Editing IPCC:AR6/WGIII/Chapter-6 (section)

=== 6.7.4 Fossil Fuels in a Low-carbon Transition ===

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Global fossil fuel use will need to decline substantially by 2050 to limit warming to 2°C (&gt;67%), and it must decline substantially by 2030 to limit warming to 1.5°C (&gt;50%) with no or limited overshoot ( ''high confidence'' ). Failing to reduce global fossil fuel use below today’s levels by 2030 will make it more challenging to limit warming to below 2°C (&gt;67%). ( ''high confidence'' ). Fossil fuel use declines by 260–330 EJ (52–73% from 2020 levels, interquartile range) through 2050 in scenarios that limit warming to 1.5°C (&gt;50%) with no or limited overshoot, and 124–231 EJ (24–51% reduction compared to 2020 levels) in scenarios that limit warming to 2°C (&gt;67%) with action starting in 2020. This will require a significant reduction in coal, oil and gas investments. Fossil fuels account for about 80% of primary energy today. In scenarios limiting warming to 1.5°C (&gt;50%) with limited or no overshoot, fossil energy provides 59–69% (interquartile range) of primary energy in 2030 and 25–40% primary energy in 2050 (AR6 Scenarios Database). In scenarios limiting warming to 2°C (&gt;67%) with action starting in 2020, fossil energy provides 71–75% (interquartile range) primary energy in 2030 and 41–57% primary energy in 2050 (AR6 Scenarios Database). The timeline for reducing production and usage varies across coal, oil, and gas due to their differing carbon intensities and uses.

Global coal consumption without CCS needs to be largely eliminated by 2040–2050 to limit warming to 1.5°C (&gt;50%), and 2050–2060 to limit warming to 2°C (&gt;67%) ( ''high confidence'' ). New investments in coal-fired electricity without CCS are inconsistent with limiting warming to 2°C (&gt;67%) or lower ( ''high confidence'' ) ( [[#Edenhofer--2018|Edenhofer et al. 2018]] ; [[#Pfeiffer--2018|Pfeiffer et al. 2018]] ; [[#Spencer--2018|Spencer et al. 2018]] ; [[#Cui--2019|Cui et al. 2019]] ). Coal consumption declines 130 EJ yr –1 to 140 EJ yr –1 in 2050 (78–99% compared to 2020 levels, interquartile range) in scenarios limiting warming to 1.5°C (&gt;50%) with no or limited overshoot and 118 EJ yr –1 to 139 EJ yr –1 (65% to 98% compared to 2020 levels) in scenarios limiting warming to 2°C (&gt;67%) with action starting in 2020. Coal consumption without CCS falls by 67% to 82% (interquartile range) in 2030 in scenarios limiting warming to 1.5°C (&gt;50%) with no or limited overshoot. Studies indicate that coal use may decline substantially in the USA and Europe over the coming decade, based on the increasing competitiveness of low-carbon sources and near-term policy actions ( [[#Grubert--2019|Grubert and Brandt 2019]] ; [[#Oei--2020|Oei et al. 2020]] ). In several developing economies, the relative youth of the coal-fired electricity fleet will make a complete phase-out before 2050 difficult ( [[#Garg--2009|Garg and Shukla 2009]] ; [[#Jewell--2016|Jewell et al. 2016]] ). There are considerable differences in projected coal phase-out timelines in major Asian economies. Some studies suggest that coal may continue to be a part of the Chinese energy mix composing around one-third of the total primary energy consumption by 2050, even if emissions are reduced by 50% by 2030 ( [[#He--2020|He et al. 2020]] ). Others indicate that a strategic transition would decrease the risk of stranded assets and enable a near-complete phase-out by 2050 ( [[#Wang--2020a|Wang et al. 2020a]] ; [[#Cui--2021|Cui et al. 2021]] ). This would entail prioritising earlier retirements of plants based on technical (efficiency), economic (profitability, local employment) and environmental considerations (e.g., water scarcity for cooling).

