Table 1 Scenario classification

From: Achieving net zero greenhouse gas emissions critical to limit climate tipping risks

Scenario

Overshoot peak temperature

NZGHG

Stabilisation temperature

Scenario assumptions

CurPol-OS-1.5 C

3.30 °C

No-NZGHG

1.5 °C

Follows current (2020) policies until 2100, then declines

ModAct-OS-1.5 C

2.69 °C

No-NZGHG

1.5 °C

Follows current (2020) pledges (NDCs) until 2100, then declines

ModAct-OS-1C

2.69 °C

No-NZGHG

1.0 °C

Follows current (2020) pledges (NDCs) until 2100, then declines

Ref-1p5

–

Not defined

1.5 °C

Reference scenario designed in temperature space

SSP5-3.4-OS

2.35 °C

No-long-term-NZGHG

1.5 °C

Tests system response to rapid emission changes

SSP1-1.9

1.53 °C

No-long-term-NZGHG

1.0 °C

Sustainable development, no long-term compensation for non-CO2 emissions

GS-NZGHG

1.70 °C

NZGHG

Pre-industrial

Gradual strengthening, returns warming to 1.5 °C by 2215

SP-NZGHG

1.57 °C

NZGHGP

Pre-industrial

Broad shift towards sustainable development

Neg-NZGHG

1.67 °C

NZGHG

Pre-industrial

Returns warming to 1.5 °C by 2100 with heavy CDR deployment

Neg-OS-0C

1.67 °C

NZGHG

Pre-industrial

Returns warming to 1.5 °C by 2100 with heavy CDR deployment

  1. The 10 analysed PROVIDEv1.2 emission pathways were classified according to their median overshoot peak temperature and achievement of net zero greenhouse gas emissions (NZGHG) (‘NZGHG’: reach NZGHG emissions by 2100 and maintain NZGHG emissions in the long term; ‘No-long-term-NZGHG’: reach NZGHG emissions by 2100 but do not maintain NZGHG emissions in the long term; ‘No-NZGHG’: do not reach NZGHG emissions by 2100), median long-term stabilisation temperatures, and scenario assumptions. Stabilisation temperature is given as median, NDCs denote Nationally Determined Contributions, and CDR denotes Carbon Dioxide Removal. For details on the NZGHG classification see Methods.
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