Climate pledges now imply 2.6°C warming as US emissions rise
If countries fulfill their climate pledges, global temperatures are projected to reach 2.6°C above pre-industrial levels by 2100, 0.1°C higher than last year's estimate; current policies imply 2.8°C. The UN report attributes the worsened pledge-based outlook partly to US withdrawal from the Paris Agreement and revised historical emissions estimates. [6] UNEP also describes a pathway to limit the extent and duration of warming above 1.5°C, combining deep emissions cuts with large-scale carbon removal. [4]
The difference between promised action and a pathway back toward 1.5°C is substantial: UNEP's overshoot-limiting scenario requires greenhouse gas emissions to fall 70% by 2040 and 320 gigatonnes of carbon dioxide to be removed by century's end. The report says each additional fraction of a degree and year above 1.5°C increases the risk of irreversible changes. [4]
Key insights
- The pledge-based projection worsened, but the current-policy projection remained at 2.8°C; those are different measures of the world's trajectory. [6]
- The report attributes the US emissions increase to greater electricity demand and a rebound in coal generation, linking the global assessment to specific energy choices. [6]
- UNEP's alternative is probabilistic, not a guaranteed recovery: its scenario gives a 66% chance of limiting peak warming to 1.8°C and even odds of returning below 1.5°C by century's end. [4]
- Carbon removal does not replace emissions cuts in this scenario: coal-fired electricity use falls 75% by 2035 and is phased out by 2040. [4]