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Near-Term Responses in a Changing Climate
Section 4
All global modelled pathways that limit warming to 2°C (>67%) 
or lower by 2100 involve reductions in both net CO2 emissions 
and non-CO2 emissions (see Figure 3.6) (high confidence). 
For example, in pathways that limit warming to 1.5°C (>50%) 
with no or limited overshoot, global CH4 (methane) emissions are 
reduced by 34 [21 to 57]% below 2019 levels by 2030 and by 
44 [31 to 63]% in 2040 (high confidence). Global CH4 emissions 
are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by 
37 [20 to 60]% in 2040 in modelled pathways that limit warming to 
2°C with action starting in 2020 (>67%) (high conﬁdence). {WGIII SPM 
C1.2, WGIII Table SPM.2, WGIII 3.3; SR1.5 SPM C.1, SR1.5 SPM C.1.2} 
(Cross-Section Box.2)
All global modelled pathways that limit warming to 2°C (>67%) 
or lower by 2100 involve GHG emission reductions in all sectors 
(high conﬁdence). The contributions of different sectors vary across 
modelled mitigation pathways. In most global modelled mitigation 
pathways, emissions from land-use, land-use change and forestry, via 
reforestation and reduced deforestation, and from the energy supply 
sector reach net zero CO2 emissions earlier than the buildings, industry 
and transport sectors (Figure 4.1). Strategies can rely on combinations 
of different options (Figure 4.1, Section 4.5), but doing less in one 
sector needs to be compensated by further reductions in other sectors if 
warming is to be limited.