Power coastal cities and cool oceans

Here is a way to provide power to cities on the coast and to cool the oceans to combat global warming. Usually the sea is warmer than the air at night. So at night use solar updraft towers, but pump heat, using a heat pump, from the sea to seawater in the solar updraft towers to heat and humidify the air in the solar updraft towers at night. Say the sea temperature was at Tsea=15 deg C and the seawater and air temperature in the solar updraft tower was 18 deg C after warming. Suppose the outside air temperature was 10 deg C. Then the heat pump would be very efficient and the air temperature difference between inside and outside the solar updraft tower would be in a nice range to start with. The heat pump could be powered by wind energy. During the day use the standard greenhouse at the base of the solar updraft tower to heat seawater in the tower to heat and humidify the air. The humid air will increase chances of rain and the clouds will reflect solar energy to space, cooling Earth. Have had a look at Greenland. It seems very suitable for this method. Ocean near the Arctic region could be cooled using this method. See
See
https://en.wikipedia.org/wiki/Solar_updraft_tower
See the the Carnot heat pump formula.at
 http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatpump.html
TH=291.15 kelvins. TL=288.15 kelvins

 COP=291.15/(291.15-288.15)=291.15/3 = 97.1