Your first sentence shows a fundamental misunderstanding of radiative physics and the thermodynamic processes taking place in the Earth's atmosphere. If what you suggest were actually taking place - that the process is NOT a continuous flow of energy both INTO and OUT OF the atmosphere - the Earth would long ago have burnt to a cinder. Keep one fact in mind: ALL matter radiates all the time. It doesn't stop radiating when it reaches thermal equilibrium. That is simply when its emission and absorption become equal.
The Earth is continually bathed in EM energy from the sun. That energy travels through the transparent atmosphere and is absorbed or reflected by the land and sea. The land and sea reradiate that energy as IR radiation which is absorbed by the GHGs in our atmosphere. The GHGs reradiate the energy, again as IR which gets absorbed by other GHG molecules. This step by step process carries on till the energy finally reaches the top of the atmosphere and radiates freely into space. So, what happens when you add more GHGs to the atmosphere? The average distance a photon travels before striking and being absorbed by a GHG molecule becomes shorter. The number of steps to the trip out of the atmosphere goes up and thus the amount of thermal energy present in the conveyor belt to space increases. That changing state is evinced by the increasing temperature of the atmosphere. Global warming.
Nice ... that's a well thought out description ...
You seem to be ignoring the quatum nature of these absorptions and re-radiations ... GHG only react to certain wavelengths, and not others ... yes, all matter radiates all the time,
what it radiates depends on temperature ... the higher the temperature, the shorter the wavelengths the material radiates it's energy ...
Consider a neutral Hydrogen atom in it's ground state ... as temperature rises, the electron will be in a higher orbital ... high enough temperature and the atom will stop absorbing and emitting the 121 nm associated with the 1 -> 2 transition ... the temperture is too high for the atom to jump down to it's ground state ... (Yes, I know in a mole of Hydrogen, we will see 121 nm emission, random chance as it were) ...
Did you look up the statements in the IPCC report about this? ... are you saying they have a fundamental misunderstanding of radiative physics? ... seems like your picking an economist's word over a climatologist's ...
I'm glad you think its easy to build and maintain sea walls but I'm afraid your estimate of 3 feet won't cut it. Consider storm surges, not infrequently cresting 20 feet above MSL and, with global warming increasing the temperature of air and water, certain to increase in height and frequency. I'm fairly certain that the economists considering this problem took into account the cost of building sea walls. In fact, I'm quite certain that they took into account a hundred factors that you and I would never think of. That would be because they're PhD economists and we're not.
But we can read the survey questions and note the question was not asked ... indeed none of the methodology is presented ... I can see why they had to publish the material themselves, this would never pass peer review ...