There can be little doubt that variation in evaporative fraction is analytically linked to variation in relative humidity.
https://journals.ametsoc.org/view/journals/clim/37/4/JCLI-D-23-0342.1.xml

The evaporative fraction (EF) is the ratio of the surface latent heat flux to the available energy at the surface

There can be little doubt that regions with moisture limited EF are warmer than other regions at the same latitudinal and topographic position.

Trends in relative humidity, and by extension trends in EF, are deeply troubling and remain poorly understood.

1979–2014 HadISDH and the ERA-Interim datasets
https://esd.copernicus.org/articles/9/915/2018/esd-9-915-2018-f04.jpg

from https://esd.copernicus.org/articles/9/915/2018/

Additionally:

CMIP6 models exhibit a huge range in annual mean evapotranspiration (ET) with estimates ranging from 406.9 mm yr−1 (FGOALS-f3-L) to 757.6 mm yr−1 (Amon-NESM3). This substantial range underpins why temperature could not be resolved better than several degrees Celsius along with little practical information about the drivers of cloud fraction, precipitation area/intensity, SW effective forcing, EEI, or GSAT.

For the period 1980 to 2014:
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024WR037608

Reanalysis shows a decreasing evapotranspiration (ET) trend of -0.20 mm yr-2, while the CMIP6 mean indicates an increase of +0.37 mm yr-2. Multi-source ensemble products such as REA, DOLCE V3.0, and CAMELE report a decline of -0.28 mm yr-2 during the same period. By contrast, land surface models (LSMs) show an increase of +0.32 mm yr-2. LSMs, which are typically coupled to CMIP-style ocean-atmosphere systems, likely share intercorrelated deficiencies that contribute to these disparities.

As previously alluded by Bjorn Stevens, the only way CMIP style models could have matched historical temperature change is by significant error compensation.

A large multi-author pre-print is extremely critical of land surface model development:
https://pages.charlotte.edu/hcl/wp-content/uploads/sites/1187/2024/04/Byrne-et-al-Theory-and-the-future-of-land-climate-science-REVISED.pdf

“”” Many of the key processes influencing land climate are spatially heterogeneous, difficult to simulate, and/or poorly observed. For example, land surface models have longstanding problems in simulating turbulent fluxes of heat and water for reasons that are not well understood. Sparse and time-limited observational records of important land-climate variables, including root-zone soil moisture and near-surface humidity, further impede efforts to advance knowledge of the land-climate system. The role of humanity presents another challenge, with large uncertainties in modelling the influences of land use and management on fluxes of carbon, energy, and water in the past, present, and future””” … “””Persistent and poorly constrained deficiencies in land surface models—highlighted by the PLUMBER project suggest that model development alone, though necessary, is unlikely to answer the key questions about land climate highlighted above.”””

In summary, a return to fundamental thermodynamic constraints and theory is essential because the tuned process level parameterization is simply not working.

The Plumbing of Land Surface Models: Is Poor Performance a Result of Methodology or Data Quality?
https://journals.ametsoc.org/view/journals/hydr/17/6/jhm-d-15-0171_1.xml

“””The Protocol for the Analysis of Land Surface Models (PALS) Land Surface Model Benchmarking Evaluation Project (PLUMBER) illustrated the value of prescribing a priori performance targets in model intercomparisons. It showed that the performance of turbulent energy flux predictions from different land surface models, at a broad range of flux tower sites using common evaluation metrics, was on average worse than relatively simple empirical models. For sensible heat fluxes, all land surface models were outperformed by a linear regression against downward shortwave radiation. For latent heat flux, all land surface models were outperformed by a regression against downward shortwave radiation, surface air temperature, and relative humidity.”””

Cutting-edge researchers in geophysical fluid dynamics discussing ECS and cloud feedback and subsequent Q&A appear to have no awareness of thermodynamic land surface process constraints whatsoever in their training. This highlights a damaging disconnect between disciplines within climate science.
https://youtu.be/CJAY5kvT7MQ?si=xGOgDrBPXK1v6bSN&t=1811

In reimagining Earth in the Earth System, Gordon Bonan and co remark:

“””Nature-based climate solutions have been advocated for centuries, but have been distorted by academic bias and colonialist prejudice”””

“””Today’s Earth system science, with its roots in global models of climate, unfolds in similar ways to the past. With Earth system models, geoscientists are again defining the ecology of the Earth system. Here we reframe Earth system science so that the biosphere and its ecology are equally integrated with the fluid Earth to enable Earth system prediction for planetary stewardship. Central to this is the need to overcome an intellectual heritage to the models that elevates geoscience and marginalizes ecology and local land knowledge. The call for kilometer-scale atmospheric and ocean models, without concomitant scientific and computational investment in the land and biosphere, perpetuates the geophysical view of Earth and will not fully provide the comprehensive actionable information needed for a changing climate.”””

“””Earth system science, while recognizing the climate services of the biosphere, has a geophysical bias in interdisciplinary collaboration”””

“””To realize the potential for planetary stewardship, Earth system models must embrace the living world equally with the fluid world”””

“””…intellectual bias is evident in today’s Earth system science and the associated Earth system models, which are the state-of-the-art models used to inform climate policy. The popular characterization of Earth system science lauds its interdisciplinary melding of physics, chemistry, and biology, but the models emphasize the physics and fluid dynamics of the atmosphere and oceans and present a limited perspective of terrestrial ecosystems in the Earth system.”””

It is undeniable that humanity is directly depleting Earth System stability through its profound disruption of land systems. Those who actively deny, distort, minimize or misrepresent this reality are doing more harm than they may realize.