Scientists now acknowledge cloud cover changes “control the Earth’s hydrological cycle,” “regulate the Earth’s climate,” and “dominate the melt signal” for the Greenland ice sheet via modulation of absorbed shortwave radiation. CO2 goes unmentioned as a contributing factor.
Climate modeling of factors influencing Greenland warming, surface melt have been 100% wrong
A few years ago scientists acknowledged “a major disparity in trends between models from the Coupled Model Intercomparison Project 5 (CMIP5) and observations for the last 20-30 years” (Hanna et al., 2018).
All 36 climate models simulating blocking over Greenland were wrong. None of the models were correct.
The abysmal performance of the modeling relative to observations has been ongoing for the last 20 to 30 years – effectively for the entire time that the CMIP5 models have been in existence.
In all other scientific fields, a one hundred percent failure rate ongoing for decades would have long ago resulted in a reassessment of modeling parameters. Climate science is apparently in a realm of its own.
Cloud forcing dominates in the Arctic
Within a matter of hours, the radiative forcing effects from clouds can vary by ±40 W/m² in the Arctic. From one year to the next, cloud radiative effects can vary by 70 W/m² and overall cloud radiative effects can reach 360 W/m² (Ebell et al., 2020).
In contrast, the total accumulated change in net impact from CO2 forcing is only 1.82 W/m² since 1750 (Feldman et al., 2015).
Simply put, cloud forcing radiatively dominates in the Arctic. CO2 is a bit player, at most.
Clouds regulate Greenland’s climate…and models grossly fail to simulate this
According to a new study (Lenaerts et al., 2020), clouds “control the Earth’s hydrological cycle”, “regulate the Earth’s climate”, and drive polar ice melt.
Further, “the surface melt climate is strongly dependent on the representation of clouds and related radiation fluxes“.
Models of cloud effects over Greenland are biased – or wrong – by 25-50 W/m².
Cloud cover decline from 1994-2017 “dominates” the warming and ice melt trend
Another new study (Hahn et al., 2020) finds reduced cloud cover from 1994-2017 led to enhanced shortwave radiation (+7.3 W/m²) and drove the warming from the 1990s to mid-2000s.
This shortwave cloud forcing trend is what “dominates” the melt signal for Greenland.
Greenland’s warming trend is shown to taper off into a pause or a slight cooling trend since ~2005.
Likewise, the ice melt trend spiked in 2012 but has been flat (or declining) overall since about 2005 too.
There is thus no clear indication in the scientific literature that atmospheric CO2 concentration changes can even remotely compete with cloud radiative effects as drivers of climate trends over Greenland.
h/t Rúnar
Read more at No Tricks Zone
True, and it does again support that CO2 is a non player but also remember that clouds are not just causal but are the result of other causes. Weather and climate are a chain of cause and effects that constantly play with each other and it is often multi directional. Many factors involved for clouds to be or not be present over time. These players; mostly in space and our high levels of the atmosphere have a large part in this but our surface level conditions resulting from this have a say in the final results as well. It would be great for meteorologists and climatologists to stop trying to force any one causal item to be the focus for any results of weather patterns and climate analysis.
This might explain why the IPCC says:
“The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible.”
– IPCC TAR WG1, Working Group I: The Scientific Basis
“…we should recognise that we are dealing with a coupled non-linear chaotic system, and therefore that the long-term prediction of future climate states is not possible.”
– IPCC TAR Chap 14, Exec Summary
Clouds are made up of the most prevalent “Greenhouse” gas, water.
We need to regulate water and have a water tax instead of a carbon tax.
Wait, I meant for that to sound utterly ridiculous, but the green eco-terrorist might find that a good idea.