Regional extreme sensitivity similar in CMIP5 and 6
CMIP6 and CMIP5 agree on how hot days, cold nights, and heavy rain scale with global warming, even though global climate sensitivity differs.
Source
Regional Climate Sensitivity of Climate Extremes in CMIP6 Versus CMIP5 Multimodel Ensembles
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.
What they did
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.
What they found
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.
The limits
What it doesn't show
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.
Key terms
- Regional climate sensitivity
- Change in a regional extreme per degree of global mean warming.
- TXx
- Annual hottest daytime temperature.
- TNn
- Annual coldest nighttime temperature.
- Rx1day
- Annual maximum 1-day precipitation.
- U_RTCS vs U_GTCS
- Uncertainty in regional extremes from regional versus global transient climate sensitivity.
Flashcards
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Quiz yourself
CMIP6 vs CMIP5 regional extreme scaling with global warming is:
Common questions
Does higher CMIP6 ECS imply different extreme maps?
Not much: regional extreme scaling with global warming looks like CMIP5.
What should be constrained besides ECS?
Land processes that set regional sensitivity, such as soil-moisture and snow feedbacks.
Which indices were used?
TXx, TNn, and Rx1day from ETCCDI.
At +1.5 °C, what dominates uncertainty?
Regional climate sensitivity in a majority of CMIP6 regions.
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