evidence: Limiting global warming will require major transitions in the energy sector. This will involve a substantial reduction in fossil fuel use, widespread electrification, improved energy efficiency, and use of alternative fuels (such as hydrogen). [...] "It’s now or never, if we want to limit global warming to 1.5°C (2.7°F)," said Skea. "Without immediate and deep emissions reductions across all sectors, it will be impossible." The global temperature will stabilise when carbon dioxide emissions reach net zero. For 1.5°C (2.7°F), this means achieving net zero carbon dioxide emissions globally in the early 2050s; for 2°C (3.6°F), it is in the early 2070s.