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

=== 1.4.3 Technology ===

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The rapid developments in technology over the past decade enhance potential for transformative changes, in particular to help deliver climate goals simultaneously with other SDGs.

The fall in renewable energy costs alongside rapid growth in capacity (Figure 1.3; see also Figures 6.8 and 6.11 in Chapter 6) has been accompanied by varied progress in many other technology areas such as electric vehicles, fuel cells for both stationary and mobile applications ( [[#Dodds--2019|Dodds 2019]] ), thermal energy (Chapter 6), and battery and other storage technologies ( [[#Freeman--2017|Freeman et al. 2017]] ) (Chapters 6, 9 and 12; Figure TS.7). Nuclear contributions may be enhanced by new generations of reactors (e.g., Generation III) and small modular reactors ( [[#Knapp--2018|Knapp and Pevec 2018]] ) (Chapter 6).

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'''Figure 1.3 | Cost reductions and adoption in solar photovoltaic and wind energy.''' Fossil fuel Levelised Cost of Electricity (LCOE) is indicated by blue shading at USD50–177 MWh –1 ( [[#IRENA--2020b|IRENA 2020b]] ). Source: data from IRENA (2021a,b).

Large-scale hydrogen developments could provide a complementary energy channel with long-term storage. Like electricity, hydrogen (H 2 ) is an energy vector with multiple potential applications, including in industrial processes such as steel and non-metallic materials production (Chapter 11), for long-range transportation (Chapter 10), and low-temperature heating in buildings (Chapter 9). Emissions depend on how it is produced, and deploying H 2 delivery infrastructure economically is a challenge when the future scale of hydrogen demand is so uncertain (Chapter 6). H 2 from natural gas with CO 2 capture and storage (CCS) may help to kick-start the H 2 economy ( [[#Sunny--2020|Sunny et al. 2020]] ).

CO 2 -based fuels and feedstocks such as synthetic methane, methanol, diesel, jet fuel and other hydrocarbons, potentially from carbon capture and utilisation (CCU), represent drop-in solutions with limited new infrastructure needs ( [[#Artz--2018|Artz et al. 2018]] ; [[#Bobeck--2019|Bobeck et al. 2019]] ; [[#Yugo--2019|Yugo and Soler 2019]] ) (Chapter 10). Deployment and development of CCS technologies (with large-scale storage of captured CO 2 ) have been much slower than projected in previous assessments ( [[#IEA--2019b|IEA 2019b]] ; [[#Page--2019|Page et al. 2019]] ) (Chapter 11).

Potential constraints on new energy technologies may include their material requirements, notably rare earth materials for electronics or lithium for batteries ( [[#Wanger--2011|Wanger 2011]] ; [[#Flexer--2018|Flexer et al. 2018]] ), stressing the importance of recycling ( [[#IPCC--2011b|IPCC 2011b]] ; [[#Rosendahl--2019|Rosendahl and Rubiano 2019]] ). Innovation is enabling greater recycling and reuse of energy-intensive materials ( [[#Shemi--2018|Shemi et al. 2018]] ), and introducing radically new and more environmentally friendly materials, however, still not all materials can be recycled ( [[#Allwood--2014|Allwood 2014]] ).

Bysequestering carbon in biomass and soils, soil carbon management, and other terrestrial strategies could offset hard-to-reduce emissions in other sectors. However, large-scale bioenergy deployment could increase risks of desertification, land degradation, and food insecurity ( [[#IPCC--2019a|IPCC 2019a]] ), and higher water withdrawals ( [[#Hasegawa--2018|Hasegawa et al. 2018]] ; [[#Fuhrman--2020|Fuhrman et al. 2020]] ), though this may be at least partially offset by innovation in agriculture, diet shifts and plant-based proteins contributing to meeting demand for food, feed, fibre and bioenergy (or bioenergy with carbon capture and storage (BECCS) with CCS) ( [[#Havlik--2014|Havlik et al. 2014]] ; [[#Popp--2017|Popp et al. 2017]] ; [[#Köberle--2020|Köberle et al. 2020]] ) (Chapters 5 and 7).

