Editing IPCC:AR6/WGIII/Chapter-3 (section)

=== 3.8.4 Enabling Factors ===

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There is strong agreement that the climate policy institutional framework as well as technological progress have a profound impact on the attainability of low-carbon pathways. Delaying international cooperation reduces the available carbon budget and locks into carbon-intensive infrastructure exacerbating implementation challenges ( [[#Keppo--2007|Keppo and Rao 2007]] ; [[#Bosetti--2009|Bosetti et al. 2009]] ; [[#Boucher--2009|Boucher et al. 2009]] ; [[#Clarke--2009|Clarke et al. 2009]] ; [[#Krey--2009|Krey and Riahi 2009]] ; [[#van%20Vliet--2009|van Vliet et al. 2009]] ; [[#Knopf--2011|Knopf et al. 2011]] ; [[#Jakob--2012|Jakob et al. 2012]] ; [[#Luderer--2013|Luderer et al. 2013]] ; [[#Rogelj--2013a|Rogelj et al. 2013a]] ; Aboumahboub et al. 2014; [[#Kriegler--2014a|Kriegler et al. 2014a]] ; [[#Popp--2014|Popp et al. 2014]] ; [[#Riahi--2015|Riahi et al. 2015]] ; [[#Gambhir--2017|Gambhir et al. 2017]] ; [[#Bertram--2021|Bertram et al. 2021]] ). Similarly, technological availability influences the feasibility of climate stabilisation, though differently for different technologies ( [[#Kriegler--2014a|Kriegler et al. 2014a]] ; [[#Iyer--2015a|Iyer et al. 2015a]] ; [[#Riahi--2015|Riahi et al. 2015]] ).

One of the most relevant factors affecting mitigation pathways and their feasibility is the rate and kind of socio-economic development. For example, certain socio-economic trends and assumptions about policy effectiveness preclude achieving stringent mitigation futures ( [[#Rogelj--2018|Rogelj et al. 2018]] b). The risk of failure increases markedly in high-growth, unequal and/or energy-intensive worlds such as those characterised by the shared socio-economic pathways SSP3, SSP4 and SSP5. On the other hand, socio-economic development conducive to mitigation relieves the energy sector transformation from relying on large-scale technology development: for example, the amount of biomass with CCS in SSP1 is one third of that in SSP5. The reason why socio-economic trends matter so much is that they both affect the CO 2 emissions in counterfactual scenarios as well as the mitigation capacity ( [[#Riahi--2017|Riahi et al. 2017]] ; [[#Rogelj--2018|Rogelj et al. 2018]] b). Economic growth assumptions are the most important determinant of scenario emissions ( [[#Marangoni--2017|Marangoni et al. 2017]] ). Degrowth and post-growth scenarios have been suggested as valuable alternatives to be considered ( [[#Hickel--2021|Hickel et al. 2021]] ; [[#Keyßer--2021|Keyßer and Lenzen 2021]] ), though substantial challenges remain regarding political feasibility ( [[#Keyßer--2021|Keyßer and Lenzen 2021]] ).

The type of policy instrument assumed to drive the decarbonisation process also plays a vital role for determining feasibility. The majority of scenarios exploring climate stabilisation pathways in the past have focused on uniform carbon pricing as the most efficient instrument to regulate emissions. However, carbon taxation raises political challenges ( [[#Beiser-McGrath--2019|Beiser-McGrath and Bernauer 2019]] ) (Chapters 13 and 14). Carbon pricing will transfer economic surplus from consumers and producers to the government. Losses for producers will be highly concentrated in those industries possessing fixed or durable assets with ‘high asset specificity’ ( [[#Murphy--2002|Murphy 2002]] ; [[#Dolphin--2020|Dolphin et al. 2020]] ). These sectors have opposed climate jurisdictions ( [[#Jenkins--2014|Jenkins 2014]] ). Citizens are sensitive to rising energy prices, though revenue recycling can be used to increase support ( [[#Carattini--2019|Carattini et al. 2019]] ). A recent model comparison project confirms findings from the extant literature: using revenues to reduce pre-existing capital or, to a lesser extent, labour taxes, reduces policy costs and eases distributional concerns ( [[#Barron--2018|Barron et al. 2018]] ; [[#Mcfarland--2018|Mcfarland et al. 2018]] ).

Nonetheless, winning support will require a mix of policies which go beyond carbon pricing, and include subsidies, mandates and feebates ( [[#Jenkins--2014|Jenkins 2014]] ; [[#Rozenberg--2018|Rozenberg et al. 2018]] ). More recent scenarios take into account a more comprehensive range of policies and regional heterogeneity in the near to medium term ( [[#Roelfsema--2020|Roelfsema et al. 2020]] ). Regulatory policies complementing carbon prices could reduce the implementation challenges by increasing short-term emission reduction, though they could eventually reduce economic efficiency ( [[#Bertram--2015b|Bertram et al. 2015b]] ; [[#Kriegler--2018a|Kriegler et al. 2018a]] ). Innovation policies such as subsidies to R&amp;D have been shown to be desirable due to innovation market failures, and also address the dynamic nature of political feasibility ( [[#Bosetti--2011|Bosetti et al. 2011]] ).

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