Climate models
Regional extreme sensitivity similar in CMIP5 and 6
Open access · cc by · source: Europe PMC
CMIP6 and CMIP5 agree on how hot days, cold nights, and heavy rain scale with global warming, even though global climate sensitivity differs.
Study at a glance
- Design
- Computational / modelling — CMIP5 vs CMIP6 ETCCDI extremes scaled to shared global-warming levels
- N
- Multimodel CMIP5/CMIP6 ensembles at +1.5/+2/+4 °C; ensemble count not a single primary N
- Population
- Regional climate extremes (TXx, TNn, Rx1day) across AR6 regions
- Outcome
- Similarity of regional extreme sensitivity in CMIP6 vs CMIP5 despite ECS differences
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Multimodel-mean regional sensitivity of yearly hottest days, coldest nights, and heaviest 1-day rain is very similar in CMIP5 and CMIP6. At +1.5 °C, regional-sensitivity uncertainty often exceeds global-sensitivity uncertainty, especially in CMIP6. Local differences include hotter SAM extremes and wetter West Africa/Sahel in CMIP6.
Methodology
Authors compared ETCCDI extremes (TXx, TNn, Rx1day) in CMIP5 RCPs and CMIP6 SSPs at +1.5, +2, and +4 °C global warming, mapped AR6-region responses, and split projection uncertainty into global versus regional transient climate sensitivity.
Limitations
The CMIP6 archive was incomplete (late March 2020). The +1.5 °C uncertainty split does not simply carry to +4 °C because the global-warming range among models widens. The analysis does not diagnose why SAM or Sahel differ.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
This library holds 4 empirical papers on climate models with measured outcomes rather than reviews.
Evidence for the claim as stated.
CMIP6 and CMIP5 agree on how hot days, cold nights, and heavy rain scale with global warming, even though global climate sensitivity differs.
Evidence for the claim as stated.
High-resolution rain over Europe is not global climate sensitivity.
Evidence for the claim as stated.
Multimodel-mean regional sensitivity of yearly hottest days, coldest nights, and heaviest 1-day rain (ETCCDI TXx, TNn, Rx1day) is very similar in CMIP5 and CMIP6 at +1.5, +2 and +4 °C. At +1.5 °C, uncertainty in regional transient sensitivity often exceeds uncertainty from global climate sensitivity, especially in CMIP6. Local differences include hotter SAM extremes and wetter West Africa/Sahel in CMIP6. The CMIP6 archive was still incomplete in late March 2020.
Evidence for the claim as stated.
Single-model large ensembles and the CMIP multimodel archive disagree about where uncertainty lives. CESM2-LE attributes most extra record-shattering rain to variability changes; other CMIP6 models are more balanced between mean and σ, and CESM2’s high climate sensitivity plus SSP3-7.0 make the probability ratio of 15 an upper-end figure. The CMIP5/6 extremes paper finds similar regional-mean sensitivity across generations but, at +1.5 °C, larger regional- than global-sensitivity uncertainty. Opening CESM2-LE is not the same as opening CMIP6.
Evidence for the claim as stated.
CMIP can match one budget and miss another. Steric TSLS (1.5±0.2) sits on observations (1.4±0.5), yet historical all-but-glacier sea-level sensitivity is ~30% above the models and Antarctic dynamics are observed, not modelled. Downstream, QQM-corrected NEX-GDDP members intensify Nile flood peaks while the same CMIP6 generation still disagrees on the sign of mean Nile rain. Agreement of a multimodel mean on ETCCDI sensitivity does not license treating every CMIP-forced hydrology run as an observation.
Evidence for the claim as stated.
Multi-model ensembles are also used as a catalogue of sensitivity. CMIP5 versus CMIP6 regional extreme sensitivity (TXx, TNn, Rx1day) at +1.5, +2 and +4 °C is very similar in the multimodel mean; at +1.5 °C, regional-sensitivity uncertainty often exceeds global-sensitivity uncertainty, especially in CMIP6. Twenty-seven CMIP6 models plus CRCM6 were the ensemble for North American cyclone pulses.
Evidence for the claim as stated.
Single-model large ensembles and CMIP multi-model ensembles disagree about where uncertainty lives. CESM2-LE attributes most extra record-shattering rain to variability changes; the CMIP5/6 extremes paper finds similar regional mean sensitivity across generations and, at +1.5 °C, larger regional- than global-sensitivity uncertainty. Which ensemble you open changes whether you emphasise σ or the transient climate response.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
High-resolution rain over Europe is not global climate sensitivity.
Single-model large ensembles and the CMIP multimodel archive disagree about where uncertainty lives. CESM2-LE attributes most extra record-shattering rain to variability changes; other CMIP6 models are more balanced between mean and σ, and CESM2’s high climate sensitivity plus SSP3-7.0 make the probability ratio of 15 an upper-end figure. The CMIP5/6 extremes paper finds similar regional-mean sensitivity across generations but, at +1.5 °C, larger regional- than global-sensitivity uncertainty. Opening CESM2-LE is not the same as opening CMIP6.
CMIP can match one budget and miss another. Steric TSLS (1.5±0.2) sits on observations (1.4±0.5), yet historical all-but-glacier sea-level sensitivity is ~30% above the models and Antarctic dynamics are observed, not modelled. Downstream, QQM-corrected NEX-GDDP members intensify Nile flood peaks while the same CMIP6 generation still disagrees on the sign of mean Nile rain. Agreement of a multimodel mean on ETCCDI sensitivity does not license treating every CMIP-forced hydrology run as an observation.
- Supports · CMIP6 sea-level sensitivity lags observations
- Supports · Nile flood peaks may jump this century
Single-model large ensembles and CMIP multi-model ensembles disagree about where uncertainty lives. CESM2-LE attributes most extra record-shattering rain to variability changes; the CMIP5/6 extremes paper finds similar regional mean sensitivity across generations and, at +1.5 °C, larger regional- than global-sensitivity uncertainty. Which ensemble you open changes whether you emphasise σ or the transient climate response.
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Same topic cluster — not a recommendation engine.