Editing IPCC:AR6/WGII/Chapter-18 (section)

==== 18.3.1.1 Energy Systems ====

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Recent observed changes in global energy systems include continued growth in energy demand, led by increased demand for electricity by industry and buildings ( ''very high confidence'' )(Dhakal et al., 2022) . Growth in energy demand has also been driven by increased demand for industrial products, materials, building energy services, floor space and all modes of transportation. This growth in demand, however, has been moderated by improvements in energy efficiency in industry, buildings and transportation sectors ( ''very high confidence'' ) (Dhakal et al., 2022). There is also a trend of moving away from coal towards cleaner fuels, owing to lower natural gas prices and lower cost renewable technologies, and structural changes away from more energy-intensive industry.

Features of sustainable development, such as enhanced energy access, energy security, reductions in air pollution and economic growth, continue to be the dominant influence on the evolution of energy systems and decision making regarding energy investments and portfolios ( ''very high confidence'' ) (Clarke et al., 2022) . To date, climate policy has been comparatively less influential in driving energy transitions globally. Yet there are examples at the local, regional and national level of policy incentivising rapid changes in energy systems ( ''very high confidence'' ) (Clarke et al., 2022) . Many sustainable development priorities have co-benefits in terms of climate mitigation, such as air pollution and conservation policies reducing short-lived climate forcers and sequestering carbon respectively, as well adaptation benefits, such as improved energy access and environmental quality enhancing adaptive capacity ( ''very high confidence'' ) (Clarke et al., 2022) ( [[#de%20Coninck--2018|de Coninck et al., 2018]] ). Alternatively, sustainable development projects can have negative climate implications with, for instance, hydroelectric projects shut down by droughts or floods resulting in greater use of bunker and fuel oil, as well as natural gas.

In addition to sustainable development priorities driving change in energy systems, observed energy system trends have implications for sustainable development (e.g., [[#IEA--2019|IEA et al., 2019]] ). Observed changes in energy system size, rate of growth, composition and operations impact energy access, equity, environmental quality and well-being, with both synergies and trade-offs, including recent improvements in global access to affordable, reliable and modern energy services. For instance, in some countries, such as the USA, there has been a significant shift away from coal as a fuel source for electricity generation in favour of natural gas. More recently, however, renewables have emerged as the dominant form of new electricity generation ( [[#Gielen--2019|Gielen et al., 2019]] ). Similarly, for energy access in developing countries, renewable energy or hybrid distributed generation systems are increasingly being prioritised because of challenges associated with access, costs and environmental impacts from traditional fossil fuel-based energy technologies ( [[#Mulugetta--2019|Mulugetta et al., 2019]] ).

Energy systems have been a historical driver of climate change, but are also adversely affected by climate change impacts, including short-term shocks and stressors from extreme weather as well as long-term shifts in climatic conditions ( ''very high confidence'' ). The potential for such factors is often incorporated into local system designs, operations and response strategies. There have been changes in observed weather and extreme event hazards for the energy system, but to date, many are not attributable solely to anthropogenic climate change (USGCRP, 2017; [[#IPCC--2021a|IPCC, 2021a]] ). Nevertheless, with observed extremes shifting outside of what has been observed historically, existing design criteria and operations may not be optimal for future climate conditions and contingencies (Chapters 2 to 16). Overall, there is limited historical evidence on the efficacy of adaptation responses in reducing vulnerability of energy systems ( ''high agreement'' , ''limited evidence'' ). However, sustainable development trends, such as improving incomes, reducing poverty, and improving health and education have reduced vulnerability (Chapter 16), and improvements in system resiliency to extreme weather events and more efficient water management have occurred that have synergies with adaptation and sustainable development in general.

Available literature indicates that greenhouse gas emissions reductions have been achieved in response to climate actions including financial incentives to promote renewable energy, carbon taxes and emissions trading, removal of fossil fuel subsidies, and promotion of energy efficiency standards ( ''very high confidence'' ) (Clarke et al., 2022). Such policies tend to lead to a lower carbon intensity of GDP, due to structural changes in the use of energy and the adoption of new energy technologies. However, other drivers of change are also present and thus ongoing energy transitions and their future evolution are a response to both climatic and non-climatic considerations, with broader sustainable development priorities being a significant driver of change {Clarke, 2022 #4316.}

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