A broad class of more speculative technologies propose to counteract effects of climate change by removing CO 2 from the atmosphere (CDR), or by directly modifying the Earth’s energy balance at a large scale (solar radiation modification or SRM). CDR technologies include ocean iron fertilisation, enhanced weathering and ocean alkalinisation (Council 2015a), along with direct air carbon capture and storage (DACCS). They could potentially draw down atmospheric CO 2 much faster than the Earth’s natural carbon cycle, and reduce reliance on biomass-based removal ( [[#Köberle--2019|Köberle 2019]] ; [[#Realmonte--2019|Realmonte et al. 2019]] ), but some present novel risks to the environment and DACCS is currently more expensive than most other forms of mitigation ( [[#Fuss--2018|Fuss et al. 2018]] ) (Cross-Chapter Box 8 in Chapter 12). Solar radiation modification (SRM) could potentially cool the planet rapidly at low estimated direct costs by reflecting incoming sunlight (Council 2015b), but entails uncertain side effects and thorny international equity and governance challenges ( [[#Netra--2018|Netra et al. 2018]] ; [[#Florin--2020|Florin et al. 2020]] ; [[#National%20Academies%20of%20Sciences--2021|National Academies of Sciences 2021]] ) (Chapter 14). Understanding the climate response to SRM remains subject to large uncertainties (AR6 WGI). Some literature uses the term ‘geoengineering’ for both CDR or SRM when applied at a planetary scale ( [[#Shepherd--2009|Shepherd 2009]] ; [[#GESAMP--2019|GESAMP 2019]] ). In this report, CDR and SRM are discussed separately, reflecting their very different geophysical characteristics.

Large improvements in information storage, processing, and communication technologies, including artificial intelligence, will affect emissions. They can enhance energy-efficient control, reduce transaction costs for energy production and distribution, improve demand-side management (DSM) ( [[#Raza--2015|Raza and Khosravi 2015]] ), and reduce the need for physical transport ( [[#Smidfelt%20Rosqvist--2016|Smidfelt Rosqvist and Winslott Hiselius 2016]] ) (Chapters 5, 6 and 9–11). However, data centres and related IT systems (including blockchain), are electricity-intensive and will raise demand for energy ( [[#Avgerinou--2017|Avgerinou et al. 2017]] ) – cryptocurrencies may be a major global source of CO 2 if the electricity production is not decarbonised ( [[#Mora--2018|Mora et al. 2018]] ) – and there is also a concern that Information technologies can compound and exacerbate current inequalities (Chapters 5, 16 and Cross-Chapter Box 11 in Chapter 16). IT may affect broader patterns of work and leisure ( [[#Boppart--2020|Boppart and Krusell 2020]] ), and the emissions intensity of how people spend their leisure time will become more important (Chapters 5 and 9). Because higher efficiency tends to reduces costs, it often involves some ‘rebound’ offsetting at least some of the emission savings ( [[#Sudbury--2016|Sudbury and Hutchinson 2016]] ; [[#Belkhir--2018|Belkhir and Elmeligi 2018]] ; [[#Cohen--2019|Cohen and Cavoli 2019]] ).

Technology can enable both emissions reductions and/or increased emissions (Chapter 16). Governments play an important role in most major innovations, in both ‘technology-push’ ( [[#Mazzucato--2013|Mazzucato 2013]] ) and induced by ‘demand-pull’ ( [[#Grubb--2021a|Grubb et al. 2021a]] ), so policy is important in determining its pace, direction and utilisation (Roberts and Geels 2019a) (Sections 1.7.1 and 1.7.3). Overall, the challenge will be to enhance the synergies and minimise the trade-offs and rebounds, including taking account of ethical and distributional dimensions ( [[#Gonella--2019|Gonella et al. 2019]] ).

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