Like all the rest - looking for book

[2FanHouse]

Read at least 20 years ago but not more than 45. Straight science fiction - not Erik Von Daniken's Chariot of the Gods.

Time: Pre-history

Plot (as much as I can remember): Advanced civilization exists that has space travel and has launched ships to other worlds/solar systems. Not sure if the ships were generational ships or not. The world had learned to harness solar power and beam it back to earth as broadcast microwave energy - or - to tap into the fluctuations of the earth's magnetic field to create power and broadcast it as microwave energy. Power reception stations were located on tops of pyramids. Plans underway to locate power stations at the poles. Some scientists and researchers believed siting power stations at the poles would cause world catastrophe. They were correct and earth suffered calamity that resulted in continents shifting, axis tilting, nuclear winter, and poisoned landscape.

Meanwhile, a scientist was doing research on a submarine (not sure what kind) and he survived the entire debacle. Not sure if he was alone or not. Some time later he started genetic engineering life forms to repopulate the planet. Several trials, failures and then he creates some sort of protohuman who looks on him as a god. The name David figures prominently in this part of the story - but I'm not sure who the name belongs to.

Later toward the end, there are spaceships returning from the colonists sent out in the beginning and that is the explanation for the repeated stories of alien visits.

That is all I can clearly remember (or that I think I clearly remember.) Any help identifying this book would be greatly appreciated. I look for it intermittently, but even searching the copyright office list of titles has not panned out as I don't have enough words to narrow the search to a manageable size and their online records only go back to 1978.

Thanks in advance for any help.