/sci/ - Science & Math

Climate Models Get Water Vapor Wildly Wrong – A ‘Major Gap In Our Understanding’
https://bpb-us-w2.wpmucdn.com/sites.coecis.cornell.edu/dist/f/423/files/2023/12/simpson23pnas.pdf

>“Here, we have demonstrated a major discrepancy between observation-based and climate model-based historical trends in near-surface atmospheric water vapor in arid and semi-ari regions.” – Simpson et al., 2024

A new study published in PNAS (Proceedings of the National Academy of Sciences) has demonstrated, once again, that climate models fail to simulate what happens in the real world with regard to fundamental climate change variables like water vapor. This is a devastating finding, as water vapor is the most significant greenhouse gas due to its alleged “feedback” capacity, accelerating warming well beyond what CO2 is said to be capable of alone.

The authors do not understate the significance of this climate modeling failure.

>“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.”

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.

Per state-of-the-art climate models, relative humidity (RH) should decline slightly as a consequence of CO2-induced global warming. But 40 years of observations (1980-) show not a slight declining trend, but 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.