Natural gas may remain part of energy systems through mid-century, both for electricity generation and use in industry and buildings, and particularly in developed economies, even if warming is limited to 2°C (&gt;67%) or lower ( ''medium confidence'' ). The decline in natural gas use from 2020 to 2050 is 38 EJ yr –1 to 78 EJ yr –1 (21–62% decline from 2020 levels, interquartile range) in scenarios limiting warming to 1.5°C (&gt;50%) with no or limited overshoot and –22 EJ yr –1 to 46 EJ yr –1 (–14% to 36% decline from 2020 levels, interquartile range) in scenarios limiting warming to 2°C (&gt;67%) with action starting in 2020. Scenarios indicate that gas use in electricity will likely peak around 2035 and 2050 if warming is limited to 1.5°C (&gt;50%) with limited or no overshoot or to 2°C (&gt;67%) with action starting in 2020, respectively. There is variability in the role gas would play in future scenarios based on national climate commitments and availability of cheap renewables (Malik et al. 2020; [[#Vishwanathan--2020|Vishwanathan and Garg 2020]] ; [[#Vrontisi--2020|Vrontisi et al. 2020]] ). Note that these differences are not only present in the electricity sector but also in other end uses.

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[[File:3aeee484e600be3a552ffbf0ddd74a8d IPCC_AR6_WGIII_Figure_6_35.png]]

'''Figure 6.35 | Global fossil fuel pathways for scenarios that limit/return warm''' '''ing to 1.''' '''5°C (&gt;50%) with no or limited/after a high, overshoot, and scenarios that limit warming to 2°C (&gt;67%), with action starting in 2020 or NDCs until 2030, during 2030–2050.''' Boxes indicate 25th and 75th percentiles while whiskers indicate 5th and 95th percentiles. Results for total consumption are expressed as a percentage relative to 2020 consumption. Results for fossil energy with CCS are expressed in total energy consumption. Oil use with CCS is not shown here as it remains below 5% of total use. Source: AR6 Scenarios Database.

While oil use is anticipated to decline substantially, due to changes in the transport sector, its use will likely continue through the mid-century, even if warming is limited to 2°C (&gt;67%) or lower ( ''medium confidence'' ) ''.'' Oil use declines by 73 EJ yr –1 to 145 EJ yr –1 (30–78% from 2020 levels, interquartile range) in scenarios that limit warming to 1.5°C (&gt;50%) with no or limited overshoot and 26 EJ yr –1 to 86 EJ yr –1 (14–45% from 2020 levels) by 2050 in scenarios that limit warming to 2°C (&gt;67%) with action starting in 2020. While oil use is anticipated to decline immediately in scenarios limiting warming to 1.5°C (&gt;50%), it is likely to continue to be used through 2050. Oil use continues to be a significant source of transport fuels in most scenarios limiting warming to 2°C (Welsby et al. 2021). Oil use may drop to about half of current levels as a transport fuel by 2050 if warming is limited to 2°C, because of the availability of other options (biofuels, green hydrogen) and rapid deployment of EVs ( [[#Feijoo--2020|Feijoo et al. 2020]] ). In the absence of rapid transport electrification, the decline is slower with some studies projecting peak oil use around 2035 ( [[#Delgado--2020|Delgado et al. 2020]] ; [[#Pan--2020|Pan et al. 2020]] ).

There is a lack of consensus about how CCS might alter fossil fuel transitions for limiting warming to 2°C (&gt;67%) or lower. CCS deployment will increase the shares of fossil fuels associated with limiting warming, and it can ease the economic transition to a low-carbon energy system ( [[#Muratori--2016|Muratori et al. 2016]] ; [[#Marcucci--2019|Marcucci et al. 2019]] ). While some studies find a significant role for fossil fuels with CCS by 2050 ( [[#Koelbl--2014|Koelbl et al. 2014]] ; [[#Eom--2015|Eom et al. 2015]] ; [[#Vishwanathan--2020|Vishwanathan and Garg 2020]] ), others find that retirement of unabated coal far outpaces the deployment of coal with CCS ( [[#Budinis--2018|Budinis et al. 2018]] ; [[#Xie--2020|Xie et al. 2020]] ; McJeon et al. 2021) Moreover, several studies also project that, with availability of CO 2 capture technology, BECCS might become significantly more appealing than fossil CCS, even before 2050 (Muratori et al. 2017; [[#Luderer--2018|Luderer et al. 2018]] b).

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