Editing IPCC:AR6/WGIII/Chapter-5 (section)

=== 5.5.2 Phases in Transitions ===

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Transitions often take several decades, unfolding through several phases. Although there is variability across innovations, sectors, and countries, the transitions literature distinguishes four phases, characterised by generic core processes and challenges: (i) emergence, (ii) early adaptation, (i) diffusion, (iv) stabilisation ( ''high confidence'' ) ( [[#Rotmans--2001|Rotmans et al. 2001]] ; [[#Markard--2012|Markard et al. 2012]] ; [[#Geels--2017|Geels et al. 2017]] ) (Cross-Chapter Box 12 in Chapter 16). These four phases do not imply that transitions are linear, teleological processes, because set-backs or reversals may occur as a result of learning processes, conflicts, or changing coalitions ( ''very high confidence'' ) ( [[#Geels--2006|Geels and Raven 2006]] ; [[#Messner--2015|Messner 2015]] ; [[#Davidescu--2018|Davidescu et al. 2018]] ). There is also no guarantee that technological, social, or business model innovations progress beyond the first phase.

In the first phase, radical innovations emerge in peripheral niches, where researchers, inventors, social movement organisations or community activists dedicate time and effort to their development ( ''high confidence'' ) ( [[#Kemp--1998|Kemp et al. 1998]] ; [[#Schot--2008|Schot and Geels 2008]] ). Radical social, technical and business model innovations are initially characterised by many uncertainties about technical performance, consumer interest, institutions and cultural meanings. Learning processes are therefore essential and can be stimulated through R&amp;D, demonstration projects, local community initiatives or grassroots projects ( [[#Borghei--2016|Borghei and Magnusson 2016]] ; [[#Hossain--2016|Hossain 2016]] ; [[#Rosenbloom--2018b|Rosenbloom et al. 2018b]] ; [[#van%20Mierlo--2020|van Mierlo and Beers 2020]] ). Typical challenges are fragmentation and high rates of project failure ( [[#den%20Hartog--2018|den Hartog et al. 2018]] ; [[#Dana--2021|Dana et al. 2021]] ), limited funding ( [[#Auerswald--2003|Auerswald and Branscomb 2003]] ), limited consumer interest, and socio-cultural acceptance problems due to being perceived as strange or unfamiliar ( [[#Lounsbury--2001|Lounsbury and Glynn 2001]] ).

In the second phase, social or technical innovations are appropriated or purchased by early adopters, which increases visibility and may provide a small but steady flow of financial resources ( ''high evidence'' , ''high agreement'' ) ( [[#Zimmerman--2002|Zimmerman and Zeitz 2002]] ; [[#Dewald--2011|Dewald and Truffer 2011]] ). Learning processes, knowledge sharing and codification activities help stabilise the innovation, leading to best practice guidelines, standards, and formalised knowledge ( ''high evidence'' , ''high agreement'' ) ( [[#Raven--2008|Raven et al. 2008]] ; [[#Borghei--2018|Borghei and Magnusson 2018]] ). User innovation may lead to the articulation of new routines and social practices, often in tandem with the integration of new technologies into people’s daily lives ( [[#Nielsen--2016|Nielsen et al. 2016]] ; [[#Schot--2016|Schot et al. 2016]] ). Radical innovations remain confined to niches in the second phase because adoption is limited to small, dedicated groups ( [[#Schot--2016|Schot et al. 2016]] ), innovations are expensive or do not appeal to wider groups, or because complementary infrastructure are missing ( [[#Markard--2016|Markard and Hoffmann 2016]] ).

In the third phase, radical innovations diffuse into wider communities and mainstream markets. Typical drivers are performance improvements, cost reductions, widespread consumer interest, investments in infrastructure and complementary technologies, institutional support and strong cultural appeal ( ''high evidence'' , ''high agreement'' ) ( [[#Wilson--2012|Wilson 2012]] ; [[#Markard--2016|Markard and Hoffmann 2016]] ; [[#Malone--2017|Malone et al. 2017]] ; [[#Raven--2017|Raven et al. 2017]] ; [[#Kanger--2019|Kanger et al. 2019]] ). The latter may be related to wider cultural shifts such as increased public attention to climate change and new framings like ‘climate emergency’ which gained traction before the Covid-19 pandemic ( [[#Bouman--2020b|Bouman et al. 2020b]] ). These concerns may not last, however, since public attention typically follows cycles ( [[#Downs--1972|Downs 1972]] ; [[#Djerf-Pierre--2012|Djerf-Pierre 2012]] ).

