Pulling heat out of 30 to 40 degree air is harder work than pulling heat out of 55 degree “ground heated” water.

Geothermal also works for air conditioning.  Pushing heat from a 75 degree room into 55 degree “ground cooled” water is easier than into 90 degree air.

I would imagine that if you lived where it was very hot for much of the year a geothermal AC would make as much sense as a geothermal heater in cold climates.  Where geothermal heat pumps should really shine are places which have hot summers and cold winters.  

This article represents a brave attempt at too broad a subject. Some confusion is easily the result. Only a closed surface loop is described (which could also be open or closed in a pond or year round river,)open and closed ground loops in two or more wells were not discussed but are more common without large available land areas. Here a disadvantage of geothermal, having to install boreholes (wells) is mentioned when it is not previously listed.

There is no mention here about the essential difference between a heat pump and an air conditioner or other types of geothermal applications. For the heat pump cycles are reversible to give heat or air conditioning from the same system. While conventional heat pumps can use lower amounts of fossil fuels if electricity comes conventional sources. If the power is from solar or wind the usage will not involve fossil fuels. Also by using principles of refrigeration it is possible to heat and cool using thermal solar panels and entirely avoid electricity (or compressors.) (principles similar to gas refrigerators.) The outside units may be placed on a roof or a pad on the ground depending upon place and local laws. While COP is a scientific measure of efficiency the same Wiki article referenced here makes clear that this is rarely seen in the US. Instead SEER ratings are the norm. Heat pumps are an interesting subject with lots of potential. Related technology is even used to produce electricity.

Some of these aspects I have mentioned in previous CT articles some are planned for future articles.

Open the blinds and this will heat the room thru glass when its sunny.

For drying clothes, they can just place it in hanger instead of using dryer as long as its not urgent.

Food can be kept outside the fridge for an hour or 2 before eating and this will bring down its temperature and also will thaw and come to room temperature before keeping it in microwave oven.