Editing IPCC:AR6/SYR/SPM (section)

=== Mitigation Pathways ===

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'''B.6 All global modelled pathways that limit warming to 1.5°C (&gt;50%) with no or limited overshoot, and those that limit warming to 2°C (&gt;67%), involve rapid and deep and, in most cases, immediate greenhouse gas emissions reductions in all sectors this decade. Global net zero CO '''''2''''' emissions are reached for these pathway categories, in the early 2050s and around the early 2070s, respectively. '''''(high confidence)''''' [[#figure-spm-5|Figure SPM.5]] [[#box-spm-1|Box SPM.1]] Links to longer report 3.3, 3.4, 4.1, 4.5, Table 3.1'''
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B.6.1 Global modelled pathways provide information on limiting warming to different levels; these pathways, particularly their sectoral and regional aspects, depend on the assumptions described in Box SPM.1. Global modelled pathways that limit warming to 1.5°C (&gt;50%) with no or limited overshoot or limit warming to 2°C (&gt;67%) are characterized by deep, rapid and, in most cases, immediate GHG emissions reductions. Pathways that limit warming to 1.5C (&gt;50%) with no or limited overshoot reach net zero CO '''2''' in the early 2050s, followed by net negative CO '''2''' emissions. Those pathways that reach net zero GHG emissions do so around the 2070s. Pathways that limit warming to 2C (&gt;67%) reach net zero CO '''2''' emissions in the early 2070s. Global GHG emissions are projected to peak between 2020 and at the latest before 2025 in global modelled pathways that limit warming to 1.5°C (&gt;50%) with no or limited overshoot and in those that limit warming to 2°C (&gt;67%) and assume immediate action. ''(high confidence) [[#table-spm-1|Table SPM.1]] Links to longer report 3.3.2, 3.3.4, 4.1, Table 3.1, Figure 3.6''

'''Table SPM.1:''' Greenhouse gas and CO 2 emission reductions from 2019, median and 5-95 percentiles. Links to longer report 3.3.1, 4.1, Table 3.1, Figure 2.5, Box SPM.1

{| class="wikitable"
|-
|
| colspan="4"| Reductions from 2019 emission levels (%)

|-
|
| 2030

| 2035

| 2040

| 2050

|-
| rowspan="2"| Limit warming to1.5°C (&gt;50%) with no or limited overshoot

| GHS

| 43 [34-60]

| 60 [49-77]

| 69 [58-90]

| 84 [73-98]

|-
| CO 2

| 48 [36-69]

| 65 [50-96]

| 80 [61-109]

| 99 [79-119]

|-
| rowspan="2"| Limit warming to 2°C (&gt;67%)

| GHG

| 21 [1-42]

| 35 [22-55]

| 46 [34-63]

| 64 [53-77]

|-
| CO 2

| 22 [1-44]

| 37 [21-59]

| 51 [36-70]

| 73 [55-90]

|}

B.6.2 Reaching net zero CO 2 or GHG emissions primarily requires deep and rapid reductions in gross emissions of CO 2 , as well as substantial reductions of non-CO 2 GHG emissions ''(high confidence)'' . For example, in modelled pathways that limit warming to 1.5°C (&gt;50%) with no or limited overshoot, global methane emissions are reduced by 34 [21–57] % by 2030 relative to 2019. However, some hard-to-abate residual GHG emissions (e.g., some emissions from agriculture, aviation, shipping, and industrial processes) remain and would need to be counterbalanced by deployment of CDR methods to achieve net zero CO 2 or GHG emissions ''(high confidence)'' . As a result, net zero CO 2 is reached earlier than net zero GHGs ''(high confidence)'' . ''[[#figure-spm-5|Figure SPM.5]] Links to longer report 3.3.2, 3.3.3, Table 3.1, Figure 3.5''

B.6.3 Global modelled mitigation pathways reaching net zero CO 2 and GHG emissions include transitioning from fossil fuels without carbon capture and storage (CCS) to very low- or zero-carbon energy sources, such as renewables or fossil fuels with CCS, demand-side measures and improving efficiency, reducing non-CO 2 GHG emissions, and, and CDR [[#footnote-010|47]] . In most global modelled pathways, land-use change and forestry (via reforestation and reduced deforestation) and the energy supply sector reach net zero CO 2 emissions earlier than the buildings, industry and transport sectors. ''(high confidence)'' ''[[#figure-spm-5|Figure SPM.5]] [[#box-spm-1|Box SPM.1]] Links to longer report 3.3.3, 4.1, 4.5, Figure 4.1''

B.6.4 Mitigation options often have synergies with other aspects of sustainable development, but some options can also have trade-offs. There are potential synergies between sustainable development and, for instance, energy efficiency and renewable energy. Similarly, depending on the context [[#footnote-009|48]] , biological CDR methods like reforestation, improved forest management, soil carbon sequestration, peatland restoration and coastal blue carbon management can enhance biodiversity and ecosystem functions, employment and local livelihoods. However, afforestation or production of biomass crops can have adverse socio-economic and environmental impacts, including on biodiversity, food and water security, local livelihoods and the rights of Indigenous Peoples, especially if implemented at large scales and where land tenure is insecure. Modelled pathways that assume using resources more efficiently or that shift global development towards sustainability include fewer challenges, such as less dependence on CDR and pressure on land and biodiversity. ''(high confidence) Links to longer report 3.4.1''

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[[File:66948f8b8e8ce93ed3e90b41422b4146 IPCC_AR6_SYR_SPM_Figure5.png]]
'''Figure SPM.5: Global emissions pathways consistent with implemented policies and mitigation strategies. Panels (a), (b)''' and '''(c)''' show the development of global GHG, CO '''2''' and methane emissions in modelled pathways, while '''panel (d)''' shows the associated timing of when GHG and CO '''2''' emissions reach net zero. Coloured ranges denote the 5th to 95th percentile across the global modelled pathways falling within a given category as described in Box SPM.1. The red ranges depict emissions pathways assuming policies that were implemented by the end of 2020. Ranges of modelled pathways that limit warming to 1.5°C (&gt;50%) with no or limited overshoot are shown in light blue (category C1) and pathways that limit warming to 2°C (&gt;67%) are shown in green (category C3). Global emission pathways that would limit warming to 1.5°C (&gt;50%) with no or limited overshoot and also reach net zero GHG in the second half of the century do so between 2070-2075. '''Panel (e)''' shows the sectoral contributions of CO 2 and non-CO 2 emissions sources and sinks at the time when net zero CO 2 emissions are reached in illustrative mitigation pathways (IMPs) consistent with limiting warming to 1.5°C with a high reliance on net negative emissions (IMP-Neg) (“high overshoot”), high resource efficiency (IMP-LD), a focus on sustainable development (IMP-SP), renewables (IMP-Ren) and limiting warming to 2°C with less rapid mitigation initially followed by a gradual strengthening (IMP-GS). Positive and negative emissions for different IMPs are compared to GHG emissions from the year 2019. Energy supply (including electricity) includes bioenergy with carbon dioxide capture and storage and direct air carbon dioxide capture and storage. CO 2 emissions from land-use change and forestry can only be shown as a net number as many models do not report emissions and sinks of this category separately ''. [[#box-spm-1|Box SPM.1]] Links to longer report Figure 3.6, 4.1''

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