This phase often involves multiple struggles: economic competition between low-carbon innovations and existing technologies and practices, business struggles between incumbents and new entrants ( [[#Hockerts--2010|Hockerts and Wüstenhagen 2010]] ), cultural and framing struggles in public opinion arenas ( [[#Kammermann--2018|Kammermann and Dermont 2018]] ; [[#Rosenbloom--2018|Rosenbloom 2018]] ; [[#Hess--2019a|Hess 2019a]] ), and political struggles over adjustments in policies and institutions, which shape markets and innovations ( [[#Meadowcroft--2011|Meadowcroft 2011]] ; [[#Roberts--2019|Roberts and Geels 2019]] ). The lock-in mechanisms of existing practices and systems tend to weaken in the third phase, either because competing innovations erode their economic viability, cultural legitimacy or institutional support ( [[#Turnheim--2012|Turnheim and Geels 2012]] ; [[#Roberts--2017|Roberts 2017]] ; [[#Kuokkanen--2018|Kuokkanen et al. 2018]] ; [[#Leipprand--2018|Leipprand and Flachsland 2018]] ) or because exogenous shocks and pressures disrupt the status quo ( [[#Kungl--2018|Kungl and Geels 2018]] ; [[#Simpson--2019|Simpson 2019]] ).

In the fourth phase, the diffusing innovations replace or substantially reconfigure existing practices and systems, which may lead to the downfall or reorientation of incumbent firms ( [[#Bergek--2013|Bergek et al. 2013]] ; [[#McMeekin--2019|McMeekin et al. 2019]] ). The new system becomes institutionalised and anchored in professional standards, technical capabilities, infrastructures, educational programmes, regulations and institutional logics, user habits, and views of normality, which create new lock-ins ( [[#Galaskiewicz--1985|Galaskiewicz 1985]] ; [[#Shove--2000|Shove and Southerton 2000]] ; [[#Barnes--2018|Barnes et al. 2018]] ).

‘Avoid’, ‘Shift’ and ‘Improve’ options vary with regard to the four transition phases. Incremental ‘Improve’ options, such as energy-efficient appliances or stand-alone insulation measures, are not transitions but upgrades of existing technologies. They have progressed furthest since they build on existing knowledge and do not require wider changes ( [[#Geels--2018|Geels et al. 2018]] ). Some radical ‘Improve’ options, which have a different technological knowledge base, are beginning to diffuse, moving from phase two to three in multiple countries. Examples are electric vehicles, light-emitting diodes (LED), or passive house designs ( [[#Franceschini--2016|Franceschini and Alkemade 2016]] ; [[#Berkeley--2017|Berkeley et al. 2017]] ). Many ‘Shift’ and ‘Avoid/Reduce’ options like heat pumps, district heating, passive house designs, compact cities, less meat initiatives, flight and car use reduction have low momentum in most countries, and are mostly in the first phase of isolated initiatives and projects ( [[#Bergman--2013|Bergman 2013]] ; [[#Morris--2014|Morris et al. 2014]] ; [[#Bows-Larkin--2015|Bows-Larkin 2015]] ; [[#Bush--2016|Bush et al. 2016]] ; [[#Kivimaa--2018|Kivimaa and Martiskainen 2018]] ; [[#Hoolohan--2018|Hoolohan et al. 2018]] ). Structural transitions in Dutch cities, Copenhagen, and more recently Paris, however, demonstrate that transitions towards low-carbon lifestyles, developed around cycling, are possible ( [[#Colville-Andersen--2018|Colville-Andersen 2018]] ). Low-carbon demand-side transitions are often still in early phases ( ''high evidence, high agreement'' ).

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