The launch loop may form a current drainage path from the conductive ionosphere to the ground.
According to wikipedia, there are 240,000 lightning strikes per year, an average of 15 coulombs and 1 GJ each. That is 3.6 megacolombs per year, or 114 mA averaged over the year. The average discharge voltage is 1GJ/15C = 67 MV, and the average power is 7.6 megawatts. The effective resistance is 240 M-ohm averaged over the year.
The conductivity of the atmosphere near the ground is 2e-10 mho-kilometers (5 G-ohm/km) in the daytime; at 80 km, it is 5e-2 mho-kilometers (20 ohm/km), and at 100 km, it is 20 mho-kilometers (0.05 ohm/km) . A layer from 100 to 110 km might have a sheet resistance of 0.005 ohms per square, although the Earth's magnetic field will likely create a very large Hall voltage for large currents. Still, for an average of a few hundred milliamps, a connection to the ionosphere anywhere is a connection to the entire layer, and a connection at the launch loop to ground (actually, to 0.2 ohm/meter seawater) will be a pretty good short to ground.
Or will it? The Earth's magnetic field tends to constrain rapid current flows to the north-south direction, while zonal (east-west) winds are relatively slow. So the charges may only be reduced to the north and south of the launch loop, and to the west given the easterly (from the east) winds at high altitude near the equator, a consequence of coriolis forces. That will be good news for western North America, same-old same-old for the Lake Maracaibo lighting zone. It will also be good news for the region around the loop itself.
Lighting produces a vanishingly small amount of ozone compared to production and destruction in the stratosphere. No big loss. Lightning also produces about 14 million tonnes of NO2 gas per year, about the same as the world's diesel automobile fleet, and those diesel emissions are blamed for 38,000 deaths per year. So, between the damage and death from lightning strikes and lightning-ignited forest fires, and the reduced NOx production, eliminating lighting may save nearly 50,000 lives a year.