DOI: 10.5061/dryad.zgmsbcckd
title: Data from: Sea-surface temperature pattern effects have slowed global warming and biased warming-based constraints on climate sensitivity

description: The observed rate of global warming since the 1970s has been
 proposed as a strong constraint on equilibrium climate
 sensitivity (ECS) and transient climate response (TCR) – key
 metrics of the global climate response to greenhouse-gas forcing.
 Using CMIP5/6 models, we show that the inter-model relationship
 between warming and these climate sensitivity metrics (the basis
 for the constraint) arises from a similarity in transient and
 equilibrium warming patterns within the models, producing an
 effective climate sensitivity (EffCS) governing recent warming
 that is comparable to the value of ECS governing long-term
 warming under CO2 forcing. However, CMIP5/6 historical
 simulations do not reproduce observed warming patterns. When
 driven by observed patterns, even high ECS models produce low
 EffCS values consistent with the observed global warming
 rate. The inability of CMIP5/6 models to reproduce observed
 warming patterns thus results in a bias in the modeled
 relationship between recent global warming and climate
 sensitivity. Correcting for this bias means that observed warming
 is consistent with wide ranges of ECS and TCR extending to higher
 values than previously recognized. These findings are
 corroborated by energy balance model simulations and coupled
 model (CESM1-CAM5) simulations that better replicate observed
 patterns via tropospheric wind nudging or Antarctic meltwater
 fluxes. Because CMIP5/6 models fail to simulate observed warming
 patterns, proposed warming-based constraints on ECS, TCR, and
 projected global warming are biased low. The results reinforce
 recent findings that the unique pattern of observed warming has
 slowed global-mean warming over recent decades, and that how the
 pattern will evolve in the future represents a major source
 of uncertainty in climate projections.
description: # Data to accompany "Sea-surface temperature pattern effects have
 slowed global warming and biased warming-based constraints on climate
 sensitivity" Data for
 "Sea-surface temperature pattern effects have slowed global warming
 and biased warming-based constraints on climate sensitivity", PNAS
 () ## Description of the
 data and file structure Included are a netcdf data file needed to make the
 figures. This includes the following variables (with descriptions).
 CMIP56_ECS: CMIP5/6 ECS values; units K CMIP56_subset_ECS: CMIP5/6 8 model
 subset ECS values (CanESM5, CNRM CM6, GISS E2, HadGEM3, IPSL CM6A, MIROC6,
 NorESM2, CESM1); units K CMIP56_subset_EffCS_amip: CMIP5/6 8-model subset
 EffCS values for AMIP models over 1981-2014 (CanESM5, CNRM CM6, GISS E2,
 HadGEM3, IPSL CM6A, MIROC6, NorESM2, CESM1); units K
 CMIP56_subset_tas_trend_amip_method1: CMIP5/6 8 model subset global
 near-surface air temperature trend over 1981-2014 estimated from EffCS in
 AMIP models and regression (CanESM5, CNRM CM6, GISS E2, HadGEM3, IPSL
 CM6A, MIROC6, NorESM2, CESM1); units K/dec
 CMIP56_subset_tas_trend_amip_method2: CMIP5/6 8 model subset global
 near-surface air temperature trend over 1981-2014 estimated from EffCS in
 AMIP models and equation 3 (CanESM5, CNRM CM6, GISS E2, HadGEM3, IPSL
 CM6A, MIROC6, NorESM2, CESM1); units K/dec CMIP56_tas_trend: CMIP56 global
 near-surface air temperature trend over 1981-2014; units K/dec
 CanESM5_EffCS: CanESM5 EffCS over 1981-2014; units K CanESM5_tas_trend:
 CanESM5 global near-surface air temperature trend over 1981-2014; units
 K/dec CESM1_EffCS: CESM1 EffCS over 1981-2014; units K CESM1_tas_trend:
 CESM1 global near-surface air temperature trend over 1981-2014; units
 K/dec CNRM_CM6_EffCS: CNRM_CM6 EffCS over 1981-2014; units K
 CNRM_CM6_tas_trend: CNRM_CM6 global near-surface air temperature trend
 over 1981-2014; units K/dec GISS_E2_EffCS: GISS_E2 EffCS over 1981-2014;
 units K GISS_E2_tas_trend: GISS_E2 global near-surface air temperature
 trend over 1981-2014; units K/dec HadGEM3_EffCS: HadGEM3 EffCS over
 1981-2014; units K HadGEM3_tas_trend: HadGEM3 global near-surface air
 temperature trend over 1981-2014; units K/dec IPSL_CM6A_EffCS: IPSL_CM6A
 EffCS over 1981-2014; units K IPSL_CM6A_tas_trend: IPSL_CM6A global
 near-surface air temperature trend over 1981-2014; units K/dec
 MIROC6_EffCS: MIROC6 EffCS over 1981-2014; units K MIROC6_tas_trend:
 MIROC6 global near-surface air temperature trend over 1981-2014; units
 K/dec NorESM2_EffCS: NorESM2 EffCS over 1981-2014; units K
 NorESM2_tas_trend: NorESM2 global near-surface air temperature trend over
 1981-2014; units K/dec