Noted in the North Atlantic is a huge vortex with it's center just southwest of Greenland. The heat noted on satelllite over the Greenland Ice is from that source.
If indeed the upper limits of the troposphere is 'storing/maintaining/building' a heat capacity due to Human Induced Global Warming and the levels are now being detected at the top of the Antarctica Blue Ice, which in the year 2007 is about 2.3 miles minimally or 3.7 kilometers, then the 'direct' detection of that heat mass would not be noted over the Greenland Ice in direct contact. The length of time for that to consistently be evident will determine the degree the upper troposphere has capacity to 'store' the excess heat from the planet under carbon dioxide.
In realizing the Lower Troposphere is measured at a distance from Earth's surface of 8 kilometers or about 5 miles and the Upper Troposphere is measured at an additional 5 kilometers (3 miles) or 13 kilometers (8 miles) the 'understanding' of the temporal dimension of carbon dioxide production in relation to the increasing storage of heat in the troposphere would depend on whether the heat goes beyond the lower troposphere, which I believe it does; the capacity of the troposphere as it increases in altitude in gaseous density to absorb heat; and the temporal element when the saturation began. My guess as to the beginning of the saturation would be some time approximately 100 years ago when carbon dioxide levels began to increase with human industrialization.
The equation to the answer as to the amount of time it will take to completely fill the lower troposphere with an 'unnatural' heat load is rather detailed, but, doable with information from balloons sent into the troposphere. The increasing variable in this temporal measurement is the increase in emissions of greenhouse gases which would refine that 'time limit.'
Guesstimate? A few years with the current abuse of humans in the First World, primarily the USA. This is a separate entity to the dynamics of a hot planet from the already hot surface of Earth and the effects on ice formations such as Greenland.
