I am actually familiar with Feldman et al 2015, it is a very good paper, as they include a good methods section.
Did you read the words above what you boldfaced?
"The time series both show statistically significant trends of 0.2 W m−2 per decade (with respective uncertainties of ±0.06 W m−2 per decade and ±0.07 W m−2 per decade) and have seasonal ranges of 0.1–0.2 W m−2. This is approximately ten per cent of the trend in downwelling longwave radiation5,6,7. "
What they measure was approximately ten per cent of what the change should have been.
If the concept of AGW is to be believed, the energy that used to be escaping to space is now re emitted back down towards earth,
forcing the atmosphere to warm to regain balance.
Throw in the first law of thermodynamics, that energy can neither be created or destroyed, and it means that all
the energy not escaping, must be staying, so what was measured was what was there.
So if they measures 0.2 W m−2 per decade over the 1.1 decades that CO2 increased from 269 ppm to 392 ppm, lets just see what CO2 imbalance would be for 2XCO2.
0.2 W m−2 per decade for 1.1 decades would be .22 W m−2, so .22/ ln(392/369)= 3.64
3.64X ln(2)=2.52 Wm-2, instead of the current 3.71 Wm-2.
This would throw off all the estimates used in the models by 32%.
