A 2024 study published in PNAS again confirmed climate models fail to simulate what happens in the real world concerning fundamental climate change variables like water vapor, Earth’s most significant greenhouse gas (due to its alleged warmth-enhancing “feedback” capacity). [emphasis, links added]
Per state-of-the-art climate models, specific humidity (SH) should increase as a consequence of CO2-induced global warming.
But 40 years of observations (1980-) show no increasing SH trend over arid/semi-arid regions.
And per state-of-the-art climate models, relative humidity (RH) should remain relatively constant, if not decline slightly as a consequence of CO2-induced global warming.
But 40 years of observations (1980-) do not show a slight declining trend, but rather a declining trend that is “about an order of magnitude more than the models on average.”
In other words, the climate models are wrong by a factor of 10.
The authors did not understate the profundity of these climate modeling failures.
“This represents a major gap in our understanding and in climate model fidelity that must be understood and fixed as soon as possible in order to provide reliable hydroclimate projections for arid/semi-arid regions in the coming decades.”
Now, a new study has once again confirmed there has been an “unexpected” decline in ocean evaporation (which accounts for 85% of the derivation of global atmospheric water vapor) since 2008, the “turning point” (TP) year.
These robust results affirming declining ocean evaporation (Eo) or water vapor trends across two-thirds of the globe – mostly in the Southern Hemisphere – can be found in all four satellite datasets used for the study.
It should be noted that in 2020, Dr. Koutsoyiannis published a paper indicating no increasing trend in global specific humidity since 2008, 1980, or even the late 1940s as predicted by climate models.
Observations do not seem to be sufficiently cooperating with the “water vapor feedback” narrative.
Read more at No Tricks Zone
It is a big mistake to publish anything by Ken Richard, who is a master of CO2 Does Nothing disinformation.
The measurements are not very accurate but absolute humidity has increased since 1980. That suggests at least a modest water vapor positive feedback to any warming of the troposphere. Since AH has increased, that must mean more evaporation from the oceans and elsewhere.. Richard is clueless as usual. Relative humidity has declined slightly since 1980 which was not expected. But the greenhouse effect of water vapor depends on absolute humidity, not relative humidity.
Note the trick Richard uses of data mining “over arid/semi-arid regions” which are about 8% of Earth’s surface (40% of land surface)..
Global average absolute humidity, or specific humidity (the amount of water vapor in the air), has been rising since the 1980s, consistent with the long-term warming trend of the planet.
Specific Humidity Increase:
Scientists have observed a significant increase in specific humidity over the Earth’s surface, with water vapor increasing by roughly 1-2% per decade globally.
Warming and Moisture:
This increase in water vapor is consistent with the long-term warming trend in the planet’s average surface temperature.
Clausius-Clapeyron Relationship:
A warmer atmosphere can hold more moisture, which is known as the Clausius-Clapeyron relationship.
Specific Humidity vs. Relative Humidity:
While specific humidity (the amount of water vapor) has increased, the relative humidity (the amount of water vapor compared to the maximum amount the air can hold) over land has decreased, and the trend in ocean relative humidity is less clear.
Regional Variations:
While the global trend is an increase in specific humidity, regional variations exist, with some areas experiencing more significant increases than others.
Impact of Humidity:
Increased humidity can lead to more intense heatwaves and changes in weather patterns.
Water Vapor as a Greenhouse Gas:
Water vapor is a potent greenhouse gas, meaning its increase can contribute to further warming of the planet.