCC assessments that inform decision making. Throughout the IPCC’s history, all three Working Groups have sought to explicitly assess and communicate scientific uncertainty ([[#Le%20Treut--2007|Le Treut et al., 2007]]; [[#Cubasch--2013|Cubasch et al., 2013]]). Over time, the IPCC has developed and revised a framework to treat uncertainties consistently across assessment cycles, reports, and Working Groups through the use of calibrated language ([[#Moss--2000|Moss and Schneider, 2000]]; [[#IPCC--2005|IPCC, 2005]]). Since its First Assessment Report (FAR; [[#IPCC--1990a|IPCC, 1990a]]), the IPCC has specified terms and methods for communicating authors’ expert judgments ([[#Mastrandrea--2011|Mastrandrea and Mach, 2011]]). During the AR5 cycle, this calibrated uncertainty language was updated and unified across all Working Groups ([[#Mastrandrea--2010|Mastrandrea et al., 2010]], 2011). Box 1.1 summarizes this framework as it is used in AR6.

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